Voelcker Academy

Research Symposium 2011


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Mary Shannon Difillipo

Association of SNPs on the MSC Loci with HIV/HCV serostatus in Intravenous Drug Users in Estonia

Mary Shannon Difillipo

Mentor(s): Dr. Sunil Ahuja

HIV has been problem worldwide for decades. It can be transferred through blood-blood, person-person, or mother- child. Many things can increase a person’s susceptibility to HIV infection such as environmental factors, viral factors, and host genetic factors. In many cases HIV is also know to be a co-infector with HCV especially in drug users. Recent studies from the genome-wide association study (GWAS) and candidate gene approaches found that few polymorphisms in Chromosome 6 at the MHC loci play a major role on viral control and susceptibility of HIV infection.


The specific aim of this project was to investigate the influence of 4 candidate single nucleotide polymorphisms at the human MHC locus on HIV, and HCV seropositivity and susceptibility in intravenous drug users of the Estonia cohort. This cohort is a seroprevalent cohort with HIV it also includes HCV (Hepatitis C), and HBV (Hepatitis B). My study focused on the influence of 4 candidate nucleotide polymorphisms (rs4418214, rs3131018, rs9264942, and rs2395029) at the human MHC locus and their influence on HIV susceptibility in the Estonia cohort. It was hypothesized that the previously identified SNPs that influence the CD4 count will greatly impact the serostatus of HIV/HCV in the Intravenous Drug Users of the Estonia cohort.


Through my research I found that the presence of the MICA SNP was greater in HCV and HIV co-infected individuals, statistically this shows that possessing at least one copy of this SNP have an almost 2 times greater risk of acquiring HCV and HIV, suggesting that this SNP has a very detrimental effect. This finding is in contrast with literature, where it was associated with a slower disease progression for HIV infection. The presence of the PSOR SNP was greater in both HCV single infected subjects and HCV/HIV dual infected subjects, statistically, compared to those double negative subjects, those who possess at least one copy of this SNP have a ~60% lower chance to be dual infected or HCV single infected. Surprisingly, although the CD4 SNP was believed to impact CD4 in normal Europeans, it did not impact the risk of HIV and/or HCV infection. Similarly, the influence of HCP5 SNP on HIV/HCV infection risk is not very high in my studied population. In summary, in a HCV/HIV dual infected cohort of Intravenous Drug Users, I found 2 SNPs that impacted risk of HIV/HCV infection, and they are in a co-infection dependent manor.

Collaborators: Mary Shannon Di Filippo, Shivali Chag, Weijing He, Sunil Ahuja PhD