ERK/STAT3 activation through CCL17/CCR4 axis-mediated type 2 cytokine-involved signaling pathways in Th2 cells regulates cutaneous drug reactions.

Cutaneous drug reactions (CDRs) are common drug-induced allergic reactions that cause severe consequences in HIV/AIDS patients. The CCL17/CCR4 axis is involved in the immune mechanism of allergic diseases, but its role in the CDRs has not been determined. Here, we aimed to determine the role of the CCL17/CCR4 axis and the underlying mechanism involved in CDRs. In this study, the serum cytokine levels in patients with CDR and healthy controls were measured. The CCL17-triggered allergic profile was screened via a PCR array. Apoptosis of keratinocytes cocultured with CCL17-stimulated Th2 cells was analyzed by flow cytometry. An NVP-induced rat CDR model was established, and dynamic inflammatory factor levels and Th2 cells in the peripheral blood of the rats were measured. Rat skin lesions and signaling pathways in Th2 cells were also analyzed. We showed that the serum CCL17 level was significantly upregulated in CDR patients (P = 0.0077), and the Th2 cell subgroup was also significantly elevated in the CDR rats. The CCL17/CCR4 axis induces Th2 cells to release IL-4 and IL-13 via the ERK/STAT3 pathway. The CCR4 antagonist compound 47 can alleviate rash symptoms resulting from NVP-induced drug eruption, Th2 cell subgroup, IL-4, and IL-13 and inhibit keratinocyte apoptosis. Taken together, these findings indicate that the CCL17/CCR4 axis mediates CDR via the ERK/STAT3 pathway in Th2 cells and type 2 cytokine-induced keratinocyte apoptosis.