Correlation Between CD38+ Cell Levels and Pulmonary Tuberculosis Complicated with Diabetes Mellitus: A Retrospective Analysis Based on Lymphocyte Subsets and Clinical Features

Purpose: This study aimed to investigate the association between CD38 + cells and the risk of pulmonary tuberculosis (PTB) complicated with diabetes mellitus (DM), providing insights into the immune mechanisms underlying PTB-DM. Patients and Methods: Clinical data and lymphocyte subset profiles of 596 TB patients admitted to Affiliated Hospital of Shaoxing University from November 2022 to November 2024 were analyzed, including 115 DM-complicated and 481 non-DM cases. Logistic regression was used to evaluate the correlations between clinical indicators, lymphocyte subsets and PTB-DM. Generalized linear models were employed to assess the association of CD38 + cells with PTB-DM risk, while restricted cubic spline curves were used to explore potential linear relationships. Results: The PTB-DM group exhibited a significantly higher prevalence of advanced age, male gender, and hypertension compared to the non-DM group ( p < 0.05). Lymphocyte subset analysis revealed marginally elevated NKT cells but reduced B lymphocytes, B1 cells, and CD38 + cells in the DM group, with the most pronounced difference in CD38 + cells ( p < 0.001). Multivariate logistic regression identified multidrug-resistant TB and hypertension as independent risk factors, whereas higher CD38 + cell counts served as an independent protective factor for TB-DM comorbidity (OR 0.50, 95% CI 0.32– 0.77). Generalized linear models demonstrated a persistent negative correlation between CD38 + cell levels (analyzed as continuous or quartile-categorized variables) and PTB-DM risk after adjusting for confounders. Restricted cubic spline analysis confirmed a significant linear inverse association ( p = 0.003) without evidence of nonlinearity ( p = 0.450). Conclusion: CD38 + cells play a critical role in the immune regulation of PTB patients, with elevated expression conferring protective effects against PTB-DM comorbidity. Keywords: CD38 + cells, tuberculosis, diabetes mellitus, immune regulation