Role of HLA-DRB1*04 in the susceptibility and HLA-DRB1*08 in the protection for development of rheumatoid arthritis in a population of Southern Mexico: brief report.

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease with an increased prevalence in Mexico. Although its etiology is unknown, its development can be influenced by environmental factors such as smoking and viral infections. But among the factors influencing susceptibility, it is the genetic factors that predominate, mainly the HLA-DRB1 genes, and specifically the alleles that have the shared epitope (SE). A transversal study was performed, in which 31 patients (28 women and 3 men) with RA, treated at the autoimmunity clinic of the High Specialty Hospital Ciudad Salud in Tapachula, Chiapas, southern México, were enrolled. Clinical, biochemical, and demographic data were analyzed; ESR (erythrocyte sedimentation rate), CRP (C-reactive protein), RF (rheumatoid factor), and ACPA (anticitrullinated peptide antibody) were recorded. All patients had at least one positive RA biological marker. For HLA alleles frequencies comparison, we enrolled ethnically matched healthy controls in a ratio of 3:1 for 25 cases and 4:1 for 6 cases in order to guarantee the balance between groups regarding the mean of age and proportion of gender (males vs females). HLA-DRB1*04 was found to be significantly increased in patients compared with ethnically matched healthy controls (p 0.0007, OR: 2.8, 95% CI 1.5-5.1); contrarily, DRB1*08 showed a protective effect (p 0.005, OR 0.1). This paper confirmed the involvement of HLA genes on risk determination for RA in a population of Mexican Mestizos from Tapachula, Chiapas. Key Points • HLA-DRB1*04 confirms the increased risk of rheumatoid arthritis. • HLA-DRB1*08 showed a more definite protective effect in southern Mexicans mestizos, a population with more Amerindian ancestry.

Inflammatory biomarkers, disease activity index, and self-reported disability may be predictors of chronic arthritis after chikungunya infection: brief report.

The chikungunya virus (ChikV) is a reemerging mosquito-borne pathogen that causes disabling chronic arthritis. The relationship between clinical evolution and inflammatory biomarkers in patients with ChikV-induced arthritis has not been fully described. We performed a prospective case series to evaluate the association among joint involvement, self-reported disability, and inflammatory biomarkers. Patients with ChikV infection were followed for 1 year. Joint involvement and self-reported disability were evaluated with disease activity index 28 (DAS-28) and World Health Organization Disablement Assessment Schedule II (WHODAS-II). Interleukin-6 (IL-6), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were used as biomarkers. Ten patients with mean age 48 ±15.04 years were included. Symptoms at diagnosis were fever, arthralgias, myalgias, rash, arthritis, nausea, vomiting, and back pain. Polyarticular involvement was present in seven cases. At diagnosis, measures were as follows: DAS-28, 5.08±1.11; WHODAS-II score, 72.3±10.3 %; CRP, 5.09±7.23 mg/dL; ESR, 33.5±17.5 mm/h; RF, 64±21.7 IU/mL; and IL-6, 17.6±10.3 pg/mL. Six patients developed subacute and chronic symptoms. During follow-up, DAS-28 index, WHODAS-II score, ESR, and IL-6 were statistically different in patients with subacute and chronic symptoms compared to those who resolved in the acute phase (p < 0.05). DAS-28 index, WHODAS-II score, and IL-6 were related to chronicity of articular symptoms and could be used as predictors of ChikV-induced arthritis.