Platelet- and granulocyte-specific antibodies after allogeneic and autologous bone marrow grafts

Selective thrombocytopenia and neutropenia occurring after bone marrow transplantation--evidence of an auto-immune basis

This study shows that hitherto unexplained thrombocytopenia and neutropenia occurring after bone marrow allografting and autografting may have an immune basis. In the case of autografts, such antibodies are, by definition, auto-antibodies, and it is suggested that similar antibodies occurring after allografting are also auto-immune.

The influence of human platelet antigen match on the success of allogeneic peripheral blood progenitor cell transplantation following a reduced-intensity conditioning regimen

BACKGROUND

Allogeneic transplantation in elderly patients requires a dose-reduced conditioning regimen. Owing to reduced-intensity conditioning, host- and donor-type immune responses may affect the early posttransplant period, whereas only later on donor-derived reactions may ensue. Mismatches in the HLA system are known to be detrimental for the outcome of transplantation. Mismatches between donor and recipient for human platelet antigens (HPAs) may also affect the success of transplantation owing to serving as minor histocompatibility antigens and therefore rendering recipients at risk for graft-versus-host disease (GVHD) or graft rejection and inhibition of thrombopoiesis attributed to platelet (PLT) antibodies.

PATIENTS AND METHODS

Therefore, the occurrence of GVHD, incidence of relapse, need of PLT support, and outcome by analysis of 45 donor-recipient pairs for HPA-1, -2, -3, and -5 allotypes and screening for PLT antibodies were evaluated before transplantation and again 1 year thereafter.

RESULTS

Mismatches within the HPA system were not associated with an increased occurrence of transplant-related mortality or GVHD, the onset of thrombopoiesis, the frequency of PLT transfusions, or the incidence of relapse. Neither were settings of homozygous donors versus heterozygous recipients (graft-vs.-host direction) nor homozygous recipients versus heterozygous donors (host-vs.-graft direction) associated with any adverse effects on the outcome of the transplantation.

CONCLUSION

Thus, the HPA match does not affect the outcome of transplantation after reduced-intensity conditioning.

Influence of human platelet antigen match on the success of stem cell transplantation after myeloablative conditioning

Mismatches between donor and recipient for human platelet antigens (HPA) may affect the success of transplantation due to: (a) serving as minor histocompa-tibility antigens and therefore render recipients at risk for graft-versus-host disease (GvHD), (b) inhibition of thrombopoiesis due to platelet antibodies. We therefore evaluated the occurrence of GvHD and need of platelet support by prospective analysis of donor-recipient pairs (n=53) for HPA-1, -2, -3, and -5 allotypes and screening for platelet antibodies prior to transplantation and in weekly intervals until day 100 after transplantation. Neither the incidence of GvHD nor the onset of thrombopoiesis, nor the CCI after platelet transfusions, nor the frequency of platelet transfusions was affected by HPA mismatches. Settings of homozygous donors vs heterozygous recipients or homozygous recipients vs heterozygous donors were not associated with any adverse effects on the outcome of the transplantation. Thus, the HPA-match does not affect the success of transplantation.

Autoimmune thrombocytopenic purpura after autologous stem cell transplantation

The pathogenesis of thrombocytopenia occurring after autologous stem cell transplantation (ASCT) remains unclear. Six cases of classical peripheral thrombocytopenia that developed after ASCT for non-Hodgkin's lymphoma (NHL) are presented. Resolution of this complication was obtained by usual treatment such as steroids, splenectomy or progressively resolved without specific treatment. Five out of six patients have been followed for more than 5 years after hematopoietic transplantation and are still alive in complete remission despite poor prognostic factors at diagnosis. Several arguments suggest that this phenomenon represents autoimmune thrombocytopenia and may be the consequence of an altered immune balance. Consequently, development of autoimmune reactions after bone marrow transplantation might be associated with an antitumoral effect (graft-versus-lymphoma effect).

