We identified 2 markers of HIV infection negatively correlated with COPD (Table 2): nadir CD4 cell-count (188 CD4 cells/mm3 in COPD-patients vs 262 CD4 cells/mm3 in non COPD-patients, P = 0.007) in the univariate analysis only, and most recent CD4 cell-count in both the univariate and multivariate analyses (OR, 0.77 for each 100 cells/mm3 increase; 95% CI, 0.68–0.88). Here, CD4 is linked to HIV infectious disease.