Biomedical subjects

Violet Esquenazi

Publications and source records attributed to Violet Esquenazi.

At least 19 recordsLinked to original sources

PubMed2005

Utilization of dried blood spot citrulline level as a noninvasive method for monitoring graft function following intestinal transplantation.

BACKGROUND: Citrulline concentrations have been proposed as a marker for intestinal allograft rejection. We instituted dried blood spot (DBS) specimen monitoring of citrulline to simplify sample collection posttransplant. This study demonstrates the correlation between plasma and dried blood spot specimen citrulline concentrations after intestinal transplantation. METHODS: Plasma and DBS samples were analyzed by hydrophilic interaction chromatography tandem mass spectrometry. Comparison of the strength of linear correlation was made according to the type of surgery, sonication time, DBS citrulline levels, and the time interval between the blood sample collection and the assay date. RESULTS: A very strong linear correlation exists between the plasma and DBS citrulline concentrations (r=0.87; P<0.001). The correlation between plasma and DBS citrulline concentrations was maintained when evaluating only the intestinal transplant recipients. There was no significant difference in the strength of linear correlation according to sonication time, cirtrulline concentrations, or length of time to assay date. CONCLUSIONS: DBS citrulline monitoring will ease sample collection following intestinal transplantation and improve the ability to detect intestinal dysfunction and rejection by a noninvasive means.

Adult↗

PubMed2005

A randomized trial of three renal transplant induction antibodies: early comparison of tacrolimus, mycophenolate mofetil, and steroid dosing, and newer immune-monitoring.

BACKGROUND: New trends in immunosuppression in clinical transplantation include the use of antibody induction agents in protocols that emphasize reduction or avoidance of steroids and calcineurin inhibitors. METHODS: In a randomized trial using three different antibody induction agents in 90 first renal transplant recipients from cadaver donors, group A received Thymoglobulin, group B received Alemtuzumab, and group C received Daclizumab. Maintenance immunosuppression included tacrolimus and mycophenolate in all three arms, and methylprednisolone in groups A and C only (standard clinical institutional practice). The targeted trough level of tacrolimus was between 8 and 10 ng/mL for groups A and C, respectively, with a targeted mycophenolate dose of 1 g twice daily. However, in group B, the target tacrolimus trough level was 4 to 7 ng/mL to reduce long-term nephrotoxicity, with 500 mg twice-daily doses of mycophenolate, without steroid maintenance. RESULTS: In this 15-month median postoperative interval report, there were no notable differences in demographics and patient and graft survivals. Acute rejection rates at 1 year were equivalent, that is, 5 of 30 in all three groups (16.6%). In group B, there was slightly lower renal function at 1 month, but no difference at 1 year. There was also significantly more leukopenia, but a greater percentage of T-regulatory cells and number of Fox-P3 mRNA copies by flow cytometry and semiquantitative polymerase chain reaction analysis, respectively, in group B. CONCLUSIONS: This preliminary analysis indicates that 80% of the patients in group B remained steroid-free 1 year postoperatively, with lower tacrolimus trough levels and no difference in other adverse events.

Adult↗

PubMed2005

Campath-1H does not alter bone marrow cell regulatory function.

We have previously reported in laboratory volunteers (in vitro) and renal transplant recipients (ex vivo) that bone marrow cells (BMC) are potent downregulators of the immune response. Also, the use of alemtuzumab (Campath-1H, C1H) for immunodepletion is associated with the most potent lasting effects yet seen on T-cell immunity in renal transplantation. We questioned whether the administration of C1H to kidney allograft recipients of donor bone marrow cell (DBMC) infusions would lead to stronger or weaker immunoregulatory effects. Human BMC depleted of T cells (nT-BMC) were either untreated or treated with C1H and rabbit complement and compared for their ability to downregulate autologous or allogeneic T-cell responses and to generate T regulatory (T reg) cells. The proliferative responses to anti-CD3 monoclonal antibody of T cells derived from cocultures with C1H-treated or untreated autologous nT-BMC were equally suppressed, i.e., an equivalent alteration in CD3 complex signaling, not regained by the addition of interleukin 2. Adenosine triphosphate levels were also markedly reduced in T cells both from C1H-treated and untreated nT-BMC cocultures. The ability of C1H-treated or untreated nT-BMC to suppress autologous T-cell cytotoxic function was also equivalent, with a marked, but equivalent, capacity to induce CD4/CD25(high) T regs from CD3(+) cells, which effectively downregulated cytotoxic T cells. To mimic the clinical infusion of DBMC into (allogeneic) recipients, peripheral blood mononuclear cells were also cultured with allogeneic C1H-treated and untreated nT-BMC. T cells derived from these cultures secondarily stimulated with the same-donor mature antigen-presenting cells exhibited suppressed cytotoxicity by 85% and 54%, respectively. These in vitro studies suggest that C1H does not abrogate BMC immunoregulation and thus may allow its lympho-depleting effect to be synergistic.

