Serial studies on the cellular immune response to streptococcal antigens in acute and convalescent rheumatic fever patients in Trinidad.

Acute rheumatic fever (ARF) has the characteristics of an autoimmune disease, triggered by cross-reactive antigens shared by the group A streptococcus and a variety of tissues including the heart, endothelium, and basal ganglia. Using two parameters of cellular reactivity, migration inhibition and blastogenic transformation, ARF patients from Trinidad show significant lymphocyte reactivity to streptococcal antigens, particularly those from an ARF associated streptococcal strain. This reactivity, studied over a 2-year period, peaked at 1 to 6 months after the acute onset and remained significantly elevated for at least 2 years. The reactivity is directed mainly toward a nonionic detergent extractable material in the cell membrane. These studies suggest a possible streptococcal strain specificity in ARF and demonstrate persistent sensitization, which explains the increased susceptibility to recurrences in the 2 years following the acute episode.