The serum bactericidal and opsonizing defect in sickle cell anaemia: restoration of activity by control serum

Abstract

Thirty-eight homozygous sickler sera were compared with a large pool of serum from healthy African non-sicklers with regard to bactericidal and phagocytic indices. One third of the sera showed reduced bactericidal activity against Salmonella enteritidis which was restored by the addition of 4% control serum; control serum provided both heat-labile (HL) and absorbable (ABS) serum factors. 76% of test sera showed greatly defective opsonization as indicated by ingestion by normal human neutrophils. Activity was not readily restored by the addition of control serum which provided only HL factors. Intracellular survival was increased when bacteria were ingested from sickler serum; activity was readily restored by control serum which provided both HL and ABS factors. In the presence of both serum and neutrophils 84% of test sera permitted increased bacterial survival; the defect was not readily reversed by the addition of control serum which provided both HL and ABS factors.