Comparative Epidemiology of Pemphigus in Tunisia and France: Unusual Incidence of Pemphigus Foliaceus in Young Tunisian Women

Abstract

Recent studies have suggested that in Tunisia, pemphigus foliaceus is more frequent in young women than expected. To confirm these findings, we compared the incidence rates of pemphigus in Tunisia as a whole and in a large area of France. New cases of pemphigus were detected retrospectively from dermatology departments and pathology laboratories over a 6-year period and classified as pemphigus vulgaris or foliaceus according to the pathology. In France, the incidence rate was 1.7 cases per million per year (95% confidence interval 1.4 to 2.1). Pemphigus vulgaris accounted for 73% of all cases, incidence increased with age, and the female-to-male sex ratio was 1.2. The incidence rate was significantly higher in Tunisia than in France: 6.7 cases per million per year (95% confidence interval 5.8 to 7.7); pemphigus foliaceus was more frequent (61%), the female-to-male sex ratio was 4.1, and the incidence rate was higher in young women. The incidence rate was 15.5 cases per million per year for pemphigus foliaceus among women aged 25 to 34 years and was even higher in some rural areas. No case was observed among household members or in neonates, and only one case occurred in childhood. Thus, we confirmed that the epidemiology of pemphigus in Tunisia is unusual. High rates of pemphigus foliaceus among young people living in rural areas are reminiscent of Brazilian pemphigus. However, the absence of cases among genetically related household members and during childhood, and the large predominance of women, contrast with Brazilian pemphigus.

Tunisian endemic pemphigus foliaceus is associated with desmoglein 1 gene polymorphism

“…The sporadic form occurs in western Europe and North America with a low incidence (Ͻ1 case per million per year) and equally affects males and females over 50 years old. 2 The endemic form is observed in different geographic regions particularly in Brazil and Tunisia, and has different epidemiological characteristics. 3 In Brazil, PF is known as folgo selvagem (FS), has a high incidence (25 cases per million per year) and predominantly affects young adults with no sex predominance.…”

“…In Tunisia, PF is mainly observed in females р35 years old, among which the incidence rate reaches 15 cases per million per year. 2,3 Patients with sporadic or endemic PF synthesize autoantibodies with similar immunochemical properties and frequently bear the same HLA class II alleles (DRB1*0102 and DRB1*0404), 4,5 The results of our recent case-control study performed on French Caucasian patients and healthy controls showed that the desmoglein 1 gene (DSG1) is polymorphic and that one of its variants is associated with sporadic PF. 6 This observation prompted us to determine whether the endemic form of PF seen in Tunisia is also associated with this polymorphic variant of DSG1.…”

Pênfigo foliáceo endêmico (fogo selvagem) em indígena Yanomami no Município de São Gabriel da Cachoeira, Estado do Amazonas, Brasil

“…O PFE, também conhecido como pênfigo foliáceo brasileiro e pênfigo foliáceo sul-americano, tem sido descrito em vários outros países das Américas -do México ao norte da Argentina, principalmente Paraguai, Bolívia, Peru, Colômbia, Venezuela -e, recentemente, na Tunísia 8,9 . Neste tipo de pênfigo, os pacientes relatam uma sensação de "queimação" no corpo.…”

Pemphigus is not associated with allotypic markers of immunoglobulin kappa

“…1 In Europe and the United States, the disease has a low incidence rate (under two cases per million per year) and is predominantly represented by PV. 2 In certain geographical areas of Brazil, PF has a much higher incidence rate (25 cases per million per year) and is called endemic pemphigus or Fogo Selvagem. 3 Recently, pemphigus has also been shown to be more frequent in Tunisia (seven cases per million per year) as a consequence of a higher incidence rate of PF which particularly involves young females.…”

“…3 Recently, pemphigus has also been shown to be more frequent in Tunisia (seven cases per million per year) as a consequence of a higher incidence rate of PF which particularly involves young females. 2,4,5 Susceptibility to pemphigus is partly determined by genetic factors among which HLA class II genes have been identified. Indeed, DR4 and DR14 haplotypes and, more precisely, DRB1*0402, DRB1*1401 and DRB1*1404 are strongly associated with PV in different ethnic groups.…”