CD4 and HIV infectious disease: Several studies have indicated that decreased CD4+ T-cell counts are associated with a reduced frequency of lung cavitations (see [9] for an overview), and we found a similar association in HIV patients from Uganda (Welch’s two-sample t-test, p = 0.030), suggesting that CD4+ T-cell counts might be a better predictor of Mtb transmissibility and TB progression than the HIV infection status alone.