Slower decline of plasma HIV-1 RNA following highly suppressive antiretroviral therapy in primary compared with chronic infection

Objectives: To study the effect of highly suppressive antiretroviral therap y on the slopes of HIV-1 RNA decline in primary compared with chronic HIV-1 infection. Methods: Slopes of HIV-1 RNA decline in plasma were compared before and aft er the start of highly suppressive antiretroviral therapy from five acutely infected patients who started treatment 2 to 5 weeks following the onset o f clinical symptoms. Slopes of decline after the initiation of therapy were also compared with those found in 12 chronically infected individuals on t he same therapy. Numbers and percentages of activated CD4 and CD8 T cells a t baseline were compared as well. Results: The pre-treatment slopes of HIV-1 RNA decline in the acutely infec ted individuals increased significantly (P = 0.0001) after the start of ant i-retroviral therapy. However, these post-treatment slopes were lower than those found in the chronically infected individuals (P = 0.012). Slopes wer e inversely correlated (P = 0.012) with baseline HIV-1 RNA. Although the nu mber of CD38+HLA-DR+ CD4 cells was higher in primary infection (P= 0.02), t he percentage did not differ between primary and chronic infection. Conclusions: These findings indicate that antiretroviral therapy contribute s significantly to the clearance of HIV-1 during primary infection. Based o n the mathematical model the less steep RNA slope following the start of tr eatment in primary infection can be predicted to be the result of lower cle arance of productively infected cells and higher burst size per cell per un it time. This may indicate a growing immune response to HIV-1 in this very early stage of infection. (C) 2000 Lippincott Williams & Wilkins.