Alemtuzumab↗

PubMed2005

The role of donor bone marrow infusions in withdrawal of immunosuppression in adult liver allotransplantation.

We investigated the role of donor bone marrow cell (DBMC) infusions in immunosuppression withdrawal in adult liver transplantation. Patients enrolled were at least 3 years post-transplantation, with stable graft function. Forty-five (study group: G1) received DBMC, and 59 (control group: G2) did not. Immunosuppression was reduced by one third upon enrollment, by another third the second year of the study and was completely withdrawn the third year. Patient and graft survival were similar between the two groups. Although rejection episodes were significantly less in G1 the first 2 years of the study (35% vs. 57%, p = 0.016), there was no significant difference overall (74% vs. 81%, p = 0.14). Until February 2004, 20 patients, 10 in each group, were immunosuppression free for 1-3 years. Approximately 20% of long-term survivors of liver transplantation can successfully discontinue their immunosuppression. DBMC infusions, do not increase this likelihood.

Bone Marrow Transplantation↗

PubMed2005

Serial ten-year follow-up of HLA and MICA antibody production prior to kidney graft failure.

The role of HLA antibodies in chronic allograft rejection was examined utilizing a unique resource of sera collected annually and stored over a 12-year period from patients with rejected or retained grafts. In patients selected for not having preformed HLA antibodies, 679 postoperative serial serum samples from 39 patients who rejected their grafts and 26 with functioning grafts were tested for HLA Class I and Class II antibodies by flow cytometry and for MICA antibodies by cytotoxicity on recombinant cell lines. HLA antibodies were found in 72% of patients who rejected grafts, compared to 46% with functioning transplants (p<0.05). In addition, the incidence of IgG HLA plus MICA antibodies was higher (77%) among those with failed transplants than those with functioning transplants (42%) (p<0.01). Finally, if patients with IgM anti-HLA antibodies were included, 95% of the 39 patients who rejected their grafts had HLA or MICA antibodies, compared to 58% with functioning grafts (p<0.01). Patients who rejected transplants had HLA and MICA antibodies more frequently than those with functioning grafts. These antibodies found in the peripheral circulation, were not necessarily donor-specific, but their association with failure is consistent with a causality hypothesis.

Adult↗

PubMed2004

Donor bone marrow infusion in deceased and living donor renal transplantation.

The infusion and persistence in a transplant recipient of donor-derived bone marrow cells (DBMC) of multi-lineage can lead to a state of permanent chimerism. In solid vascular organ transplantation, the donor bone marrow lineage cells can even be derived from the transplant organ, and these cells can be detected in very small numbers in the recipient. This has been called microchimerism. Much controversy has developed with respect to the function of chimeric cells in organ transplantation. One idea is that the occurrence of these donor cells found in microchimerism in the recipient are coincidental and have no long-term beneficial effect on engraftment. A second and opposing view, is that these donor cells have immunoregulatory function that affect both the acute and chronic phases of the recipient anti-donor responses. It follows that detecting quantitative changes in chimerism might serve as an indication of the donor-specific alloimmune or regulatory response that could occur in concert with or independent of other adaptive immune responses. The latter, including autoimmune native disease, need to be controlled in the transplant organ. The safety and immune tolerance potential of DBMC infusion with deceased and living donor renal transplants was evaluated in a non-randomized trial at this center and compared with non-infused controls given identical immunosuppression. Overall DBMC infusions were well tolerated by the recipients. There were no complications from the infusion(s), no episodes of graft-vs-host disease (GVHD) and no increase infections or other complications. In the deceased DBMC-kidney trial, actuarial graft survival at 5 years was superior especially when graft survival was censored for recipient death. Acute rejections were significant reduced in patients given two DBMC infusions, and chronic rejection was dramatically reduced in all DBMC treated patients. The most interesting finding was that the degree of microchimerism slowly increased over the years the DBMC group that had exhibited no rejection episodes. In the DBMC-living related trial, the incidence of acute rejection did not differ between groups. However, DBMC chimerism in recipient iliac crest marrow had increased more rapidly than might be predicted from results previously seen in the cadaver group, despite four times fewer DBMC infused, with the generation of T- regulartory cells in-vitro assays.

