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.