Comparative evaluation of INF-γ as an immunological healing marker based on anti-tubercular treatment among diabetic and non-diabetic pulmonary tuberculosis patients.

Objectives: Tuberculosis is an infectious airborne disease caused by Mycobacterium tuberculosis. Pulmonary tuberculosis is the ninth most frequent complication of diabetes mellitus. The co-existence of TB and DM in patient causes severe TB symptoms, modify radiological findings, slower response to treatment outcomes and prognosis. IFN-γ is the key cytokine which play role in the protective immune response against mycobacterium infection. The main function of IFN-γ is macrophage activation which is able to exert its microbicidal functions. Estimation and comparison of pre and post treatment serum IFN-γ among pulmonary tuberculosis among diabetic and non-diabetic patients.

Methods: The study was conducted in the Departments of Biochemistry and Pulmonary Medicine, FMHS, SGT University, Budhera, Gurugram and District TB Centre, Gurugram, Haryana, India. In this study, 100 newly diagnosed PTB patients without diabetes mellitus and 100 newly diagnosed PTB patients with diabetes mellitus (PTB-DM) above 15 years of age were included after obtaining written consent. 5 mL venous blood was collected from patients of pre and post anti-tubercular treatment. The level of IFN-γ was measured by ELISA method.

Results: The circulating level of IFN-γ in PTB patients was significantly decreased in post-treatment (25.53 ± 6.12 pg/mL) compared to pre-treatment (58.76 ± 16.02 pg/mL) with t-value 32.03 and p-value <0.001. The circulating level of IFN-γ in PTB-DM patients was significantly decreased in post treatment (29.11 ± 7.41 pg/mL) compared to pre-treatment (44.14 ± 10.85 pg/mL) with t-value 31.35 and p-value <0.001. In the present study, level of IFN-γ in pre-treatment PTB patients (58.76 ± 16.02 pg/mL) was significantly raised compared to PTB-DM patients (44.14 ± 10.85 pg/mL) with t-value 7.55 and p-value <0.001. However, level of IFN-γ in post-treatment PTB patients (25.53 ± 6.12 pg/mL) was significantly low compared to PTB-DM patients (29.11 ± 7.41 pg/mL) with t-value 3.71 and p-value <0.001.

Conclusions: The decreased level of IFN-γ in post-treatment compared to pre-treatment in both PTB and PTB-DM patients had shown efficacy of anti-tubercular treatment. However, the post treatment level of IFN-γ was high in PTB-DM patients compared to PTB patients which verified that effect of ATT was low in PTB-DM.