The frequency of granulocyte‐specific antibodies in postpartum sera and a family study of the 6B antigen

Abstract

We examined sera from 2313 postpartum women as a potential source of granulocyte specific antibodies. Lymphocyte cytotoxic (LC) antibodies were detected in 397 (17.2%) specimens and granulocyte agglutinating (GA) antibodies in 291 (12.6%). Only two GA positive sera had reactivity for previously defined granulocyte specific antigens (one NA1 and NB1). One additional serum had GA reactivity similar to a serum previously reported by van Rood and called anti‐6B. The frequency of granulocyte specific antibodies (0.1 percent) in our study indicates that the productivity of random screening of parous sera for granulocyte specific antibodies is low. A four‐generation family study of the 6B antigen demonstrated a parallel association between HLA‐B7 and B40 and 6B reactivity in the LC, GA, and granulocyte immunofluorescence (GIF) assay. This illustrates that the granulocyte reactivity of anti‐6B is not granulocyte specific but is HLA related. This report provides additional evidence that HLA antibodies such as anti‐B7 (6B) can react with granulocytes bearing these antigens in the GA and GIF assays currently used to identify granulocyte specific antibodies.