Progression of HIV to AIDS: a protective role for HLA-B27?

Abstract

HLA-B27 is known for its strong association with inflammatory spondyloarthropathies (SpA), a group of rheumatic diseases. Apart from playing its role in the onset of these inflammatory diseases, HLA-827 is so ubiquitous in the world that the carrying of this gene must have also have an advantage. There are some indications that a beneficial effect can be found as a less severe course of viral infections among B27-carriers. The literature on this subject was reviewed and revealed a favorable course of infection with influenza virus, herpes simplex type 2 virus, Epstein-Barr virus and, even more interesting, a protective effect of HLA-B27 in the progression of HIV infections. The course of HIV infection differs among individuals and is thought to be partly related to host-factor variability, reflecting broad genetic heterogeneity. The polymorphic human leukocyte antigens (HLA) are herein analyzed intensively with respect to this relationship. Cytotoxic T lymphocyte (CTL) responses, activated by HLA antigen presentation, are implicated in the control of HIV replication. An immunological explanation for the protective role for HLA B27 in HIV disease is that B27+ patients have a specific and strong CTL response against the p24 epitope, a conservative HIV protein that does not easily mutate. Some HLA genes seen in long-term non-progressors (LTNP) (>10 years disease free) are associated with a favorable prognosis. One of the alleles found predominantly in LTNPs is HLA-B27. More genetic factors seem to influence disease progression in HIV infections. Therefore, it would be interesting to further explore the influence of the genetic make up of these HIV-infected individuals. Knowledge of the immunogenetic profile might give clues for the individual course of the HIV infection, may influence the development of drug-resistant viruses and will possibly lead to a tailored therapeutic strategy in HIV-infected persons.