Objective: To evaluate if the administration of highly active antiretroviral therapy (HAART) during primary HIV infection (PHI) may affect the antibody avidity evolution.
Methods: In 13 subjects with symptomatic PHI, of whom 8 initiated HAART at diagnosis, the Avidity Index (AI) and Western blot evolution patterns were analyzed on serial serum/plasma samples for 1 year. In 4 patients, who subsequently interrupted HAART, additional specimens were analyzed.
Results: At diagnosis, the range of HIV viremia was 0.003 to 38 x 10(6) copies/mL. In untreated patients, viremia reached the set point in 4 to 6 months, whereas in treated patients, early suppression of viremia was observed, remaining undetectable during therapy. At diagnosis, the median AI was low in untreated (0.42, range: 0.33 to 0.43) and treated (0.44, range: 0.40 to 0.72) patients. At 3, 6, and 12 months, the AI progressively increased in untreated patients, whereas it remained <0.80 in all treated patients. In the 4 patients interrupting HAART, the AI increased after therapy interruption to greater than 0.80 in < or = 6 months. The Western blot pattern transiently/partially reversed during HAART in 2 patients.
Conclusions: Antibody avidity maturation takes place only in the presence of ongoing viral replication. These results may have relevant implications in understanding the complex mechanism of maturation of the immune response to HIV.