CD41+ and CD42+ hematopoietic progenitor cells may predict platelet engraftment after allogeneic peripheral blood stem cell transplantation

The objective of this study was to quantify subpopulations of CD34+ cells such as CD41+ and CD42+ cells that might represent megakaryocyte (MK) precursors in peripheral blood stem cell (PBSC) collections of normal, recombinant human granulocyte-colony stimulating factor (rhG-CSF) primed donors and to determine whether there is a statistical association between the dose infused megakaryocytic precursors and the time course of the platelet recovery following an allogeneic PBSC transplantation. Twenty-six patients with various hematologic malignancies transplanted from their HLA identical siblings between July 1997 and December 1999 were used. All patients except one with severe aplastic anemia who had cyclophosphamide (CY) alone received busulfan-CY as preparative regimen and cyclosporine-methotrexate for GVHD prophylaxis. Normal healthy donors were given rhG-CSF 10 microg/kg/day subcutaneously twice daily and PBSCs were collected on days 5 and 6. The median number of infused CD34+, CD41+ and CD42+ cells were 6.61 x 10(6)/kg (range 1.47-21.41), 54.85 x 10(4)/kg (5.38-204.19), and 49.86 x 10(4)/kg (6.82-430.10), respectively. Median days of ANC 0.5 x 10(9)/L and platelet 20 x 10(9)/L were 11.5 (range 9-15) and 13 (8-33), respectively. In this study, the number of CD41+ and CD42+ cells infused much better correlated than the number of CD34+ cells infused with the time to platelet recovery of 20 x 10(9)/L in 26 patients receiving an allogeneic match sibling PBSC transplantation (r = -0.727 and P < 0.001 for CD41+ cells, r = -0.806 and P < 0.001 for CD42+ cells, r = -0.336 and P > 0.05 for CD34+ cells). There was an inverse correlation between the number of infused CD41+ and CD42+ cells and duration of platelet engraftment. Therefore, as the number of CD41+ and CD42+ cells increased, duration of platelet engraftment (time to reach platelet count of > or = 20 x 10(9)/L) shortened significantly. Based on this data we may conclude that flow cytometric measurement of CD41+ and CD42+ progenitor cells may provide an accurate indication of platelet reconstitutive capacity of the allogeneic PBSC transplant.

Identification of megakaryocyte precursors in peripheral blood stem cell collections from normal donors

Platelet engraftment, the time course and magnitude of platelet recovery (PR) post-transplant, is imprecisely defined but is most often reported as the time to transfusion (tx) independence and/or a platelet count > or = 20,000/microl. While correlations between engraftment time for granulocytes (PMN) and the dose of CD34-positive cells per kilogram are established, such associations have not been established for platelet engraftment. The objective of this study was to quantify subpopulations of CD34-positive cells in peripheral blood stem cell (PBSC) collections of normal, colony-stimulating factor-granulocyte) (G-CSF) primed donors that might represent megakaryocyte (MK) precursors, and to determine whether there is a statistical association between the dose transfused and the time course of the recovery. Based on previously published data of the sequential expression of CD34, HLA-DR, and CD61, among others, during MK maturation, a combination of corresponding antibodies for the detection of various antigen coexpressions by flow cytometry fluorescence-activated cell sorting [FACS] was chosen. CD34-positive cells were further subdivided into CD34++ (bright) and + (dim). Ploidy of density-gradient separated cells was examined in subsequent donor samples by FACS. For the entire group of patients, there was no strong correlation between any of the studied subpopulations and time to PR. Only in a selected groups of patients whose platelet counts showed a sustained increase during the first 6 days after engraftment, there was a weak correlation between the time to PR and the quantity of CD34+/+CD61+ (r = -0.57) and CD34++HLA-DR-CD61+ (r = -0.62) cells infused. The magnitude of platelet production in these pt., a product of the peripheral blood platelet count and the patient's blood volume, was correlated with the time to PR (r = -0.73). We conclude from this study that subpopulations within CD34+ cells are making some contribution to PR in allogeneic peripheral blood stem cell transplantation, but the correlations are not sufficiently strong because there are probably too many unpredictable and unknown variables in the allogeneic setting that influence the pattern of engraftment.

