Session Information
Date: Wednesday, November 16, 2016
Title: Spondylarthropathies Psoriatic Arthritis – Pathogenesis, Etiology II
Session Type: ACR Concurrent Abstract Session
Session Time: 9:00AM-10:30AM
Background/Purpose: Enthesitis is an important pathophysiologic component in psoriatic arthritis (PsA). Ultrasound is emerging as an optimal method to evaluate enthesitis. HLA genes are implicated in the pathogenesis of PsA. Little is known about the relation between HLA genetic susceptibility markers and enthesitis in PsA patients. Hence, our aim was to examine the association between HLA genetic susceptibility markers and sonographic enthesitis in patient with PsA.
Methods: A cross-sectional analysis was performed in patients followed at a large PsA cohort. Sonographic enthesitis was assessed according to the MAdrid Sonography Enthesitis Index (MASEI) scoring system which quantifies the extent of sonographic entheseal abnormalities in 12 entheseal sites adjacent to large joints. Total MASEI was further categorized into: bone scores (enthesophytes, erosions) and soft tissue scores (structural entheseal changes, vascularization, bursitis). HLA genotyping was performed using sequence-specific oligonucleotide probes. The association between 6 HLA susceptibility markers of PsA and the severity of sonographic enthesitis (by MASEI) was assessed using multivariate linear regression models adjusted for age, sex, BMI and disease duration.
Results: Two hundred and twenty five patients were included, 57% male with mean (s.d.) age of 55.8 (12.9) years and PsA duration of 16.4 (12.3) years. The majority of the patients were Caucasians (88%). The frequencies of the HLA alleles were: HLA-B*27: 15.1%; HLA-B*38: 18.2%; HLA-B*39: 4.9%; HLA-B*44: 21.8%; HLA-B*08: 17.3% and HLA-C*06: 27.5%. In the univariate analysis HLA-B*27 (β 3.8, p=0.005) was associated with more severe enthesitis while HLA-C*06 (β -2.4, p=0.03) was associated with less severe enthesitis. The results of the multivariate regression model are shown in Table 1. The interaction between HLA-B*27 and PsA duration was statistically significant, showing an increasing effect of HLA-B*27 with longer PsA duration (p=0.004). The results remained essentially the same after restricting the analysis to Caucasians. Other predictors of enthesitis severity included male gender (p=0.02) and BMI (p<0.001). The interaction between HLA-B*27 and PsA duration was also associated with higher MASEI-bone scores (p=0.002). HLA-B*27 was also associated with higher MASEI-soft tissue scores (p=0.01).
Conclusion: HLA-B*27 is associated with the severity of sonographic enthesitis in PsA, particularly in patients with longer disease duration. This finding highlights the potential role of genetic variants to predispose to severe enthesitis in patients with PsA.
| Table 1: Multivariate Regression Model assessing the association between HLA alleles and MASEI score (Total MASEI include active GS and PD abnormalities) | ||||
|
Variable* |
Multivariate Model (N=225)
|
Multivariate Model (Caucasians) (N=196) |
||
|
Estimate (95% CI) |
P value |
Estimate (95% CI) |
P value |
|
| HLA-B*27 |
4.64 (0.39, 8.89) |
0.03 |
4.45 (0.12, 8.87) |
0.04 |
| HLA-B*27* PsA Duration |
4.78 (1.54, 8.02) |
0.004 |
4.62 (1.38, 7.87) |
0.005 |
| HLA-C*06 |
-2.27 (-5.62, 1.06) |
0.18 |
-1.52 (5.08, 2.03) |
0.40 |
| Age (10 years) |
1.02 (-0.26, 2.31) |
0.12 |
1.37 (0.01, 0.27) |
0.047 |
| Sex |
3.71 (0.67, 6.67) |
0.02 |
4.32 (1.10, 7.54) |
0.008 |
| BMI |
0.56 (0.31, 0.81) |
<0.0001 |
0.56 (0.30, 0.82) |
<0.0001 |
| PsA Duration (10 years) |
0.54 (-0.90, 2.00) |
0.46 |
0.54 (-0.95, 2.04) |
0.47 |
| *This model included variables that were statitically significant in the univariate analysis GS – Gray scale, PD – Power Doppler | ||||
To cite this abstract in AMA style:
Polachek A, Cook RJ, Chandran V, Abji F, Gladman DD, Eder L. The Association Between HLA Genetic Susceptibility Markers and Sonographic Enthesitis in Psoriatic Arthritis [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/the-association-between-hla-genetic-susceptibility-markers-and-sonographic-enthesitis-in-psoriatic-arthritis/. Accessed .« Back to 2016 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-association-between-hla-genetic-susceptibility-markers-and-sonographic-enthesitis-in-psoriatic-arthritis/