IL-17 in cutaneous lupus erythematosus

Lupus erythematosus (LE) is a heterogeneous disease with broad clinical spectrum from cutaneous to visceral and systemic inflammation. IL-17 isoforms (IL-17A and IL-17F) are proinflammatory cytokines with unclear implications in lupus erythematosus pathogenesis. In this study we focused upon IL-17 in normal and modified lupus skin with a correlative study between local and serological expression.

89 subjects were recruited and divided in 5 groups-10 patients with psoriasis (disease control group), 13 healthy controls, 26 with discoid chronic lupus (DLE), 23 with systemic lupus erythematosus (SLE) and 17 with subacute lupus erythematosus (SCLE). Blood samples and skin punched-biopsy specimens were performed. Serum IL-17A, IL-17F, and IL-23 concentrations were determined by ELISA. Skin IL-17A and CD4 expression were evaluated by immunohistochemistry.

Immunohistochemical expression of IL-17A was higher in DLE, SCLE and SLE patients than in negative control subjects (all p<0.05). Serum IL-17A concentrations were higher in DLE and SLE patients than in negative controls (p<0.05). Serum IL-17A levels were similar in SCLE and negative controls (p>0.05). Serum IL-17F concentrations were higher in DLE, SCLE and SLE patients than in healthy controls (all p<0.05). In DLE, SCLE, SLE patients and healthy controls we observed comparable levels of IL-23 (p>0.05). Serum anti Ro antibodies correlate with IL-17A+ lymphocytes from SCLE lesion and SLE normal skin (all p<0.05).

IL-17 isoforms (IL-17A and IL-17F) are implicated in SLE but also in DLE and SCLE immunopathogenesis.