Bone Marrow Transplantation↗

PubMed2004

The use of Campath-1H as induction therapy in renal transplantation: preliminary results.

BACKGROUND: In an attempt to reduce both initial and long-term (nephrotoxic) calcineurin inhibitor maintenance dosage and totally eliminate maintenance corticosteroids, alemtuzumab (Campath-1H) was used as induction therapy in first cadaver and non-HLA-identical living donor renal transplantation. METHODS: Forty-four de novo renal allograft recipients were treated with Campath-1H (0.3 mg/kg) on days 0 and 4 postoperatively, preceded by methylprednisolone boluses. Maintenance target 12-hr tacrolimus trough levels of 5 to 7 ng/mL were operational from the outset as well as (reduced) mycophenolate mofetil dosage of 500 mg twice daily. No corticosteroids were planned to be given after the first week postoperatively. RESULTS: With a median follow-up of 9 (range, 1-19) months, patient and graft survival rates are each at 100%. Biopsy-proven acute rejection was diagnosed in four patients. Infections requiring hospitalization developed in four patients. Thirty-eight recipients remain without the need for long-term corticosteroid therapy. CONCLUSIONS: In an early assessment, the combination of Campath-1H, low dosing of tacrolimus and mycophenolate mofetil, and avoidance of maintenance corticosteroid use seems to be safe and effective for kidney transplant recipients. Long-term outcomes will be reported in the future.

Alemtuzumab↗

PubMed2004

Preliminary experience with alemtuzumab (Campath-1H) and low-dose tacrolimus immunosuppression in adult liver transplantation.

BACKGROUND: The administration of alemtuzumab (Campath-1H [C1H]; Berlex Laboratories, Montville, NJ) at transplantation prevents a vigorous immune response and is believed to allow a gradual engagement of the host immune system. We report our preliminary experience with C1H and tacrolimus (Tac) immunosuppression in adult liver transplantation. METHODS: We administered C1H and low-dose Tac to 40 adult recipients of cadaveric liver allografts between December 2001 and April 2003. A control group who met the same eligibility criteria consisted of 50 liver transplant recipients treated with our standard Tac and steroids protocol. RESULTS: Baseline characteristics and patient and graft survival were similar (P >0.15). The incidence of acute rejection was significantly lower during the first 2 months posttransplantation (P =0.002) and slightly lower overall in the study group versus the control group at 12 months (46% vs. 55%, P =0.12, log-rank test). Median time to rejection among those experiencing rejection was significantly longer in the study group versus control group (2.76 vs. 0.34 months, P =0.0007). The mean Tac dose, 12-hr trough level, and percentage of patients receiving maintenance steroids were significantly lower in the group receiving C1H and Tac (P <0.0001 during the first 3 months, P <0.05 thereafter), as were the mean creatinine levels (P <0.05) and incidence of nephrotoxicity (P =0.004, conversion from Tac to other agents). Finally, in the group receiving C1H/Tac, patients with an average Tac trough level less than 6.5 ng/mL during the first 2 months post-transplantation demonstrated a significantly higher rejection rate beyond that time (P =0.02). CONCLUSION: C1H and low-dose Tac seems to be at least as effective as our standard Tac and steroids regimen in preventing acute rejection in adult liver allotransplantation with less renal toxicity and less use of maintenance steroids.

Acute Disease↗

PubMed2004

Toward tolerance to human organ transplants: a few additional corollaries and questions.

