Antineutrophil cytoplasmic autoantibodies and myeloperoxidase autoantibodies in clinical expression of Churg-Strauss syndrome

Background: The clinical significance of antineutrophil cytoplasmic antibodies (ANCAs) in the phenotypic expression of Churg-Strauss syndrome (CSS) is uncertain. Objective: We sought to investigate the relationship between ANCA status and the clinical expression of CSS in a case series derived from the US Food and Drug Administration's adverse events database. Methods: All cases of CSS reported to the US Food and Drug Administration from 1997 to April 2003 were reviewed. Information about basic demographics, suspect medication use, clinical manifestations, histologic findings, ANCA staining patterns, and the presence of antibodies to myeloperoxidase (anti-MPO) or proteinase 3 (anti-PR3) was recorded when available. Results: There were 93 case reports of CSS with sufficient documentation, including ANCA status. There were 38 (40.9%) of 93 cases with positive ANCA results, of which 15 cases reported a positive ELISA, all of which were positive for anti-MPO. ANCA negativity was associated with an increased proportion of cardiac involvement (risk difference [RD], 38.2%; 95% CI, 25.3% to 51.0%), gastrointestinal involvement (RD, 25.5%; 95% CI, 13.9% to 37.0%), pulmonary infiltrates (odds ratio, 4.9; 95% CI, 1.5-16.2), and the outcome of a life-threatening event or death (RD, 30.9%; 95% CI, 18.7% to 43.1%) when compared with anti-MPO-positive cases. ANCA negativity was associated with a decreased proportion of peripheral neuropathy (odds ratio, 0.3; 95% CI, 0.07-0.9). Conclusion: These findings support the hypothesis that the presence or absence of autoantibodies influences the clinical expression and severity of CSS. (J Allergy Clin Immunol 2013;131:571-6.)