The cellular immune response after splenectomy in humans. Impaired immunoglobulin synthesis in vitro.

The in vitro immune functions of peripheral blood lymphocytes have been studied in 70 splenectomized patients. 45 patients were splenectomized due to traumatic rupture of the spleen; in 22 of these patients residual splenic tissue was detected, employing a selective spleen scintigraphy. 14 patients were splenectomized due to hereditary spherocytosis and 11 patients due to immune thrombocytopenia or autoimmune haemolytic anaemia; they were all without ectopic splenic tissue. The study revealed that splenectomized patients have (i) an elevated number of blood lymphocytes, (ii) an elevated relative number of EA-RFC, but normal %s of E, EAC-RFC and SmIg positive cells, (iii) normal T-cell mitogenic responses induced by PHA, but enhanced responses induced by ConA and PWM, (iv) normal cell-mediated enhancement of the PWM-induced proliferative B-cell response, (v) no cell-mediated inhibition of the T-cell dependent and PWM-induced proliferative B-cell response and (vi) an impaired number of PFC after stimulation with PWM. The findings were unrelated to the cause of the splenectomies or to the presence of residual splenic tissue. It is possible that the impaired B-cell response as shown by the reduced number of PFC after stimulation with PWM may be of significance for the in vivo resistance to infections in splenectomized patients.