Antistreptolysin Content of Blood Serum of Children. Its Significance in Rheumatic Fever

Abstract

Todd^1a described a method of titrating antistreptolysin in blood serum by which a diagnosis of a preceding hemolytic streptococcus infection may be made. Coburn and Pauli 2 considered the antistreptolysin titre of 200 units or higher at the onset of rheumatic fever as immunologic evidence that the hemolytic streptococcus initiates the disease. Myers and Keefer, 3 however, obtained an average of 200 units in normal subjects with a higher average (500 units) in rheumatic fever.

The majority of these observations were made in adults. They represent either single determinations or repeated tests over a short period and give a wide normal range of from 50 to 500 units.

In view of these findings it seemed of interest to obtain information as to the antistreptolysin titre in children of various ages, including: (1) Subjects apparently well; (2) Convalescents following streptococcus and miscellaneous infections; and (3) Rheumatic children during active and inactive periods.

Method. Todd's technic^1b was closely followed. A standard horse serum and patients'serums of known titre were used as controls in each series of tests.

Control series included 150 subjects from 3 months to 16 years of age; a group of 67 subjects in apparent health (no history of streptococcus infection); 51 convalescing from miscellaneous infections (varicella, pertussis, pneumonia); and 32 convalescing from hemolytic streptococcus infections (scarlet fever, erysipelas, respiratory infections). The rheumatic series included 133 subjects under weekly observation for from 9 to 12 months; 41 patients with active rheumatic fever (chorea, carditis, arthritis); and 92 subjects in the inactive stage.

Observations are summarized in Table I.