Agregación de autoinmunidad en familias extremas con Síndrome de Sjogren: una aproximación a la medicina personalizada

Objetivo: investigar la agregación de autoinmunidad en familiares en primer grado (FPG) de probandos con Síndrome de Sjogren (SS) con poliautoinmunidad y autoinmunidad familiar. Metodología: estudio de corte transversal en el cual se incluyeron 14 familias de mujeres con SS. Se realizó un análisis genético a través del cálculo de riesgos relativos para cada enfermedad autoinmune (EAI). La agregación familiar se calculó para los FPG, teniendo en cuenta la prevalencia de la enfermedad en cada familia y en la población general. Resultados: Se analizaron un total de 112 individuos, con una media de edad de 51.7 años ± 12.9. Veintidós individuos de los FPG tuvieron al menos una EAI (28.2%). La prevalencia de poliautoinmunidad fue del 93% y 6.4% en probandos y FPG, respectivamente. Se observaron valores que soportaron la agregación familiar para varias EAIs, entre ellas púrpura trombocitopénica idiopática, granulomatosis con poliangeiitis, síndrome antifosfolipídico, lupus eritematoso sistémico y artritis reumatoide. Discusión: estos resultados indican que las EAIs se agregan entre familias con SS, sugiriendo un origen común entre ellas. La elección de fenotipos clínicamente relevantes representa una nueva aproximación a la medicina personalizada en autoinmunidad.

PTPN22 Association in Systemic Lupus Erythematosus (SLE) with Respect to Individual Ancestry and Clinical Sub-Phenotypes

Protein tyrosine phosphatase non-receptor type 22 (PTPN22) is a negative regulator of T-cell activation associated with several autoimmune diseases, including systemic lupus erythematosus (SLE). Missense rs2476601 is associated with SLE in individuals with European ancestry. Since the rs2476601 risk allele frequency differs dramatically across ethnicities, we assessed robustness of PTPN22 association with SLE and its clinical subphenotypes across four ethnically diverse populations. Ten SNPs were genotyped in 8220 SLE cases and 7369 controls from in European-Americans (EA), African-Americans (AA), Asians (AS), and Hispanics (HS). We performed imputation-based association followed by conditional analysis to identify independent associations. Significantly associated SNPs were tested for association with SLE clinical sub-phenotypes, including autoantibody profiles. Multiple testing was accounted for by using false discovery rate. We successfully imputed and tested allelic association for 107 SNPs within the PTPN22 region and detected evidence of ethnic-specific associations from EA and HS. In EA, the strongest association was at rs2476601 (P = 4.761029, OR = 1.40 (95% CI = 1.25–1.56)). Independent association with rs1217414 was also observed in EA, and both SNPs are correlated with increased European ancestry. For HS imputed intronic SNP, rs3765598, predicted to be a cis-eQTL, was associated (P = 0.007, OR = 0.79 and 95% CI = 0.67–0.94). No significant associations were observed in AA or AS. Case-only analysis using lupus-related clinical criteria revealed differences between EA SLE patients positive for moderate to high titers of IgG anti-cardiolipin (aCL IgG .20) versus negative aCL IgG at rs2476601 (P = 0.012, OR = 1.65). Association was reinforced when these cases were compared to controls (P = 2.761025, OR = 2.11). Our results validate that rs2476601 is the most significantly associated SNP in individuals with European ancestry. Additionally, rs1217414 and rs3765598 may be associated with SLE. Further studies are required to confirm the involvement of rs2476601 with aCL IgG.