Lessons learned from early HAART in acute HIV infection
Ross Hewitt, HIVandHepatitis.com
Dr Bruce Walker from Boston discussed his small but provocative cohort of 14 patients who were treated after identification of very early HIV infection (within 90 days). He had previously reported that early treatment of acute HIV infection augments T helper cell responses. In early stages, CD4 cells get activated and infected and rendered dysfunctional. HIV also preferentially infects HIV specific CD4 cells. But, does early treatment enhance immune control?
After initial control, his protocol called for interruptions of HAART followed by restarting it if the viral load rose to greater than 5,000 and interrupting again after viral control was re-established. Three of eight patients went on to control after the first interruption, and have remained off HAART. One patient developed an HIV superinfection and lost viral control but prior to that had controlled the initial HIV infection. For most patients, there is a slow, stepwise loss of control over time that enables them to remain off therapy, some for more than two years. What kind of immune responses are seen?
After treatment interruptions, CD8 cell responses recognise more than 25 epitopes (pieces of HIV) compared to before interruption when only two epitopes are recognised. Only three of 11 patients in follow up were able to control HIV for 1,000 days off therapy and they continue off therapy with viral load <3,000 copies/ml.
When compared to MACS data for progression, 50% of these patients meet the viral parameters of the lowest 25% of the MACS cohort, suggesting that some benefit may be occurring. Genetic factors may also be important. Patients who are HLA B27 positive are more likely to control acute HIV infection and be asymptomatic during acute infection.
The bottom line is that the results of this cohort are intriguing, but do not provide definitive evidence of a significant effect of early treatment with STI.
Walker BD. Prospects for immunotherapy of HIV infection. State of the art talk. Session 12. 2nd IAS Conference on HIV Pathogenesis and Treatment, 13-16 July 2003, Paris. Abstract not submitted.
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