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Biomedical subjects

A B Cosimi

Publications and source records attributed to A B Cosimi.

At least 19 recordsLinked to original sources

BK virus in solid organ transplant recipients: an emerging syndrome.

BK virus is a human polyomavirus associated with a range of clinical presentations from asymptomatic viruria with pyuria to ureteral ulceration with ureteral stenosis in renal transplant patients or hemorrhagic cystitis in bone marrow transplant recipients. Infection of renal allografts has been associated with diminished graft function in some individuals. Fortunately, however, the majority of patients with BK virus infections are asymptomatic. The type, duration, and intensity of immunosuppression are major contributors to susceptibility to the activation of BK virus infection. Histopathology is required for the demonstration of renal parenchymal involvement; urine cytology and viral polymerase chain reaction methods are useful adjunctive diagnostic tools. Current, treatment of immunosuppressed patients with polyomavirus viruria is largely supportive and directed toward minimizing immunosuppression. Improved diagnostic tools and antiviral therapies are needed for polyomavirus infections.

BK Virus↗

Postmenopausal tubo-ovarian abscess due to Pseudomonas aeruginosa in a renal transplant patient: a case report and review of the literature.

BACKGROUND: Pseudomonas aeruginosa is an uncommon cause of infection in the female genital tract. We report a case of postmenopausal tubo-ovarian abscess (TOA) due to P. aeruginosa in a renal transplant recipient. The presentation included mild abdominal symptoms with rapid progression of peritonitis and surgical abscess drainage. This is the first such case in an organ transplant recipient described in the English literature. METHODS AND RESULTS: Published reports of 1040 cases of TOA were reviewed. The most common features were a history of sexually transmitted disease or pelvic inflammatory disease, and symptoms including abdominal pain and fever. Escherichia coli, Bacteroides spp., and Klebsiella pneumoniae were the most frequently encountered pathogens. Neisseria gonorrhoeae and Chlamydia trachomatis, which are frequently isolated from cervical cultures, are uncommonly isolated from tubo-ovarian abscesses. Forty percent of patients were treated with antibiotics alone, 18.8% with abdominal surgery, and 32% with surgery and antimicrobial therapy. CONCLUSION: This report illustrates the muted presentation and atypical microbiology of gynecologic infection in an organ transplant recipient.

Abscess↗

Posttransplant diabetes mellitus in liver transplant recipients: risk factors, temporal relationship with hepatitis C virus allograft hepatitis, and impact on mortality.

BACKGROUND: Recent studies suggest an association between diabetes mellitus and hepatitis C virus (HCV) infection. Our aim was to determine (1) the prevalence and determinants of new onset posttransplant diabetes mellitus (PTDM) in HCV (+) liver transplant (OLT) recipients, (2) the temporal relationship between recurrent allograft hepatitis and the onset of PTDM, and (3) the effects of antiviral therapy on glycemic control. METHODS: Between January of 1991 and December of 1998, of 185 OLTs performed in 176 adult patients, 47 HCV (+) cases and 111 HCV (-) controls were analyzed. We reviewed and analyzed the demographics, etiology of liver failure, pretransplant alcohol abuse, prevalence of diabetes mellitus, and clinical characteristics of both groups. In HCV (+) patients, the development of recurrent allograft hepatitis and its therapy were also studied in detail. RESULTS: The prevalence of pretransplant diabetes was similar in the two groups, whereas the prevalence of PTDM was significantly higher in HCV (+) than in HCV (-) patients (64% vs. 28%, P=0.0001). By multivariate analysis, HCV infection (hazard ratio 2.5, P=0.001) and methylprednisolone boluses (hazard ratio 1.09 per bolus, P=0.02) were found to be independent risk factors for the development of PTDM. Development of PTDM was found to be an independent risk factor for mortality (hazard ratio 3.67, P<0.0001). The cumulative mortality in HCV (+) PTDM (+) versus HCV (+) PTDM (-) patients was 56% vs. 14% (P=0.001). In HCV (+) patients with PTDM, we could identify two groups based on the temporal relationship between the allograft hepatitis and the onset of PTDM: 13 patients developed PTDM either before or in the absence of hepatitis (group A), and 12 concurrently with the diagnosis of hepatitis (group B). In gr. B, 11 of 12 patients received antiviral therapy. Normalization of liver function tests with improvement in viremia was achieved in 4 of 11 patients, who also demonstrated a marked improvement in their glycemic control. CONCLUSION: We found a high prevalence of PTDM in HCV (+) recipients. PTDM after OLT was associated with significantly increased mortality. HCV infection and methylprednisolone boluses were found to be independent risk factors for the development of PTDM. In approximately half of the HCV (+) patients with PTDM, the onset of PTDM was related to the recurrence of allograft hepatitis. Improvement in glycemic control was achieved in the patients who responded to antiviral therapy.

