HLA class II alleles have been associated with an increased risk of developing cervical cancer through infection with oncogenic forms of human papilloma virus (HPV). We have examined the association of variation at the DRB1 and DQB1 loci with HPV16 infection and risk of development of cervical cancer by analysis of 440 cases diagnosed with cervical cancer in situ and 476 age-matched controls in a retrospective casecontrol study. The infection history of a woman was studied by analysis of cervical smears taken at multiple times during a period of up to 27 years (1969 -95
Key words: HLA; HPV; cervical cancerInfection with oncogenic forms of human papillomavirus (HPV) is the major etiologic factor for the development of cervical cancer. Using sensitive detection methods, oncogenic HPVs have been found in almost every cervical tumor. 1,2 However, infection with oncogenic HPVs is common among women having normal cytology, 3 mild lesions regress without intervention and most infections are cleared spontaneously. This implies that factors determining the course of an HPV infection contribute to the risk of developing cervical cancer. Such factors may include the inherent ability to respond to HPV infection.It has been suggested that differences in the immune response to HPV affect whether an HPV infection is cleared or becomes persistent. 4 Given the pivotal role of HLA molecules in the recognition of foreign peptides, several studies have been performed to examine the association of specific HLA alleles with HPV infection status and development of cervical cancer. In 1991, the HLA-DQw3 antigen was reported to be associated with cervical cancer in a German cohort, 4 and later studies in Spanish, 5 British 6 and African-American cohorts 7 showed similar results. Other HLA alleles have also been proposed to increase the risk of cervical cancer: DRB1*1501, 5,8 DRB1*04 and DRB1*11. 9 A number of alleles that are less common in patients relative to controls have also been reported, e.g., DRB1*1301, 8 DQB1*0501 9 and DQB1*0603. 5 An increased risk for HPV16-associated cervical cancer has been reported for the DRB1*1501-DQB1*0602 haplotype, 10 the DQA1*0102-DQB1*0602 haplotype 11 and for the DRB1*0701 allele. 12,13 Finally, an HPV16-specific protective effect for DR13 alleles has been reported. 10 While a direct comparison between these studies is somewhat difficult due to differences in cancer stage studied, laboratory methods and study population, they indicate an effect of HLA alleles on risk of cervical cancer. In our study, we have used a large case-control material to investigate the association of HLA class II alleles with infection by HPV16 and to the risk of developing cervical cancer in situ. Our results show that HLA class II alleles are associated primarily with infection of HPV and only secondarily with cervical cancer.
MATERIAL AND METHODS
SubjectsThe participants in our study were selected from a cohort of women residing in Uppsala County, Sweden, between 1969 -95. 14 The participants had to fulfill the follow...