Background. Type I interferon (IFN) has been reported to have an important role in the development of cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE). A new subset of CD4+ T cells, T helper (Th)17 cells, also plays a role in the development of autoimmunity.

Aim. To investigate expression of interleukin (IL)‐17 and IFN‐α in different CLE subsets, and their associations with the pathogenesis of LE.

Methods. Skin tissue samples from 33 cases, including chronic discoid LE (n = 24), acute (A)CLE (n = 4), subacute CLE (n = 1) and lupus panniculitis (n = 4) were collected for immunohistochemistry. Expression of IL‐6, IL‐17A, IFN‐α, IFN‐γ, myxovirus protein (Mx)A and transforming growth factor (TGF)‐β was assessed in these samples.

Results. All LE specimens had staining for IL‐6 and TGF‐β in the infiltrated inflammatory cells. IL‐17A staining was seen in 84.8% of specimens, and IFN‐α or MxA was seen in 93.9%. TGF‐β expression in ACLE was significantly greater than that in both chronic cutaneous (CC)LE and in lupus panniculitis (P = 0.02 for both). Expression of IL‐17A was positively associated with expression of IFN‐α and MxA (Spearman’s ρ = 0.56 and 0.39, respectively). In addition, the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) correlated positively with expression of IFN‐α and MxA (ρ = 0.40 for both), whereas there was no correlation with IL‐17A expression.

Conclusions. Two major cytokines, IL‐17A and IFN‐α, may play roles in the pathogenesis of CLE. Their patterns of expression positively correlated with each other.