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Biomedical subjects

M N Fernández

Publications and source records attributed to M N Fernández.

At least 19 recordsLinked to original sources

Engraftment kinetics of human CD34+ cells from cord blood and mobilized peripheral blood co-transplanted into NOD/SCID mice.

We have reported short periods of post transplant neutropenia in human patients co-transplanted with cord blood (CB) and low numbers of haploidentical mobilized peripheral blood (MPB) CD34+ cells. To investigate the effect that the proportion of MPB to CB cells may have on engraftment kinetics, we have co-transplanted fixed numbers of human CB CD34+ cells mixed with different numbers of MPB CD34+ cells into NOD/SCID mice. We periodically quantified the proportion of human cells and the relative contribution of MPB and CB cells to the human engraftment on marrow aspirates. At the lowest MPB/CB ratios (5 : 1, 10 : 1), the contribution of CB cells predominated at all time points analyzed, and in three out of four experiments MPB cell contributions progressively decreased from day +15. At higher MPB/CB ratios, MPB cells had a more important contribution to both early and late engraftment, with the highest cell ratio resulting in only marginal CB cell engraftment. Therefore, our results showed greater potential, on a per cell basis, of human CB vs MPB cells for competitive sustained engraftment in the xenogeneic model used, which was only abrogated by the co-infusion of very high numbers of MPB cells.

Animals↗

Active idiotypic vaccination in a patient with biclonal follicular lymphoma.

Specific immunological responses to the idiotypic epitopes present in the surface immunoglobulin (Ig) of the clonal tumour population can be induced for active immunotherapy in patients with B-cell non-Hodgkin lymphoma (NHL). The clonality of the tumour cells should have important implications for the success of the implemented therapy. Here we report on the case of a patient enrolled in a protocol of active idiotypic immunotherapy in which previous cytofluorometric analysis showed a major IgM+, kappap+ population in the tumoral cell suspensions. However, sequence analysis of both tumour sample and tumour-derived hybrids revealed the presence of two unrelated clones that used different VH and VK gene segments. It was possible to obtain hybridomas secreting these two different IgM, kappap idiotypic proteins. The patient was immunised with a mixture of these two idiotypic Igs conjugated to keyhole limpet haemocyanin. Anti-idiotypic antibodies directed against both tumour-associated proteins were detected. This is the first case of anti-idiotypic therapy in a patient with a biclonal NHL. Our work calls attention to the question of clonality in the context of idiotypic vaccination in NHL patients.

Adult↗

Cord blood transplants: early recovery of neutrophils from co-transplanted sibling haploidentical progenitor cells and lack of engraftment of cultured cord blood cells, as ascertained by analysis of DNA polymorphisms.

The number of infused cells is a very important factor in cord blood transplant (CBT) engraftment. Prior ex vivo expansion of aliquots of transplanted cord blood (CB) units is being investigated as a procedure to increase engraftment potential, but results are difficult to evaluate due to a lack of markers for assessing the contribution of expanded cells. We transplanted five patients, infusing the best available CB unit and cells from a second donor simultaneously. In two patients, these cells were obtained from another frozen CB unit by CD34(+)positive selection and culture expansion; the other three patients received uncultured highly purified haploidentical CD34(+) cells. The first two patients had DNA from the culture expanded CB cells detected only for a few days around day +11 when the absolute neutrophil count (ANC) was >200/microl; thereafter and when the ANC was <500/microl, only donor DNA from the uncultured CB was detected. For the other three patients, DNA analysis showed early and transient granulocyte engraftment of haploidentical cells, progressively replaced by the CB-derived granulocytes. We concluded that: (1) simultaneous infusion of lymphocyte-depleted HLA highly mismatched haematopoietic progenitor cells has not produced unfavourable effects for CBT; (2) the double transplant model is suitable for evaluating the engraftment potential of ex vivocultured CB cells in the clinical setting; (3) the culture conditions used did not result in early recovery of ANC; and (4) co-transplantation of purified uncultured HLA haploidentical CD34(+) cells may reduce the time of neutropenia following CBT.

