Antihyaluronidase level in children with rheumatic fever and other streptococcal infection

1) The serum ASO and AH assays were performed and compared in a series of 90 healthy children and 7 pediatric patients with rheumatic fever and other disorders related to hemolytic streptococcus infection. 2) The upper physiological limit of serum AH titer was estimated to be 256X for children. 3) In rheumatic fever, sometimes the serum AH level rises earlier than elevation of serum ASO and remains to be high over a long period even after the serum ASO has returned to normal level. 4) The results suggest importance of the serum AH determination in the serologic diagnosis of rheumatic fever and other conditions of hemolytic streptococcus infection.