Pas de quatre: an interaction of HLA-B*27:05 and KIR3DL2 homodimers in spondyloarthropathies

The effect of LILRB1 but not LILRA3 gene polymorphism in immunopathology of ankylosing spondylitis-A parallel to KIR genes

LILR and KIR receptors recognize HLA-B27 and may influence immune response in ankylosing spondylitis (AS) development. Purpose of the study was to analyse LILRB1/LILRA3 polymorphisms in AS. We observed a possible protective effect of the T allele of LILRB1 rs1061680:T>C and no association with insertion/deletion polymorphisms of LILRA3 with AS.

Role of HLA-B27 in the pathogenesis of ankylosing spondylitis (Review)

The study of ankylosing spondylitis (AS) has made significant progress over the last decade. Genome-wide association studies have identified and further substantiated the role of susceptibility genes outside the major histocompatibility complex locus. However, human leukocyte antigen (HLA)-B27 has been suggested to be important in the pathogenesis of AS, contributing to ~20.1% of AS heritability. The current review will present the classical and non-classical forms of HLA-B27, as well as their pathogenic roles, and further discuss the hypotheses regarding the potential pathogenesis of AS. In addition, the association between the pathogenic role of HLA-B27 and inflammatory indexes, including the interleukin-23/−17 axis will be investigated to provide novel insights into the pathogenesis of AS. The aim of the present review is to provide an update of the current research into the pathogenesis of AS, and provide a comprehensive description of the pathogenic role of HLA-B27 in AS.

Presence of the full-length KIR2DS4 gene reduces the chance of rheumatoid arthritis patients to respond to methotrexate treatment

Background

KIR genes coding for natural killer cell immunoglobulin-like receptors, KIR, influence the effector and regulatory function of NK cells as well as some subpopulations of T lymphocytes (e.g. CD4+CD28-KIR+) depending on presence of ligands (particularly HLA-C molecules). KIR-KIR ligand interaction may lead to the development of autoimmune disorders, including rheumatoid arthritis (RA). However, their role in the response of RA patients to methotrexate therapy is not known.

Methods

KIR genes and KIR-ligand (HLA-C C1/C2 allomorphs) genotyping was performed using the PCR-SSP method in 312 RA patients (179 classified as good responders and 133 as poor responders using DAS28 criteria). Thus, we evaluated the association of KIR genes and HLA-C allomorphs with the response to methotrexate (MTX) treatment.

Results

We observed that patients possessing the full-length KIR2DS4 (KIR2DS4f) gene had a lower chance of responding in comparison to KIR2DS4f-negative cases. This phenomenon was observed both in erosive disease (ED) and rheumatoid factor (RF) positive and in ED- and RF-negative patients. Interestingly, the observed effect of the KIR2DS4f gene was strongest in individuals possessing medium values (20-33 mm/h) of the erythrocyte sedimentation rate (ESR). Patients with high ESR values had low probability and, in contrast, patients with low ESR had a high probability of MTX response, and the presence of KIR2DS4f did not affect their outcome. Additionally, we show that the KIR2DS4f effect did not depend on the presence of either C1 or C2 allomorphs.

Conclusion

Our results suggest that the response of RA patients with medium ESR values to MTX treatment may be dependent on the full-length KIR2DS4 gene.