Venous thromboembolism in patients with pemphigus: A cohort study

A Global View of Pemphigus: Geographical Variations

Pemphigus, an autoimmune intraepidermal bullous disease group with roughly eight distinct forms, includes pemphigus vulgaris (PV) and pemphigus foliaceus (PF) as its predominant global forms. Despite the increased utilization of global health records and reporting systems, epidemiological data remain limited and poorly categorized. Therefore, this study aimed to conduct a review to track, identify, and characterize cases of PV and PF published and categorized worldwide. A research question was formulated; studies were selected based on the inclusion criteria; and data from these publications were systematically collected, summarized, and presented using narrative descriptions. The search strategy yielded 3,212 articles, of which 95 underwent critical analysis and data extraction. Studies from 52 countries contributed to the dataset, covering various pemphigus variants. Notably, only two countries, Iran (18.87%) and South Korea (11.43%), accounted for approximately a third of the reported PV cases, while Brazil contributed 40.25% of the foliaceus variants cases documented in the literature. These findings offer valuable insights into the global distribution of pemphigus and inform future research and healthcare efforts.

Risk of Incident Venous Thromboembolism Among Patients With Bullous Pemphigoid or Pemphigus Vulgaris: A Nationwide Cohort Study With Meta-Analysis

Background Bullous pemphigoid (BP) and pemphigus vulgaris (PV) share similar pathophysiology with venous thromboembolism (VTE) involving platelet activation, immune dysregulation, and systemic inflammation. Nevertheless, their associations have not been well established. Methods and Results To examine the risk of incident VTE among patients with BP or PV, we performed a nationwide cohort study using Taiwan's National Health Insurance Research Database and enrolled 12 162 adults with BP or PV and 12 162 controls. A Cox regression model considering stabilized inverse probability weighting was used to calculate the hazard ratios (HRs) for incident VTE associated with BP or PV. To consolidate the findings, a meta-analysis that incorporated results from the present cohort study with previous literature was also conducted. Compared with controls, patients with BP or PV had an increased risk for incident VTE (HR, 1.87 [95% CI, 1.55-2.26]; P<0.001). The incidence of VTE was 6.47 and 2.20 per 1000 person-years in the BP and PV cohorts, respectively. The risk for incident VTE significantly increased among patients with BP (HR, 1.85 [95% CI, 1.52-2.24]; P<0.001) and PV (HR, 1.99 [95% CI, 1.02-3.91]; P=0.04). In the meta-analysis of 8 studies including ours, BP and PV were associated with an increased risk for incident VTE (pooled relative risk, 2.17 [95% CI, 1.82-2.62]; P<0.001). Conclusions BP and PV are associated with an increased risk for VTE. Preventive approaches and cardiovascular evaluation should be considered particularly for patients with BP or PV with concomitant risk factors such as hospitalization or immobilization.

Association of inflammatory skin diseases with venous thromboembolism in US adults

Patients with certain inflammatory skin diseases have multiple risk factors for venous thromboembolism (VTE). The objective of the study was to determine whether atopic dermatitis (AD), psoriasis, pemphigus, pemphigoid and/or hidradenitis is associated with VTE in US adults. Data were analyzed from the 2002-2012 Nationwide Inpatient Sample, a representative cohort of US hospitalizations (N = 72,512,581 adults, including 1,389,292 with VTE). In multivariable logistic regression models including age, sex, insurance, household income and race/ethnicity, hospitalization for AD (adjusted odds ratio [95% confidence intervals] 1.22 [1.17-1.27]), pemphigus (1.96 [1.68-2.28]) and pemphigoid (1.64 [1.47-1.83]) was associated with VTE. These associations remained significant in virtually all patient subsets, including males and females, different age groups and those with and without long-term corticosteroid use. In particular, AD, pemphigus and pemphigoid were each associated with DVT and PE. VTE was associated with increased inpatient length of stay, cost of care and mortality across all the inflammatory skin diseases. HS and psoriasis were not consistently associated with VTE. AD, pemphigus and pemphigoid and some subsets of patients with HS were associated with higher odds of hospitalization for VTE. Patients with these inflammatory skin diseases may benefit from increased screening and prevention of VTE.

