Correlation Between CD38<sup>+</sup> 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 + cells in the DM group, with the most pronounced difference in CD38 + cells ( p + 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.