The Molecular Biology and Treatment of Systemic Vasculitis in Children

HLA-DRB1 gene polymorphisms in Iranian children with Henoch-Schönlein purpura

BACKGROUND

People of all ages can suffer from Henoch-Schönlein purpura (HSP), but it is the most common vasculitis in childhood. The most important involving gene is located on chromosome 6p21.3, a region coding for human leukocyte antigens (HLAs). Among HLA genes, because of the high rate of polymorphisms, HLA-DRB1 is estimated to have a strong association with HSP. In this study, we aimed to assess the association of HLA-DRB1 alleles with HSP in Iranian children.

MATERIALS AND METHODS

This study consisted of thirty Iranian children with HSP and 35 healthy controls. Genomic DNA was extracted, and HLA typing was performed by polymerase chain reaction with sequence-specific primers technique.

RESULTS

The results have shown that HLA-DRB1*01 and HLA-DRB1*11 (P = 0.002, odds ratio [OR] = 7.579, confidence interval [CI] = 1.934-29.697 and P = 0.039, OR = 3.333, CI = 1.030-10.788), respectively, are the most frequent alleles associated with HSP in Iranian children population. The frequency of other alleles was not significantly different in both groups. The results also show no correlation between HLA types and disease manifestations.

CONCLUSION

According to these results, there is an association between HLA-DRB1*01 and HLA-DRB1*11 gene polymorphisms and susceptibility to HSP in our study group.

Vasculitis update: pathogenesis and biomarkers

Better understanding of the pathogenesis and treatment of primary systemic vasculitides (PSV) has led to the development of many potentially clinically relevant biomarkers. Genome-wide association studies have highlighted that MHC class II polymorphisms may influence the development of particular anti-neutrophil cytoplasmic antibody (ANCA) serotypes, but not the clinical phenotype of ANCA-associated vasculitis (AAV). Although ANCAs are overall poor biomarkers of disease activity, they may be useful for the prediction of flares of renal and/or pulmonary vasculitis. Moreover, patients with proteinase 3 (PR3)-AAV may respond better to rituximab than cyclophosphamide. Newer biomarkers of renal vasculitis in AAV include urinary soluble CD163, and may in the future reduce the requirement for renal biopsy. Better understanding of dysregulated neutrophil activation in AAV has led to the identification of novel biomarkers including circulating microparticles, and neutrophil extracellular traps (NETs), although their clinical utility has not yet been realised. Studies examining endothelial injury and repair responses have additionally revealed indices that may have utility as disease activity and/or prognostic biomarkers. Last, next-generation sequencing technologies are revealing monogenic forms of vasculitis, such as deficiency of adenosine deaminase type 2 (DADA2), and are profoundly influencing the approach to the diagnosis and treatment of vasculitis in the young.