Research on juvenile SLE has shown that leukocyte-associated-immunoglobulin-like receptor 1 (LAIR1), one of the observably downregulated differential expression proteins in juvenile SLE patients, binds to the Src homologue 2 domain of protein tyrosine phosphatase non-receptor type 11 (PTPN11) through its two cytoplasmic tyrosine inhibitory motifs, and has a potential inhibitory effect on lymphocytes and leads to dephosphorylation of subsequent kinases. This evidence concerns the gene PTPN11 and systemic lupus erythematosus.