Objective: The immunoglobulin-like transcript (ILT) family is located in chromosomal region 19q13 and consists of a group of activating and inhibitory receptors. The ILT receptors are expressed on antigen-presenting cells (macrophages, dendritic cells, B lymphocytes), as well as on T cells and natural killer cells. ILT2 and ILT4 play a role in tolerance induction, and ILT3 has been shown to induce Treg cells. A homozygous deletion of ILT6 has been shown to be associated with multiple sclerosis. Since ILT6 may be a modulator of the immune system, we undertook this study to examine the association of ILT6 deficiency with Sjögren's syndrome (SS).
Methods: We genotyped 149 patients with SS and 749 healthy controls, using polymerase chain reaction to test for the presence or absence of ILT6.
Results: Homozygous ILT6 deficiency was detected in 8% of SS patients and in only 3% of controls.
Conclusion: Our findings indicate that ILT6 deficiency may be a genetic risk factor for SS.