Clinical background
The major histocompatibility complex (MHC) is the genetic region that contains the most polymorphic loci of the human genome. It is involved in the mechanism of antigen presentation and, as such, defines the general immunological response.
Within the MHC, the allelic family HLA-B*27 is part of the HLA-B locus. The frequency of individuals carrying HLA-B*27 varies widely across populations, being approximately 7-9% in Caucasians.
The first leukocyte antigen (HLA) haplotype association with human inflammatory disease was discovered in 1972, correlating HLA-B*27 with ankylosing spondylitis (AS). This remains one of the strongest known relationships between a major histocompatibility complex antigen and a disease. HLA-B*27 alleles are present in up to 90% of patients in the majority of ethnic groups that suffer from AS.
In a similar way, high prevalence of this antigen was shown in other HLA-B*27 associated disorders including reactive arthritis (previously referred to as Reiter syndrome) (60-70%), psoriatic arthritis (14-40%), juvenile enthesitis related arthritis (60-90%) and acute anterior uveitis (50%).
Source: manufacturer product information, Blackhills Diagnostic Resources.
