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Abstract

From the letter entitled Causes for low positive predictive values of CD4 counts for antiretroviral treatment failure by Eisenhut,1Eisenhut M. Causes for low positive predictive values of CD4 counts for antiretroviral treatment failure. Int J Infect Dis 2008 [Publisher note, preceding paper].Google Scholar we agree with the author that based on the finding from our study of a very low positive predictive value of the CD4 count for antiretroviral treatment failure,2Chaiwarith R. Wachirakaphan C. Kotarathititum W. Praparatanaphan J. Sirisanthana T. Supparatpinyo K. Sensitivity and specificity of using CD4+ measurement and clinical evaluation to determine antiretroviral treatment failure in Thailand.Int J Infect Dis. 2007; 11: 413-416Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar there may be other causes for low CD4 counts in Thai HIV patients on antiretroviral treatment. Although it has been demonstrated that malnutrition can affect the levels of CD4 cell counts in the African population,3Eisenhut M. Malnutrition and variability in CD4+ cell counts in African populations.J Infect Dis. 2007; 195: 1550Crossref PubMed Scopus (5) Google Scholar a study from Bangkok failed to show the impact of micronutrient supplementation on CD4 cell count or plasma viral load.4Jiamton S. Pepin J. Suttent R. Filteau S. Mahakkanukrauh B. Hanshaoworakul W. et al.A randomized trial of the impact of multiple micronutrient supplementation on mortality among HIV-infected individuals living in Bangkok.AIDS. 2003; 17: 2461-2469Crossref PubMed Scopus (129) Google Scholar Concerning zidovudine-induced lymphopenia, data from our cohort showed that three of 35 patients (8.6%) who had immunologic failure were taking zidovudine compared to 14 of 292 patients (4.8%) who had a good immunologic response. However, this is not statistically significant (p = 0.342). No patient in our study was taking tenofovir and didanosine, which can cause the imbalance of adenosine metabolites. While the causes of low CD4 counts without virological failure may require further study, we still suggest that this measure should not be used to determine antiretroviral treatment failure due to an unacceptably low sensitivity. In Thailand, it is now the standard recommendation to monitor plasma HIV RNA every 6 months in HIV-infected patients on highly active antiretroviral therapy, in order to detect antiretroviral treatment failure early so that there can be a prompt switch to a suppressive antiretroviral regimen. Conflict of interest: No conflict of interest to declare. Causes for low positive predictive values of CD4 counts for antiretroviral treatment failureInternational Journal of Infectious DiseasesVol. 12Issue 5PreviewChaiwarith et al. made the observation that compared to HIV viral load, CD4 count measurements showed a sensitivity of only 13.3% for detecting antiretroviral failure.1 The authors also noted a low positive predictive value of the CD4 count for antiretroviral treatment failure of 8.6%, which was significantly lower than clinical criteria. This is an important finding indicating that there may be causes for low CD4 counts in HIV patients on antiretroviral treatment different from HIV-induced immune suppression. Full-Text PDF Open Archive