Phenotype Differences in HLA-B27 Positive Versus Negative Patients with Ankylosing Spondylitis in a Population That Show Relatively Weaker Association with HLA-B27

Handan Yarkan¹, Zhixiu Li², Gokce Kenar³, Sedat Capar⁴, Fernur Çapa⁵, Rudi Steffensen⁶, Servet Akar⁷, Dilek Solmaz⁸, Pınar Cetin⁹, Berrin Zengin³, Erika de Guzman¹⁰, Katie Cremin², Gerçek Can¹¹, Zeynep Yüce⁵, Ismail Sari¹², Fatos Onen¹³, Matt Brown² and Nurullah Akkoc¹⁴, ¹Rheumatology, Dokuz Eylul University Faculty of Medicine, İzmir, Turkey, ²Translational Genomics Group, Institute of Health and Biomedical Innovation, Queensland University of Technology, Translational Research Institute, Brisbane, Australia, Brisbane, Australia, ³Rheumatology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey, ⁴Statistics, Dokuz Eylul University School of Medicine, Izmir, Turkey, ⁵Department of Molecular Medicine, Dokuz Eylül University Health Sciences Institute, IZMIR, Turkey, ⁶Department of Clinical Immunology, Aalborg University Hospital, Aalborg, Denmark, ⁷Rheumatology, Izmir Katip Celebi University, School of Medicine, Rheumatology, Izmir, Turkey, ⁸Rheumatology, Izmir Katip Celebi University, School of Medicine, Rheumatology, izmir, Turkey, ⁹Rheumatology, Dokuz Eylul University Faculty of Medicine, izmir, Turkey, ¹⁰Translational Genomics Group, Institute of Health and Biomedical Innovation, Queensland University of Technology, Translational Research Institute, Brisbane, Australia, Brisbane, Austria, ¹¹TURKBIO, İzmir, Turkey, İzmir, Turkey, ¹²Rheumatology, Toronto Western Hospital, University of Toronto, Spondylitis Clinic, Toronto, ON, Canada, ¹³TURKBIO, İzmir, Turkey, Izmir, Turkey, ¹⁴Rheumatology, Private Practice, Rheumatology, İzmir, Turkey

Meeting: 2017 ACR/ARHP Annual Meeting

Date of first publication: September 18, 2017

Keywords: ankylosing spondylitis (AS) and human leukocyte antigens (HLA)

Session Information

Date: Monday, November 6, 2017

Title: Spondyloarthropathies and Psoriatic Arthritis – Clinical Aspects and Treatment Poster II

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose:

The association of HLA-B*27 and ankylosing spondylitis (AS) is relatively weak in some populations. The aim of this study is to compare the clinical manifestations between HLA-B*27⁺ and HLA-B*27^– patients in a Turkish AS population, which has been reported to have a low HLA-B*27 prevalence.

Methods:

A total of 881 AS patients and 900 healthy controls were included in the analysis. All patients fulfilled the modified New York criteria for AS. Clinical and demographic parameters were compared between the HLA-B*27⁺ and HLA-B*27^– patients. Group comparisons were performed using t-tests for continuous measures that were normally distributed and x2 tests were used for categorical measures.

Results:

HLA-B*27 was positive in 64% of patients (n=561) and 6.3% of controls (n=57). All results are summarized in Table 1. Seventy-four percent of the HLA-B*27⁺ patients and 60% of HLA-B*27^– patients were male (<0.001). HLA-B*27⁺ patients had a younger age at symptom onset, as well as a shorter delay in diagnosis. Moreover, uveitis and a family history for AS were significantly more frequent among HLA-B*27⁺ AS patients, whereas co-existent psoriasis and inflammatory bowel disease (IBD) were more frequent among HLA-B*27^– patients. Further, HLA-B27⁺ patients had a 22% higher CRP (P<0.05) and 13% higher ESR (P=0.06) than HLA-B*27^– patients. Prevalence of peripheral arthritis, dactylitis, biologic use, hip replacement surgery, family history for psoriasis or IBD or uveitis were not different between the two groups. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Metrology Index (BASMI) were also similar in both groups.

