Pneumocystis jirovecii prophylaxis discontinuation based upon total lymphocyte count in HIV-infected adults treated with antiretroviral therapy

Pneumocystis jirovecii pneumonia (PCP) prophylaxis may be discontinued when CD4 is ≥200 cells/mm³ for three months in response to highly active antiretroviral therapy (HAART). Unlike CD4, the total lymphocyte count (TLC) is inexpensive and widely available in resource-constrained countries. Paired TLC and CD4 values of HIV-infected patients attending an HIV clinic from 1998 to 2005 were analysed by Spearman's correlation. The sensitivity, specificity, positive predictive value, negative predictive value and receiver operating characteristics (ROC) using TLC cut-off points between ≥1400 and ≥2000 cells/mm³ to predict CD4 ≥200 cells/mm³ were calculated. Next, a cohort of patients who had a TLC ≤1200 cells/mm ³ and subsequently achieved various TLC cut-off points sustained over three months while receiving HAART was identified. Subjects with subsequent CD4 ≥200 cells/mm³ in response to HAART were considered to have negligible risk for PCP. There was significant correlation between TLC and CD4 in 46,250 observations from 4307 individuals (r = 0.695, P ≤ 0.001). The area under the ROC curve was 0.85 (95% CI = 0.85-0.86). In the historical cohort analysis, 85% and 70% of subjects who achieved TLC ≥2000 cells/mm³ and ≥1400, respectively, had a corresponding CD4 ≥200 cells/mm ³. A sustained rise in TLC in response to HAART may potentially serve as a criterion for discontinuing PCP prophylaxis in resource-constrained countries.