Several component mechanisms of "central" (thymic) and "peripheral" tolerance in human organ transplant recipients are briefly discussed, in opposition to a more confined view limited to clonal depletion and exhaustion as proposed by Starzl (Transplantation 2004; 77(6): 926). Attention is directed to more than 40 years of experimental work in adult animal species dealing with immunoregulation. This work is in contradistinction to the simpler depletion/exhaustion explanation of Starzl (and Zinkernagel) regarding the potential of human organ transplant recipients to be significantly (or totally) withdrawn from continuous immunosuppression. Other observations are included touching on the roles of certain viral infections, the thymus, and the bone marrow in arriving at a state of "alloimmune homeostasis" in humans.

Humans↗

PubMed2004

TNF-alpha, TGF-beta, IL-10, IL-6, and INF-gamma alleles among African Americans and Cuban Americans. Report of the ASHI Minority Workshops: Part IV.

Point mutations or single nucleotide substitutions in the regulatory regions of cytokine genes may affect levels of cytokine expression and have been associated with acute and chronic rejection in organ transplantation, severity of graft-versus-host disease in hematopoietic stem cell transplants, and predisposition to autoimmune disorders. Because these cytokine variants have been studied primarily among Caucasians, we defined the alleles and frequencies of five cytokines among 691 unrelated, adult African Americans and 296 Cuban Americans in the American Society for Histocompatibility/National Institutes of Health Minority HLA Workshops. The genotypes of all cytokines, except for transforming growth factor (TGF)-beta among African Americans, were found to be in Hardy-Weinberg's equilibrium. Genotype frequencies among African American and Cuban American participants were compared with those of 75 North American Caucasian bone marrow donors and with published frequencies. Significant differences were observed in all comparisons except between Cuban and Caucasian Americans for alleles of interferon (IFN)-gamma, interleukin (IL)-6, and IL-10. The most notable differences were in genotype frequencies of African Americans compared with those of the two other populations. The frequency of the IFN-gamma genotype A/A, which is associated with low expression, was significantly higher in African Americans than in Caucasian or Cuban Americans (0.66 vs 0.37 and 0.26, respectively; p < 0.0001 for both comparisons). The high-expression G/G genotype for IL-6 was more than twice as prevalent among African Americans as among Caucasians and 1.5 times more frequent than among Cuban Americans (respective frequencies: 0.85 vs 0.38 and 0.49; p < 0.0001 for both comparisons). In African Americans, the frequency of the high-expression genotype for IL-10, GCC/GCC, was approximately half that of the frequency in Cuban and Caucasian Americans (0.10 vs 0.19 and 0.23, respectively; p < 0.0001, p = 0.004). Because levels of expression can affect inflammation and immune regulation, differences in cytokine allele frequencies between racial or ethnic groups may contribute to different incidences of autoimmunity and allograft rejection.

Adult↗

PubMed2003

Alemtuzumab (Campath-1H) combined with tacrolimus in intestinal and multivisceral transplantation.

BACKGROUND: We combined alemtuzumab (Campath-1H, Berlex Laboratories, Montville, NJ) and tacrolimus (Tac) immunosuppression for intestinal and multivisceral transplantation. MATERIALS AND METHODS: A total of 21 adult patients received 24 grafts: 14 intestinal, nine multivisceral, and one liver-intestinal graft. Alemtuzumab was administered perioperatively in four doses with low-dose Tac (levels 10-15 ng/dL) and no maintenance steroids. Tac was substituted with sirolimus in case of Tac-related complications. Suspected or mild rejections were treated with steroids. Moderate rejections were treated with steroids or OKT3. Severe rejections were treated with OKT3. RESULTS: Of the 16 patients that were followed up for an average of 9 months, 12 are alive with functioning grafts. Two patients experienced severe rejection, three experienced moderate rejection episodes, and seven experienced mild acute rejection episodes. Four patients never developed acute rejection. Infectious complications included a cytomegalovirus enteritis and four fungal infections (related to central venous access). CONCLUSIONS: The combination of alemtuzumab and Tac therapy without steroid use seems to efficiently prevent acute rejection in a significant number of patients without causing frequent opportunistic infections.

Adult↗

PubMed2003

A novel micro-cell-mediated lympholytic assay for the evaluation of regulatory cells in human alloreactive CTL responses.

