Contribution of an interferon gamma released assay to the detection of latent tuberculosis in chronic dialysis patients in sub-saharan africa

Abstract

Introduction: Tuberculosis (TB) is common in patients with chronic renal failure due to their immunosuppressed state. Diagnosing TB is difficult because of the latency of the clinical and biological picture. This study was conducted to assess the performance of the Interferon Gamma Released Assay (IGRA) in the diagnosis of latent TB infection in chronic dialysis patients in Senegal. Materials and methods: This is a cross-sectional study carried out in Nephrology Department of Aristide Le Dantec University Hospital during 6 month. All patients with chronic haemodialysis or chronic peritoneal dialysis were included. A group of patients with non-dialyzed kidney disease was also included. Patients with active TB at the time of the study were not included. A tuberculin skin test (TST) and an IGRA were performed. The QuantiFERON® (QFT) was repeated 3 months later in the group of dialysis patients. Results: Sixty-two patients were included: 22 haemodialysis (HD) patients, 19 peritoneal dialysis (PD) patients and 21 patients with non-dialyzed kidney disease (NDKD). The mean age was 44 ± 12 years with a sex ratio M/F of 1.06. Nineteen patients were vaccinated with BCG. TST was positive in 22 patients (35.4%). Subjects with a positive TST had a significantly higher rate of BCG vaccination (P=0.002) than those with a negative TST. QFT was positive in 17 patients (28%) and undetermined in 9 patients (14%). In patients with a positive QFT, six (27%) were in HD, four (21%) in peritoneal dialysis and seven (33%) in NDKD. A total of 9/17 (52%) QFT-positive patients developed active TB. Correlation (r=0.998, p=0.001) indicates that T cell functionality was not affected by the duration of renal replacement therapy. Conclusion: These results highlight the advantage of Quantiferon test over TST for diagnosis of latent TB in immunocompromised patients, including chronic dialysis patients