Background: Due to the prohibitively high cost of plasma viral load in resource-limited countries,  monitoring of HIV progression and response to HAART largely depends on CD4 count.  However, the routine use of CD4 count in management has also been hampered by high price per test.  The cost of a single CD4 count in resource limited setting ranges from $25 to $100.  In this era of large price reductions in triple antiretroviral drug regimens that are increasing access to treatment in developing countries, more affordable surrogate markers for evaluation, such as total lymphocyte count (TLC) are needed if therapy is to be routinely monitored. 

Methods: The correlation of TLC to CD4 count was analyzed in 405 HIV-positive patients attending YRG CARE in Chennai, India from 1997-2000.  TLC ranges that predict CD4 count < 200 and < 350 cells/mm3 were identified.  Also, retrospective review of  patients with CD4 < 350 starting dual nucleoside therapy at YRG CARE and retrospective review of  patients with CD4 < 350 starting triple drug regimen at Brown University was conducted to determine if changes in TLC correspond to changes in CD4 count. 

Results: The Spearman's correlation for 650 paired CD4 and TLC from 405 YRG Care patients was 0.74.  The positive predictive value and sensitivity of TLC < 1250 for CD4 < 200 was 80% and 68%, respectively.  Both the positive predictive value and sensitivity of TLC < 2000 for CD4 < 350 was 79%.  At 3 months, YRG patients starting dual nucleoside therapy with a statistically significant rise in mean CD4 count also had a rise in mean TLC (p < 0.001).  At 6 months, Brown University patients starting a triple regimen with a statistically significant rise in mean CD4 count also had a rise in mean TLC (p < 0.001). 

Conclusions: Since cost of monitoring remains significantly high relative to proposed prices of antiretroviral regimens, it is unrealistic to expect that patients from resource limited countries will be able to afford regular CD4 counts while on therapy.  TLC may be used as a surrogate for or in combination with CD4 count to determine when to start therapy and to enable routine monitoring.