One study that is currently submitted for publication has examined Hepatitis B infection and host genetics. Hepatitis B viral infection remains a serious global health problem despite the availability of a highly effective vaccine. Approximately 5% of HBV-infected adults develop chronic hepatitis B, which may result in liver cirrhosis or hepatocellular carcinoma. Variants of interleukin-10 (IL10) have been previously associated with chronic hepatitis B infection and progression to hepatocellular carcinoma. Single nucleotide polymorphisms (SNPs, n = 42) from the IL10, IL19, and IL20 gene regions were examined for an association with HBV infection outcome, either chronic or recovered, in a nested case-control study of African Americans (AA) and European Americans (EA). Among AA, three SNPs in IL10, two SNPs in IL20, and one haplotype in IL20 were statistically significantly associated with HBV infection outcome (P = 0.005-0.04). The SNP, rs1518108 in IL20, deviated significantly from Hardy-Weinberg equilibrium in AA, with a large excess of heterozygotes in chronic HBV-infected cases (P = 0.0006), suggesting a strong genetic effect. Among EA, one SNP and one haplotype in IL20 were significantly associated with HBV recovery (P = 0.01-0.04). These results support the hypothesis that IL10 and IL20 gene variants influence HBV infection outcome and encourage the pursuit of further studies of these cytokines in HBV pathogenesis. Another that is in progress has examined the Y chromosome in regards to HIV-1/AIDS. Major haplotype groups of the Y chromosome are being examined in regards to infection and progression.