Antiviral Agents↗

Long-term islet allograft function in the absence of chronic immunosuppression: a case report of a nonhuman primate previously made tolerant to a renal allograft from the same donor.

UNLABELLED: Development of mixed chimerism by donor bone marrow transplantation (DBMT) has led to long-term tolerance of solid organ allografts in nonhuman primates. As an initial attempt to extend this approach to cellular transplant, islet transplant from the same donor was attempted in the recipient previously made tolerant to a kidney allograft. METHODS: After the conditioning with ATG, total body irradiation, thymic irradiation, and splenectomy, DBMT was performed followed by 4 weeks of cyclosporine. Kidney transplantation and native nephrectomies were subsequently performed on day 89. After 2.8 years of DBMT, diabetes was induced by streptozocin (STZ) and islets from bone marrow and kidney donor were transplanted without immunosuppression. RESULTS: After DBMT, the recipient developed chimerism and no evidence of kidney rejection for more than 1000 days. STZ induced diabetes was reversed after the islet transplantation. Islet biopsies demonstrated insulin staining without rejection. Although the recipient became diabetic 300 days after islet transplantation, viable transplanted islets were found in the liver and under the kidney capsule without any evidence of rejection. CONCLUSION: Tolerance with a nonmyeloablative conditioning can allow successful pancreatic islet transplantation without immunosuppression. Because no histological evidence of rejection was identified, recurrent diabetes is presumed to be inadequate islet mass.

ABO Blood-Group System↗

Control of antidonor antibody production with tacrolimus and mycophenolate mofetil in renal allograft recipients with chronic rejection.

BACKGROUND: In renal transplantation, chronic rejection is a major cause of late allograft loss. Recent studies indicate that a subset of chronic rejection is associated with anti-HLA donor specific antibodies (DSA) and complement C4d deposition in peritubular capillaries (PTC). Since rescue therapy with tacrolimus and mycophenolate mofetil has been found to limit antidonor B-cell responses in recipients with acute humoral rejection, we sought to determine whether a similar immunosuppressive regimen might be effective in patients with 'chronic humoral rejection'. METHODS: Four renal allograft recipients with 'chronic humoral rejection' were prospectively identified. The diagnosis was based on: (1) progressive rise in serum creatinine over 12 months; (2) typical pathologic features by light microscopy (transplant arteriopathy and glomerulopathy); (3) widespread C4d deposits in PTC by immunofluorescence; (4) detection of 'de novo' DSA at the time of biopsy. Maintenance immunosuppression was CsA, prednisone and azathioprine (n=3) or prednisone and azathioprine (n=1). Rescue therapy with tacrolimus and mycophenolate mofetil was initiated in all patients, 12 hr after cyclosporine and azathioprine discontinuation. RESULTS: At diagnosis, the mean serum creatinine was 3.9 mg/dl (range: 3.3 to 5.4 mg/dl). DSA was an IgG directed against HLA class II (n=3) or class I (n=2), that is one patient had both anti-HLA class I and class II antibodies. Pretreatment antibody titers varied between 1:8 and 1:128. Rescue therapy was associated with a rapid and sustained decrease in antibody titers. In two patients, DSA became undetectable after 9 months and a repeat biopsy performed after 12 months revealed a decrease in C4d deposition in PTC. CONCLUSION: These results suggest that a decrease in DSA production can be induced in renal allograft recipients with 'chronic humoral rejection' by using an immunosuppressive regimen that combines tacrolimus and mycophenolate mofetil. Limitation of antidonor antibody synthesis may be important for the treatment or the prevention of chronic rejection in organ transplantation.

Adult↗

Complement activation products in plasma after heart transplantation in humans.

BACKGROUND: Complement activation has recently been implicated as a contributing factor to early and late allograft dysfunction in cardiac transplantation. The current study was designed to determine whether measurement of plasma complement fragments C4d and SC5b-9 would be useful in detecting acute rejection or accelerated graft atherosclerosis (AGA) in cardiac allograft recipients. METHODS: We measured complement activation products, C4d (classical pathway) and SC5b-9 (terminal pathway), at the time of routine endomyocardial biopsy in heart transplant recipients. Ten patients in the immediate posttransplantation period (0-100 days) and 19 patients more than 6 months after transplantation were studied. RESULTS: No correlation was found between plasma levels of complement activation fragments and the presence of biopsy-proven acute allograft rejection or AGA (assessed by coronary angiography). However, plasma C4d and SC5b-9 were significantly elevated in 9 of 10 and 7 of 10 patients, respectively, in the immediate posttransplantation period. This was followed by progressive decrease in the levels of C4d and SC5b-9 fragments during the first 4-6 weeks after transplantation. CONCLUSION: We conclude that measuring plasma levels of fragments C4d and SC5b-9 is not a useful noninvasive method for detecting acute rejection or AGA after heart transplantation. However, this study provides further evidence that early complement activation after heart transplantation may play a pathogenic role in allograft injury.

