Innate lymphoid cells are increased in systemic lupus erythematosus

Objective. Innate lymphoid cells (ILCs) are emerging mediators of immunity and accumulation of inflammatory ILC populations can occur in inflammatory-mediated conditions. We aimed to examine the proportion of different subgroups of ILCs in the peripheral blood of patients with systemic lupus erythematosus (SLE) to evaluate the pathogenesis of SLE. Methods. Peripheral blood mononuclear cells were collected from 51 SLE patients and 26 healthy controls. Subpopulations of ILCs were analysed by flow cytometry. Results. Compared with the control group, ILCs (Lin-CD127(+)CD45(+) cells) were higher in SLE patients (p<0.01), and the distribution of ILC population changed between groups, ILC1 (LinCD127(+)CD45(+)CRTH2-CD117-cells)/ILC3 (Lin-CD127(+)CD45(+)CRTH2-CD117(+)cells) count increased (p<0.0001) and correlated with nephritis and disease activity. Conclusion. We found that SLE is accompanied by alterations in circulating ILCs. Specifically, circulating ILC1s and ILC3s were significantly increased, whereas circulating ILC2s were significantly decreased in SLE, indicating abnormal ILC homeostasis.