CD4 and tuberculosis: Moreover, we found that PAM scores were not associated with CD4 count, which might be explained by the fact that CD4 counts are affected by numerous immune and nonimmune factors, such as tuberculosis (TB) co-infection, hepatitis B virus (HBV) co-infection and CD4 count at baseline (38), and therefore it serves as a crude indicator of HIV disease severity (13); On the other hand, this may have been due to the sample size was not large enough to detect the relationship between patient activation and CD4 count in low- and middle-income settings.