Pemphigus foliaceus associated with imatinib therapy in a patient with gastrointestinal stromal tumor

Autoantibody-Specific Signalling in Pemphigus

Pemphigus is a severe autoimmune disease impairing barrier functions of epidermis and mucosa. Autoantibodies primarily target the desmosomal adhesion molecules desmoglein (Dsg) 1 and Dsg 3 and induce loss of desmosomal adhesion. Strikingly, autoantibody profiles in pemphigus correlate with clinical phenotypes. Mucosal-dominant pemphigus vulgaris (PV) is characterised by autoantibodies (PV-IgG) against Dsg3 whereas epidermal blistering in PV and pemphigus foliaceus (PF) is associated with autoantibodies against Dsg1. Therapy in pemphigus is evolving towards specific suppression of autoantibody formation and autoantibody depletion. Nevertheless, during the acute phase and relapses of the disease additional treatment options to stabilise desmosomes and thereby rescue keratinocyte adhesion would be beneficial. Therefore, the mechanisms by which autoantibodies interfere with adhesion of desmosomes need to be characterised in detail. Besides direct inhibition of Dsg adhesion, autoantibodies engage signalling pathways interfering with different steps of desmosome turn-over. With this respect, recent data indicate that autoantibodies induce separate signalling responses in keratinocytes via specific signalling complexes organised by Dsg1 and Dsg3 which transfer the signal of autoantibody binding into the cell. This hypothesis may also explain the different clinical pemphigus phenotypes.

Drug-induced pemphigus: A systematic review of 170 patients

Pemphigus encompasses a rare heterogeneous group of autoimmune blistering diseases characterized by cutaneous and/or mucosal blistering. Multiple factors, such as some specific types of drugs, have been found to be involved in the induction of pemphigus. Here, we have designed a systematic review by searching PubMed/Medline and Embase databases to find the drugs, involved in pemphigus induction and exacerbation (updated on 19 August 2019). From 1856 initially found articles, 134 studies (198 patients; 170 patients in the drug-induced patients and 28 in exacerbation group) have been included. Regarding drug-induced cases, the mean age was 57.19 ± 16.9-year-old (ranged 8-105), and patients had developed pemphigus within a mean of 154.27 days. Pemphigus vulgaris (38.9%), pemphigus foliaceus (33.5%), and paraneoplastic pemphigus (3.6%) were the most common subtypes. Furthermore, penicillamine (33.1%), captopril (7.7%), and bucillamine (6.5%) were the most reported drugs related to pemphigus induction; penicillamine was associated with the most persistent disease. Regardless of disease subtype, cutaneous, mucocutaneous, and mucosal involvements were reported in 68.6%, 30.1%, and 1.3% of patients, respectively. In total, the IgG deposition in the pathological studies, being positive for autoreactive antibodies in the serum against desmoglein 3 (Dsg3), and desmoglein 1 (Dsg1), were reported in 93%, 34.9%, and 72.7% of reported patients, respectively. Regarding the management of such patients, in 75% of healed cases, treatment (mainly transient systemic and topical corticosteroids and/or azathioprine) was needed besides stopping the probable pemphigus-inducing culprit drug, while drug cessation was enough to control the disease in 25%. As the outcomes, the lesions in 129 of 147 (87.8%) patients had been healed, while in 18 (12.2%), no healing was reported; fifteen out of 18 had died. In conclusion, some specific groups of treatments can induce pemphigus, including penicillamine, captopril, and bucillamine; despite the similar clinical and pathological manifestations to classical pemphigus, most of the cases are less severe and have a better prognosis.