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Open Access

Interleukin-6 receptor in the recent-onset rheumatoid arthritis

  • Marco Antonio Montes-Cano1,
  • Sonsoles Reneses1,
  • Jose Raul García-Lozano1,
  • Fuensanta Torrecillas1,
  • Cristina Abad-Molina1,
  • Alicia García1,
  • Antonio Núñez Roldán1 and
  • Maria Francisca González-Escribano1
Journal of Translational Medicine20119(Suppl 2):P39

Published: 23 November 2011


Rheumatoid ArthritisAspartic AcidHealthy Control GroupRs2228145 PolymorphismTaqman Assay


The α subunit of the soluble receptor interleukin-6 (sIL-6R) is mainly generated by shedding of the membrane-bound form. This process is influenced by a functional polymorphism (rs 2228145 A>C) resulting in a substitution of aspartic acid to alanine (D358A) at the proteolytic cleavage site.


To investigate the influence of the rs2228145 polymorphism in sIL-6R plasma levels.

Patients and methods

A total of 141 RA patients and 206 unrelated healthy individuals matched by age and gender were included in the study. RA patients were diagnosed according ACR criteria and they had less than 1 year of evolution at the study time. The sIL-6R protein levels were determined by an ELISA quantitative sandwich and the rs2228145 genotyping was performed using a Taqman assay. Non parametric tests (U Mann-Whitney and Kruskal-Wallis) were used for median comparison and the chi-square test for comparison of the genotypic distribution.


The sIL-6R median concentration was lower in patients than in healthy control group (164.4 ng/mL vs. 185.3 ng/mL, p=0.0002). Moreover, median of sIL-6R concentration was different according with the rs2228145 genotype in both groups, RA patients (AA: 135.8, AC: 189.3 and CC: 233.0, p <0.0001) and controls (AA: 142, AC: 200.2 and CC: 242.7, p <0.0001). When the patients and controls were stratified according to their genotypes (AA and AC+CC), the sIL-6R median concentration was lower in both patient groups compared with their corresponding healthy controls (p=0.01 for AA and p=0.04 for AC+CC). Finally, no differences in the distribution of the rs2228145 genotypes were found on comparing patient and control groups (p=0.18).


The functional Asp358Ala polymorphism influences the sIL-6R concentration. Nevertheless, additional factors are necessary to explain the lower sIL-6R concentration found in patients since the differences among both groups remain after stratification by genotypes.

Authors’ Affiliations

Servicio de Inmunología, Hospital Virgen del Rocío/IBIS, Sevilla, Spain


© Montes-Cano et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.