Detection of Latent Tuberculosis Infection in Individuals with Rheumatic Diseases Receiving Immunosuppressive Therapy

Abstract

Objective : to identify latent tuberculosis infection (LTBI) in patients with rheumatic diseases receiving immunosuppressive therapy using modern methods of immunodiagnostics. Materials and methods . A combined retrospective-prospective controlled study was conducted. The study group included 79 patients with rheumatic diseases receiving immunosuppressive therapy and having no documented contact with tuberculosis (TB) patients. The control group consisted of 69 healthy individuals with no history of TB contact and no signs of exacerbated chronic diseases. All study participants underwent an interferon-gamma release assay (IGRA) and/or a skin test with a recombinant tuberculosis antigen (RTA). Results : LTBI was detected in 13.9% (11/79) of participants in the study group, which was significantly higher than in the control group (4.4% (3/69); χ²=3.944, p=0.048). During follow-up, positive RTA test results in the study group were observed in 16.1% (9/56) of cases at the second assessment and in 16.7% (6/36) of cases at the third assessment. These rates were higher than at the first (χ²=0.148, p = 0.701) and second assessments (χ²=0.006, p = 0.940), showing no statistically significant differences, although an upward trend was observed.