Pemphigus

Pemphigus consists of a group of rare and severe autoimmune blistering diseases mediated by pathogenic autoantibodies mainly directed against two desmosomal adhesion proteins, desmoglein (Dsg)1 and Dsg3 (also known as DG1 and DG3), which are present in the skin and surface-close mucosae. The binding of autoantibodies to Dsg proteins induces a separation of neighbouring keratinocytes, in a process known as acantholysis. The two main pemphigus variants are pemphigus vulgaris, which often originates with painful oral erosions, and pemphigus foliaceus, which is characterised by exclusive skin lesions. Pemphigus is diagnosed on the basis of either IgG or complement component 3 deposits (or both) at the keratinocyte cell membrane, detected by direct immunofluorescence microscopy of a perilesional biopsy, with serum anti-Dsg1 or anti-Dsg3 antibodies (or both) detected by ELISA. Corticosteroids are the therapeutic mainstay, which have recently been complemented by the anti-CD20 antibody rituximab in moderate and severe disease. Rituximab induces complete remission off therapy in 90% of patients, despite rapid tapering of corticosteroids, thus allowing for a major corticosteroid-sparing effect and a halved number of adverse events related to corticosteroids.

The Risk of Pulmonary Embolism in Patients With Pemphigus: A Population-Based Large-Scale Longitudinal Study

Growing evidence suggests that inflammation may pose an atypical risk factor for pulmonary embolism (PE), as it drives venous thrombosis via several pathways. The increased risk of PE in several autoimmune diseases has lent weight to this concept. However, the relative risk of PE among patients with pemphigus has not yet been established. We aimed to examine the risk of PE in patients with pemphigus. A large-scale population-based longitudinal cohort study was conducted to evaluate the relative risk (RR) of PE among 1,985 patients with pemphigus relative to 9,874 age-, sex-, and ethnicity-matched control subjects. A multivariate Cox regression model was utilized. The incidence of PE was 3.0 (95% CI, 2.2–4.0) and 1.2 (95% CI, 1.0–1.5) per 1,000 person-years among patients with pemphigus and controls, respectively. The period prevalence of PE corresponding to the study period was 2.2% (95% CI, 1.6–2.9%) among cases and 0.9% (95% CI, 0.7–1.1%) among controls. Patients with pemphigus were twice as likely to develop PE as compared to control subjects (adjusted RR, 1.98; 95% confidence interval [CI], 1.29–3.04). The highest PE risk was observed during the 1st year following the diagnosis of pemphigus (adjusted RR, 3.55; 95% CI, 1.78–7.09) and decreased over time. The increased risk was robust to a sensitivity analysis that included only cases managed by pemphigus-related systemic medications (adjusted RR, 1.82; 95% CI, 1.11–2.98). In conclusion, pemphigus is associated with an increased risk of PE, particularly during the 1st year of the disease. An awareness of this risk should be increased, additional precipitating factors for PE should be avoided, and thromboprophylaxis may be evaluated in high-risk patients. Further research is required to establish this risk.

Targeted Therapies for Autoimmune Bullous Diseases: Current Status

Autoimmune bullous skin disorders are rare but meaningful chronic inflammatory diseases, many of which had a poor or devastating prognosis prior to the advent of immunosuppressive drugs such as systemic corticosteroids, which down-regulate the immune pathogenesis in these disorders. Glucocorticoids and adjuvant immunosuppressive drugs have been of major benefit for the fast control of most of these disorders, but their long-term use is limited by major side effects such as blood cytopenia, osteoporosis, diabetes mellitus, hypertension, and gastrointestinal ulcers. In recent years, major efforts were made to identify key elements in the pathogenesis of autoimmune bullous disorders, leading to the identification of their autoantigens, which are mainly located in desmosomes (pemphigus) and the basement membrane zone (pemphigoids). In the majority of cases, immunoglobulin G, and to a lesser extent, immunoglobulin A autoantibodies directed against distinct cutaneous adhesion molecules are directly responsible for the loss of cell-cell and cell-basement membrane adhesion, which is clinically related to the formation of blisters and/or erosions of the skin and mucous membranes. We describe and discuss novel therapeutic strategies that directly interfere with the production and regulation of pathogenic autoantibodies (rituximab), their catabolism (intravenous immunoglobulins), and their presence in the circulation and extravascular tissues such as the skin (immunoadsorption), leading to a significant amelioration of disease. Moreover, we show that these novel therapies have pleiotropic effects on various proinflammatory cells and cytokines. Recent studies in bullous pemphigoid suggest that targeting of immunoglobulin E autoantibodies (omalizumab) may be also beneficial. In summary, the introduction of targeted therapies in pemphigus and pemphigoid holds major promise because of the high efficacy and fewer side effects compared with conventional global immunosuppressive therapy.