Autoimmune bullous diseases during COVID-19 pandemic: 2022 update on rituximab and vaccine

COVID-19 infection is associated with an elevated risk for autoimmune blistering diseases while COVID-19 vaccination decreases the risk: A large-scale population-based cohort study of 112 million individuals

BACKGROUND

Numerous diseases associated with COVID-19 infection and vaccination have been reported, including conditions such as the autoimmune blistering diseases (AIBDs) pemphigus and pemphigoid. However, robust evidence supporting these associations is lacking.

OBJECTIVE

To investigate the risk of developing AIBD following COVID-19 infection and vaccination.

METHODS

Population-based retrospective cohort study utilizing data from over 112 million patients. The risk of AIBD within 3 months was compared among 3 cohorts: COVID-19 infection, COVID-19 vaccination, and controls, along with 7 sensitivity analyses.

RESULTS

COVID-19 infection was associated with an increased risk of AIBD (hazard ratio [HR] 1.508, 95% CI 1.260-1.805), with the risk being more pronounced for pemphigus (HR 2.432, 1.618-3.657) compared to bullous pemphigoid (HR 1.376, 1.019-1.857). Conversely, COVID-19 vaccination was associated with an almost halved risk of AIBD (HR 0.514, 0.394-0.672), with the risk reduction most significant for pemphigus (HR 0.477, 0.241-0.946). Comparisons between COVID-19 infection and vaccination revealed a more than threefold increased risk of AIBD in the infection cohort (HR 3.130, 2.411-4.063), particularly for pemphigus (HR 5.508, 2.973-10.205).

LIMITATIONS

Retrospective design and potential under-reporting of COVID-19 cases and vaccinations.

CONCLUSION

COVID-19 infection significantly increases the risk of AIBD while vaccination appears to reduce this risk.

Associated factors related to production of autoantibodies and dermo-epidermal separation in bullous pemphigoid

Bullous pemphigoid (BP) is a debilitating autoimmune skin blistering disease, characterized by the deposition of specific autoantibodies at the dermal-epidermal junction. This leads to an inflammatory cascade involving the activation of complement proteins, mast cell degranulation, immune cell recruitment, and the release of proteases by granulocytes. While several cytokines and signaling pathways have been implicated in the pathogenesis of BP, the precise mechanism behind autoantibody production remains unclear. A variety of factors, including natural aging, genetic polymorphisms, microbiota, medications, vaccinations, and infection, may contribute to disease onset. Recent evidence also suggests that both vaccination against severe acute respiratory syndrome coronavirus-2 and infection with severe acute respiratory syndrome coronavirus-2 may also play a role in BP's development. This review aims to elucidate the mechanism underlying the production of autoantibodies in BP, address gaps in understanding disease progression, and explore opportunities for improving diagnosis and prognosis to enhance patient care.

The Unseen Aftermath: Associations Between the COVID-19 Pandemic and Shifts in Mortality Trends in Japan

The COVID-19 pandemic disrupted healthcare systems globally, potentially altering mortality trends for non-COVID-19 diseases, particularly in aging populations like Japan's. Assessing these impacts is essential for responsive healthcare planning. We analyzed Japanese vital registration mortality records from January 2018 to December 2021 for adults aged 25 and older, excluding COVID-19-related deaths. Data were stratified by sex and ICD-10 cause-of-death chapters. Poisson regression models assessed changes in mortality rates and trends, incorporating pandemic-related variables and interactions between time, age group, and the pandemic term. Among the 4,920,942 deaths analyzed, 2,456,750 occurred during the pandemic years. Significant sex-specific changes in mortality trends were observed. Women experienced increases in mortality rates and trends for endocrine, nutritional, and metabolic diseases; skin and subcutaneous tissue diseases; circulatory diseases; and genitourinary diseases, reversing some pre-pandemic declines. Men showed increases in mortality trends for endocrine, nutritional, and metabolic diseases and genitourinary diseases but no significant changes for skin or circulatory diseases. These findings indicate that the pandemic differentially affected mortality trends between sexes, with women experiencing broader increases across multiple disease categories. The COVID-19 pandemic was associated with significant changes in mortality trends for certain non-COVID-19 diseases in Japan, with notable sex differences. Increased mortality among women across multiple disease categories highlights the pandemic's indirect health impacts and underscores the need for sex-specific healthcare strategies in the post-pandemic era.

