Deficiency in kwashiorkor serum of factors required for optimal lymphocyte transformation in vitro.
Blastogenic responses of normal human peripheral blood lymphocytes cultured in media supplemented with serum from children with kwashiorkor were, on average, 47.7% of those observed when the same cells were cultured in the presence of normal AB serum. Incorporation of radioactive uridine was also diminished in the presence of normal AB serum. Incorporation of radioactive uridine was also diminished in the presence of kwashiorkor serum indicating that lectin-induced RNA synthesis was also affected. The kwashiorkor serum effect was not due to a cytotoxic action nor could it be attributed to the presence of saccharides or other inhibitors of the inducing lectins. Mixing experiments showed that kwashiorkor serum was not inhibitory, but that it lacked factors present in normal serum that are required for optimal lymphocyte blastogenesis. The deficiency of these factors could largely be rectified by supplementing kwashiorkor serum with an ultrafiltrate of normal serum containing components with molecular weights of less than 500 Daltons. We conclude that nutritional deprivation of severity sufficient to cause kwashiorkor leads to a deficiency of low molecular weight lymphocyte growth factors. This lack may contribute to the immunodeficiency associated with the disease.