Spectrum of anti-neutrophil cytoplasmic antibodies in patients with pulmonary tuberculosis overlaps with that of Wegener's granulomatosis.
OBJECTIVE
Mycobacterial infections are known to induce the development of autoantibodies and a few of these antibodies are also known to be diagnostic markers for some other diseases and it is uncertain whether these autoantibodies play a role in the pathogenesis of autoimmune disorders. This study was undertaken to determine the prevalence of autoantibodies like anti-neutrophil cytoplasmic antibodies (ANCA), anti-nuclear antibodies (ANA), anti-double stranded antibodies (anti-dsDNA) and anti-histone antibodies (AHA)in pulmonary Tuberculosis.


METHODS
Seventy consecutive pulmonary TB patients, 30 patients of interstitial lung disease and 100 normal individuals were studied. ANCA and ANA were detected by indirect immunofluorescence test (IIF). Anti-dsDNA and AHA were tested by ELISA.


RESULTS
ANCA was detected in 30% cases, and of these 52.4% showed perinuclear pattern (p-ANCA), 38.1% cytoplasmic (c-ANCA) and 9.5% showed an "atypical" pattern. ANCA specificities by ELISA revealed that, 47.6% had anti-Myeloperoxidase (anti-MPO), 28.6% had anti-Proteinase3 (anti-PR3) and 19.1% had anti-Lactoferrin (anti-LF) antibodies. ANA and AHA were present in 24.3% and 21.4% cases respectively whereas anti-ds DNA antibodies were absent. Normal controls showed 4% and 2% positivity for ANA and ANCA whereas disease control group of ILD showed 7% of ANA and ANCA posititivy.


CONCLUSIONS
The presence of autoantibodies in TB patients could have a multifactorial etiology. Clinically relevant is the presence of anti-PR3 antibodies. This finding along with pulmonary and renal manifestations could lead to a false diagnosis of Wegener's granulomatosis or vice versa because these autoantibodies may be present in both diseases.
Institute of Immunohaematology, Indian Council of Medical Research, 13th floor, K.E.M. Hospital, Parel, Mumbai - 400 012, India.
Vandana D
VD
Pradhan
Suresh S
SS
Badakere
Kanjaksha
K
Ghosh
Aruna R
AR
Pawar
D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D000974:Antibodies, Antinuclear / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003951:Diagnostic Errors; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis / Q000276:immunology*; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000276:immunology; D008297:Male; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
D019268:Antibodies, Antineutrophil Cytoplasmic; D000974:Antibodies, Antinuclear; D015415:Biomarkers