A simple technique for red blood cell removal in major ABO-incompatible bone marrow transplantation

Human Leucocyte Antigen Sensitisation and Its Impact on Transfusion Practice

Human leucocyte antigen (HLA) sensitisation, including the formation of antibodies against HLA, can cause serious effects in patients receiving blood. Under certain circumstances, donor HLA antibodies in the blood product can trigger the patient's granulocytes to release mediators that cause transfusion-associated lung injury (TRALI), a serious complication of transfusion. The HLA systems of both donor and patient are involved in transfusion-associated graft-versus-host disease, which is a rare disease with a high mortality. Patient HLA antibodies can destroy incompatible platelets and may cause refractoriness to platelet transfusion. Identification of a patient's HLA antibody specificities is necessary for issuing compatible platelets to overcome refractoriness. Many techniques for the detection and identification of HLA antibodies have been developed, including complement-dependent cytotoxicity assay, bead-based assays, the platelet adhesion immunofluorescence test, and the monoclonal antibody-specific immobilisation of platelet antigens assay. Different strategies for the selection of HLA-compatible platelets are applied. These strategies depend on the breadth of antibody reactivity and range from avoiding single HLA antigens in the platelet concentrates issued to apheresis of platelets from HLA-identical donors. The mechanisms of HLA sensitisation and the efforts made to provide compatible blood products to sensitised patients are reviewed in this article from the perspective of clinical transfusion medicine.

Is hydroxyethyl starch necessary for sedimentation of bone marrow?

Hydroxyethyl starch (HES) is used to separate hematopoietic progenitor cells after bone marrow (BM) collection from red blood cells. The aims were to study alternatives for HAES-steril (200 kDa; not available anymore) and to optimize the sedimentation process. Using WBC-enriched product (10 × 10(9) WBC/L), instead of BM, sedimentation at 10% hematocrit using final 0.6 or 0.39% Voluven (130 kDa) or without HES appeared to be good alternatives for 0.6% HAES-steril. MNC recovery >80% and RBC depletion >90% was reached. Optimal sedimentation was reached using 110-140 mL volume. Centrifugation appeared not suitable for sedimentation. Additional testing with BM might be necessary to confirm these results.

Risk factors for moderate-to-severe acute graft-vs.-host disease after allogeneic stem cell transplantation in children

Severe acute graft-vs.-host disease (aGVHD) remains a major cause of transplantation-related mortality. However, because of a graft-vs.-leukaemia effect, a mild (grade I) aGVHD is desirable. As risk factors predisposing for aGVHD are not necessarily the same in children and adults, we have performed a retrospective analysis of risk factors (RFs) for grade II-IV aGVHD in 258 paediatric patients undergoing allogeneic stem cell transplantation at our centre. Thirty-two potential RFs were assessed with univariate analysis in logistic regression. Eleven factors were selected for further evaluation in stepwise elimination multivariate analysis. Three independent RFs were found: (1) donor other than human lekocyte antigen (HLA)-identical sibling [odds ratio (OR) 6.1, p < 0.001); (2) single drug [cyclosporine A (CsA) or methotrexate (Mtx)] graft-vs.-host disease (GVHD) prophylaxis (OR 7.0, p < 0.001); and (3) ABO disparity of any kind (OR 2.4, p = 0.02). The RFs were additive: moderate-to-severe aGVHD was seen in none of the patients without any RFs; in 16% with one RF; in 32% with two RFs and in 67% with all three RFs present. Single drug GVHD prophylaxis (CsA or Mtx), any kind of ABO mismatch, and non-sibling donors are RFs for grade II-IV acute GVHD in paediatric SCT. We encourage the use of combination GVHD prophylaxis in children. ABO mismatch should be considered when choosing between otherwise equally suitable donors.

Regeneration of erythropoiesis after related- and unrelated-donor BMT or peripheral blood HPC transplantation: a major ABO mismatch means problems

BACKGROUND

Blood group incompatibility in allogeneic BMT is common but does not appear to affect the outcome in terms of incidence of graft rejection or delayed engraftment. However, major ABO incompatibility may be associated with prolonged erythroid aplasia.

STUDY DESIGN AND METHODS

In a retrospective analysis of 286 allogeneic transplant recipients, the prevalence of prolonged erythroid aplasia, including pure RBC aplasia, was determined.

RESULTS

Patients receiving major ABO-incompatible grafts showed a significant delay in reticulocyte engraftment (median, 32 days; range, 12-347) from that in patients receiving ABO-identical (20; 10-152) or minor ABO-incompatible (21; 12-47) grafts. Pure RBC aplasia occurred in 7 (3%) of 240 evaluable recipients and was observed only in the major ABO-incompatible group (7/43, 16%). Treatment of pure RBC aplasia consisted of either plasma exchange, which resulted in a response within 16 to 68 days, or immunoadsorption, in which the response occurred between Days 119 and 204 after initiation of treatment.

CONCLUSION

Major ABO incompatibility may lead to delayed reticulocyte engraftment, resulting in prolonged transfusion dependency and increased risks of transmission of infection and iron overload. Therefore, therapeutic strategies should be taken into consideration to allow erythroid reconstitution in these patients.