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Background & Aims: Antibody-induced bile salt export pump deficiency (AIBD) is an acquired form of intrahepatic cholestasis, which may develop following orthotopic liver transplantation (OLT) for progressive familial intrahepatic cholestasis type 2 (PFIC-2). Approximately 8-33% of patients with PFIC-2 who underwent a transplant develop bile salt export pump (BSEP) antibodies, which trans-inhibit this bile salt transporter from the extracellular, biliary side. AIBD is diagnosed by demonstration of BSEP-reactive and BSEP-inhibitory antibodies in patient serum. We developed a cell-based test directly measuring BSEP trans-inhibition by antibodies in serum samples to confirm AIBD diagnosis. Methods: Sera from healthy controls and cholestatic non-AIBD or AIBD cases were tested (1) for anticanalicular reactivity by immunofluorescence staining of human liver cryosections, (2) for anti-BSEP reactivity by immunofluorescence staining of human embryonic kidney 293 (HEK293) cells expressing BSEP-enhanced yellow fluorescent protein (EYFP) and immunodetection of BSEP-EYFP on Western blot, and (3) for BSEP trans-inhibition using HEK293 cells stably expressing Na+/taurocholate cotransporting polypeptide (NTCP)-mCherry and BSEP-EYFP. The trans-inhibition test uses [3H]-taurocholate as substrate and is divided into an uptake phase dominated by NTCP followed by BSEP-mediated export. For functional analysis, sera were bile salt depleted. Results: We found BSEP trans-inhibition by seven sera containing anti-BSEP antibodies, but not by five cholestatic or nine control sera, all lacking BSEP reactivity. Prospective screening of a patient with PFIC-2 post OLT showed seroconversion to AIBD, and the novel test method allowed monitoring of treatment response. Notably, we identified a patient with PFIC-2 post OLT with anti-BSEP antibodies yet without BSEP trans-inhibition activity, in line with asymptomatic presentation at serum sampling. Conclusions: Our cell-based assay is the first direct functional test for AIBD and allows confirmation of diagnosis as well as monitoring under therapy. We propose an updated workflow for AIBD diagnosis including this functional assay. Impact and Implications: Antibody-induced BSEP deficiency (AIBD) is a potentially serious complication that may affect patients with PFIC-2 after liver transplantation. To improve its early diagnosis and thus immediate treatment, we developed a novel functional assay to confirm AIBD diagnosis using a patient's serum and propose an updated diagnostic algorithm for AIBD.
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Background: Alopecia is a complication of autoimmune blistering diseases (AIBDs) that affects patients' quality of life; however, it has generally been overlooked in patients with severe disease because it is regarded as a cosmetic issue. Objective: To study the epidemiologic data and clinical presentations of alopecia in our cohort of patients with AIBDs. Methods: Forty-one patients with AIBDs were assessed in this cross-sectional study. An assessment tool to collate patient information, including AIBD scalp involvement, trichoscopic findings, and Severity of Alopecia Tool II scores, was used. Results: More than 70% of patients in our cohort had at least 1 type of alopecia, with 10% presenting with a nonspecific (end-stage) scarring alopecia. Elevated Dsg1 ratios were predictive of hair loss in pemphigus vulgaris (P < .001) and increased alopecia was associated with worse disease severity in bullous pemphigoid (P = .001). Limitations: The small sample size and lack of severe cases. Conclusion: There is a likelihood that 1 in 10 patients with AIBDs have a scarring alopecia related to their disease. To our knowledge, this is the first study including alopecia prevalence in patients with bullous pemphigoid, which was not significantly increased despite providing clues to disease severity.