Acute Disease↗

Evaluation of engraftment of ex vivo expanded cord blood cells in humans.

Cord blood transplants (CBT) result in high rates of engraftment in patients transplanted because of inherited diseases even across marked HLA disparities, mostly in children, with less severe manifestations of GVHD than BM and PBSC transplants. Evaluation of engraftment potential of CBT based on early progenitor content is difficult due to their inaccurate quantification. Instead, post-thaw nucleated cell counts (Pt-NCC) are commonly used for this purpose. We have analyzed engraftment as a function of pre-freeze nucleated cell counts (Pf-NCC) in patients receiving CBT because of inherited diseases. We have observed median times to engraftment of 26 days or less, shortest times ranging 8 to 13 days, late engraftment or graft failures tending to be associated with age >15 years and infusions of <3.7 x 10(7)/Pf-NCC/kg. These data may be appropriate references to evaluate engraftment of CBT performed with previously ex vivo expanded cells. CBT performed with units of which one aliquot has been previously culture-expanded have resulted in times to engraftment similar to the ones observed in the above-mentioned analysis. In these trials it is not possible to trace the actual origin of the early engrafting cells because the pre-cultured cells lack differentiating markers. To better evaluate the engraftment dynamics of culture-expanded CB cells in humans, we have used a model of simultaneously transplanting cells from two different donors to the same patient. Preliminary results of patients that have simultaneously received one uncultured CB unit and culture-expanded purified CB CD34+ cells obtained from a second one show no significant contribution of cultured cells to early engraftment, and no prohibitive unfavorable immunological problems have been observed.

Adolescent↗

Infusion of lymphocytes obtained from a donor immunised with the paraprotein idiotype as a treatment in a relapsed myeloma.

A 48-year-old patient with IgA k multiple myeloma received a BMT from his HLA-matched sibling. After transplantation, the disease relapsed. Melphalan therapy followed by reinfusion of haemopoietic blood stem cells collected from the patient led to the improvement of the clinical status, although mixed chimerism and an elevated serum IgA persisted. Successful donor immunisation against an immunogenic preparation of the recipient monoclonal protein was performed before the infusion of donor T lymphocytes (DLI) into the patient. Ten weeks after the lymphocyte infusions, no monoclonal band was evidenced and donor complete chimerism was detected. The patient did not develop GVHD. Once complete remission was achieved, the idiotype vaccine was administered to the patient. Nineteen months after DLI, the patient remains in remission. Bone Marrow Transplantation (2000).

Antineoplastic Agents, Alkylating↗

Delayed engraftment of nonobese diabetic/severe combined immunodeficient mice transplanted with ex vivo-expanded human CD34(+) cord blood cells.

