Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Association Between Human Leukocyte Antigen and Killer-Cell Immunoglobulin-Like Receptor Gene Variants and Type II Psoriasis and Dactylitis in Psoriatic Arthritis.

Chandran1,  Vinod, Pellett1,  Fawnda, Thavaneswaran1,  Arane, Pollock1,  Remy, Ayearst1,  Renise, Gladman2,  Dafna D.

Toronto Western Hospital and University of Toronto, Toronto, ON
Toronto Western Hospital, University of Toronto, Toronto, ON

Background/Purpose:

HLA and KIR genes are associated with PsA. However, since the vast majority of patients with psoriatic arthritis (PsA) have associated cutaneous psoriasis it is difficult to determine whether the primary association is with musculoskeletal disease or with skin disease. Markers associated with Type II psoriasis (onset after age 40 years) as well as dactylitis are likely markers for musculoskeletal disease in PsA. We therefore conducted association studies to identify HLA alleles and KIR genes associated with type II psoriasis as well as with dactylitis in subjects with PsA.

Methods:

135 PsA cases with type II psoriasis and 688 healthy ethnically matched controls were selected to study association between PsA and type II psoriasis. For the study on dactylitis, a case-only study comparing 378 subjects with dactylitis to 299 without dactylitis was performed. KIR typing was performed by PCR-SSP, and HLA typing by PCR-SSO with appropriate quality control. The difference in the frequency of individual markers in cases and controls were tested for significance using c2 test and Fisher's exact test. Trends for increasing susceptibility to PsA from combined genotypes (HLA-KIR and HLA) were evaluated by the Cochran-Armitage trend test. Multivariate analyses were conducted using logistic regression.

Results:

When comparing PsA with type II psoriasis to controls, HLA- C*01, C*12, B*27, B*38 increased risk, whereas HLA-B*51 decreased risk in univariate analyses. Multivariate analysis showed that only HLA B*27 (OR 3.3, p<0.0001, 95% CI 1.94, 5.61) and HLA B*38 (OR 8.95, p<0.0001, 95% CI 4.33, 18.49) independently increased risk. HLA-B Bw4 and KIR2DS2 was also associated with PsA and type II psoriasis. When comparing PsA with dactylitis to PsA without dactylitis only HLA-C *02 and -B*27 was associated with dactylitis in univariate analyses. Multivariate analysis confirmed that both HLA- C*02 (OR 1.85, p=0.05, 95% CI 1.01, 3.38) and -B*27 (OR 1.74, p=0.03, 95% CI 1.06, 2.85) were independently associated with dactylitis. KIR2DS2 was also associated with dactylitis in univariate and multivariate analysis.

Conclusion:

HLA-C*02, -B*27, -B*38 and KIR2DS2 may be specific markers for musculoskeletal disease in PsA. These results need to be confirmed in large scale studies comparing well-phenotyped patients with PsA to those with psoriasis without PsA.

To cite this abstract, please use the following information:
Chandran, Vinod, Pellett, Fawnda, Thavaneswaran, Arane, Pollock, Remy, Ayearst, Renise, Gladman, Dafna D.; Association Between Human Leukocyte Antigen and Killer-Cell Immunoglobulin-Like Receptor Gene Variants and Type II Psoriasis and Dactylitis in Psoriatic Arthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1360
DOI:

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