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BACKGROUND: Autoimmune blistering disorders (AIBDs) are rare, potentially life-threatening conditions often requiring immunosuppression. Throughout the SARS-CoV-2 pandemic, infection risk and mortality in patients with AIBDs are unknown. OBJECTIVE: We report the outcomes of SARS-CoV-2 infections in patients with AIBDs and determined if patients on rituximab have an increased risk of SARS-CoV-2 infection. METHODS: We examined clinical outcomes in 10 patients with AIBDs who developed SARS-CoV-2 infections at an American hospital. We performed a retrospective analysis of 132 patients with AIBDs enrolled in a clinical trial. RESULTS: Patients with severe SARS-CoV-2 (n = 4) or death (n = 2) trended to be older. These patients had higher mortality than the national average (20% vs 1.6%). Our cohort included 52 patients with a history of rituximab treatment, 35 of whom were immunosuppressed by rituximab during the pandemic, and 45 patients never treated with rituximab. We found no difference between the rates of SARS-CoV-2 positivity in patients with AIBDs immunosuppressed by rituximab and those not on rituximab (9.1% vs 12.1%). LIMITATIONS: Testing for SARS-CoV-2 was performed on demand rather than surveillance. Overall transmission varied over time, and outcomes depended on accepted treatments. The small sample size of our cohort limits the generalizability of our results. CONCLUSION: This study suggests that rituximab does not increase the risk of SARS-CoV-2 test positivity in patients with AIBDs. However, these results should be interpreted with caution due to our relatively small sample size.
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BACKGROUND: Glucocorticoids are the mainstay of treatment for autoimmune blistering diseases (AIBDs). The Glucocorticoid Toxicity Index (GTI) is a novel, outcome-based glucocorticoid-induced adverse effects monitoring instrument. OBJECTIVE: To investigate whether the GTI score was able to accurately quantify the glucocorticoid-induced toxicity in patients with AIBDs. METHODS: The prospective cohort study included patients with confirmed diagnoses of AIBDs (group1, currently receiving glucocorticoids; and group 2, had glucocorticoids ceased earlier). Data were collected minimally at baseline (V1) and 3 months (V2). Further data from patients who were able to complete the follow-up visits at 6 months (V3) and 12 months (V4) amid the COVID-19 pandemic were also included. GTI scores were calculated after data collection. RESULTS: Analysis of data from V1 and V2 found a linear correlation between GTI score and prednisone doses (P < .05) and a significant difference in GTI scores between group1 and group 2 (P < .05). Data from V3 and V4 suggested that GTI scores continued to rise progressively alongside increasing cumulative prednisone dose. LIMITATIONS: Small sample size, further exacerbated by the COVID-19 pandemic. Single-center study. CONCLUSION: The GTI sensitively and specifically captured the changes in glucocorticoids toxicity over time among patients with AIBDs. The GTI could be a feasible tool that can be used in future clinical trials as a glucocorticoid-induced toxicity outcome measure.
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Background: Systemic glucocorticoids are first-line treatment options for autoimmune blistering diseases; however, their long-term use is associated with significant toxicities. Objective: To evaluate the side effects of steroid-sparing agents and compare them with those of steroids. Methods: We searched Cochrane Reviews, Embase, MEDLINE, and Scopus between October 1978 and May 2020 using the keywords "bullous pemphigoid," "pemphigus," "autoimmune blistering diseases," and "side effects." A total of 31 randomized controlled trials and retrospective case series were critically appraised. Results: This review includes a total of 1685 patients with autoimmune blistering diseases, of whom 781 had bullous pemphigoid and 904 had either pemphigus vulgaris or pemphigus foliaceous. Limitations: A major limitation is that because adjuvants are generally used in combination with steroids, only 12 of the studies reviewed included a "steroid-only" arm to allow for a direct comparison of side effects. Additionally, there is inadequate literature and lack of standardized grade reporting of specific side effects of each steroid-sparing agent. Conclusion: In the future, researchers should consider implementing the Common Terminology Criteria for Adverse Events, version 5.0, for reporting of all side effects to allow for consistency and standardization. It would be useful to have an index similar to the Glucocorticoid Toxicity Index to quantify these side effects.
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Pemphigus is an epidemiologically heterogeneous group of autoimmune bullous diseases comprising pemphigus vulgaris (PV), pemphigus foliaceus, paraneoplastic pemphigus, IgA pemphigus, and pemphigus herpetiformis. Recently, our knowledge about the frequency of pemphigus, which is highly variable between different populations, has considerably expanded, and the first non-HLA genes associated with PV have been identified. In addition, a variety of comorbidities, including other autoimmune diseases, hematological malignancies, and psoriasis, have been described in this variant. Here, initial data about the impact of COVID-19 on this fragile patient population are discussed and perspectives for future epidemiological studies are outlined.