Figure 2.

Immunoglobulin-like transcript 3 (ILT3) expression levels on dendritic cells of healthy controls and systemic lupus erythematosus (SLE) patients. ILT3 expression levels on plasmacytoid dendritic cells (PDCs) and monocytoid dendritic cells (MDCs) was determined by flow cytometry as described in Materials and Methods. ILT3 levels on (A) PDCs and (B) MDCs are similar between healthy controls, SLE patients, and in SLE patient subgroups with high or low serum type I IFN activity. (C) Serum type I IFN activity of patients sampled for data in this figure. ILT3 levels on (D) PDCs and (E) MDCs vary between SLE patients when data is stratified by ILT3 genotype with the rs11540761 single nucleotide polymorphism associating with significantly lower ILT3 levels on MDCs (coding change affecting amino acid position 18, G(Ser) or T(Arg)). Genotypes are shown as allelic combinations, for ex. GG, homozygous for G allele; GT, heterozygous, etc. No subjects were homozygous for rs11540761 in the flow cytometry experiments. Specific fluorescent intensities (SFI) values equal the fold increase in geometric mean fluorescence intensities of cells incubated with anti-ILT3 IgG₁-PE to cells incubated with IgG₁-PE. Mean+SD are shown. SFI values were compared by Student’s unpaired t-test. N, number of subjects.