Since cell-mediated lympholysis (CML), the most commonly used in vitro experimental cytotoxic method for the evaluation of regulatory cells, requires large numbers of cells that are often the limiting factor, we have developed a new micro-cell-mediated lympholytic (m-CML) assay. Various numbers of responding cells were stimulated with equivalent numbers of allogeneic irradiated stimulator cells in the presence of (fivefold) serial dilutions of regulatory cells. On the 8th day, 4-h 51Cr-release assays were performed by adding 5000 labeled target cells from the corresponding stimulators to the cultures. Even though results that were comparable to the macro- (bulk) CML and MLR modulation experiments were obtained with all the cell combinations tested in the m-CML, the combinations with 50,000 responder cells and stimulating cells and dilutions of 25,000 to 40 modulator (regulatory) cells were found to be the most reproducible for assaying regulatory cell potency in vitro. Similarly, expression of the results as percentage inhibition using percent specific lysis values was the simplest method of calculation. This assay was standardized for the evaluation of the inhibitory activity of a variety of regulatory cells, including long-term cultures of cadaver-donor vertebral body bone marrow cells (vDBMC-L), in vitro generated CD8 positive and CD28 negative suppressor T cells and donor chimeric cells isolated from renal transplant recipients who had been perioperatively infused with donor bone marrow cells (DBMC). The results indicate that the m-CML assay is a sensitive and reliable micromethod with at least 10-fold fewer responders, stimulator and modulator cell numbers needed than macro-CML assays for the evaluation of regulatory cells obtained from a variety of immune systems in vitro.

Bone Marrow Cells↗

PubMed2003

Human donor bone marrow cells induce in vitro "suppressor T cells" that functionally suppress autologous B cells.

We have reported a beneficial effect of donor vertebral body bone marrow cells (DBMC) infusions in cadaver renal allograft recipients in a 6-year follow-up, but with a transient increase in early (6 month) postoperative CMV infections and concomitant suppressed immunoglobulins (Ig) production. We also found that although there was no difference between the DBMC-infused and non-infused (control) groups in the development of donor-specific antibody, we now describe an additional difference seen in the percent reactive antibody (PRA) reactivity against a panel of HLA antigens that developed postoperatively. We hypothesize that (allogeneic) antigen presenting cells in the DBMC, systemically infused, caused the generation of recipient T suppressor (T4-suppressor) cells, thereby "inducing" a negative influence on B cell Ig production. We tested this notion in vitro by incubating PBL from CMV IgG positive laboratory volunteers with either (allogeneic) T-cell depleted DBMC or donor spleen cells (DSPC) from (the same) cadaver donors. After 7 days, the (responding) T cells were collected using magnetic beads and placed in culture with purified B cells freshly obtained from the same (autologous) CMV positive volunteer. To these cultures were added either media or 40 ng of CMV antigen. After 3, 5, 7, and 9 days, the expression of surface anti-CMV Ig was measured by flow cytometry using a panel of fluorescent markers double-labeled for activated B cells (CD20, CD19, and HLA DRw) and CMV-FITC. We also determined the phenotype of the cultured T cells using anti-CD3, CD4, and CD62L specific monoclonal antibodies. B cells that had been in contact with autologous T cells derived from DBMC cultures (TBM) were less likely to express anti-CMV surface Ig than those cultured with DSPC (TSP). The flow cytometry analysis revealed an increase in the number of T4 suppressor cells (CD3+, CD4+, CD62L+) in the TBM group, whereas the T4 helper phenotype (CD3+, CD4+, CD62L-) predominated in the TSP group. These in vitro findings support the notion that (allogeneic) DBMC infusions can induce a T4 suppressor (regulatory) influence and thereby indirectly affect B-cell function.

Bone Marrow↗

PubMed2003

Mucosal vascular alterations in isolated small-bowel allografts: relationship to humoral sensitization.

