Correlation analysis on total lymphocyte count and CD4 count in HIV-infected patients: a retrospective evaluation

CD4 count is the standard method for determining eligibility for highly active antiretroviral therapy (HAART) and monitoring HIV/AIDS disease progression, but it is not widely available in resource-limited settings. This study examined the correlation between total lymphocyte count (TLC) and CD4 count of HIV-infected patients before and after HAART, and assessed the thresholds of TLC for making decisions about the initiation and for monitoring HAART. A retrospective study was performed, and 665 HIV-infected patients with TLC and CD4 count from four counties (Shangcai, Queshan, Shenqiu and Weishi) were included in the study. Pearson correlation and receiver operating characteristic (ROC) were used. TLC and CD4 count after HAART was significantly increased as compared with pre-HAART (P<0.01). An overall positive correlation was noted between TLC and CD4 count (pre-HAART, r=0.73, P=0.0001; follow-up HAART, r=0.56, P=0.0001). The ROC curve between TLC and CD4 count showed that TLC ≤ 1200 cells/mm³ could predict CD4 < 200 cells/mm³ with a sensitivity of 71.12%, specificity of 66.35% at pre-HAART. After 12-month HAART, the optimum prediction for CD4 count < 200 cells/mm3 was a TLC ≤ 1300 cells/mm³, with a sensitivity of 63.27%, and a specificity of 74.84%. Further finding indicated that TLC change was positively correlated to CD4 change (r=0.77, P=0.0001) at the time point of 12-month treatment, and the best prediction point of TLC change for CD4 increasing was 135 cells/mm³. TLC and its change can be used as a surrogate marker for CD4 count and its change of HIV-infected individuals for making decisions about the initiation and for monitoring HAART in resource-limited settings.