Divergent Specificity Development of IgG1 and IgG4 Autoantibodies in Endemic Pemphigus Foliaceus (Fogo Selvagem).

We have shown that although the IgG response in fogo selvagem (FS) is mainly restricted to desmoglein (Dsg) 1, other keratinocyte cadherins are also targeted by FS patients and healthy control subjects living in the endemic region of Limão Verde, Brazil (endemic controls). Evaluating nonpathogenic IgG1 and pathogenic IgG4 subclass responses to desmosomal proteins may reveal important differences between pathogenic and nonpathogenic responses, and how these differences relate to the pathogenic IgG4 response and resultant FS. In this study, we tested by ELISA >100 sera from each FS patient, endemic control, and nonendemic control for IgG1 and IgG4 autoantibodies to keratinocyte cadherins besides Dsg1.

Overlapping IgG4 Responses to Self- and Environmental Antigens in Endemic Pemphigus Foliaceus.

The etiology of human autoimmune diseases in general remains largely unknown, although the genetic and environmental interplay may be relevant. This applies to the autoimmune diseases of the skin such as the pemphigus phenotypes and others. In this group, there is an endemic form of pemphigus foliaceus (also known as fogo selvagem [FS]) in which the pathogenic IgG4 autoantibody response to the self-antigen desmoglein 1 (Dsg1) cross-reacts with the LJM11 sand fly salivary gland Ag.

Update on fogo selvagem, an endemic form of pemphigus foliaceus.

Pemphigus are organ-specific autoimmune diseases, where autoantibodies (mainly immunoglobulin [Ig]G) directed against epidermal targets (glycoproteins of the desmosomal core) are detected. Endemic pemphigus foliaceus or fogo selvagem (FS) is one of the variants of pemphigus foliaceus pemphigus foliaceus that shares the same clinical and immunopathological features of the classic non-endemic pemphigus foliaceus form, including pathogenic IgG (mainly IgG4) autoantibodies directed against the ectodomain of desmoglein 1 (Dsg1), that lead to acantholysis. Pathogenesis of FS is complex, involving genetic, environmental and immunological factors.