Sustained virological response in HIV/HCV co-infected patients treated with pegylated interferon/ribavirin can be predicted from the overall rate of viral load decline over the first 4 weeks of therapy

Human Leukocyte Antigen (HLA) and Immune Regulation: How Do Classical and Non-Classical HLA Alleles Modulate Immune Response to Human Immunodeficiency Virus and Hepatitis C Virus Infections?

The genetic factors associated with susceptibility or resistance to viral infections are likely to involve a sophisticated array of immune response. These genetic elements may modulate other biological factors that account for significant influence on the gene expression and/or protein function in the host. Among them, the role of the major histocompatibility complex in viral pathogenesis in particular human immunodeficiency virus (HIV) and hepatitis C virus (HCV), is very well documented. We, recently, added a novel insight into the field by identifying the molecular mechanism associated with the protective role of human leukocyte antigen (HLA)-B27/B57 CD8⁺ T cells in the context of HIV-1 infection and why these alleles act as a double-edged sword protecting against viral infections but predisposing the host to autoimmune diseases. The focus of this review will be reexamining the role of classical and non-classical HLA alleles, including class Ia (HLA-A, -B, -C), class Ib (HLA-E, -F, -G, -H), and class II (HLA-DR, -DQ, -DM, and -DP) in immune regulation and viral pathogenesis (e.g., HIV and HCV). To our knowledge, this is the very first review of its kind to comprehensively analyze the role of these molecules in immune regulation associated with chronic viral infections.

HCV viral decline at week 2 of Peg-IFN-alpha-2a/RBV therapy as a predictive tool for tailoring treatment in HIV/HCV genotype 1 co-infected patients

Background

Optimizing HCV genotype 1 therapy in terms of response prediction and tailoring treatment is undoubtedly the cornerstone of treating HIV co-infected patients in clinical practice. Accordingly, our aim was to analyze the predictive value of HCV viral decline for sustained virological response (SVR), measured at a time point as early as week 2 of therapy with pegylated interferon alpha-2a plus ribavirin (Peg-IFN/RBV).

Methods

Previously untreated HIV/HCV genotype 1 co-infected patients were included in this study. The HCV RNA titer was measured at week 2 after starting treatment with Peg-IFN/RBV. The likelihood of reaching SVR when HCV RNA viral titers declined at week 2 was evaluated relative to predictive baseline factors.

Results

A total of 192 HIV/HCV genotype-1 co-infected patients were enrolled in the study and began therapy. One hundred and sixty-three patients completed a full course of Peg-IFN/RBV treatment for 2 weeks and 59 of these (36.2%) reached SVR. An HCV RNA viral load decline of ≥1.5 log IU/mL at week 2 had the maximum positive predictive value for SVR (83.3%; 95% CI: 68.5%–92.9%) and was identified as the strongest independent predictive factor for reaching SVR across all baseline predictive factors.

Conclusions

HCV viral decline at week 2 had a high predictive value for identifying patients with a high and low likelihood of reaching SVR using dual therapy, regardless of strong predictive baseline factors. This finding may be useful for developing a predictive tool to help tailor HCV genotype 1 therapy in HIV co-infected patients.