Mycobacterium tuberculosis infection in systemic lupus erythematosus patients

Abstract

Aim of the workTo estimate prevalence of tuberculosis (TB) infection in systemic lupus erythematosus (SLE) patients; to study its relation to disease duration, activity, damage and treatment as well as to compare the performance of interferon gamma (IFN-γ) release assay and tuberculin skin test (TST) in detection of TB infection. Patients and methodsThe study enrolled 100 adult SLE patients. Disease activity was assessed using the British Isles Lupus Assessment Group (BILAG) activity index and damage using the Systemic Lupus International Collaborative Clinics damage Index (SLICCDI). Tuberculin skin tests and QuantiFERON-TB GOLD In-Tube (QFT-GIT) test were performed. ResultsThe mean age of the patients was 29.82±7.9years; 90% females and 10% males with a mean disease duration 5.5±5.4years. The BILAG index showing that 30% had category A renal activity and the mean of SLICCDI was 1.4±1.7. All patients were Bacille Calmette-Guérin(BCG) vaccinated; none of them had a previous history or contact to members with TB infection. QFT-GIT was positive in 13 patients and TST was positive in 2 patients. 15 patients were diagnosed as latent tuberculosis infection (LTBI). No patients were identified with active TB and microscopic examination and culture were negative. The agreement between the QFT-GIT and TST was poor. No significant difference between patients with positive and negative QFT-GIT results as regard disease duration, corticosteroids and immunosuppressive drugs used, BILAG, SLICCDI, chest X-ray and laboratory investigations. ConclusionThe prevalence of LTBI in SLE patients in our study was 15% with poor agreement between the QFT-GIT and TST.