Acute vascular rejection (AVR) in human small-bowel transplantation is an inadequately characterized entity whose frequency and severity is not well understood. As compared to severe AVR, changes identifying early, mild or evolving AVR are not known. We created a scoring system to evaluate subtle mucosal vascular changes and examined 188 biopsies from 21 patients obtained in the first 3 months post transplant. A majority of patients had a transient rise in vascular injury, often within 30 days of transplant. Small-vessel congestion and erythrocyte extravasation were the most common alterations. The vascular injury score was not related to acute cellular rejection, HLA type or HLA antigen disparities. However, the patients with the vascular changes had significantly higher peak panel reactive antibodies (PRA) and a higher incidence of positive T-cell and B-cell crossmatch. Finally, graft survival was significantly lower in the patients demonstrating the early vascular lesions. These data suggest that the vascular injury is partially associated with humoral presensitization of the recipient and may be a form of acute vascular rejection. Since these vascular changes are frequent, we advocate early post-transplant monitoring to identify and manage potentially high-risk patients.

Antibodies↗

PubMed2002

Regulation of alloimmune responses (GvH reactions) in vitro by autologous donor bone marrow cell preparation used in clinical organ transplantation.

BACKGROUND: Cadaver donor bone marrow cells (DBMC) are capable of a low-grade response to allogeneic stimulation in vitro, indicating their potential ability to cause graft versus host disease (GvHD). However, at this center, we have observed a lack of GvHD in kidney transplant recipients who received DBMC perioperatively. Therefore, we questioned whether an intrinsic immunoregulatory function of (subpopulations of) DBMC might play a role in this observation. METHODS: In in vitro assays, DBMC was added to autologous splenic responder cells taking part in allogeneic mixed lymphocyte reaction (MLR) and cell-mediated lympholysis (CML) reactions. RESULTS: When compared with autologous donor irradiated spleen cells as control modulators, DBMC significantly inhibited the CML, but to a much lesser extent than MLR, of autologous responding cells stimulated with allogeneic irradiated cells in a dose dependent manner. The down-regulation of CML responses was observed even in the presence of pharmacological concentrations FK506, mycophenolic acid, or cyclosporine-A. The inhibition could not be overcome by the addition of exogenous helper factors. Moreover, in contrast with findings previously reported from this laboratory of the in vitro inhibitory effect of DBMC on allogeneic responding cells in MLR and CML reactions to stimulating cells of the DBMC donor (allogeneic host versus graft inhibition), the following unique observations were made using DBMC inhibiting autologous reactions (GvH): (1) optimal restimulation of autologous responder cells in secondary cultures could not abrogate this inhibition; even activated responder cells could be inhibited by autologous DBMC, and (2) soluble factors were at least partially operative in this autologous (GvH) inhibition as indicated by experiments in transwells and by the CML inhibition caused by 50% supernatants from DBMC cultures. CONCLUSION: These in vitro results indicate that DBMC treatment brings about a marked down-regulation of autologous immunocompetent cells in cytotoxicity reactions, partially at least through secreted soluble factor(s), (and in presence of immunosuppressive drugs in vivo) thereby preventing overt clinical GvHD.

Bone Marrow Cells↗

PubMed2002

Effect of living-related donor bone marrow infusion on chimerism and in vitro immunoregulatory activity in kidney transplant recipients.

BACKGROUND: In a previously reported series of donor-specific bone marrow cell (DBMC) infusions in cadaver kidney transplant recipients, there appeared to be an improvement in long-term graft survival (6 years) and fewer chronic rejections, which correlated with increasing DBMC chimerism (approximately 1.4% in the iliac crest bone marrow compartment now at 6 years). Prompted by this, we embarked on a study of DBMC infusion in living-related donor (LRD) kidney transplant recipients. METHODS: Between November 1996 and May 2000, 47 LRD kidney transplant recipients received donor iliac crest marrow (1.8 x 10(8)+/-1.9 x 10(8) cells/kg body weight+/-SD) in a single infusion 4 days postoperatively. Either OKT3 (n=26) or daclizumab (n=21) were used for induction therapy, with maintenance tacrolimus, mycophenolate mofetil, and methylprednisolone immunosuppression. These recipients were prospectively compared with 39 noninfused LRD kidney transplants (control group), which received equivalent immunosuppression in the same time period. Clinical follow-up ranged from 19.0 months to 61.6 months (mean 33.2 months). Polymerase chain reaction-flow chimerism analysis and in vitro assays of immunoregulatory activity of chimeric cells were performed. RESULTS: The incidence of acute rejection over this period of time was 10.6% and 10.3%, respectively (i.e., did not differ between groups). Immunosuppressive dosages were somewhat (but not statistically) lower over time in the DBMC group. Four-year actuarial patient and graft survival for the DBMC-infused group was 98% and 98%, and 98% and 95% for the control group, respectively ( =NS). DBMC infusion was well tolerated, with no increase in infectious episodes. DBMC chimerism in recipient iliac crest marrow has increased more rapidly than might be predicted from results previously seen in the cadaver group, despite four times fewer DBMC infused. DBMCs and (donor) peripheral blood mononuclear cells purified by immunobeads from recipient blood or bone marrow (recipient-derived donor cells) inhibited mixed leukocyte responses of the recipient to the donor more strongly than freshly obtained peripheral blood cells drawn from the donors or even compared with bone marrow cells aspirated from the donors in a previously reported group of experiments. Additionally, similarly purified recipient-derived recipient cells from the same chimeric recipient more strongly inhibited the same mixed leukocyte response reactions autologously than a large group of nonchimeric (autologous) bone marrow modulating cells in similar reactions. CONCLUSIONS: These observations confirm that an immunoregulatory process appears to have been generated by DBMC infusion, encouraging a further decrease in immunosuppressive dosing using such assays in the future.

