Genes encoding SLAM family receptors are located at 1q23, implicated in systemic lupus erythematosus (SLE). In this study, we have investigated

the expression and alternative splicing of CS1 and 2B4 in immune cells from SLE patients. The surface expression of CS1 and 2B4 on total peripheral find more blood mononuclear cells (PBMCs), T, B, natural killer (NK) cells and monocytes in 45 patients with SLE and 30 healthy individuals was analysed by flow cytometry. CS1-positive B cell population was increased significantly in SLE patients. Because CS1 is a self-ligand and homophilic interaction of CS1 induces B cell proliferation and autocrine cytokine secretion, this could account for autoreactive B cell proliferation in SLE. The proportion of NK cells and monocytes expressing 2B4 on their surface was significantly lower in patients with SLE compared to healthy controls. Our study demonstrated altered expression of splice variants of CS1 and 2B4 that mediate

click here differential signalling in PBMC from patients with SLE. Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease, characterized by the improper regulation of B cells that leads to the production of autoantibodies. The incidence of disease is gender-biased, with a female to male ratio of 9 : 1, and the onset of disease is usually during the child-bearing years [1]. Using lupus model mice such as MRL/lpr, NZB/NZW and NZM2410, which develop SLE spontaneously, Etofibrate mouse chromosome 1 has been shown to contain lupus susceptibility genes [2–5]. Genomic characterization of the Sle1b locus, the most potent member of lupus susceptibility region on murine chromosome 1, identified a highly polymorphic cluster of genes coding for the signalling lymphocyte activation molecule (SLAM) family receptors [6]. Similarly, genome-wide linkage analyses of SLE families have shown a strong association of SLE with the 1q23 region of the human genome, which also includes SLAM family receptors [7–9].

SLAM family receptors are expressed broadly on haematopoietic cells, and play an important role in immune regulation. Members of this family are SLAM (SLAMF1, CD150), CD229 (SLAMF3, Ly-9), 2B4 (SLAMF4, CD244), CD84 (SLAMF5), NTB-A (SLAMF6; Ly108 in mouse) and CS1 (SLAMF7, CRACC, CD319). All these receptors have immunoreceptor tyrosine-based switch motifs (ITSMs) in their intracellular domain, which can be bound by small adaptor proteins such as SLAM-associated protein (SAP, SH2D1A), Ewing’s sarcoma (EWS)-activated transcript 2 [Ewing's sarcoma-activated transcript-2 (EAT-2), SH2D1B] and EAT-2-related transducer (ERT, SH2D1C, only in rodents). Mutations in SH2D1A, the gene encoding SAP, are responsible for the primary immunodeficiency X-linked lymphoproliferative disease (XLP) in humans [10–12].