1. To evaluate the frequency of LILRA3 in Ankylosing spondylitis and Axial psoriatic arthritis patients.
2. To investigate the association of LILRA3 with Ankylosing spondylitis and Axial psoriatic arthritis disease activity and severity.

Axial spondyloarthritis (axSpA) is a complex inflammatory condition that affects the axial skeleton including the sacroiliac joints and the spine (1). It also affects peripheral joints and can be associated with extra-musculoskeletal manifestations including uveitis, psoriasis, and inflammatory bowel disease (1).

Axial spondyloarthritis include ankylosing spondylitis (AS), certain forms of psoriatic arthritis (PsA), reactive arthritis with axial involvement, and arthritis associated with inflammatory bowel disease (2).

The diagnosis of axSpA remains very challenging with years of delays attributed to several different factors. There is also a strong need to identify new serological biomarkers that can aid clinicians for diagnosis of axSpA.

Leucocyte immunoglobulin-like receptor A3 (LILRA3) belongs to a family of leucocyte receptors produced as a soluble molecule by monocytes and macrophages. (3) The function of LILRA3 remains obscure, but LILRA3 could bind to HLA class I molecules HLA-G and HLA- C (4) and may act as an antagonist on other LILRs or a soluble ligand to other receptors(5) Growing evidence shows that (LILRA3) is associated with many autoimmune disorders.(6) (7) The functional LILRA3 is a susceptibility factor for AS and axial psoriatic arthritis (axPsA) has not been investigated.

Inclusion Criteria:Adult AS and axPsA patients <18 years Who fulfilled the Assessment of SpondyloArthritis international Society (ASAS) criteria for axSpA.

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Exclusion Criteria:1-patients less than 18 years old

2-Individuals with other autoimmune diseases

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Egyptian population