Decrease in soluble CD8 antigen levels in splenectomized patients as an index for reduced suppressor/cytotoxic cell activity.

To investigate the effect of splenectomy on lymphocyte subpopulations we monitored changes in serum concentrations of soluble suppressor/cytotoxic (sCD8) and soluble helper/inducer (sCD4) antigen in 11 splenectomized patients. Indications for splenectomy were hereditary spherocytosis in 2, idiopathic thrombocytopenic purpura in 2, gastric carcinoma in 4, Hodgkin's disease in 2 and pancreatitis in 1 patient. Lymphocyte subpopulations were also analyzed by means of conventional immunophenotyping with monoclonal antibodies to CD4 and CD8. We consistently found an early postoperative drop of sCD8 and sCD4 levels within the first week after splenectomy, paralleling changes in the percentages of CD4+ and CD8+ lymphocytes. While alterations of lymphocyte subsets in the peripheral blood were completely reversible and sCD4 levels returned to preoperative values, sCD8 concentrations remained suppressed even 3 months after splenectomy. SCD8 levels at the nadir and those 3 months after splenectomy were significantly lower than preoperative values (P = 0.003, P = 0.149 respectively). Since sCD8 levels reflect suppressor/cytotoxic cell activity, we suggest that suppressor cell activity is reduced in splenectomized patients.