RTX was usually used as an adjuvant treatment, and its application did not switch concomitant treatments. a median period of 27 months. Results We recognized 18 MMP patients who received at least one cycle of RTX to treat MMP. RTX was usually used as an adjuvant treatment, and its application did not switch concomitant treatments. Under treatment with RTX, 67% of the patients achieved an improvement in their disease activity within 6 months. This was also reflected in a statistically significant reduction in the (MMPDAI) activity score. The frequency of infections under RTX treatment increased only slightly. Conclusions The use of RTX is usually associated with an attenuation of MMP in a large proportion of MMP patients in our study. At the same time, its application was not found to further increase the susceptibility of the most strongly immunocompromised Belizatinib populace of MMP patients to opportunistic infections. Collectively, our results suggest that the potential benefits of RTX outweigh its risks in patients with refractory MMP. Keywords: mucous membrane pemphigoid, rituximab, pemphigoid disease, autoantibodies, side-effects, B cell depletion, retrospective study, mucous membrane pemphigoid disease TNF index Introduction Mucous membrane pemphigoid (MMP) is an antibody-mediated autoimmune disease. The most common autoantigens are the C-terminus of type XVII collagen (BP180), BP230, laminin 332, integrin 64, and type VII collagen (1). MMP differs from other pemphigoid diseases in that it primarily affects the mucosa of the conjunctiva, oral cavity, esophagus, nose, pharynx, larynx, trachea, anal canal, and genitalia (2). Scarring is usually another symptom of MMP unique to pemphigoid diseases. It mostly manifests at the eye and as strictures in the esophagus, pharynx, and larynx. Preventing the development of scarring is an important goal in the treatment of MMP and often requires a swiftly initiated, marked, and long-term managed immunosuppression. Drugs used in the treatment of MMP, mostly in combination, include systemic and topical corticosteroids, mycophenolate mofetil, azathioprine, dapsone, intravenous immunoglobulins, cyclophosphamide, and rituximab (RTX) (2). RTX is an anti-CD20 antibody designed to deplete B cells (3). In MMP, it is used off-label following the pharmacological rationale that depleting B cells to blunt the production of pathogenic autoantibodies should have beneficial effects. However, with clinical trials of adequate size around the impact of RTX on MMP still lacking, the effectiveness and security of RTX in MMP have remained controversial. We have therefore retrospectively analyzed the long-term impact of rituximab on disease and adverse events in 18 MMP patients treated in our department specializing in pemphigoid diseases between 2008 and 2019. Materials and methods The study was approved by the ethics committee of the University or college of Lbeck (20-130A). The medical records of all patients treated for MMP at the University or college of Lbeck between 2008 and 2019 were retrieved. Patients who received RTX at least once were recognized, and their medical history before and after the first administration of RTX was examined by analyzing all medical records of in- and outpatient visits available. Disease activity was categorized as active disease, disease control, partial remission, and total remission according to the definitions of an international consensus conference (4). We altered this categorization to additionally distinguish total remission on therapy and partial remission on therapy ( Supplementary Table S1 ). All side effects were recorded to detect potential adverse events associated with the administration of RTX. The period of 6 months after RTX administration was given special attention throughout all analyses of efficacy in MMP because the effect of RTX is Belizatinib supposed to reach its maximum at this time. (MMPDAI) scores before and approximately 6 months after RTX were statistically analyzed using the Wilcoxon signed-rank test. Statistical significance was defined by a = 11). The black lines connect the MMPDAI activity scores before and after the RTX for the individual individual. The MMPDAI before and after RTX was compared by a Wilcoxon signed-rank test (= 0.0073). In 11 patients, the MMPDAI activity score (4) was assessed repeatedly before and after treatment Belizatinib with RTX, allowing a more objective comparison of disease activity at the initiation of RTX therapy (day 0) and approximately 180 days thereafter. This comparison revealed a statistically significant decrease from a median of 9 Belizatinib to.