Publication:

Prevalence and diagnostic implications of anti-citrullinated peptide antibody in smear-positive pulmonary tuberculosis patients

Background Generation of autoantibodies have been described in several infectious diseases including tuberculosis. Rheumatoid arthritis-specific autoantibodies: anti-citrullinated protein antibody presents in pulmonary tuberculosis, patient without evidence of cross-reactivity in tuberculosis bacilli antigens. To evaluate prevalence of ACPA positivity and its association with sputum smear acid-fast bacilli (AFB) grading in pulmonary tuberculosis patients with positive smear.

Methods This descriptive, observational study was carried out during June 2020 to July 2021 at the Department of Rheumatology, Bangladesh Medical University and National Institute of Diseases of Chest and Hospital Dhaka. One hundred adult, smear-positive pulmonary tuberculosis (TB) patients were recruited by consecutive sampling. Levels of serum ACPA were detected by ELISA. Sociodemographic, clinical and laboratory measures were described with descriptive statistics and compared by chi-square tests.

Results Positivity of ACPAs was found in 28.0% of patients, with 12.0% showing high levels of ACPA (>60 IU/ml). The median value in the serum ACPA positive patients was 66.0 IU/ml (IQR: 48.5–88.0). Positive-ACPA was also slightly more common in patients with sputum smear grade of 2+ to 3+ compared to that of the lower smearing grades, but without statistical significance (p=0.821).

Conclusions A significant proportion of smear-positive pulmonary tuberculosis cases showed positivity to ACPA. These results indicated that ACPAs should be interpreted with caution in tuberculosis-endemic regions to prevent the misdiagnosis of inflammatory arthritis.