Effect of HLA Bw4/Bw6 compatibility on platelet transfusion responses of refractory thrombocytopenic patients

Abstract

Platelet transfusions from donors matched for cross-reactive antigens have been shown to be effective in providing hemostasis in alloimmunized thrombocytopenic patients. A significant number of these transfusions, however, fail to provide posttransfusion platelet recoveries. We investigated incompatibility in the Bw4/bw6 system as a possible explanation for these failures. The Bw4/Bw6 system is a biallelic antigen system closely associated with HLA-B. HLA-B locus antigens that are cross-reactive frequently differ in their Bw4/Bw6 specificity. Posttransfusion platelet recoveries from 21 alloimmunized thrombocytopenic patients homozygous for Bw4 or Bw6 and transfused with both Bw4/Bw6 compatible and incompatible platelets were analyzed. The mean 1-hr posttransfusion recovery was 84% following Bw4/Bw6-compatible platelets versus 52% with Bw4/Bw6-incompatible platelets (p less than 0.02). Twenty-four hours following transfusion, mean recoveries were 44% and 24%, respectively, (p less than 0.01). A subgroup of 8 patients (38%) was identified who had markedly lower responses following Bw4/Bw6- incompatible transfusions as compared to Bw4/Bw6-compatible transfusions (mean recoveries: 1 hr--compatible 100%, incompatible 27%, p less than 0.001; 24 hr--compatible 45%, incompatible 7%, p less than 0.01). These data suggest that the Bw4/Bw6 antigen system has clinical significance for some patients requiring platelet transfusion therapy and, when appropriate, should be considered in the selection of donors.

Efficacy of HLA‐matched platelet transfusions for patients with hypoproliferative thrombocytopenia: a systematic review

“…24,26 Fifteen studies were prospective 13,16,[24][25][26][27][28][29][30][31][32][33][34]45,46 and 14 were retrospective. 12,17,22,[35][36][37][38][39][40][41][42][43][44]47 Twenty-one of the nonrandomized studies focused on patients with refractory thrombocytopenia, 12 Two full text articles identified by authors n = 2…”

“…25,28 Nineteen studies indicated single-donor PLTs were used. 12,13,16,24,[26][27][28][30][31][32][33][34]37,38,40,41,[43][44][45] The assessment of study quality is displayed in Table S3 (available as supporting information in the online version of this paper). Nine of the 29 studies did not specify the source of sample of patients, that is, how patients were recruited.…”

“…Nine of the 29 studies did not specify the source of sample of patients, that is, how patients were recruited. 22,24,25,29,35,36,38,42,43 Eleven studies detailed sampling methods, 12,16,17,26,27,37,38,40,41,46,47 and one indicated that a random sample was selected but a clear definition of randomization was not provided. 25 The sample size was not predetermined in any study and the assessment of the outcomes was not blinded.…”

“…Fifteen studies clearly defined the eligibility criteria for inclusion of patients, 13,16,17,[26][27][28][29]35,[37][38][39]41,[45][46][47] and most provided clear definitions of outcome. 12,13,16,17,22,[24][25][26][27][28][29][31][32][33][34][35][36][37]39,[41][42][43][44][45][46] Three studies had acceptable control group and comparable characteristics, 16,28,35 five studies 17,22,29,35,47 described details of quality measures for the collection of data and laboratory tests (e.g., accuracy, reproducibility, calibration), and six analyzed confounding factors that potentially influenced the outcomes.…”

“…B3-B4 (p < 0.001), vs. C (p < 0.001), vs. D (p < 0.0001) Median B1-B2 vs. B3-B4 (p < 0.05), vs. D (p < 0.02) The effect of HLA seen only when LCT > 20%, clinical factors more important than HLA for 1-hr recovery and vice versa for 24-hr recovery by regression analysis Heal, 1987 38 CCI Ն 7.5 ¥ 10 9 /L 33% for CXM+, 57% for CXM-(p < 0.01), A/BU 74%, BX 62%, C 51%, p = 0.03 for A/BU vs. C CXM most significant predictor of CCI vs. HLA and ABO, p = 0.002, HLA > ABO, p = 0.02 Klingemann, 1987 39 5/71 (7%) refractory patients did not respond to HLA-matched PLTs Levy, 1984 40 Mean increment 33.0 ¥ 10 9 /L with HLA-matched PLTs McElligott, 1982 41 1-hr recovery for HLA Bw4/Bw6 compatible 84% vs. incompatible 52%, p < 0.02 24-hr recovery for compatible 44% vs. incompatible 24%, p < 0.01 Daly, 1980 42 For refractory patients (CCI < 10.0 ¥ 10 9 /L at 1 hr) CCI at 1 hr were 15.0 ¥ 10 9 /L with HLA-matched vs. 3.0 ¥ 10 9 /L with RDP (p < 0.001), For refractory patients (CCI<10.0 ¥ 109/L at 1 hr) CCI at 18 hr were 9.0 ¥ 10 9 /L with HLA matched vs.…”