Complement Activation↗

Acute humoral rejection in renal allograft recipients: I. Incidence, serology and clinical characteristics.

BACKGROUND: Acute rejection (AR) associated with de novo production of donor-specific antibodies (DSA) is a clinicopathological entity that carries a poor prognosis (acute humoral rejection, AHR). The aim of this study was to determine the incidence and clinical characteristics of AHR in renal allograft recipients, and to further analyze the antibodies involved. METHODS: During a 4-year period, 232 renal transplants (Tx) were performed at our institution. Assays for DSA included T and B cell cytotoxic and/or flow cytometric cross-matches and cytotoxic antibody screens (PRA). C4d complement staining was performed on frozen biopsy tissue. RESULTS: A total of 81 patients (35%) suffered at least one episode of AR within the first 3 months: 51 had steroid-insensitive AR whereas the remaining 30 had steroid-sensitive AR. No DSA were found in patients with steroid-sensitive AR. In contrast, circulating DSA were found in 19/51 patients (37%) with steroid-insensitive AR, and widespread C4d deposits in peritubular capillaries were present in 18 of these 19 (95%). In at least three cases, antibodies were against donor HLA class II antigens. DSA were not found in the remaining 32 patients but C4d staining was positive in 2 of 32. The DSA/C4d positive (n=18) and DSA/C4d negative (n=30) groups differed in pre-Tx PRA levels, percentage of re-Tx patients, refractoriness to antilymphocyte therapy, and outcome. Plasmapheresis and tacrolimus-mycophenolate mofetil rescue reversed rejection in 9 of 10 recipients with refractory AHR. CONCLUSION: More than one-third of the patients with steroid-insensitive AR had evidence of AHR, often resistant to antilymphocyte therapy. Most cases (95%) with DSA at the time of rejection had widespread C4d deposits in peritubular capillaries, suggesting a pathogenic role of the circulating alloantibody. Combined DSA testing and C4d staining provides a useful approach for the early diagnosis of AHR, a condition that often necessitates a more intensive therapeutic rescue regimen.

Acute Disease↗

Managing the highly sensitized transplant recipient and B cell tolerance.

The detection of anti-donor-HLA antibodies in a renal allograft recipient's serum, either at the time of or after transplantation, is usually associated with specific antibody-mediated clinical syndromes. These can be divided temporally into three categories: hyperacute rejection, acute humoral rejection and chronic humoral rejection. With the identification of new immunosuppressive drug combinations, more-effective control of alloantibody production has been recently achieved in humans. Thus, prevention and/or treatment of antibody-mediated allograft injury are now possible. Ultimately, the induction of mixed hematopoietic chimerism may allow us to overcome the problem of allosensitization and accept an allograft without chronic immunosuppression.

Animals↗

Preliminary results of a liver allocation plan using a continuous medical severity score that de-emphasizes waiting time.

Liver allocation remains problematic because current policy prioritizes status 2B or 3 patients by waiting time rather than medical urgency. On February 21, 2000, we implemented a variance to the United Network for Organ Sharing liver allocation policy that redefined status 2A by much more rigid, definable criteria and prioritized status 2B patients by using a continuous medical urgency score based on the Child-Turcotte-Pugh score and other medical conditions. In this system, waiting time is used only to differentiate status 2B candidates with equal medical urgency scores. Comparing the 6-month period (period 1; n = 67) before implementation of this system to the 6-month period after implementation (period 2; n = 75), there was a significant reduction in the number of transplantations performed for patients listed as status 2A (46.3% to 14.7%; P =.002) and an increase in the number of patients listed as status 2B who received transplants (44.8% to 70.7%; P =.10). Most dramatically, there was a 37.1% reduction in overall deaths on the waiting list from 94 deaths in period 1 to 62 deaths in period 2 (P =.005), with the most significant reduction for patients removed from this list at status 2B (52 v 18 patients; P =.04). There were 3 postoperative deaths in each period, with only 1 graft lost in period 2. Status 2B patients with the greatest degree of medical urgency received transplants without multiple peer reviews requesting elevation to 2A status. We conclude that a continuous medical urgency score system allocates donor livers much more fairly to those in medical need and reduces waiting list mortality without sacrificing efficacy.