Successful matched unrelated transplantation from a donor with idiopathic thrombocytopenic purpura (ITP)

The case of a 5 year old male is described who had acute myeloblastic leukaemia (AML M5) and was in third remission when he underwent an allogeneic T cell depleted bone marrow transplantation (BMT). The bone marrow was from an HLA matched unrelated donor (MUD) who suffered from chronic idiopathic thrombocytopenic purpura (ITP). In spite of this, the patient had rapid platelet engraftment post BMT (> 50 x 10(9) l-1 on day 20). He is now 12 months post-transplantation and has normal platelet counts, without any clinical or laboratory evidence of ITP. Autoimmune manifestations such as ITP occurring in bone marrow recipients following BMT have been previously reported. Furthermore, severe and protracted thrombocytopenia is a known complication following MUD transplantation and with its respective high risk of graft versus host disease (GVHD). In this case, no signs of ITP could be detected in the recipient despite the fact that the donor had ITP. Our data suggest that in the absence of an alternative choice, a person with ITP should be considered as an appropriate donor for transplantation.

Collection and use of stem cells; role of transfusion centers in bone marrow transplantation

Marrow transplantation is increasing, hematopoietic stem cells are being obtained from a wider variety of donors, and the cells almost always undergo some processing steps. These activities, along with the hematologic complexities of marrow transplant patients, create many varied opportunities for blood centers.

Relative importance of immune and non-immune causes of platelet refractoriness

In this prospective study, 26 consecutive patients being treated for haematological malignancies receiving standard (i.e. non-leucocyte-depleted) blood components were observed for the development of refractoriness to platelet transfusions. One hundred and sixteen of the 266 (44%) platelet transfusions failed to produce a satisfactory response. In 102/116 (88%), the poor response was in the presence of non-immune factors known to be associated with platelet refractoriness. Non-immune factors were present alone in 78/116 (67%), and in combination with immune factors in a further 24/116 (21%). Immune factors (HLA and platelet-specific antibodies) were present during 29/116 (25%) of unsuccessful platelet transfusions. Statistical analysis confirmed that platelet refractoriness was significantly associated with the presence of non-immune factors. The non-immune factors associated with refractoriness were often multiple, most frequently a combination of fever, infection and antibiotic therapy. This study provides evidence that immune mechanisms were not the predominant cause of platelet refractoriness in the patient population studied. It also suggests that measures for the prevention of HLA alloimmunisation, such as leucocyte depletion, may have a limited impact in reducing the incidence of refractoriness to platelet transfusions.

Prospective evaluation of the chemiluminescence test for the detection of granulocyte antibodies: comparison with the granulocyte immunofluorescence test

A series of 213 neutropenic patients were tested for the presence of granulocyte antibodies using the granulocyte chemiluminescence test (GCLT) and the granulocyte immunofluorescence test (GIFT). Sera containing lymphocyte (HLA) antibodies were excluded from the study. A direct GIFT was performed on granulocytes from 56 patients. Samples were obtained from patients with a range of clinical conditions including primary adult autoimmune neutropenia, autoimmune neutropenia of infancy, autoimmune neutropenia secondary to Felty's syndrome, rheumatoid arthritis, idiopathic thrombocytopenic purpura, systemic lupus erythematosus, proliferative disorders, bone marrow transplantation and patients with documented febrile or pulmonary transfusion reactions. Overall, granulocyte antibodies were detected in 52.1% of patient sera. Results for the GCLT and GIFT (IgG) were strongly correlated (p < 0.001) for both primary and secondary immune neutropenias. The results confirm the applicability of the GCLT in the granulocyte serology laboratory.

Antibody-mediated neutropenia following bone marrow transplantation

Unexpected neutropenia following allogeneic or autologous bone marrow transplantation may be caused by graft rejection, intrinsic stem cell failure, infection, graft-versus-host disease, relapse of the underlying neoplasm, or drug-induced myelosuppression. Over the past decade an increasing number of reports have documented that the differential diagnosis also includes antibody-mediated neutropenia, a syndrome distinct from conventional graft rejection. In contrast to many of the other common causes of unexpected post-transplant neutropenia, antibody-mediated neutropenia usually responds well to treatment with corticosteroids, plasma exchange, intravenous immunoglobulin, splenectomy, or other similar measures.

Serological screening, using three different test systems of platelet-transfused patients with hematologic-oncologic disorders

Sera of hematologic-oncologic patients were tested regularly after platelet transfusions in three test systems: lymphocytotoxicity test, platelet adhesion immunofluorescence test, and--only selected sera--in the monoclonal antibody-specific immobilization of platelet antigen test. Of 388 patients 53 (14%) had HLA antibodies 5 of these in combination with platelet-specific alloantibodies. Lymphocyte-restricted (non-HLA) reactions were observed in 20 patients, the majority of which was attributed to lymphocyte-specific auto- or alloantibodies. Sera of 27 patients showed platelet-specific reactions, usually cold-reacting autoantibodies which have no effect in vivo.

