HLA class II Ab in TRALI donors

TRALI (Transfusion Related Acute Lung Injury) occurs in 11–16 patients and is associated with 3–4 deaths per year in the UK. It is caused by HLA (e.g. anti-HLA-A2), neutrophil (e.g. anti-NA2) and leucocyte-panreactive (e.g. anti-5b) Ab. Recently an IvIg preparation enriched for HLA class I and II Ab caused TRALI in an untransfused male volunteer (Dooren et al. Lancet 1998; 358: 1601–1602). We therefore ascertained the incidence of class II Ab in sera in donors implicated in TRALI using commercial ELISA kits. Sera from 32 donors were tested for HLA class II antibodies using GTI B-Screen ELISA kits. All of these sera had previously been tested for leucocyte-reactive Ab using the GLAM assay, and for HLA class I Ab by LCT and ELISA (GTI QuikScreen® kits). The following reaction patterns were obtained: Hence HLA class II Ab were detected in 8/32 (25%) of sera implicated in TRALI. We suspect that they are more frequent than neutrophil-specific Ab in TRALI donors: we identified the latter in only 8/123 (6·5%) donors tested in the course of investigating 31 TRALI cases, i.e. in 6/21 (28%) donors who were LCT-GLAM+ and in 2/9 (22%) who were LCT+GLAM+.