Adult↗

PubMed2002

Host-derived enterocytes in intestinal grafts.

Replacement of donor lymphoid tissue by lymphocytes of recipient origin is an established phenomenon in small bowel transplants. However, replacement of donor epithelial cells of bowel grafts by host cells has not been demonstrated. The objective of our study was to determine whether donor enterocytes are replaced by host-derived enterocytes in the intestinal allograft. Graft biopsy specimens, obtained from five human male recipients of female intestine, were examined for the presence of male enterocytes. The biopsies dated from 90 to 770 days posttransplant. Formalin-fixed 3-microm specimen sections were stained for X and Y chromosomes by fluorescent in situ hybridization technique. Fluorescent microscopy of the stained sections identified male enterocytes in four patients, with a percentage of male cells ranging from 0.09% to 0.26% of the total enterocyte mass. Using the fluorescent in situ hybridization technique, we demonstrated the presence of host-derived male (XY) enterocytes in the female intestinal graft.

Enterocytes↗

PubMed2002

Daclizumab induction, tacrolimus, mycophenolate mofetil and steroids as an immunosuppression regimen for primary kidney transplant recipients.

BACKGROUND: Recent reports have demonstrated the efficacy of interleukin-2-receptor blockers in lowering the incidence of early acute rejection in cyclosporine-treated kidney recipients when compared to patients not induced with an antibody product. The addition of daclizumab to a tacrolimus-mycophenolate mofetil-based immunosuppressive protocol was tested to evaluate whether there might be an additional reduction of the risk of rejection after renal transplantation. METHODS: Since March 1998, we studied the effect of daclizumab in a nonrandomized, prospective study of 233 sequential recipients of first renal transplant. They were retrospective compared with a control group of 225 renal transplant recipients receiving a 10-day course of OKT3 induction, and tacrolimus, mycophenolate mofetil, and methylprednisolone maintenance. The study group received the same immunosuppressive regimen with the addition of daclizumab at 1 mg/kg for five doses over 10 weeks in the place of OKT3 therapy. There was at least 1HLA DR antigen compatibility match present between all donors and recipients. Patients were followed for 1 year after renal transplantation for the incidence of biopsy-proven acute rejection, patient and graft survival, and adverse events. RESULTS: At 12 months, patient and graft survival for the daclizumab was 98 and 96 vs. 96 and 94% for the OKT3 group, respectively, and were not statistically different. Acute rejection rates (<6 months) were lower in the daclizumab group as compared with the OKT3 group, i.e., 5 (2.1%) vs. 16 (7.1%) (P=0.011) respectively. The incidence of infection requiring hospitalization appeared to be lower with daclizumab (7.3 vs. 16%, P<0.0036) with a similar trend with cyclomegalovirus infection, i.e., 1.6 vs. 4%, respectively (P=0.14). CONCLUSIONS: The combination of daclizumab, tacrolimus, mycophenolate mofetil, and steroids is safe and effective for kidney transplant recipients in lowering the incidence of early acute rejection and without any increase in morbidity when compared to our previous protocol, which may have an eventual impact in long-term graft survival.

Adolescent↗