Health Care Rationing↗

The kidney transplant program at the Massachusetts general hospital.

Between February 1963 and December 2000, 1,627 kidney transplants were performed at the Massachusetts General Hospital. The majority (62%) were from cadaveric donors, although in recent years (1996-2000) 52% have been allografts from living donors, with an increase in living unrelated donors. The introduction of CsA and OKT3 in 1984 was associated with a significant improvement in actuarial renal allograft survival, although a persistent late attrition of allografts continues beyond the first year after transplantation. As reported in other centers, current actuarial survival for living unrelated allografts is superior to that of cadaveric allografts, and is quite similar to that observed in recipients of non-HLA identical living-related transplants. Our preliminary laparoscopic donor nephrectomy experience is encouraging as excellent allograft survival and function has been observed, with minimal morbidity associated with the procedure and a low rate of conversion to open nephrectomy. Recent changes in immunosuppressive protocols have resulted in lower early acute rejection rates, however the incidence of delayed graft function remains unchanged in cadaveric renal transplantation. The role of humoral immunity in allograft rejection has been progressively clarified and new approaches to control donor specific alloantibody production have been shown to be effective. Current clinical studies are ongoing to determine the optimal type and dose of calcineurin inhibitors beyond the first year after transplantation and to study whether avoidance of steroids is safe and feasible. Finally, an innovative tolerance induction protocol using the mixed chimerism approach has been successfully accomplished in selected patients with end-stage renal disease secondary to multiple myeloma. These encouraging observations emphasize that major changes from current immunosuppressive regimens are likely to occur over the next few years as more approaches to tolerance induction are explored clinically.

Graft Rejection↗

Association of natural killer cell depletion with induction of mixed chimerism and allograft tolerance in non-human primates.

BACKGROUND: Nonmyeloablative T cell depletion followed by donor bone marrow infusion has proved to be an effective approach to induction of mixed chimerism and tolerance of organ allografts in non-human primates. To help define the mechanisms involved we have compared T cell depletion with ATG versus anti-CD2 monoclonal antibody with respect to establishment of mixed chimerism and induction of tolerance. METHOD: Both nonmyeloablative regimens included low dose total body irradiation (1.5 Gy x 2), thymic irradiation (7 Gy), splenectomy and kidney plus donor bone marrow transplantation, followed by a 4-week posttransplant course of cyclosporine. In addition, the ATG group (13 recipients) received antithymocyte globulin, although the LOCD2b group (10 recipients) were treated with an anti-CD2 monoclonal antibody (LOCD2b). RESULTS: In the ATG group, 11 of 13 monkeys developed multilineage chimerism and 9 survived for more than 100 days without kidney allograft rejection. In contrast, 0/10 monkeys in the LOCD2b group developed chimerism, 5 died of infection and 5 suffered progressive rejection; only 1 recipient survived beyond 100 days. Sequential monitoring of peripheral blood mononuclear cells revealed greater T cell (CD3+) depletion in the LOCD2b-treated animals compared to those receiving ATG. However, NK cells (CD16+CD8+) were significantly more depleted in the ATG group and NK function remained abrogated longer after ATG than LOCD2b treatment (3 weeks vs. <5 days). CONCLUSION: Despite excellent T cell depletion by LoCD2b, ATG was more effective in inducing chimerism and tolerance. This difference correlated with anti-NK activity of the two reagents. These data suggest that NK cells may also resist engraftment of allogeneic bone marrow cells in this model.

Animals↗

Idiopathic giant esophageal ulcers in a renal transplant patient responsive to steroid therapy.

Idiopathic giant esophageal ulcers in immunocompromised patients have been described only in patients with acquired immunodeficiency syndrome. A solitary report of an idiopathic giant esophageal ulcer in an immunocompetent patient exists. We describe a case of idiopathic esophageal ulceration ultimately responsive to steroid therapy in a 31-year old immunosuppressed, human immunodeficiency virus-negative renal transplant patient. The case is described with particular reference to the evaluation, differential diagnosis, and therapeutic response to steroids. Similarities in presentation and treatment to giant esophageal ulcers in human immunodeficiency virus infection suggest an underlying immune defect as the likely cause. This is the first described case of giant esophageal ulceration responsive to steroids in an immunosuppressed human immunodeficiency virus-negative patient. This entity should be added to the differential diagnosis of esophageal ulceration in solid organ transplant recipients.

