Association Between HLA Class II Genes and Autoantibodies to Cyclic Citrullinated Peptides (CCPs) Influences the Severity of Rheumatoid Arthritis.
van Gaalen, Floris A. MD 1; van Aken, Jill MD 1; Huizinga, Tom W. J. MD, PhD 1; Schreuder, Geziena M. Th. PhD 1; Breedveld, Ferdinand C. MD, PhD 1; Zanelli, Eric PhD 1; van Venrooij, Walther J. PhD 2; Verweij, Cornelis L. PhD 3; Toes, Rene E. M. PhD 1; de Vries, Rene R. P. PhD 1
[Article] Arthritis & Rheumatism. 50(7):2113-2121, July 2004.

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Objective: The functional role of HLA class II molecules in the pathogenesis of rheumatoid arthritis (RA) is unclear. HLA class II molecules are involved in the interaction between T and B lymphocytes required for long-lived B cell responses and generation of high-affinity IgG antibodies. We undertook this study to investigate the relationship between HLA class II gene polymorphisms and RA-specific IgG antibodies against cyclic citrullinated peptides (anti-CCP antibodies).

Methods: High-resolution HLA-DR and DQ typing and anti-CCP-2 antibody testing were performed on 268 RA patients from the Early Arthritis Clinic cohort at the Department of Rheumatology of the Leiden University Medical Center. The presence of anti-CCP antibodies was analyzed in carriers of the different DR and DQ alleles. Disease progression was measured over a period of 4 years by scoring radiographs of the hands and feet using the Sharp/van der Heijde method.

Results: Carriership of the individual alleles HLA-DRB1*0401, DRB1*1001, DQB1*0302, and DQB1*0501 was associated with the presence of anti-CCP antibodies. Carriers of DQ-DR genotypes containing proposed RA susceptibility alleles were significantly more often anti-CCP antibody positive. Carriership of one or two HLA-DRB1 shared epitope (SE) alleles was significantly associated with production of anti-CCP antibodies (odds ratio [OR] 3.3, 95% confidence interval [95% CI] 1.8-6.0 and OR 13.3, 95% CI 4.6-40.4, respectively). An increased rate of joint destruction was observed in SE , anti-CCP patients (mean Sharp score 7.6 points per year) compared with that in SE-, anti-CCP patients (2.4 points per year) (P = 0.04), SE , anti-CCP- patients (1.6 points per year) (P < 0.001), and SE-, anti-CCP- patients (1.6 points per year) (P < 0.001).

Conclusion: HLA class II RA susceptibility alleles are associated with production of anti-CCP antibodies. Moreover, more severe disease progression is found in RA patients with both anti-CCP antibodies and SE alleles.

(C) 2004, American College of Rheumatology