IL6 and tuberculosis: Similarly, a study of HIV-infected persons in South Africa showed elevated levels of circulating soluble CD14, C-reactive protein, IL-6 and interferon gamma-induced protein 10 (IP10) among patients with HIV and LTBI co-infection, compared to HIV patients without evidence of tuberculosis infection based on a negative TST, negative IFN- γ ELISpot, negative chest-X-ray, negative induced sputum for M. tuberculosis and no tuberculosis disease symptoms [31].