Whilst the missense polymorphism (1858C>T ; rs2476601) in the PTPN22 gene has recently been shown to be associated with risk of developing rheumatoid arthritis, as well as some other autoimmune diseases (such as lupus and type 1 diabetes), the potential influence of the gene on clinical outcomes has previously been unclear. As such, the study team aimed to investigate the extent to which the PTPN22 polymorphism was associated with the presence of autoantibodies and rate of radiographic progression in rheumatoid arthritis.
The team genotyped a cohort of 238 Norwegian rheumatoid arthritis patients (56% RF positive, aged between 20 to 70 years, with an average disease duration of 2.3 years). Radiographic damage was assessed by hand radiographs scored with the van der Heijde modified Sharp score (vdH Sharp score) by one reader.
Results from the study revealed RA association with carriage of the T allele (34.6 % in patients vs 21.4 % in controls; OR=1.94 (1.35-2.79), p= 0.0003) as well as an association between annual progression rate of vdH Sharp score and T-allele carriers (p=0.01).
No significant association was observed between the presence of the T-allele and either RF status (36% in RF+ vs 33% in RF-) or anti-CCP status (37% in anti-CCP+ vs 31% in anti-CCP-). To look for evidence of epistasis between PTPN22 and DRB1, the team also stratified for presence or absence of the shared epitope (SE), however no difference was seen between the two groups.
"Results from this study reveal the PTPN22 gene risk variant was associated with the progression rate for the articular damage" explained Dr. Benedicte Lie, Institute of Immunology, Rikshospitalet University Hospital, Oslo, Norway, and the study's lead author. "Our findings indicate that this candidate gene is associated not only with disease susceptibility, but also with disease progression – a potentially valuable discovery in the search for effective treatments to treat and ultimately prevent onset of rheumatoid arthritis" she continued.
For further information on this study, or to request an interview with the study lead, please do not hesitate to contact the EULAR congress press office on:
Jim Baxter - Onsite tel: +44 (0) 7900 605652
Jo Spadaccino - Onsite tel: +44 (0) 7773 271930
Mia Gannedahl - Office tel: +44 (0) 20 7331 2325
Abstract number: OP0068
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
Published on PsychCentral.com. All rights reserved.