Impaired proliferative response to B-lymphocyte activators in common variable immunodeficiency.

The cell-mediated immune responses of 39 patients with common variable immunodeficiency (CVI) were studied in vitro, using Staphylococcus aureus and Escherichia coli prepared as whole cells and Candida albicans extract. These microbial activators wee found to require intact B-lymphocyte function for normal proliferative response. The patient group was observed to have significantly depressed lymphocyte responses compared wit those of controls studied in parallel (P less than 0.01). Negative lymphocyte response to one activator and strongly positive response to another were found in individual patients. Examination of patients' lymphocyte response to S. aureus and E. coli in association with serum IgG levels demonstrated that a rough correlation could be drawn, showing that patients with serum IgG less than 125 mg/dl had markedly lower (P less than 0.01) lymphocyte responses than those with serum IgG greater than 300 mg/dl. No similar correlation with phytohaemagglutinin activation was observed. Since depressed lymphocyte responses did not correlate with reduced B-cell number in these patients, intrinsic B-lymphocyte deficiency was indicated. These preparations of microbial activators are potentially useful tools in exploring lymphocyte subpopulation functions in primary immunodeficiency diseases.