The ex vivo expansion of hematopoietic progenitors is a promising approach for accelerating the engraftment of recipients, particularly when cord blood (CB) is used as a source of hematopoietic graft. With the aim of defining the in vivo repopulating properties of ex vivo-expanded CB cells, purified CD34(+) cells were subjected to ex vivo expansion, and equivalent proportions of fresh and ex vivo-expanded samples were transplanted into irradiated nonobese diabetic (NOD)/severe combined immunodeficient (SCID) mice. At periodic intervals after transplantation, femoral bone marrow (BM) samples were obtained from NOD/SCID recipients and the kinetics of engraftment evaluated individually. The transplantation of fresh CD34(+) cells generated a dose-dependent engraftment of recipients, which was evident in all of the posttransplantation times analyzed (15 to 120 days). When compared with fresh CB, samples stimulated for 6 days with interleukin-3 (IL-3)/IL-6/stem cell factor (SCF) contained increased numbers of hematopoietic progenitors (20-fold increase in colony-forming unit granulocyte-macrophage [CFU-GM]). However, a significant impairment in the short-term repopulation of recipients was associated with the transplantation of the ex vivo-expanded versus the fresh CB cells (CD45(+) repopulation in NOD/SCIDs BM: 3. 7% +/- 1.2% v 26.2% +/- 5.9%, respectively, at 20 days posttransplantation; P <.005). An impaired short-term engraftment was also observed in mice transplanted with CB cells incubated with IL-11/SCF/FLT-3 ligand (3.5% +/- 1.7% of CD45(+) cells in femoral BM at 20 days posttransplantation). In contrast to these data, a similar repopulation with the fresh and the ex vivo-expanded cells was observed at later stages posttransplantation. At 120 days, the repopulation of CD45(+) and CD45(+)/CD34(+) cells in the femoral BM of recipients ranged between 67.2% to 81.1% and 8.6% to 12.6%, respectively, and no significant differences of engraftment between recipients transplanted with fresh and the ex vivo-expanded samples were found. The analysis of the engrafted CD45(+) cells showed that both the fresh and the in vitro-incubated samples were capable of lymphomyeloid reconstitution. Our results suggest that although the ex vivo expansion of CB cells preserves the long-term repopulating ability of the sample, an unexpected delay of engraftment is associated with the transplantation of these manipulated cells.

Animals↗

Umbilical cord blood banking for unrelated transplantation: evaluation of cell separation and storage methods.

Cost-efficient umbilical cord blood (UCB) banking requires well-standardized methods of volume reduction and storage. To compare UCB fractionation using a technique of hydroxyethyl starch (HES) sedimentation with the Ficoll (double) and Percoll methods, 50 whole units was allocated randomly to each procedure. HES resulted in a significantly better recovery of mononuclear cells (87.5%), granulocyte/macrophage colony-forming units (CFU-GM) (88.4%), and CD34- cells (87.4%) and lesser volume reduction (85.5%). HES was the least laborious, time consuming, and expensive of the three procedures, costing 3.4- and 4.4-fold less than the Ficoll and Percoll methods, respectively. Five units processed by each method was frozen in 4.5-mL cryotubes under optimal conditions. After thawing, the greatest degree of recovery of viable nucleated cells and number of CFU-GM per unit were obtained using the HES procedure. Using 4.5-mL cryotubes, the calculated number of units that could be stored in 600-L containers was 3.8- and 2.2-fold higher for Ficoll- and Percoll-separated than for HES-separated units, respectively. Nevertheless, the higher direct costs of the density gradient separation procedures outweighed their lower storage cost. For long-term cryopreservation, we assessed the freezing of HES-processed units in 50-mL cryobags and their specifically designed canisters. We found cell recoveries similar to those obtained with cryotubes, but storage capacity was decreased. Special racks designed for these canisters resulted in a 5-fold increase over the number of units stored in standard cryobags. This system also is feasible for Percoll- and Ficoll-separated units, resulting in comparable storage costs for the three separation methods. We conclude that this HES procedure and the 50-mL cryobags constitute a cost-efficient system for large-scale UCB banking.

Blood Preservation↗

[Detection of PNH clones using flow cytometry in aplastic anemia and paroxysmal nocturnal hemoglobinuria].

