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.

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The long axis of epidermal cambial cells determining the direction of their division is determined before the beginning of division and is oriented perpendicularly, but not parallel, to the basal membrane, as in other basal cells. As a result, only one of the two newly formed cells adheres to the basal membrane and at the expense of traction forces detaching one cell from the other and elastic force of the basal membrane is formed as a maternal cell and stays in the focus of multiplication. The other cell, turning around under the effect of traction forces perpendicularly to the maternal cell, cardinally changes the direction of its long axis and is polarized parallel to the basal membrane like other cells. This cell becomes the daughter cell, its shape with the "head" and "tail" allows its rapid migration into other rosettes for differentiation.

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