Alterations of the immune system following splenectomy in childhood.

After splenectomy due to blunt abdominal trauma, splenectomized children showed a restricted pattern of T-cell immunodeficiency compared to age and sex-matched normal children. Peripheral blood total (CD3) T-cell counts of 11 splenectomized children of 43%, double positive helper (CD4) inducer subpopulation (CD29) cell counts of nine splenectomized children of 7%, and phytohemagglutinin (PHA)-induced T-cell proliferation of 11 splenectomized children of 53,206 c.p.m. were significantly (p less than 0.05) lower than values of normal children (61% CD3 cells, n = 12; 13% CD4CD29 cells, n = 11; 107,832 c.p.m. PHA-induced proliferation, n = 12). The deficit of CD4CD29 cell numbers may be due to impaired maturation of these particular CD4 lymphocytes and may explain diminished PHA-induced proliferation in small children. The significantly higher B-lymphocyte counts of splenectomized children (21%, n = 11; 558 cells/mm3, n = 10) compared with 12 normal children (14%; 329 cells/mm3) may be due to loss of the reservoir function of the spleen.