The immune cellular response tested by lymphocyte transformation in the streptococcal infections.

Thirty-five children between 6 and 17 years treated in the clinic for scarlet fever, rheumatic fever and other non-streptococcal infections as controls, were tested by lymphocyte transformation to four streptococcal antigens. In all cases of scarlet fever and especially of rheumatic fever the lymphocytes were better stimulated by streptococcal products than in the control group. The SO and the MAP fraction showed a good stimulating activity. The response in the rheumatic fever patients was not influenced by the steroid treatment, nor by the stage of the illness. A parallelism with high humoral and cellular responses to SO at the beginning of the acute rheumatic fever was observed, followed by a dissociation of both responses during the evolution with the maintenance of the cellular one and the decrease of the ASO titre.