The bactericidal and opsonic effects of serum from patients with sickle cell anaemia.

The bactericidal and opsonic activity of serum from 12 homozygous sicklers was compared with that of a single control pool of healthy nonsickler African serum. Factorially designed experiments were used to calculate 4 indices which were expressed as the ratio of test to control. Using S. enteritidis and normal human neutrophils viability indices (VI) were calculated for serum, for ingested organisms and for cells + serum, together with a phagocytic index (PI) for cells. Only 1 of the 12 sickler sera gave values equal to that for the control, the remainder showing marked deviation. The survival of organisms in sickler serum was 3 times that in control serum. Phagocytosis by neutrophils in the presence of test sera was only 10% of that in control sera and survival of ingested bacteria was 6 times greater. In the presence of neutrophils overall bacterial survival was 22 times greater for sickler than for control serum.