Spectrum of disease in patients with positive antineutrophil cytoplasmic antibodies in general hospitals

Abstract

Objective To investigate clinical significance of positive antineutrophil cytoplasmic antibodies (ANCA) in diagnosis for vasculitis or other diseases. Methods From January 2005 to December 2008, 104 patients with positive ANCA detected by enzyme-linked immunosorbent assay (ELISA) in People's Hospital of Peking University were randomly selected and their clinical features and diagnoses were analyzed retrospectively. Results Among 104 ANCA-positive patients, 22 were diagnosed as vasculitis and 13 as ANCA-associated vasculitis, and 82 (78. 8% )were diagnosed as non-vasculitis including 40 of connective diseases such as systematic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and 42 of non-connective diseases with the most common of ulcerative colitis. According to the results of ANCA tests by ELISA, ANCA-positive patients could be divided into those with proteinase 3 (PR3)-positive and myeloperoxideaso (MPO)-positive. More organs were involved in MPO-positive patients (n =48 ) than that in PR3-positive ones ( n = 49), and more frequent involvement of the kidneys and less frequent involvement of the gastrointestinal tract in MPO-positive than those in PR3-positive ones (P < 0. 01 ). As compared to those with non-vasculitis, more organs (2. 28 organs vs. 3.55 organs in average) were involved in patients with vasculitis (P <0. 01 ) and more frequent involvement of the upper or lower respiratory tracts and the kidneys in vasculitis patients ( P <0. 01 or <0. 05, respectively). Elevated leukocyte count and accelerated erythrocyte sedimentation rate (ESR) were also more common in vasculitis patients than those in non-vasculitis ones (P <0. 01 and P <0. 05, respectively). Positive ANCA combined with number of organs involved, clinical manifestations and other laboratory findings, its positive predictive value (PPV) in diagnosis for vasculitis can be improved. Conclusions Spectrum of disease in patients with positive ANCA was varied. Diagnostic value of positive ANCA in diagnosis for vasculitis can be improved if combined with comprehensive analysis of their clinical features and laboratory examinations. Key words: Antibodies; antineutrophil cytoplasmic; Vasculitis; Diagnosis