Human papillomavirus (HPV) infection is considered to be a sexually transmitted disease, and the risk of HPV infection is increased by certain sexual behaviours . HPV plays a role in the pathogenesis of distinct squamous cell cancers: there is a strong and consistent association between high-risk HPV types and cervical , anal , penile [4,5], oropharyngeal [6,7] and conjunctival  cancers. Some of these HPV-associated malignancies occur at increased rates in persons with HIV/AIDS . Likewise, the incidence of anal cancer among HIV-positive men who have sex with men (MSM) has been estimated to be twice that of HIV-negative MSM [10,11], and HAART has not been associated with a reduced prevalence .
Current data on the spread of HPV infection to the different body parts implicated in sexual practices in both MSM and heterosexual men are limited. A cross-sectional study was carried out to evaluate the prevalence of HPV infection in the anus, penis and mouth in this population.
Between April and September 2005, all HIV-positive men ≥ 18 years, who were consecutively interviewed in the outpatient HIV Clinical Unit, were asked to participate in the study. Those with a history of previous anal, penile or oral pathology, and non-acceptance to participate in the study were excluded. The ethical committee approved the protocol and written consent was obtained.
All participants underwent high-resolution anoscopy and direct visual examination of the penis and mouth. Using a cytobrush, samples for HPV-DNA analysis from the anus (anal canal), penis (coronal sulcus, glands and urethra distal), and mouth (oral cavity, and oral rinse sample) were obtained. The sample from the anus was used to carry out a cytological analysis (Thin-Prep, Biomerieux, France). A blood sample was extracted for CD4 cell determination by flow cytometry and HIV-1 plasma viral load (Nuclisens, Cytyc UK, UK; detection limit, 50 copies/ml).
Polymerase chain reaction (PCR) as described previously  was used for assessing the presence of HPV-DNA (positive or negative) and different high oncogenetic risk (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68) and low oncogenetic risk (6, 11) HPV genotypes.
Behavioural data were collected with a questionnaire distributed by a person who was not the participant's primary caregiver. The questionnaire collected detailed information regarding patients' sexual history, sexual preferences (heterosexual, homosexual or bisexual), drug and tobacco use, sexually transmitted diseases, HIV infection, and anal–penile–oral pathologies.
A descriptive analysis of HPV infection and exploratory analyses (univariate and multivariate) of the potential risk factors were performed.
The study included 74 men: 52 MSM (12 of them bisexual) and 22 heterosexuals. The mean age was 42 years (SD = 8.7), 74% were taking HAART, 72% had a HIV viral load < 50 copies/ml and the mean CD4 cell count was 509 cells/μl (SD = 265).
The overall prevalence of anal HPV infection in HIV-positive men was 78% [95% confidence interval (CI), 67–87%], with a prevalence of 83% (95% CI, 70–92%) in MSM and 68% (95% CI, 45–86%) in heterosexual men, P = 0.22. The median number of different HPV types in the anus of HPV-infected patients was 3 [interquartile range (IQR), 1–4], and the most widespread HPV types were 16 and 33 (Table 1). Alcohol use [odds ratio (OR), 8.9; 95% CI, 1.6–49.9] was found to be related to anal HPV infection. Age, sexual preference, CD4 nadir (OR, 1.0; 95% CI, 0.9–1.1), HIV viral load, use of HAART, tobacco use, previous sexual illnesses, number of sexual partners and receptive anal intercourse (RAI) (OR, 8.1; 95% CI, 0.8–83.2) were not associated with higher anal HPV infection.
The global prevalence of anal cytology abnormalities in HIV-positive men was 43% (95% CI, 32–55%) [ASCUS (atypical squamous cells of unknown significance), 13%; L-SIL (low-grade squamous intraepithelial lesions), 19%; H-SIL (high-grade squamous intraepithelial lesions), 11%], with 48% (95% CI, 34–62%) in MSM and 32% (95% CI, 14–55%) in heterosexual men, P = 0.2. An HIV viral load of > 400 copies/ml (OR, 3.5; 95% CI, 1.1–10.7) and having practised RAI more than five times in their lifetime (OR, 4.6; 95% CI, 1.3–16.1) were associated with pathological anal cytology. Furthermore, HPV was present in all patients with abnormal cytology [median number of different HPV types = 3 (IQR, 2–4)]; the most frequent high-risk HPV types were 16, 33, 39, 18. HPV was detected in 62% (26/42) of patients with a negative cytological result [median different HPV types = 2 (IQR, 1–3)]; in these patients HPV-16 and HPV-33 were the most common types.
The prevalence of penile HPV infection in HIV-positive men was 36% (95% CI, 26–48%), with a prevalence of 38% (95% CI, 25–53%) in MSM and 32% (95% CI, 14–55%) in heterosexual men, P = 0.43. Only anal HPV infection (OR, 5.1; 95% CI, 1.1–24.5) was related to penile HPV infection.
The prevalence of oral HPV infection in HIV-positive men was 30% (95% CI, 20–41%), with a prevalence of 33% (95% CI, 20–47%) in MSM and 23% (95% CI, 8–45%) in heterosexual men, P = 0.58 (OR, 3.5; 95% CI, 1.1–10.7). Penile HPV infection (OR, 2.7; 95% CI, 1.0–7.7) was related to oral HPV infection.
The overall prevalence of concomitant HPV infection in two or three different body parts involved in sexual practices was 46% (95% CI, 34–58%), with a prevalence of 48% (95% CI, 34–62%) in MSM and 41% (95% CI, 21–64%) in heterosexual men.
This study is distinct from previous research because it screened for the presence of HPV infection in the different body parts involved in sexual practices in the same patient (including MSM and heterosexuals). We have found in MSM and heterosexual HIV-infected patients a high prevalence of HPV infection simultaneously at different levels (anus, penis, mouth), in the same individual. Indeed, our results confirmed the high prevalence reported previously of anal  and oral  high-risk HPV infection in HIV-positive men. In addition, 62% had an anal HPV infection despite having normal anal cytology. Due to the well established association between HPV infection and squamous cell cancers, our findings support the need for a close follow up in all HIV/HPV co-infected patients in order to detect early cancer changes in the anus, penis and mouth. The fact that a slightly increased trend has been observed  might be related to the significant post HAART increase in life expectancy. Interestingly, the rate of high-risk penile HPV infection may account for the spread of the disease and forces all co-infected patients to use condoms, even for oral sex. According to these results, the upcoming first generation HPV vaccines (solely covering HPV-16 and 18) would have been useful for preventing only 43% of the anal cancer cases in the patients we have studied.
Our findings suggest that the presence of HPV infection in the anus, penis and mouth should be determined in any HIV-infected male patient. In the event that a high-risk HPV infection is detected, monitoring with diagnostic procedures for squamous cell cancers is recommended.
The authors are very grateful to Mrs Raquel Lopez for the statistical analysis, to Dr Mariano Sust (external biostatistician) for his methodological advice, and to Ms Denise Cinquegrana for English correction.
Sponsorship: This study was funded by a grant from the Lluita Contra La SIDA Foundation.
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