Phagocytosis in patients with sickle cell disease.

Twenty sickle cell disease (SCD) patients, homozygous for sickle hemoglobin, were studied during asymptomatic periods. After clinical evaluation, several peripheral phagocyte parameters were evaluated. These were: ingestion rate, percentage of phagocytes with ingested particles, nitro-blue-tetrazolium (NBT) reduction rate, candidacidal activity; as well as serum levels of total haemolytic complement activity (CH50); third and fourth complement components (C3 and C4). Our data show a significant decrease of all studied phagocytosis parameters in the presence of sickle serum which indicate that asymptomatic SCD patients have basically deficient phagocytosis due to serum factors. Nine of the same patients were also evaluated during and after a painful crisis. Our results indicate that a painful crisis is not associated with further abnormalities of phagocytosis in SCD patients.