HTB

HPV genotypes in HIV-positive women in Zimbabwe and Uganda

30 August 2008. Related: Conference reports, Women's health, .

Polly Clayden, HIV i-Base

Two posters evaluated HPV genotypes in HIV-positive from Zimbabwe and Uganda. HIV is known to be risk factor for human papillomavirus (HPV) prevalence and persistence. Both current HPV vaccines however are only known to be effective against types 16 and 18 of HPV.

David Hill and coworkers (from Stanford University School of Medicine, Wake Forest University Baptist Medical Centre, Caradon Consulting San Carlos and University of California), looked at HPV genotypes in HIV-positive pregnant Zambian women with subtype C HIV-1 and assessed cervical HPV infection and HIV-1 virus shedding. [1]

In this study, women were evaluated for HIV and HPV infection by assays of cervical swab samples. For HPV, real-time polymerase chain reaction (RT-PCR) was performed followed by a generic HPV probe using DNA hybridisation. Positive samples were re-probed for 29 individual HPV types and a probe mixture of 10 types. Cervical HIV RNA was measured using RT-PCR.

119 women were enrolled (5 were excluded from HPV analyses due to insufficient DNA).

The investigators found, 82% (94/114) of samples were HPV-positive.

Re-probing revealed 27 unique HPV types in 72 women. 58% (66/114) of women had high cancer risk genotypes: HPV 58 in 19 women, followed by HPV 66, in 14 women.

Additionally, HIV cervical virus was detected in 88% (46/52) of cervical samples tested. The median cervical viral load was 3.54 log copies/mL.

The investigators found no correlation between HIV-1 shedding and the presence of HPV, or specific HPV types in cervical samples tested.

The investigators wrote: “A high proportion of HIV-positive pregnant women in Zimbabwe shed HIV-1 RNA and carried high risk cervical HPV types associated with increased cervical cancer risk. However, only 16 of 94 (17%) were infected with HPV-16 or -18, types against which current vaccines are known to be protective.”

They added: “These data suggest that current HPV vaccines may not prevent HPV infections or provide protection against the high risk HPV types prevalent among HIV-infected women in Zimbabwe.”

In the Ugandan study Janis Taube and coworkers from Johns Hopkins Medical Institute, Baltimore, MD, US; Makerere University, Johns Hopkins University Research Collaboration, Kampala, Uganda; and Makerere University, Kampala, Uganda looked at HPV genotype prevalence in HIV-positive and HIV-negative women in Kampala. Additionally they wished to determine which genotypes are associated with cervical pathology in this population. [2]

200 women aged 18 to 30 years were recruited to the study at 4 to 12 weeks post-partum at Mulago Hospital. The women underwent rapid HIV testing and a pelvic exam. Cervical cytology samples were collected and processed.

Among these women, the investigators reported an HIV prevalence of 19% and an HPV prevalence of 65%. The most frequent high-risk HPV genotypes were 16 (9%), 33 (9%), 35 (6.5%), 45 (6.5%), and 58 (6%). The most frequent low-risk genotypes were 62 (22%), 61 (11%), 81 (11%), 70 (10%), and 53 (10%). The prevalence of HPV 6, 11, and 18 was 2.5%, 1%, and 4%, respectively.

They found there was no significant difference between the presence of HPV 16 or HPV 18 in HIV-positive or HIV-negative women (13.9% vs 7.3%, p=0.20 and 3.7% vs 5.6%, p=0.64, respectively). HIV-positive women were more likely to have other HPV genotypes (both high and low risk) than HIV-negative women (72.2% vs 40.9%, p<0.001 and 63.9% vs 36.6%, p= 0.0046, respectively).

They also found HIV-positive women had a greater median number and range of HPV genotypes vs HIV-negative women (median of 2, range 0-8 vs median of 1, range 0-6, p<0.001). HIV-positive women were significantly more likely to have an abnormal Pap smear vs HIV negative women (43% vs 11%, p<0.001). And HPV prevalence was 58% in women with normal cytology and 97% in women with abnormal cytology. They noted that HPV 16 and 18 prevalence in women with normal cytology was 9.9% and in women with abnormal cytology was 28%.

They concluded: “Our results show that while HPV types 16 and 18 may be seen in association with cervical pathology, preventative, or therapeutic vaccines will need to target a broad-spectrum of HPV genotypes to effectively combat cervical disease in this population”.

Comment

Both these studies and another from Zambia [3] highlight the question of whether current HPV vaccines will be effective in populations with a significant diversity and multiplicity of HPV types. HPV vaccine development of the future needs to consider a broader range of HPV types if these advances are to have a wider global impact.

References:

  1. Hill D, Katzenstein D, Shetty A et al. Cervical human papillomavirus infection in HIV-1-infected pregnant women in Zimbabwe. 15th CROI. February 2008. Boston, US. Poster abstract 1023.
  2. Taube J, Kamira B, Motevalli M et al. Human papillomavirus prevalence and genotype correlation with cervical cytopathology in Ugandan women. 15th CROI. February 2008. Boston, US. Poster abstract 1024.
  3. Parham G, Sahasrabuddhe V, Vermund S et al. Prevalence and predictors of squamous intraepithelial lesions of the cervix in HIV-infected women in Lusaka, Zambia. XVI International AIDS Conference, Toronto, Canada.13-18 August 2006. Oral Abstract TUAB0303.

Links to other websites are current at date of posting but not maintained.