Infection of group A streptococcus and antibody response to extracellular antigens.

A study demonstrating the relationship between pharyngeal infection of group A streptococci and the antibody response was performed. Group A streptococci were recovered from 44 (9.4%) of 466 children, of which 41 strains were typable by T-protein. Fifty-five percent of 41 children from whom group A streptococci were recovered showed a significant rise in anti-streptolysin O (ASO) titers in sera. In children from whom group A streptococci were recovered and with elevated ASO titers, titers of antideoxyribonuclease B (ADNase B) were significantly higher than those who were negative for group A streptococci and also showed elevated or normal titers for ASO. Patients with acute rheumatic fever demonstrated elevated titers of both ASO and ADNase B. These findings suggest that a combination of ASO and ADNase B titers should be applied to diagnose the streptococcal infections. Antinicotinamideadenine dinucleotidase showed a low level of titers in children who had group A streptococci in their throat and exhibited elevated titers in streptococcal antibodies, and also in patients with acute rheumatic fever.