Dissertation for Medicine Doctoral degree at Sahlgrenska Academy, Institute of Neuroscience and Physiology, Department of Pharmacology
Epidemiology of Human Papillomavirus Infections in East Africa - Aspects on HIV, Genetics and Immunology
Opponent: Professor Joakim Dillner, Department of Clinical Science, Intervention and Technology, Karolinska institutet, Stockholm
Examining committee: Professor Kristina Eriksson (chair), Professor Magnus Evander (UmU) and Associate Professor Karin Bergmark
The disputation is held in English
Chair of the defence: Lars Westberg
Human papillomavirus (HPV) infection is a well-documented etiological factor in the development of cervical, anogenital, and head and neck malignancies. East Africa has ranked first with the highest prevalence of HPV infection and cervical cancer's highest mortality rate. This thesis aimed to identify strategies for identifying patients at risk of developing chronic HPV infection and associated cancers.
The thesis is based on four specific objectives addressed in four studies:
Study I: HPV is prevalent in other mucous membranes than the cervix. The prevalence of HPV infection in other mucous membranes was assessed on 50 HIV-positive concordance couples from Rwanda, and samples were collected from the oral cavity and anogenital. All samples were ana-lyzed by Real-Time polymerase chain reaction (RT-PCR) for the presence of twelve High-risk (HR) and two low-risk (LR) HPV types.
Study II: HPV is prevalent in the head and neck in Zambia. The prevalence of HPV infection in the head and neck in Zambia was assessed in rural and urban populations, such as the Ndola and Mansi districts. HPV testing was done as described above on oral samples from 399 participants.
Study III: This study assessed the concordance between vaginal and cercal HPV infection. Vag-inal and cervical swabs were collected from 413 HIV-positive women in Rwanda. HPV was tested as described in the first paper.
Study IV: Genetics influences the development of chronic HPV infection. This study assessed the influence of genetics on the development of chronic HPV infection. The 385 women Living with HIV were recruited at baseline in 2021 and followed up after 2 years. HR and LR-HPV were tested both at baseline and at follow-up with RT-PCR. Single Nucleotide polymorphisms (SNPs) were tested on Blood samples collected at baseline using the Illumina Global Screening Array-Multi Disease version 3.
The results showed that HPV infection is prevalent in different mucous membranes in HIV-posi-tive concordant couples in Rwanda (Study I). Oral HPV prevalence is low in Zambia (Study II). HPV infection is concordant in vaginal and cervical; vaginal samples could be used for HPV screening in the future in Rwanda (Study III). The rs13158830 SNP in intro 1 of PPARGC1B was the most significant identified (Study IV).
In the thesis, we addressed the prevalence of HPV in other mucous membranes. The high concordance between vaginal HPV and cervical HPV confirmed that vaginal HPV screening is representative of cervical HPV status and could be used in the future in Rwanda. Finally, we showed that SNPs are linked to the contraction of HPV and the development of chronic HPV infections. We pointed out future research interest in genetic biomarkers.