COVID-19 Vaccine: A Potential Risk Factor for Accelerating the Onset of Bullous Pemphigoid

Bullous pemphigoid (BP) is the most common autoimmune bullous disease, whose main autoantigens are hemidesmosomal components BP180 and BP230. Although recent studies found no association between COVID-19 vaccines and BP, since mass vaccinations started, more than 90 vaccine-associated BP cases have been reported. To find an agreement among real-life clinical observations and recent epidemiologic data, we further investigated this topic. A total of 64 patients with BP onset in 2021 were demographically, clinically, and serologically characterized: 14 (21.9%) vaccine-associated patients (VA) developed BP within 5 weeks from the first/second vaccine dose. VA and vaccine-non-associated (VNA) patients had similar demographics and clinical and immunological characteristics. Noteworthy, the monthly distribution of BP onset during mass vaccinations paralleled vaccine administration to the elderly in the same catchment area. Additionally, in 2021, BP onsets in April-May and June-July significantly increased (p = 0.004) and declined (p = 0.027), respectively, compared to the three years before vaccination campaigns (2018-2020). Interestingly, VA and VNA patients showed statistically significant differences in the use of inhalers and diuretics. Our findings suggest that the COVID-19 vaccine may constitute an accelerating factor that, together with other triggering factors, could act in genetically predisposed individuals with possible sub-clinical autoreactivity against BP antigens, slightly accelerating BP onset.

Pemphigus: trigger and predisposing factors

Pemphigus is a life-threatening autoimmune blistering disease affecting skin and mucous membranes. Despite its etiopathogenesis remains largely unknown, several trigger and predisposing factors have been reported. Pemphigus is caused by autoantibodies that target desmoglein 1 and desmoglein 3, impacting desmosome function. However, circulating autoantibodies are often the consequence of a precipitating factor that occurs in predisposed individuals. This review aims to describe and discuss almost all trigger and predisposing factors reported as possible or probable cause of the disease. Among the reported trigger factors that may induce or exacerbate pemphigus, we have found of particular interest: drug intake (especially thiol- and phenol-containing compounds), vaccines, infections, as well as some reports about pregnancy, radiations, emotional stress, pesticides and physical trauma. Moreover, we discuss the possible role of food intake in pemphigus onset and particular attention is given to dietary factors containing thiol, phenol and tannin compounds. A trigger factor is "the straw that breaks the camel's back," and often acts together with predisposing factors. Here we discuss how pemphigus onset may be influenced by genetic susceptibility and comorbidities like thyroid diseases, malignancies and other autoimmune disorders. To identify other hitherto unknown trigger and predisposing factors, well designed prospective studies are needed. In this context, future research should explore their connection with the aim to advance our understanding of pemphigus pathogenesis.

Considerations for the use of immunosuppression for the management of pemphigus during the COVID-19 pandemic with a focus on rituximab: Case reports from a single center experience in Australia

Pemphigus is a rare group of autoimmune mucocutaneous blistering conditions for which the mainstay of treatment is immunosuppression. This is usually achieved with high dose corticosteroids as well as steroid sparing agents. Rituximab is now recommended as a first line treatment for moderate to severe pemphigus vulgaris, the commonest form of pemphigus, alongside corticosteroids. During the early stages of the COVID-19 pandemic the use of rituximab was reduced in our department due to its long term irreversible B-cell suppression. During the COVID-19 pandemic careful pharmacological selection was undertaken for our pemphigus patients to balance the risks of immunosuppression. To demonstrate this, we report three pemphigus patients who required treatment for COVID-19 and assessment throughout the pandemic. To date there has been limited published data regarding the clinical outcomes of pemphigus patients who have developed COVID-19 infections following rituximab infusions, especially in those patients who have received COVID-19 vaccinations. Following careful personalized consideration, all three pemphigus patients presented received rituximab infusions since the start of the COVID-19 pandemic. These patients had also received COVID-19 vaccinations prior to becoming infected with COVID-19. Each patient had a mild COVID-19 infection after receiving rituximab. We advocate for all pemphigus patients to have a full course of COVID-19 vaccinations. Antibody response to COVID-19 vaccinations should ideally be confirmed by measuring pemphigus patient’s SARS-CoV-2 antibodies prior to receiving rituximab.