Patient age influences CD4+ cell recovery with HAART

Younger HIV-infected patients who receive highly active antiretroviral therapy (HAART) achieve a more rapid and greater CD4+ cell response than older patients receiving HAART, according to a report published in the April 15th issue of the Journal of Infectious Diseases.

Dr. Jean-Paul Viard from Hopital Necker in Paris and colleagues studied the effect of age on CD4+ cell response to HAART in 1956 HIV-infected patients who participated in the EuroSIDA study. All subjects were at least 16 years of age and the median age was 37.2 years. The median follow-up period was 31 months.

The median initial CD4+ cell count was 192 cells/µL and did not differ significantly based on patient age. Furthermore, baseline HIV RNA load and treatment history were also not linked to patient age, the authors state.

Overall, the median time to maximum CD4+ cell response was 20 months. However, CD4+ cell increase, maximum CD4+ cell increase, and maximum CD4+ cell count did show a significant inverse relationship with patient age. The inverse relationship between age and maximum CD4+ cell response was confirmed on multivariate analysis, the researchers note.

The investigators found that the time needed to achieve a CD4+ cell increase of >200 cells/µL was directly associated with patient age.

“Quantitative CD4+ cell response to HAART is variable and not fully explained,” the researchers state. “The favourable influence of younger age on CD4+ cell recovery while a patient is receiving HAART may be explained by more effective thymic function,” they add.

“The present findings confirm that renewal of CD4+ cells is a long-term process and demonstrate that age is inversely correlated with the magnitude and speed of CD4+ cell recovery in actively treated HIV infection,” the authors note. “These are additional arguments for the involvement of renewed lymphopoiesis in CD4+ cell reconstitution.”