Effect of Diabetes Mellitus on Effector T-Cell Immune Response among Active Pulmonary Tuberculosis Patients in Addis Ababa, Ethiopia

Abstract

Background: -The merging epidemics of tuberculosis (TB) and diabetes mellitus (DM) become major causes of morbidity and mortality throughout the world. Despite the clinical and public health significance posed by the dual burden of the two disease worldwide, there is little evidence on the prevalence of DM among pulmonary tuberculosis patients in Ethiopia, and very little is known about the immunological relationship of DM and TB. Accordingly, the objective is devised to determine the prevalence and the effect of DM on T-cell immune response among active pulmonary tuberculosis (PTB) patients in Addis Ababa, Ethiopia. Methods: - A comparative cross sectional study was conducted and consecutive screening of 205 active PTB cases for DM was done from June 2014-February 2015. Socio demographic and clinical data were collected using structured questionnaire. Blood was collected from 17 PTB with diabetic co-incidence, and 20 PTB patients for T cell phenotyping. Flow cytometry was used to determine the frequency of memory and T regulatory cells. Cross tab, logistic regression and Mann–Whitney test were done using SPSS V22 and Graph pad prism V5.03. P value < 0.05 was taken as statistically significant. Results: - The overall prevalence of DM and Impaired Fasting Glucose was 8.3 % and 26%, respectively. BMI with > 25 kg/m2 (p=0. 000), alcohol drinking ( OR 2.942 and 95% CI [1.077- 8.035]) and smear positive PTB (OR 3.036 and 95% CI [1.029-8.961]) had a statistical association with increased occurrence of DM. PTB coincident with DM is characterized by the increased percentage of activated T cell (Median, 3.360; IQR, 2.515-3.910 vs 2.605 IQR 2.130- 3.078, (p=0. 0373)) and T regulatory cells (Median, 3.660; IQR, 2.445 -4.010 vs 2.165; IQR, 1.943-2.858, (p=0. 0174)). Poor glycemic control (95 % CI; 0.0793 to 0.8205, p=0. 0221) was also correlated with an increased activated and T regulatory cell percentage. There was no significant difference in CD4+, CD8+ and CD45RO + memory cells. Conclusion and recommendation: - The present study has shown a higher prevalence of DM than the estimated prevalence in the general population. PTB with coincident DM was characterized by elevated T activated and T regulatory cell indicating that immune alteration is associated with expansion of these cells in favor pathogen survival. Further studies with a comprehensive study design are warranted to get a representative figure and functionality assay of pathogen specific Tregulatory cells in TB-DM patients should be done.