Cytokine production and gene polymorphisms of IFN-gamma, IFN-gR1 and IL12

Household contacts constitute an important target for early prevention and control of tuberculosis(TB). Cytokines implicated in protective immunity may aid in identification of diagnostics and new vaccines. The role for IL-12 and IFN- ? has been established in protection against mycobacterial infections. The balance between the secretions of IL-12/IFN-? appears to be essential for the regulation of inflammation in response to Mycobacterium tuberculosis. The aim of the present study was to evaluate the cytokine production in serum and culture supernatants and the single nucleotide polymorphisms (SNPs) of IFN-? and IL-12 in active pulmonary tuberculosis patients and household contacts. The cytokine levels were estimated by enzyme-linked immunosorbent assay (ELISA) and their polymorphisms were studied by amplification refractory mutation systems polymerase chain reaction (ARMs PCR) in active pulmonary tuberculosis patients (APTB), household contacts (HHC), and healthy controls (HCs). The mean serum levels of IFN- ? and IL12 were high in APTB and HHC compared to HCs The mean stimulated levels of IFN-? were significantly low in APTB and HHC compared to HC. While the IL-12 cytokine levels were highly significant in APTB and HHC compared to HCs. The AT genotype of IFN-? +874 A/T, CC and TC genotypes of IFNgR1-56C/T was found to be associated with TB. In conclusion, further mutational studies  of IFNgR1 and IFN- ? and follow-up studies of stimulated cytokine levels might be helpful for identification of household contacts who are at risk of developing active TB.