Study on serum antistreptococcal esterase among school children.

Antistreptococcal esterase (an antibody to extracellular esterase produced by Group A streptococci: ASE) was evaluated according to Hayano's method by using an assay kit on sera of children from two schools, one (F-school) in a non-epidemic state and the other (I-school) in an epidemic state of Group A streptococcal infection. Out of 104 children of F-school, 51 with negative throat cultures for Group A streptococci showed a mean serum ASE titer of 191 +/- 144 unit, and 53 with positive throat cultures for Group A streptococci showed a mean serum ASE titer of 360 +/- 147 unit. Follow-up determinations on serum antibodies to four Group A streptococcal antigens were performed on the children from I-school during a period of 13 months after an epidemic infection of Group A streptococci. The initially elevated serum ASE titer showed a decreasing trend on subsequent bleedings during the study period as well as antistreptolysin O (ASO) and antideoxyribonuclease B (ADN-B) titers. However, the changing pattern of the antistreptococcal polysaccharide (ASP) titer was different from that of the other three antibodies. A positive correlation was observed statistically between ASE and ASO titers, and also between ASE and ADN-B titers. The ASE tests appear to be useful for serological evidence of a streptococcal infection.