Conclusion:

The results of this study conducted in an AS population with a relatively low prevalence of HLA-B*27 are in line with those of other studies performed in other populations. HLA- B*27⁺ AS patients are more likely to be males and have an earlier age of symptom onset, and a shorter delay in diagnosis as compared to AS patients lacking HLA-B*27. Moreover, HLA-B*27⁺ AS patients show a greater risk for occurrence of acute anterior uveitis, a greater familial occurrence, and an elevated CRP/ESR, the latter suggesting that HLA-B*27 carriage influences degree of inflammation in AS.

*Table 1. Comparison of baseline characteristics between HLA-B27 positive and negative patients**
	HLA-B27⁺* (n=561)	HLA-B27^–* (n=257)	P value (n=818)
Male, n (%)	415 (%74)	154 (%59.9)	<0.001
Age, Mean ± SD (year)	43.8 ± 12.2	45.5 ± 12.4	0.07
Age at diagnosis, Mean ± SD (year)	34.1 ± 11.9	38.1 ± 12.5	<0.001
Age of symptom onset, Mean ± SD (year)	27.4 ± 10.1	30.2 ± 11.4	<0.001
Duration of axial symptoms Mean ± SD(year)	16.5 ± 11.1	15.3 ± 11.1	0.18
Delay in diagnosis, Mean ± SD (year)	6.9 ± 8	8.6 ± 9.2	0.009
Family history
Family history of AS, n (%)	207 (36.9%)	50 (19.5%)	<0.001
Family history of psoriasis, n (%)	15 (2.7%)	9 (3.5%)	0.5
Family history of uveitis, n (%)	12 (3.7%)	2 (1.3%)	0.13
Family history of IBD, n (%)	8 (2.5%)	4 (2.5%)	0.99
Peripheral arthritis, n (%)	249 (44.4%)	112 (43.6%)	0.83
Enthesitis, n (%)	222 (39.6%)	110 (42.8%)	0.4
Psoriasis, n (%)	14 (2.5%)	14 (5.4%)	0.03
Uveitis, n (%)	135 (24.1%)	27 (10.5%)	<0.001
IBD, n (%)	14 (2.5%)	24 (9.3%)	<0.001
Dactylitis, n (%)	39 (7%)	27 (10.5%)	0.08
Current biologic use, n (%)	168 (29.9%)	73 (28.4)	0.6
Ever biologic use, n (%)	183 (32.6%)	79 (30.7%)	0.6
Hip prothesis, n (%)	25 (4.5%)	9 (3.5%)	0.52
Elevated CRP, n (%)	353 (62.9%)	135 (52.5%)	0.005
CRP Mean ± SD (mg/l)	21.9 ± 26.2	18 ± 25.6	0.05
ESR, Mean ± SD (mm/h)	33 ± 25.6	29.3 ±23.9	0.06
BASDAI, Mean ± SD	3.7 ± 2.4	3.9 ± 2.3	0.22
BASFI, Mean ± SD	2.9 ± 2.7	3 ± 2.6	0.57
BASMI, Mean ± SD	3.1 ± 2.6	2.9 ±2.3	0.19

Disclosure: H. Yarkan, None; Z. Li, None; G. Kenar, None; S. Capar, None; F. Çapa, None; R. Steffensen, None; S. Akar, None; D. Solmaz, None; P. Cetin, None; B. Zengin, None; E. D. Guzman, None; K. Cremin, None; G. Can, None; Z. Yüce, None; I. Sari, None; F. Onen, None; M. Brown, None; N. Akkoc, None.

To cite this abstract in AMA style:

Yarkan H, Li Z, Kenar G, Capar S, Çapa F, Steffensen R, Akar S, Solmaz D, Cetin P, Zengin B, Guzman ED, Cremin K, Can G, Yüce Z, Sari I, Onen F, Brown M, Akkoc N. Phenotype Differences in HLA-B27 Positive Versus Negative Patients with Ankylosing Spondylitis in a Population That Show Relatively Weaker Association with HLA-B27 [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/phenotype-differences-in-hla-b27-positive-versus-negative-patients-with-ankylosing-spondylitis-in-a-population-that-show-relatively-weaker-association-with-hla-b27/. Accessed .

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