Factors influencing haematological recovery in 53 patients with acute myeloid leukaemia in first remission after autologous bone marrow transplantation

The kinetics of haematological recovery were retrospectively analysed in 53 patients with acute myeloid leukaemia in first remission after myeloablative chemoradiotherapy followed by autologous bone marrow transplantation. The median time to achieve a neutrophil count of 1 x 10(9)/l was 46 d (22-196 d) and median time to achieve unsupported platelet counts of 20 x 10(9)/l and 50 x 10(9)/l was 70 d (24-310 d) and 126 d (29-497 d) respectively. Multivariate analysis revealed two factors that were significantly associated with delayed neutrophil and platelet recovery: (1) use of high dose fractionated TBI and mononuclear cell cryopreservation, and (2) low platelet count at the time of bone marrow harvest. There was no correlation with: number of courses of chemotherapy, remission to ABMT interval, CMV status, indices of autograft quality or the development of elevated platelet associated immunoglobulin. Delayed haematological recovery did not predict for relapse or death. Delayed platelet recovery did, however, present significant problems with increased blood and platelet requirements and lengthening of hospital stay.

Late onset immune pancytopenia following bone marrow transplantation

A 17-year-old boy developed autoimmune pancytopenia in the absence of chronic graft-versus-host disease 170 d after allogeneic bone marrow transplantation (BMT) from his HLA identical brother. The anaemia and thrombocytopenia responded to conventional immunosuppressive treatment, but the neutropenia was refractory to this and to splenectomy and subsequent removal of splenic remnant. Following total lymphoid irradiation the neutrophil count rose to low normal levels but thrombocytopenia and anaemia secondary to marrow hypoplasia required transfusion support. Bone marrow function was finally normalized by an additional transfusion of donor marrow without prior immunosuppressive therapy. We conclude that late onset immune pancytopenia post BMT caused by antibodies of probable donor origin may be life threatening in the absence of chronic graft-versus-host disease.

Alloimmunization to RhD by platelet transfusions in autologous bone marrow transplant recipients

Platelet transfusions from RhD-positive (D-positive) donors are often given to RhD-negative (D-negative) cancer patients. The low observed rate of alloimmunization has been attributed to disease and therapy-related immunosuppression. We have studied the occurrence of alloimmunization in 16 D-negative patients who did not have detectable anti-D prior to autologous bone marrow transplantation for malignant disease. All received D-positive platelets, but no other D-positive blood product. Three patients (19%) developed anti-D at 13, 24 and 83 days, respectively, after first receiving D-positive platelets, and after a total dose of 53, 65 and 119 D-positive platelet unit equivalents, respectively. Two of them also developed anti-C. The 13 patients in whom anti-D was not detected were also heavily transfused with D-positive platelets (mean +/- SD = 136 +/- 82 platelet unit equivalents). In 6 of them, the last recorded antibody screen was less than 3 months after the first D-positive platelets, and may not exclude a primary immune response. Thus, despite profound immunosuppression associated with autologous marrow transplantation, alloimmune responses to D-positive red cells in platelet concentrates can occur in some D-negative recipients.

Identification of the target platelet glycoprotein in autoimmune thrombocytopenia occurring after allogeneic bone marrow transplantation

We report the case of a patient who developed autoimmune thrombocytopenia after allogeneic bone marrow transplantation from her HLA-identical sister. An IgG autoantibody was detected that bound to the platelet glycoprotein IIb/IIIa and to the HLA class I proteins. Immunoprecipitation studies with radiolabeled platelets revealed additional antibody binding sites on proteins of 214 kDa molecular weight under nonreduced conditions and 65 and 56 kDa molecular weight under reduced conditions.

Immune thrombocytopenia more than a year after allogeneic marrow transplantation due to antibodies against donor platelets with anti-PlA1 specificity: evidence for a host-derived immune reaction

We report on a male patient transplanted from his HLA-matched sister for Ph1-chromosome positive chronic myelogenous leukaemia who developed immune thrombocytopenia more than 1 year after transplantation. The platelet antibody reacted with the platelet specific antigen PlA1 on donor platelets, and also on recipient platelets after engraftment. A presumed host-versus-donor induced thrombocytopenia was supported by Southern blot analysis using a Y-chromosome specific probe demonstrating residual host-origin cells in the patient's excised spleen.

