Abstract
Background: About 30% of cases with psoriasis suffer from psoriatic arthritis (PsA). Heritable element plays a role in PsA as different genes are involved. However, few genes are involved in both psoriasis and PsA. This study aimed to investigate the predictive value of Toll-like receptor (TLR) 4 and colony stimulating factor (CSF) 2 gene expression for early detection of axial spondyloarthritis in psoriatic patients. Methods: This study included 200 subjects; 100 psoriatic patients subdivided into two groups; Group 1: included 66 patients with plaque psoriasis without any articular complaint, and Group 2: included 44 patients with psoriatic arthritis. Group 3 included: 100 age and sex matched healthy controls. Laboratory assessment of TLR4 and CSF2 gene expression by real time polymerase chain reaction technique, and axial joint radiological assessment by Magnetic Resonance Imaging.
Results: There were significant increase of CSF2 and TLR4 gene expression levels in cases compared with controls (p <0.001) for both. Additionally, a significant rise of CSF2 and TLR4 gene expression levels in cases with psoriatic arthritis compared to cases with psoriatic skin affection only (U=2.45, p= 0.01, 3.34, p= 0.001 respectively. Receiver operating characteristic curve done for earlier detection of sub-clinical changes of axSpA regarding positive MRI results in cases with psoriasis and PsA respectively with P value <0.001.
Conclusion: TLR4 and CSF2 gene expression have strong predictive value in early detection of axial SpA changes in asymptomatic and non-radiographic psoriatic patients which is equivalent and equal to MRI predictive value.
Key words: psoriasis- psoriatic arthritis