Discordant Virological and Immunological Response to HAART Raises Risk of Disease Progression

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A microscope image of the HIV virus.

Typically, an HIV positive person's viral load will decline rapidly and CD4 cell count will rise somewhat more slowly after starting effective combination antiretroviral therapy. In some cases, however, virological and immunological response may not occur together, a phenomenon known as discordant response.

Researchers at the University of Alabama at Birmingham conducted a study to look at the clinical significance of discordant response, as reported in the February 14, 2008 advance online edition of the Journal of Acquired Immune Deficiency Syndromes.

The analysis included 404 antiretroviral-naive patients who started HAART at an urban HIV outpatient clinic between 1995 and 2004. The association between treatment responses at 3 to 9 months after HAART initiation and development of an opportunistic infection (OI) or death was determined using Cox proportional hazards modeling. Logistic regression analysis was used to assess the association between discordant response and patient characteristics.

Results

• Of the 404 patients:
• 70.5% experienced favorable concordant responses, achieving ndetectable viral load and a CD4 count increase of at least 50 cells/mm3.

• 15.8% experienced only immunological response (CD4 cell recovery).

• 8.7% experienced only virological response.

• 5.0% experienced unfavorable concordant non-response, with neither viral load suppression nor CD4 cell recovery.
• Both types of discordant response (immunological only or virological only), concordant non-response, and lower baseline CD4 cell count were significantly associated with earlier development of an OI or death.

• In a multivariate analysis, discordant response was associated with non-white (primarily African-American) race/ethnicity.

Conclusion

Based on these findings, the authors concluded, "Discordant immunologic and virologic responses at 3 to 9 months after HAART initiation play important roles in predicting long-term clinical outcomes in treatment-naive patients."

2/29/08

Reference
R Tan, AO Westfall, JH Willig, and others. Clinical Outcome of HIV-Infected Antiretroviral-Naive Patients With Discordant Immunologic and Virologic Responses to Highly Active Antiretroviral Therapy. Journal of Acquired Immune Deficiency Syndromes. February 14, 2008 [Epub ahead of print].