Autoantibodies against desmocollins in European patients with pemphigus.

BACKGROUND: Autoimmune bullous disorders of the pemphigus group are characterized by autoantibodies targeting desmoglein (Dsg)1, Dsg3 and Dsg4 and occasionally, desmocollin (Dsc)1, Dsc2 and Dsc3. Both Dsg and Dsc are components of desmosomal adhesion complexes.

AIM: To investigate the presence of IgG and IgA autoantibodies against Dsc1, Dsc2 and Dsc3 in a cohort of patients with bullous disorders.

METHODS: IgG and IgA autoantibodies against Dsc1, Dsc2 and Dsc3 were investigated by ELISA and immunoblotting analysis in a cohort of European patients with pemphigus vulgaris (PV; n = 74), IgA pemphigus (n = 3), paraneoplastic pemphigus (PNP; n = 3) and two cases of atypical pemphigus (n = 2).

RESULTS: Of the two cases with atypical pemphigus, one showed IgA reactivity against Dsc1 and Dsc3 and weak reactivity against Dsc2, and the other showed both IgG and IgA reactivity against Dsc1. One patient with IgA pemphigus had IgA autoantibodies against Dsc1, Dsc2 and Dsg1, and one patient with PNP had IgG reactivity against with Dsc3. In contrast, all the PV sera showed IgG reactivity against Dsg3 but not against Dsc1-3. Thus, IgG and IgA reactivity against Dsc was restricted to cases of PNP, IgA pemphigus and atypical pemphigus.

CONCLUSIONS: These findings support the concept that desmocollins are not important autoantigens in PV.