Predicting the magnitude of short-term CD4(+) T-cell recovery in HIV-infected patients during first-line highly active antiretroviral therapy

Background: The extent of short-term CD4(+)T-cell recovery in patients tolerating first-line highly active antiretroviral therapy (HAART) and attaining undetectable HIV RNA levels is inadequately defined. Methods: We retrospectively analysed patients in four Italian cohorts who started HAART between January 1996 and September 2006. All patients had known HCV coinfection status, did not modify the regimen for 6 months and had <50 HIV RNA copies/ml at the end of the sixth month. Results: The analysis involved 1,488 patients (1,096 males, 73.7%) with a median age of 43 years (interquartile range [IQR) 39-49); 435 (29.2%) were positive for HCV, 71 (4.8%) were positive for hepatitis B surface antigen (HBsAg) and 76 (5.1%) had experienced a previous AIDS-defining event. At baseline, patient CD4(+) T-cell counts were 226 cells/mu l (IQR 99-332), CD4(+) T-cell percentages were 14.7% (IQR 8.7-21.2) and HIV RNA levels were 4.91 log(10) copies/ml (IQR 4.38-5.34). Overall, 24-week CD4(+) T-cell recovery was 144 cells/mu l (IQR 70-240). At multivariable analysis, T-cell recovery was positively related to the use of a boosted protease inhibitor (P<0.0001) or thymidine analogues (P<0.0001), baseline HIV RNA levels (P<0.0001), the baseline percentage of CD4(+) T-cells (P<0.0001) and the absence of HCV coinfection (P=0.006). Age, gender, baseline CD4(+)/CD8(+) T-cell ratio and a history of AIDS-defining events had no independent effect on CD4(+) T-cell recovery. Conclusions: Among HIV-infected patients tolerating first-line HAART and with undetectable HIV RNA after 6 months, CD4(+) T-cell recovery is significantly greater in those without HCV coinfection, with a high baseline viral load, a high baseline percentage of CD4(+) T-cells and in those treated with a boosted protease inhibitor.