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).
We genotyped 149 patients with SS and 749 healthy controls, using polymerase chain reaction to test for the presence or absence of ILT6.
Homozygous ILT6 deficiency was detected in 8% of SS patients and in only 3% of controls.
Our findings indicate that ILT6 deficiency may be a genetic risk factor for SS.