Non-specific elevation of antistreptolysin antibody (ASO) in the absence of streptococcal pharyngitis

Elevated antistreptolysin antibody (ASO) has been found in five patients without history, physical findings, rapid antigen tests or cultures suggestive of streptococcal pharyngitis. Histories and data are reviewed. 1. JK, 10 year old male, presented with urticaria, lymphadenopathy and oral ulcers following treatment with amoxycillin and clarithromycin. Past history included recent Stevens-Johnson syndrome. Laboratory tests: elevated antinuclear antibodies (1:320), elevated erythrocyte sedimentation rate, neutropenia and massive elevation of ASO at 2,638 (0-200 IU/ml). Diagnosed with drug induced lupus. 2. JA, 56 year old, with hyper-IgM syndrome and bronchiectasis, treated with intravenous immunoglobulin (IVIG), presented with leukocytoclastic angiitis. Laboratory tests: positive antineutrophil cytoplasmic antibodies (ANCA) and suppressed complement. Two months after discontinuation of IVIG ASO was 91 U/dL (0-85) but eventually normalized. Reintroduction of IVIG was tolerated without elevation of ANCA or ASO. 3. KB, 19 year old female, referred for recurrent sinusitis, lymphadenopathy, buccal ulcers and recent mononucleosis, had elevated antinuclear antibodies and suppressed complement. ASO has been borderline (84 U/dL) and mildly elevated (96 U/dL, reference: 0-85). Diagnosed with Sjoegren syndrome. 4. TS, 35 year old, presented with chronic urticaria for 6 years, started shortly after his diagnosis with Guillain-Barre syndrome. Chronic inflammatory demyelinating polyneuropathy is possible. ASO titers vary from 71 to 95 U/dL (reference 0-85). 5. DM, 7 year old, presented with angioedema-urticaria, due to penicillin allergy. ASO titer was 242 U/dL (reference 0-200). Elevated ASO titers occur without streptococcal pharyngitis. Polyclonal activation of B-cells due to autoimmunity, drug allergy or viral infections, is a likely mechanism.