PURPOSE: To detect and quantify by flow cytometry (FC) PNH clones in paroxysmal nocturnal haemoglobinuria (PNH) and aplastic anaemia (AA) patients. PATIENTS AND METHODS: We have performed a flow cytometric analysis to determine the granulocyte expression of CD55 and CD59 from 29 patients with AA and 11 patients with PNH. RESULTS: In the 11 PNH patients the study showed 58 +/- 34% and 56 +/- 32% (mean +/- SD) CD55(-) y CD59(-) granulocytes. A good correlation was found between the results of FC and haemolysis. The follow-up study showed PNH clone progression in one case and stability in 5 cases. Among 11 AA patients studied at diagnosis, two presented a population of CD55(-) granulocytes (14% and 48%) with CD59 normal, this defect disappeared in both patients after immunosuppressive therapy. The FC study revealed PNH clones in 7 cases among the 26 analyzed after treatment (23 with ATG and/or CyA), in 3 cases with negative Ham's test (in two this became positive 6 and 12 months later). The mean values obtained in these 7 patients with PNH-AA syndrome were 26 +/- 15% y 36 +/- 30% (mean +/- SD) CD55(-) and CD59(-) granulocytes. The median time from diagnosis to detection of PNH phenomenon was 83 months. In the follow-up study, 4 cases had stability, one case had a decrease and one a progression of the abnormal clone. In a retrospective analysis, among the 7 patients with PNH-AA syndrome, 5 had a partial response after the initial treatment. CONCLUSIONS: The FC on granulocytes is a useful method to diagnose and characterize PNH. This test is good for early detection of PNH clones in AA patients at initial diagnosis and in long term survivors. In both diseases it permits measuring the extent of the abnormal clone and its follow up. The extent of the defect is more related to haemolysis than the haematopoietic deficiency. PNH development seems to be more frequent in AA patients with incomplete response after immunosuppressive therapy and in some cases the defect could be latent at the time of diagnosis.

Adult↗

Detection of maternal DNA in umbilical cord blood by polymerase chain reaction amplification of minisatellite sequences.

One of the concerns about the use of cord blood as a source of hematopoietic stem cells for allogeneic transplantation is the possibility of contamination by maternal cells which could cause life-threatening GVHD. We have assessed cord blood contamination using PCR analysis of several minisatellite regions to detect maternal DNA. Eighty mother-cord pairs were obtained for this study. In one case there were no specific maternal alleles at any loci and, therefore, cord blood could not be evaluated. Thus, there was a total of 79 informative cases for the detection of maternal cells in the fetal circulation. In most cases, the level of detection was between 0.5 and 1%. We detected maternal DNA in the cord blood sample in only one case (1.26%), and the analysis of dilution experiments led to an estimate of 0.5-1% maternal cells. In conclusion, using PCR amplification of hypervariable regions, maternal DNA is very rarely detected in the cord blood collected at birth, although this approach has a relatively low level of sensitivity.

Chimera↗

Rhinocerebral mucormycosis following donor leukocyte infusion: successful treatment with liposomal amphotericin B and surgical debridement.

A 24-year-old male developed cytogenetic relapse of chronic myeloid leukemia (CML) four years after allogeneic BMT. After a year of treatment with IFN-alpha, he achieved a partial cytogenetic response. Treatment with donor leukocyte infusions (DLI) was given (total dose 1 x 10(8) T lymphocytes/kg). Two months later, he developed acute GVHD (skin and liver), that improved with CsA and methylprednisolone and resulted in cytogenetic remission with complete donor chimerism. One month later he developed rhinocerebral mucormycosis and was successfully treated with surgical debridement and liposomal amphotericin B (total dose 12 g). This is the first case of mucormycosis described after DLI.

Adult↗

Detection of herpesvirus-like sequences in Kaposi's sarcoma from heart transplant recipients.

BACKGROUND: Herpesvirus-like DNA sequences have been found in lesions from patients with Kaposi's sarcoma in its several forms, suggesting that this tumor may be caused by a new herpesvirus, referred to as Kaposi's sarcoma-associated herpesvirus or human herpesvirus 8. METHODS: We analyzed DNA from skin and lung lesions, healthy skin, and peripheral blood mononuclear cells of three heart transplant recipients with Kaposi's sarcoma. We also studied DNA from normal skin and from peripheral blood of Kaposi's sarcoma-free heart transplant recipients. Samples were analyzed by polymerase chain reaction with specific primers to amplify the KS 330 sequence. RESULTS: The KS 330 fragment was found in Kaposi's sarcoma tissue of all three patients, in normal skin of one of them, and in peripheral blood of two. It was not detected in any of the samples from skin or peripheral blood of heart transplant recipients not affected by Kaposi's sarcoma. DNA extracted from a peripheral blood sample of one patient before transplantation showed that the KS 330 sequence was already detectable at that time. CONCLUSIONS: These findings suggest that Kaposi's sarcoma-associated herpesvirus may play a significant role in the pathogenesis of all forms of Kaposi's sarcoma. The development of the tumor in transplant recipients may be related, at least in some cases, to transplantation-associated immunosuppression, rather than to the acquisition of the virus from the donor.

