Distribution of LILRA3 (ILT6/LIR4) deletion in psoriatic patients and healthy controls.

The leukocyte immunoglobulinlike receptor (LILRA3; ILT6) gene is localized on human chromosome 19 in the region 19q13.4, in the leukocyte receptor complex that encodes leukocyte receptors LILR (ILT/LIR), killer cell immunoglobulinlike receptors (KIR), LAIR, Fc IgA receptor, and others. The biologic role of the LILRA3 molecule and the nature of its ligand are not known. Comparison of LILRA3 gene sequence with those of other LILRs suggests LILRA3 is a soluble molecule. If LILRA3 binds human leukocyte antigen (HLA) class I molecules like other LILRs whose ligands are known, then it might block recognition of HLA by these receptors, influencing immune response and susceptibility to HLA class I associated disease. A deletion of LILRA3 gene was found in a minority of British population. We typed 108 healthy individuals from the Low Silesia region and 103 patients diagnosed with psoriasis vulgaris (a disease associated with HLA class I antigen, HLA-Cw6) for LILRA3 to examine whether LILRA3 deletion was distributed differently in patients affected with the disease. No differences in frequencies of the LILRA3 deletion were found between controls and patients or between HLA-Cw6(+) and HLA-Cw6(-) controls or patients, suggesting that LILRA3 has no role in psoriasis.