Monocyte cytotoxicity after splenectomy.

Antibody-dependent cell-mediated cytotoxicity (ADCC) by monocytes was determined in 45 adults approximately 4 years after splenectomy for either abdominal trauma or accidental injury during operation for benign gastroduodenal ulcer. Compared to controls, both groups of splenectomized persons showed increased numbers of monocytes and decreased monocyte ADCC. The decrease of monocyte ADCC was only significant in those splenectomized persons in whom accessory splenic tissue was not detectable by isotope scanning. Addition of the spleen-dependent peptide tuftsin to monocytes in vitro did not augment their ADCC. An increase serum concentration of immune complexes was neither related to the presence of splenic tissue nor to the monocyte cytotoxicity. Vaccination with pneumococcal polysaccharide had no effect on monocyte ADCC. It is suggested that the defective monocyte cytotoxicity observed in splenectomized persons without detectable splenic tissue might be relevant to post splenectomy infectious susceptibility.