REFRACTORINESS TO DONOR PLATELETS TRANSFUSION IN PATIENTS WITH APLASTIC ANEMIA AND HEMOBLASTOSIS

Refractoriness to transfusions of platelet concentrates (PC) adversely affects the conduct of complex therapy in hematological patients. Individual selection of platelets is recommended for such patients. In cases of high degree of alloimmunization with the formation of polyspecific antibodies, when individual selection is difficult, procedures plasmapheresis (PPs) is included in the treatment program.Aims: to evaluate the effectiveness of PC transfusions by individual selection in patients refractory to transfusions and the use of PPs as a second line therapy in combination with individual platelet selection.Materials and methods: from September 2015 to December 2017, 91 patients with refractory to PC transfusions from 1263 patients who received PC transfusion were observed in the center’s clinics. The median age was 43 (18–71) years. M/F – 38/53. Patients: 20 – aplastic anemia (AA), 17 – myelodysplastic syndrome (MDS), 45 – acute myeloid leukemia (AML), 9 – acute lymphoblastic leukemia (ALL). All patients underwent PC transfusion by individual selection (HLA/HPA) Immucor’s Capture-P solid phase technology. In 28 (30 %) of 91 patients, due to the inability to select, there was a need for PP as a second line therapy. Patients: AA – 4 (20 %); MDS – 8 (47 %); AML – 12 (26 %); ALL– 4 (44 %). The median age was 48 (23–71) years. M/F – 8/20. From 2 to 15 procedures were performed (on average – 6) for each patient. All patients received PC transfusions by individual selection by cross-matching immediately after the PP procedure. The efficacy of PC transfusions was assessed by Absolute Platelet Increment (API) and Corrected Count Increment (CCI), relief of hemorrhagic syndrome.Results: in 26 of 28 refractory to PC transfusions patients, in the absence of compatible donor platelets, carrying out PPs in combination with subsequent individual platelet selection promoted relief of hemorrhagic syndrome, increase in API from 3.3 × 109/L at 29.5 × 109/L and CCI from 1.3 to 10.7. Against the background of PPs, combined with individual selection, the degree of alloimmunization (the percentage of incompatible pairs) decreased on average: AA (n = 4) – from 91.7 to 50.2 %; MDS (n = 8) – from 89.6 to 31.6 %; AML (n = 12) – 86.0 to 40.5 % and ALL (n = 4) – from 91.7 to 37.7 %. In 2 patients with a high degree of alloimmunization and after carrying out PPs, it was not possible to select compatible platelets, PC transfusions were ineffective (API = 5 × 109/L, CCI = 1), and hemorrhagic syndrome was not completely managed, but its severity was reduced.Conclusions. With the development of refractoriness to PC transfusions and the ineffectiveness of individual platelet selection, PPs should be used as the second line of therapy, which, combined with individual selection, increases the likelihood of compatible donor-recipient pairs and increases the clinical efficacy of PC transfusions. When PPs is ineffective in combination with individual selection, it is necessary to exclude the syndrome of increased consumption and other mechanisms of refractoriness

Detection of platelet-associated immunoglobulins and complement system components in patients with aplastic anemia and hemoblastosis

Background. In addition to anti-HLA-I and anti-HPA-antibodies and specific cytotoxic T-lymphocytes, another cause of immune refractoriness to donor's platelet transfusions could be a platelet-associated different classes immunoglobulins PAIg (G, M, A) and C3 / C4‑components of complement system (PAC3, PAC4). These markers can be detected by flow cytofluorometry of double-stained platelets. The fixation density of immunoglobulins and components of complement systems were measured by the mean fluorescence intensity (MFI).Objective: to study additional factors that aggravate the course of refractoriness to donor's platelet transfusions in patients with aplastic anemia (AA) and hemoblastosis.Materials and methods. 77 patients (AA – 47, myelodysplastic syndrome (MDS) – 10, acute myeloid leukemia (AML) – 20) admitted to National Research Centre for Hematology during 11.09.2016–04.28.2018 were enrolled in the study. M / f ratio was 33 / 44, median age was 36 yrs. (19–71 yrs.). Plasmapheresis and cross-matching for PRP selection were used for patients with refractoriness to donor's platelet transfusion. PAIg (G, M, A) and PAC3 / C4 detection and density (MFI) were evaluated in all patients by flow cytofluorometry of doublestained platelets (CD41a-PE; IgA, M, G-FITC; C3 / C4‑FITC) and MFI measurement. Patients with AA were investigated on different stages of therapy and if refractoriness to donor's platelet transfusion is developed. Blood donors (n = 28) MFI measurement results were established as negative control.Results. It was found that MFI PAIgG/M/А and PAC3/С4 was higher in all groups of the patients (АА, MDS, AML), as compared with donors. MFI of PAIgM and PAIgA in patients were significant higher than MFI of PAIgG and PAC3 / C4. Combination of PAIgM / A, PAIgM / C3 / C4 and PAIgA / C3 / C4 were more frequent. Multiple transfusions of PRP were associated with PAIgA and PAC3 detection. Development of refractoriness to donor's platelet transfusions was accompanied by alloantibodies (HLA-I, HPA) and PAIgM, PAC4 detection. In patients of AA group during development of refractoriness to donor's platelet transfusions and multiple infection complications the high density of PAIgM and PAIgA were identified. Relapse of AA was accompanied MFI of PAC3 density increment.Conclusion. In addition to application of a certain transfusion therapy algorithm it is also necessary to detect PAIg (G, M, A) and PAC3 / C4 for prediction of severe refractoriness to donor's platelet transfusions