26 March 2013
HIV-1 subtype affected initial CD4 count and rate of CD4 decline—but not initial viral load—in a study of adults in the European CASCADE collaboration.
To compare initial CD4 and viral load levels and CD4 changes by subtype after HIV seroconversion, CASCADE investigators studied people 15 or older with a documented seroconversion date since 1996. They used mixed effects models to calculate CD4 decline and median regression to figure viral load set point, defined as the average HIV RNA 6 to 24 months after seroconversion.
The analysis focused on 3364 seroconverters with known HIV-1 subtype. CD4 count at seroconversion was significantly higher for people with circulating recombinant form (CRF)01 and lower for people with subtype C than for those with subtype B.
CD4-cell decline after infection was significantly slower for subtype A and CRF02 than for subtype B and marginally slower for subtype C than for subtype B.
The researchers compared average CD4-cell loss 2 years after seroconversion for white men infected with HIV through sex between men, aged 30 to 39 years, who seroconverted since 2006, enrolled in the cohort within 6 months of seroconversion, and did not have acute HIV infection. Those averages were 88, 142, 100, 130, 103, and 167 cells/µL for subtypes A, B, C, CRF01_AE, CRF02_AG, and G.
Adjusted analysis determined that median viral load set point and time to clinical AIDS or death did not differ significantly by subtype. However, all subtypes except C tended to have lower viral load set points than subtype B.
The CASCADE team suggests their findings “may be helpful to HIV-positive individuals and their attending physicians in understanding disease progression.”
Source: Giota Touloumi, Nikos Pantazis, Deenan Pillay, Dimitrios Paraskevis, Marie-Laure Chaix, Heiner C. Bucher, Claudia Kücherer, Robert Zangerle, Anne-Marte Bakken Kran, Kholoud Porter, and on behalf of the CASCADE collaboration in EuroCoord. Impact of HIV-1 subtype on CD4 count at HIV seroconversion, rate of decline, and viral load set point in European seroconverter cohorts. Clinical Infectious Diseases. 2013; 56: 888-897.
For the study abstract
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