'Auto'-immune neutropenia after allogeneic bone marrow transplantation unresponsive to conventional immunosuppression but resolving promptly after splenectomy

A 32-year-old male presented with isolated neutropenia 6 months after allogeneic bone marrow transplantation for CML from his HLA-matched brother. The presence of granulocyte-specific IgM and IgG antibodies in the patient's serum indicated an immune-mediated basis for the neutropenia. A variety of manoeuvres to suppress antibody production or to reduce peripheral destruction, including high-dose intravenous immunoglobulins 400 mg/kg (total 24 g) on 5 consecutive days, prednisolone 80 mg for 10 d and plasmapheresis on 3 consecutive d, failed to raise the neutrophil count. Splenectomy, however, resulted in a prompt and sustained rise of neutrophils to normal values.

Transfusion and bone marrow transplantation

Bone marrow transplantation has prolonged the lives of a significant percentage of patients with a variety of both malignant and nonmalignant disorders. However, the impact of this treatment on a transfusion service is substantial. Large numbers of often specialized blood products are required to support these patients, and the logistics of accomplishing this taxes the ingenuity and resources of even large regional blood programs.

Incidence and mechanism of neutropenia and thrombocytopenia in patients with human immunodeficiency virus infection

The incidence of lymphopenia, thrombocytopenia and neutropenia was studied in 105 homosexual men with HIV infection. Lymphopenia was common in patients with AIDS (75%), but its incidence in PGL (24%) was not significantly different from that in asymptomatic anti-HIV positive (15%) homosexual men. Neutropenia and thrombocytopenia were found in patients with AIDS or PGL, but not in asymptomatic anti-HIV positive homosexuals. The study suggests that the neutropenia and thrombocytopenia in these patients were due to autoimmune destruction of neutrophils and platelets.

Autologous bone marrow transplantation following high dose chemotherapy for the treatment of adult patients with acute myeloid leukaemia

24 adult patients with acute myeloid leukaemia (AML) were treated with intensive chemotherapy followed by autologous marrow rescue. The procedure was repeated twice in eight patients. 11 of 16 patients treated in first remission continue in first unmaintained remission (9-54 months, median 17 months). Eight patients treated at relapse or second remission have relapsed again and died within 14 months of their first autologous bone marrow transplant (ABMT). This form of intensification therapy would appear valuable for adult AML patients in first remission.

Autoimmune thrombocytopenia and neutropenia after remission induction therapy for acute leukaemia

Patients with acute leukaemia who are exposed to intensive chemotherapy, with or without radiotherapy, may remain thrombocytopenic or neutropenic in remission. The incidence of these prolonged cytopenias was examined retrospectively in 46 patients in remission and prospectively in 14 patients. The patients were tested for the presence of autoantibodies to platelets and neutrophils using a fluorescent antihuman globulin technique with paraformaldehyde-fixed cells. In the retrospective study nine patients (20%) had neutrophil autoantibodies and seven (15%) had platelet autoantibodies; only one of the former had neutropenia and one of the latter thrombocytopenia. In the prospective study three (21%) had neutrophil autoantibodies and seven (50%) had platelet autoantibodies. One of the patients with platelet autoantibodies had transient thrombocytopenia, and shortened platelet survival was demonstrated. None of the patients with neutrophil autoantibodies had neutropenia. The rare occurrence of cytopenias in association with these autoantibodies was possibly due to bone marrow compensation for antibody-mediated cell destruction, although other possible mechanisms are discussed.

Acquired autoimmune thrombocytopenia after allogeneic bone marrow transplantation

A 29-year-old man in remission from acute myeloblastic leukaemia was treated by chemoradiotherapy and transplantation of bone marrow (BMT) collected from his HLA identical brother. Engraftment was documented on D12. Transient acute GVHD (grade II) appeared from D34. No infection complicated the BMT. Nevertheless severe thrombocytopenia persisted and was unresponsive to marrow donor platelet transfusion. The platelet immunofluorescence test demonstrated the autoimmune basis of the thrombocytopenia. This study suggests that the transient immune imbalance observed in the early post graft period could facilitate the appearance of autoimmune cytopenias.