Association between Perinuclear Antineutrophil Cytoplasmic Antibodies and Infection: A Retrospective Study

Abstract

Background & objectives: Antineutrophil cytoplasmic antibody (ANCA) is often used in laboratory tests to confirm paucicellular vasculitis. However, ANCA is also occasionally found in patients with infectious disorders independent of any vasculitic process. We retrospectively studied the association between perinuclear antineutrophil cytoplasmic antibody (p-ANCA) and clinical conditions, especially infectious diseases. Methods: Between 2007 and 2010, 1291 patients (118 p-ANCA-positive and 1173 p-ANCA-negative patients) were tested for ANCA. We selected the total 118 p-ANCA-positive patients, and selected 118 of the 1173 p-ANCA-negative patients randomly. They were divided into 2 equal groups according to the presence or absence of p-ANCA. Data on their medical history and hospitalization course were retrospectively analyzed using their medical records. Results: Overall, 44 p-ANCA-positive patients (37.3%) and 14 p-ANCA-negative patients (11.9%) had infections. From the former group, 36 patients (81.8%) had Staphylococcus aureus infection, 15 (34.1%) had multidrug resistant gram-negative bacterial infection, and 21 (47.7%) had Pseudomonas aeruginosa infection. Of the latter group, 6 patients (42.9%) had Staphylococcus aureus infection, 4 (28.6%) had multidrug resistant gram-negative bacterial infection, and 5 (35.7%) had Pseudomonas aeruginosa infection. Further, 21 p-ANCA-positive patients (17.8%) and 7 p-ANCA-negative patients (5.9%) were diagnosed with vasculitis. Lastly, 37 p-ANCA-positive patients (31.4%) and 16 p-ANCA-negative patients (13.8%) required intensive care unit admission. Conclusions: p-ANCA is significantly associated with some infections. Patients with severe infections may produce p-ANCA, especially those requiring ICU admission. Those who test positive for p-ANCA should be thoroughly investigated not only for vasculitis but also for infectious conditions.