Gliptin-associated bullous pemphigoid shows peculiar features of anti-BP180 and -BP230 humoral response: Results of a multicenter study

Background: Recently, several case-control studies demonstrated an association between gliptins and bullous pemphigoid (BP) occurrence. However, data on the clinical and immunologic features of gliptin-associated bullous pemphigoid (GABP) are controversial. Objective: This study aimed to clinically and immunologically characterize a large cohort of GABP patients to get an insight into the pathophysiology of this emerging drug-induced variant of BP. Methods: Seventy-four GABP patients were prospectively enrolled and characterized from 9 different Italian dermatology units between 2013 and 2020. Results: Our findings demonstrated the following in the GABP patients: (1) a noninflammatory phenotype, which is characterized by low amounts of circulating and skin-infiltrating eosinophils, is frequently found; (2) immunoglobulin (Ig)G, IgE, and IgA humoral responses to BP180 and BP230 antigens are reduced in frequency and titers compared with those in patients with idiopathic BP; (3) IgG reactivity targets multiple BP180 epitopes other than noncollagenous region 16A. Limitations: A limitation of the study is that the control group did not comprise only type 2 diabetes mellitus patients with BP. Conclusion: GABP patients show peculiar features of anti-BP180 and -BP230 humoral responses, laying the foundation for diagnostic improvements and getting novel insights into understanding the mechanism of BP onset.