Use of interferon-gamma release assay (IGRA) and CXCL-10/IP-10 for latent tuberculosis infection (LTBI) screening in chronic kidney disease and hemodialysis patients.

BACKGROUND

There is increasing evidence that patients with chronic kidney disease (CKD) are at risk of acquiring latent tuberculosis infection (LTBI) or developing active tuberculosis (TB). However, the diagnosis of LTBI is still a challenge due to the limitations of current tests, which rely on the host’s cellular immune response against Mycobacterium tuberculosis (Mtb) – that may be compromised in this population. Herein, we assessed the prevalence of LTBI and its predictors among patients with CKD, including those undergoing routine hemodialysis (HD).

METHODS

A prospective cross-sectional study was conducted in a tertiary nephrology referral center in Rio de Janeiro, Brazil. LTBI was diagnosed using interferon-gamma release assay (IGRA; QuantiFERON-TB Gold Plus, QFT-Plus). CXCL-10/IP-10 release assay was measured in QFT-Plus supernatants.

RESULTS

A total of 123 patients were enrolled, including 111 (90.2%) from the CKD group and 12 (9.8%) from the HD group. IGRA results positive in 39 (31.7%) overall: 36/111 (32.4%) in CKD group and 3/12 (25%) in HD group. Indeterminate IGRA results were found in 4/123 (3.3%) patients. Positive CXCL-10/IP-10 responses were observed in 49/123 (39.8%) patients. A significant agreement was observed between IGRA and CXCL-10/IP-10 results, with concordance in 69% of cases (p < o.05). Multivariate regression analysis identified that lack of BCG vaccination with (adjusted odds ratio [aOR] 7.4; 95% CI 2.15–25.48; p = 0.0014) and a positive CXCL-10/IP-10 result (aOR 4.48; 95% CI 1.87–10.76]; p = < 0.001) as independent risk factors for LTBI in both CKD and HD patients.

CONCLUSION

The IGRA QFT-Plus was shown to be a useful method in the surveillance of LTBI in critical stages of CKD and routine hemodialysis. Mtb-specific CXCL-10/IP-10 responses were associated with a positive IGRA and could provide an useful adjuvant LTBI biomarker in this population.