Anti-PR3 and anti-MPO antibodies are not present in sera of patients with pulmonary tuberculosis.

Anti-neutrophil cytoplasmic antibodies (ANCA) are autoantibodies directed to intracellular components of neutrophils and are present in several vasculitic syndromes. Recently, these autoantibodies have been described in other autoimmune disorders as well as in infectious diseases such as tuberculosis (TB). As there are some clinical similarities between TB and granulomatosis with polyangiitis, we searched for ANCA in a group of patients with proven TB. Patients with TB confirmed by chest X-ray and sputum bacilloscopy either before or within 30 days after beginning treatment were included in this study. Anti-MPO and anti-PR3 antibodies were studied using well-standardized ELISA kits (INOVA Diagnostics, Inc.). ANCA were also investigated by indirect immunofluorescence (IIF). Fifty TB patients (26 females, mean age 47.34 ± 17 years) were enrolled in the present study. No patient tested positive for ANCA by IIF, or anti-MPO or anti-PR3 antibodies by ELISA. Although previous studies have shown the presence of ANCA in some infectious diseases, the findings of the present study demonstrated the absence of such antibodies in TB. The discrepancy in the prevalence of ANCA in TB among different studies may be attributed to methodological factors and/or the genetic background of the studied populations.