DPP4i-associated bullous pemphigoid shows distinct skin cytokine profile

The cutaneous cytokine expression is different in patients with dipeptidyl peptidase 4 inhibitor (DPP4i)-associated bullous pemphigoid (BP), as opposed to those with typical BP, reports a new study.

Researchers took lesional and nonlesional skin samples from 17 patients with DPP4i-associated BP and 18 with typical BP. Luminex and enzyme-linked immunosorbent assays were used to measure and compare levels of 32 cytokines and two proteases between the patient groups. A parallel group of 12 healthy controls was also included.

Ten analytes were significantly decreased in skin samples from non-BP controls as opposed to lesional samples from BP patients. These included the CC chemokine ligands (CCL) 1, 2, 16, and 26, as well as interleukins (IL) 6 and 8. Between patient groups, levels of CCL17, CCL26, and thymic stromal lymphoprotein were also significantly upregulated in DPP4i-related BP nonlesional skin.

More quantitative comparisons showed that IL-6 was very strongly upregulated in lesional skin of patients with typical BP, being elevated by more than 320-fold as opposed to controls. Such elevation was also apparent in patients with DPP4i-associated BP, but to a much lower degree (72-fold). No difference was reported between the two BP subgroups.

Aside from IL-6, levels of the B-cell activating factor, CCL4, and the CXC chemokine ligand 12 were higher in lesional skin samples of typical BP as compared to DPP4i-associated BP. Meanwhile, the latter subgroup showed elevated levels of CCL1, CCL17, CCL26, and IL-5.

“Taken together, our current work demonstrates that skin cytokine expression differs between regular BP and DPP4i-BP patients,” the researchers said.