Acquired Immunodeficiency Syndrome↗

Anti-Galalpha1-3Gal antibody levels in organ transplant recipients receiving immunosuppressive therapy.

The effect of long-term pharmacologic immunosuppression (PI) on anti-Galalpha1-3Gal (alphaGal) antibody (Ab) levels has not been determined previously in humans. In this study, we measured alpha Gal Ab levels by ELISA in 14 healthy volunteers (controls) and in 70 patients with grafts (kidney, heart, liver) who had received different combinations of PI (including cyclosporine, tacrolimus, azathioprine, mycophenolate mofetil, and steroids) for >3 months. There was great variation in Gal IgM (<80-fold) and IgG (<160-fold). There was no difference in Gal IgM or Gal IgG between any one group and any other. In kidney patients with either high (mean 68%) or low (mean 6%) panel-reactive alloantibodies, there was no difference in alpha Gal Ab level or serum cytotoxicity to pig cells. In vitro immunoadsorption of alphaGal Ab from the serum did not change panel-reactive alloantibody positivity. Therapy with OKT3, a mouse product that might stimulate alphaGal Ab production, led to no significant change in patient Ab levels. We conclude that long-term (>3 months) PI does not reduce Gal Ab levels sufficiently to be of clinical value in xenotransplantation.

Adult↗

Dosing of intravenous ganciclovir for the prophylaxis and treatment of cytomegalovirus infection in solid organ transplant recipients.

BACKGROUND: The optimal regimen for the prevention and treatment of cytomegalovirus (CMV) disease in solid organ transplant recipients remains to be defined, particularly for patients with abnormal or changing renal function. METHODS: A prospective trial was conducted in patients receiving i.v. ganciclovir using a standardized dosing nomogram that corrects for renal function. Steady state peak (P) and trough (T) serum levels were determined by high-performance liquid chromatography and correlated with therapeutic outcomes and toxicities attributable to ganciclovir. RESULTS: Over the study period, 44 individuals received ganciclovir prophylaxis (5 mg(kg/day) and 25 patients were treated (5 mg/kd q12 hr) for symptomatic CMV disease. Ganciclovir levels (microg/ml+/-SD) achieved in prophylaxis were P: 7.98+/-3.34, T: 3.03+/-2.63; and in treatment were P: 9.00+/-3.72, T: 2.65+/-1.82. Despite corrections for renal dysfunction, undialyzed patients with serum creatinine >3.0 mg/dl had trough levels in excess of the population mean (T: range 3-8 microg/ml). Failure of prophylaxis (disease) or therapy (relapse) occurred in 14 patients; 8 of these were at risk for primary infection (donor CMV seropositive, recipient seronegative, P<0.01). Patients at greatest risk for relapse after treatment of CMV disease were liver transplant recipients, patients with ganciclovir-resistant viral isolates, and renal patients with six antigen MHC donor-recipient mismatches. CONCLUSIONS: This trial demonstrates the efficacy of a nomogram for ganciclovir dosing during renal dysfunction; reduced doses can be used for prophylaxis for undialyzed patients with renal dysfunction (1.25 mg/kg/day for Cr > or =3.0, 1.25 mg/kg QOD for Cr > or =5.0). Some groups of transplant recipients may require more intensive anti-CMV regimens.

Adult↗

Lymphedema after sentinel lymph node biopsy for cutaneous melanoma: a report of 5 cases.

BACKGROUND: Sentinel lymph node (SLN) biopsy has rapidly become the procedure of choice for assessing the lymph node status of patients with 1992 American Joint Committee on Cancer stages I and II melanoma. The procedure was designed to be less invasive and, therefore, less likely to cause complications than a complete lymph node dissection. To our knowledge, this is the first report in the literature documenting extremity lymphedema following SLN biopsy. OBSERVATION: We report 5 cases of lymphedema after SLN biopsy in patients being routinely followed up after melanoma surgery at the Massachusetts General Hospital Melanoma Center, Boston. Three cases were mild, and 2 were moderate. Potential contributing causes of lymphedema were present in 4 patients and included the transient formation of hematomas and seromas, obesity, the possibility of occult metastatic melanoma, and the proximal extremity location of the primary melanoma excision. Four of the patients underwent an SLN biopsy at our institution. We used the total number of SLN procedures (N = 235) that we have performed to calculate a 1.7% baseline incidence of lymphedema after SLN biopsy. CONCLUSIONS: Sentinel lymph node biopsy can be complicated by mild and moderate degrees of lymphedema, with an incidence of at least 1.7%. Some patients may have contributing causes for lymphedema other than the SLN biopsy, but many of these causes are difficult to modify or avoid.

Adult↗