Pregnant women with endemic pemphigus foliaceus (Fogo Selvagem) give birth to disease-free babies.

Endemic pemphigus foliaceus (PF), also known as Fogo Selvagem (FS), is an organ-specific autoimmune disease mediated by autoantibodies. These autoantibodies are disease specific, predominantly restricted to the IgG4 subclass, and pathogenic, as demonstrated by passive transfer studies. In contrast to pemphigus vulgaris, neonatal skin disease does not appear to occur in babies born to mothers with non-endemic PF or FS. In the present study we have examined 19 mother/neonate pairs where the mother had documented FS. Mothers and neonates were examined soon after delivery and tested by immunofluorescent (IF) techniques for FS autoantibodies either in circulation (mothers' sera or babies' cord blood) or bound to the neonatal epidermis. All neonates included in this study were born with normal skin. Twelve biopsies from 17 neonates showed negative direct IF using both FITC-antihuman IgG or monoclonal anti-IgG subclass antibodies. In five biopsies the epidermal ICS of the babies showed weak staining. In 10 of the 19 cord sera tested, FS IgG autoantibodies were undetectable; in nine, these autoantibodies were present in low titers (less than 1:40). The sera of the mothers showed higher titers of FS autoantibodies, and IgG4 was the predominant IgG subclass autoantibodies. It appears that human placenta may modulate the expression of disease in the newborn by operating as a "biologic immunoadsorbent" of pathogenic autoantibodies.

Endemic pemphigus foliaceus (fogo selvagem) in native Americans from Brazil.

BACKGROUND: Fogo selvagem (FS) is an autoimmune disease that is endemic in certain regions of Brazil and appears to be precipitated by an environmental factor. OBJECTIVE: Our purpose was to confirm the occurrence and prevalence of FS in a population of Xavante Indians living in an endemic region of central Brazil. METHODS: Clinical, anthropologic, and immunologic studies were carried out in patients and in normal inhabitants of the Pimentel Barbosa Indian Reservation, Mato Grosso, Brazil. RESULTS: FS was identified and confirmed in 10 patients from a patient pool of 295 with various skin diseases. The Xavante settlement has a total population of 746. Anti-desmoglein 1 autoantibodies were detected in all patients with FS and were absent from more than 300 serum samples collected from randomly selected unaffected persons. CONCLUSION: FS is strongly linked to outdoor activities and is largely restricted to immunogenetically predisposed persons. FS appears to have been endemic in certain regions of South America for several centuries.