In numerous case series, many patients achieve remission after one cycle of rituximab. Treatment is more successful if initiated early on in the course of disease, perhaps even at diagnosis. Rituximab treatment combined with monthly IV immunoglobulin infusions has resulted in long-term remission with no recurrence of disease in 10 years after treatment was halted. This was a small trial study of 11 patients with 10 patients followed to completion. Rituximab demonstrated superior efficacy compared to mycophenolate mofetil in a Phase III clinical trial, results of which were published in 2021. Epidemiology
Pemphigus vulgaris is a relatively rare disease that only affects about 1 to 5 people in 1 million in the United Kingdom, with an incidence of 1-10 cases per 1 million people across the world. There is an estimated prevalence of 30,000-40,000 cases in the United States. Cases of P. vulgaris usually dont develop until after the age of 50 or so. The disease is not contagious which means it cannot be spread from person to person. There is currently no way of knowing who will be affected with P. vulgaris in their life as it is usually not a genetic disorder and is usually triggered later in life by environmental factors. Men and women are both equally affected and the disease has been found to affect people of many different cultures and racial backgrounds, especially Ashkenazi Jews, people of Mediterranean, North Indian and Persian descent.
Diagnosis
Because it is a rare disease, diagnosis is often complicated and takes a long time. Early in the disease patients may have erosions in the mouth or blisters on the skin. These blisters can be itchy or painful. Theoretically, the blisters should demonstrate a positive Nikolskys sign, in which the skin sloughs off from slight rubbing, but this is not always reliable. The gold standard for diagnosis is a punch biopsy from the area around the lesion that is examined by direct immunofluorescent staining, in which cells are acantholytic, that is, lacking the normal intercellular connections that hold them together. These can also be seen on a Tzanck smear. These cells are basically rounded, nucleated keratinocytes formed due to antibody mediated damage to cell adhesion protein desmoglein. Pemphigus vulgaris is easily confused with impetigo and candidiasis. IgG4 is considered pathogenic. The diagnosis can be confirmed by testing for the infections that cause these other conditions, and by a lack of response to antibiotic treatment. Treatment
Corticosteroids and other immunosuppressive medications have historically been employed to reduce pemphigus symptoms, yet steroids are associated with serious and long-lasting side effects and their use should be limited as much as possible. Intravenous immunoglobulin, mycophenolate mofetil, methotrexate, azathioprine, and cyclophosphamide have also been used with varying degrees of success. An established alternative to steroids are monoclonal antibodies such as rituximab, which are increasingly being used as first-line treatment. In summer 2018, the FDA granted full approval to rituximab for this application, following successful fast track evaluation.