In this study we investigated the HR-HPV viral load in HIV-positive and HIV-negative women. To our knowledge this is the first study to report individual HR-HPV type viral loads in HIV-positive and HIV-negative women detected by this kind of RT-PCR assay. HIV co-infection significantly increased cervical HR-HPV prevalence in HIV-positive women. The prevalence of HR-HPV in HIV-positive women (73.3%) and HIV-negative women (45.5%) was lower than that reported by Luchters et al.,
. This difference could be due to the fact that the current study included 12 HR-HPV types, while that of Luchters et al. studied 15 types , 3 more HR-HPV types (HPV-53, -66 and -68) compared to our study
. The high HR-HPV prevalence and viral load in HIV-positive women may be due to the immune suppression caused by HIV infection, which could also result in the reactivation of latent infection and a high susceptibility to new HPV acquisition
[6, 18]. The increased rate of latent HPV infection reactivation and a high susceptibility to new HPV acquisition among HIV-positive individuals also results in a high prevalence of multiple infections
HIV-positive women were found to have increased α9 HPV viral load compared to HIV-negative women, similar to findings reported in other studies
[2, 15, 17, 19, 20]. The observed significantly higher viral load in HIV-positive women when α9 HPV species were combined but not for the individual HPV types may be explained by two factors. Firstly, the larger numbers of α9 HPV-positive cases, when compared to the numbers positive for individual types, implies greater statistical power to detect an HIV effect. Secondly, HIV is known to increase the risk of multiple HPV types
, therefore an individual infected with multiple α9 types is likely to have a higher combined α9 viral load than an individual infected with a single α9 type.
The association of the immune system with HPV viral load is reflected in the increasing α7 HPV viral load with decreasing CD4 count among HIV-positive women. Levi et al. reported that women with low CD4 counts were at increased risk of high HPV viral load and cervical abnormal cytology compared to women with higher CD4 counts
. We did not find a consistent effect of CD4 count on HPV viral load, similar to other studies demonstrating inconsistent effects of CD4 count on HPV viral load
[7, 16, 21]. The low numbers of participants in the groupings for CD4 count limited the statistical power in determining the association between CD4 count and HR-HPV viral load.
HIV infection and high HPV viral load were found to be predictors of abnormal cytology, however; in multivariate analysis after controlling for HPV viral load, the effect of HIV status on this association was not statistically significant
[22–24]. Infection with HPV species α6, α7 and α9 (and high viral loads in the case of species α7 and α9) were found to be predictors of abnormal cytology in this report. High HPV viral load has previously been reported as a predictor of HPV persistent infection and risk of developing precancerous lesions and cancer
[25, 26]. In the study of Fontaine et al. women who did not develop cervical abnormalities during follow-up were those with stable HPV viral load, while those who developed cervical disease were more likely to be those with increased HPV viral load