ISR Autumn Meeting 2016

Clinical Poster

Ali Al Shamsi
Department of Rheumatology and Diagnostic Imaging*, St Vincent’s University Hospital, Dublin.

Poster (16A126)

Spinal Magnetic Resonance Imaging (MRI) manifestations in axial psoriatic arthritis patients with specific genotypes.

Author(s)

Ali Al Shamsi, Natsumi Ikumi, Phil Gallagher, Eric Heffernan*, Oliver FitzGerald preprocess

Department(s)/Institutions

Department of Rheumatology and Diagnostic Imaging*, St Vincent’s University Hospital, Dublin. 

Introduction

Our previous studies have shown that symmetrical involvement of the sacroiliac joints is associated with the presence of HLA-B27 whereas asymmetrical involvement is strongly associated with HLA-B08. Furthermore, McGonagle et al have previously shown that HLA-B27 positivity defines a group of PsA patients with more severe axial bone marrow edema that is likely related to the classic AS phenotype. Clinically, HLA-B27-negative PsA is more likely to be reported as a "negative" MRI examination result. In this study, we further examine and compare the clinical and MRI features of spinal involvement in our PsA patients defined by the presence of HLA-B27 or HLA-B08.  

Aims/Background

To describe the clinical and spinal MRI features in axial PsA patients who have either HLA-B08 or HLA-B27 genotypes. 

Method

40 patients with PsA all meeting CASPAR criteria and who had previous evidence of sacroiliac disease from our recent cohort study, were divided into three groups: either HLA-B08, (n= 24), HLA-B27 (n=12) or both HLA-B08 and HLA-B27 (n=4) genotypes. Assessments detail in table 1. 37 patients underwent thoracolumbar spinal MRI evaluation; 3 further in progress. Scans were analyzed blind to the clinical or genetic data by consultant musculoskeletal radiologist. Features evaluated included presence/location of bone marrow edema (BME), syndesmophyte formation, and presence of enthesitis or synovitis. Spinal MRI findings were considered asymmetric when the ratio between right and left sided involvement of the spine is < 50%; findings were considered symmetric when the ratio is > 50%. 

Results

Clinical features in patients with HLA-B08 and HLA-B27 genotypes were similar (Table1).  Patients with HLA-B08 were older with more asymmetric sacroiliac involvement as previously described. While there was no difference in presence/location of bone marrow edema, syndesmophyte formation, and presence of enthesitis or synovitis, patients with HLA-B08 had more asymmetrical spinal involvement on MRI while HLA-B27 positive patients had more symmetrical disease (Table 2). Finally, there was no correlation observed between measures of clinical disease activity (defined as BASDAI >4) and activity on MRI defined by presence of BME (6 vs 9 in HLAB 08 and 3 vs 5 patients in HLAB 27 respectively ); only 4 patients (3 HLAB 08; 1 HLAB 27) had a combination of both clinical activity and BME.   

Conclusions

This study suggests that symmetry or asymmetry of spinal disease in PsA may be dependent on patient genotype. Furthermore, spinal MRI identifies spinal inflammation where clinical assessments suggest good disease control.

Note: this abstract is only for poster.

IIS funded by AbbVie. 

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