Female↗

Hemostasis and blood requirements in orthotopic liver transplantation with and without high-dose aprotinin.

BACKGROUND AND OBJECTIVE: Several factors seem to lead to considerable bleeding and transfusion requirements during orthotopic liver transplantation (OLT) and postoperatively, but hyperfibrinolysis appears to be the most important factor. Aprotinin, a broad-spectrum serine protease inhibitor, has been shown to inhibit hyperfibrinolytic states. DESIGN AND METHODS: A non-randomized, controlled clinical trial was performed to assess the efficacy of aprotinin in 20 consecutive OLT procedures (group A). The results obtained were compared with the findings in two groups of patients who did not receive aprotinin: one control group (C1) consisting of the 20 consecutive recipients who underwent OLT immediately prior to group A, and a second control group (C2) consisting of the 30 consecutive recipients undergoing OLT immediately after group A. Twenty-three hemostatic parameters were studied in group A and C1 and the blood product requirements were compared in all three group. RESULTS: We observed a markedly reduced fibrinolysis in group A during the non-hepatic and reperfusion phases demonstrated by reduced tissue-type plasminogen activator (t-PA), alpha 2 antiplasmin-plasmin complex (APP) and D dimer levels and an increase in antiplasmin activity compared to C1 group (p < 0.05). In vitro experiments showed aprotinin to have an antiplasmin effect. The intraoperative transfusion of units of RBC and fresh frozen plasma (FFP) was significantly diminished in group A (8.1 and 16.7 U, respectively) when compared with groups C1 (20.4 and 36.0 U) and C2 (13.0 and 28.0 U) (p < 0.05); there was also a significantly greater number of patients not requiring intraoperative platelet transfusion in group A (p < 0.05). During the first 5 postoperative days, the number of patients in group A who did not require RBC transfusion was significantly larger than in groups C1 and C2 (p = 0.04). INTERPRETATION AND CONCLUSIONS: In this study, the inhibition of fibrinolysis associated with the prophylaxis with aprotinin, administered in high doses by continuous intravenous infusion, appears to reduce the need for blood product transfusion during the OLT procedure.

Adolescent↗

WWW accessible system for national/regional registries of clinical results of cord blood transplants: a tool to facilitate cooperative clinical research.

A system, accessible via internet, has been developed to support the Spanish Registry of Cord Blood Transplants (RETSCU). The system includes a database of clinical results directly accessible by transplant centers (TCs) and cord blood banks (CBBs) (restricted to own cases regarding primary data and unrestricted regarding statistics derived from validated data) and gives open access to Web pages containing results approved for publication. It also includes internal mail for two-way and broadcast messages. Patients' data are essentially those included in Eurocord forms. Additional features of the system are: confidentiality; inalterability of validated primary data; identifiability of data sources. The Unix central computer is accessible via the WWW. For security, data transmission is encrypted and passwords are required for access. Copies are regularly updated. Data can be loaded from CBBs and TCs. The procedure for creating and updating records is user-friendly, with the possibility of errors being minimized by extensive automated checks. Validation of patients' records by a manager is required before making data available for general statistical analysis. TCs and CBBs may retrieve data on their own cases, regardless of validation, as individual records or in tables directly transferable to common statistical programs. Statistical analysis may be done on validated data from all the patients in the Registry or from groups selected according to HLA compatibility and disease, type of transplant (related/unrelated), or protocol. Several similarly designed and managed national/regional Registries might be networked and their data integrated into a multinational Registry. Our system would require some additional developments to be used in this way.

Hematopoietic Stem Cell Transplantation↗