Immune correlates of Mycobacterium Tuberculosis patients in Zambia stratified by HIV serostatus and level of immunity-a cross-sectional analytical laboratory based study

Abstract

Background People living with HIV (PLHIV) co-infected with tuberculosis (TB) have a distinct clinical presentation and poorer treatment outcomes compared to HIV-seronegative TB patients. Excluding low CD4 count, innate immune factors associated with TB are not fully elucidated. We, therefore, characterised and compared the expression of IL-6, TNF-α, IFN-γ, and IL-10 in whole blood of treatment naïve TB patients stimulated with heat-killed Mycobacterium tuberculosis stratified by HIV status and the level of CD4 count. Results We recruited 39 HIV seropositive and 31 HIV seronegative TB patients. Median (IQR) age was 35(28–42) years and 31(25–36) years respectively, and a majority had pulmonary tuberculosis i.e. 38(95%) and 30(97%), respectively. The two groups were significantly different in the distribution of CD4 count, 563 [465–702.5 cells/mm3] vs 345 [157–483 cell/mm3] in HIV negative vs HIV positive respectively p = <0.001. Post stimulation, the expression of IL-6 in HIV negative TB patients was significantly higher than in the HIV positive 16,757366 [8,827–23,686 pg/ml] vs. 9,508 [5,514–15,008 pg/ml], respectively; p = 0.0360. TNF-α and IFN-γ were highly expressed in HIV negative TB patients compared to the HIV positive though not statistically significant. We only observed higher expression of IL-6 in HIV negative patients in comparison to the HIV positive when stratified by level of CD4 counts as < 500 and ≥ 500 cell/mm3 for both cohorts. 21,953 [8,990–24,206 pg/ml] vs 9,505 [5,400–15,313 pg/ml], p value = 0.0585 in patients with CD4 count < 500 cell/mm3 and 13,168 [7,087–22,584 pg/ml] vs 10,413 [7,397–14,806 pg/ml], p value = 0.3744 for patients with CD4 count of ≥ 500 cell/mm3 respectively. We found a positive pairwise correlation between TNF-α -alpha and IL-6 in both HIV positive and HIV negative patients, r = 0.61 (95% CI 0.36–0.72; p < 0.0001) and r = 0.48 (95% CI 0.15–0.68; p = 0.005) respectively. The IFNγ/IL-10 ratio was higher in HIV negative when compared to HIV positive individuals, 0.052 [0.0–0.28] vs 0.007 [0–0.32] respectively; p = 0.05759. IL-6 independently reduced the probability of TB/HIV, Adjusted odds ratio 0.99, p value 0.007. Conclusions This study suggests that HIV seronegative TB patients have a higher pro-inflammatory response to MTB than HIV seropositive TB patients. Further, it also shows that the level of CD4 influences immunomodulation. The findings suggest that the difference in cytokine expression may be responsible for the distinct patterns of TB presentation between HIV positive and HIV negative patient.

Association between prior tuberculosis disease and dysglycemia within an HIV-endemic, rural South African population

“…Notably, HIV-negative persons with active TB have different pro-inflammatory cytokine responses compared to persons living with HIV and TB. [34,35] We hypothesize that these differential inflammatory responses and their potential metabolic effects may contribute to the HIV-subgroup differences in our study.…”

Strain structure analysis of Mycobacterium tuberculosis circulating among HIV negative, positive and drug resistant TB patients attending chest clinics in Western Kenya

“…This was the first study to determine strain diversity and distribution in Western Kenya circulating among HIV negative and positive patients in the region. HIV/AIDS is the major risk factor to acquiring TB in Western Kenya due to its effecting compromising human immune system [ 27 ]. high prevalence rates of the HIV epidemic in this region especially among the five counties; Kisumu, Homa Bay, Siaya, Busia and Migori [ 28 ].…”