Patients coinfected with human T-cell lymphotropic virus 1 (HTLV-1) and HIV continue to have elevated CD4+ T-cell counts, even though there is no difference in their HIV viral load levels after antiretroviral therapy when compared with patients who just have HIV (Curr HIV Res 2017).
'Our results indicate that CD4+ T-cell count testing may not be a useful strategy to monitor ART response in the presence of HTLV-1 infection,' the researchers said.
Alain Vandormael, PhD, of the Wellcome Trust Africa Centre for Population Health and University of KwaZulu-Natal, South Africa, and his colleagues compared the CD4+ T-cell counts and HIV-1 RNA viral loads of 383 patients who were either monoinfected with HIV or coinfected with HTLV-1/HIV. They looked at patient data from a poor and rural community in the KwaZulu-Natal province of South Africa, at the epicenter of the global HIV epidemic.
Coinfected patients were more likely to have higher CD4+ T-cell counts before the initiation of ART with no immunologic benefit. However, the researchers expected any differences in the CD4+ T-cell counts to disappear once the coinfected and monoinfected patients began to fail their ART regimens.
Instead, the researchers found that HTLV-1/HIV-coinfected patients continued to have elevated CD4+ T-cell counts, on average 115 cells/mcL higher than their HIV-monoinfected counterparts, over the two-year study period. But when the authors compared the HIV viral loads over the same period, they could not find any statistically significant difference between the two groups of patients.
The World Health Organization recommends HIV viral load testing as an accurate strategy for monitoring a patient's response to ART. However, CD4+ T-cell testing is often used in resource-limited settings because it is more affordable. The continued use of CD4+ T-cell testing has implications for the clinical management of HIV-positive patients, Dr. Vandormael said. Results from the present study suggest that HTLV-1/HIV coinfection could delay the identification of patients who are failing ART.
Against this background, HIV viral load testing could be both an accurate and cost-effective treatment monitoring strategy, he said.