Lymphocyte Transformation Tests and Patch Tests to Identify Drugs Potentially Associated With Bullous Pemphigoid Development.

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease, with a rising incidence in the elderly. BP is associated with multiple triggering factors, including drug exposure. However, evidence in this respect is limited, and the underlying immune mechanisms remain unknown. Our study aims to identify the role of specific drugs in BP pathogenesis using in vitro lymphocyte transformation tests (LTT) and in vivo patch testing, aiding in the differentiation between truly associated drugs and coincidental associations.

METHODS

Thirty-three patients with suspected BP and no ongoing systemic treatment were enrolled. LTT and patch tests were conducted 3 months after diagnosis. BP disease activity was assessed using the Bullous Pemphigoid Disease Activity Index (BPDAI) at diagnosis and at follow-up visits at 3 and 6 months.

RESULTS

LTT results were positive in 60% of patients for dipeptidyl peptidase 4 inhibitors, loop diuretics, hydrochlorothiazide, levetiracetam, nivolumab, enalapril, and amlodipine. Patients showed a reduction in BPDAI over the study period, regardless of LTT results. Although limited by the low sample size, positive LTT patients showed a trend toward clinical improvement when the implicated drug was discontinued. Patch testing was positive in one patient, who also had a corresponding positive LTT.

CONCLUSIONS

Our findings demonstrate the existence of a potential role for certain drugs in BP pathogenesis, suggesting that these drugs may trigger the disease in genetically predisposed individuals. Although further studies are needed, LTT may serve as a useful and available tool in the management of BP patients in the future.