The Search for a Genetic Factor Associating with Immune Restoration Disease in HIV Patients Co-Infected with Mycobacterium tuberculosis

BACKGROUND Up to 43% of HIV-infected patients co-infected with Mycobacterium tuberculosis experience exacerbations of tuberculosis (TB) after commencing antiretroviral therapy (ART). These are termed immune restoration disease (IRD). It is unclear why individual susceptibility varies. OBJECTIVE We investigate if single nucleotide polymorphisms (SNP) in genes encoding cytokines, chemokines and their receptors associate with development of an IRD event in patients of two different ethnicities. METHODS DNA samples were available from small well-characterised groups of HIV patients treated in Cambodia (TB-IRD, n=17; HIV(+)TB(+) controls, n=55) and India (TB-IRD, n=19; HIV(+)TB(+) controls, n= 43). HIV patients with a TB diagnosis but no evidence of IRD were included to control for susceptibility to TB per se. Sixteen SNP implicated in inflammation or mycobacterial disease were genotyped. RESULTS Susceptibility to TB-IRD associated with carriage of TNFA-1031*T (rs1799964; P=0.05) and SLC11A1 D543N*G (rs17235409; P=0.04) in Cambodian patients and carriage of IL18-607*G (rs1946518; P=0.02) and VDR FokI (F/f)*T (rs10735810; P=0.05) in Indian patients. CONCLUSIONS Associations between polymorphisms in immune-related genes and TB-IRD were found, but none were common across two ethnicities.