INFLUENCE OF VITAMIN D LEVELS ON IMMUNE MARKERS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Objective: This study aimed to investigate the association between serum vitamin D levels and immune markers in COPD patients compared to healthy controls, focusing on humoral and cellular immunity. Methods: A cross-sectional study was conducted with 75 COPD patients and 75 healthy controls. Serum vitamin D levels were measured using ELISA, and immune markers, including IgG levels and T-cell subsets (CD3+, CD4+, CD8+), were assessed via flow cytometry. Demographic and clinical data, such as age, gender, BMI, and smoking history, were collected. Statistical analyses, including t-tests and chi-square tests, were performed using SPSS-27 to evaluate differences and correlations between groups. Results: COPD patients exhibited significantly lower serum vitamin D levels (17.19 ± 5.40 ng/mL) compared to controls (28.19 ± 3.73 ng/mL; p < 0.001). IgG levels were reduced in COPD patients (6.71 ± 1.71 mg/dL vs. 8.84 ± 1.94 mg/dL; p < 0.001), indicating impaired humoral immunity. Total T-cell (CD3+) and helper T-cell (CD4+) counts were lower in COPD patients (716.53 ± 167.31 cells/µL vs. 1024.44 ± 219.19 cells/µL; p < 0.001, and 659.33 ± 169.54 cells/µL vs. 821.23 ± 160.63 cells/µL; p < 0.001, respectively), while cytotoxic T-cell (CD8+) counts were elevated (1268.69 ± 229.69 cells/µL vs. 1029.61 ± 133.93 cells/µL; p < 0.001), leading to a reduced CD4/CD8 ratio (0.57 ± 0.28 vs. 0.80 ± 0.16; p < 0.001). Strong correlations were observed between vitamin D levels and immune markers (IgG, CD3, CD4, CD8) in COPD patients. Conclusion: COPD patients display significant vitamin D deficiency alongside compromised humoral and cellular immunity, marked by reduced IgG, CD3+, and CD4+ levels, elevated CD8+ levels, and a lower CD4/CD8 ratio. These findings suggest that vitamin D deficiency may contribute to immune dysregulation in COPD, highlighting its potential as a diagnostic marker and therapeutic target for improving immune function and reducing infection risk in this population.