Antibody response to group A streptococci in an epidemic of streptococcal pharyngitis.

An epidemic of acute pharyngitis involving 280 cases occurred in a kibbutz in Israel during the fall and winter of 1972-1973. Group M and/or T type 12 streptococci was associated with the outbreak. No cases of rheumatic fever and no acute nephritis appeared in spite of the vigorous immune response to both cellular and extracellular antigens of group A streptococci documented in 50% to 80% of patients, suggesting that strain variation may be a feature of rheumatogenicity as well as nephritogenicity of group A streptococcal pharyngitis.