Treatment-naïve pemphigus patients showing IgG tissue deposits have serum IgG antibodies against desmoglein 1 detected more often than those against desmoglein 3: a monocentre laboratory experience

INTRODUCTION: Pemphigus is a heterogeneous group of autoimmune acantholytic diseases. AIM: To check whether there is a relationship between detecting IgG deposits in the direct immunofluorescence (DIF) and finding IgG antibodies against particular desmoglein (DSG) isoforms in ELISA techniques in patients with pemphigus. MATERIAL AND METHODS: Single-step DIF for revealing the deposits of IgA, IgM, IgG, IgG1, IgG4 and C3, and monoanalyte ELISAs or the multiplex ELISA were used for diagnosis. The Z test for two independent proportions was used for the statistical analysis. RESULTS: We evaluated 19 consecutive treatment-naïve pemphigus patients, who exhibited IgG deposits, accompanied by other types of immunoreactants in various combinations, in DIF. Serum IgG antibodies against DSG1 were detected in 18 patients, whereas serum IgG antibodies against DSG3 were found in 10 patients. The statistical analysis showed that the proportion of anti-DSG1 antibody-positive individuals (18 of 19, 94.74%) was statistically significantly higher than the proportion of anti-DSG3 antibody-positive ones (10 of 19, 52.63%) (p = 0.0099). CONCLUSIONS: IgG deposition in the pemphigus pattern seems to be related to the presence of serum IgG antibodies against DSG1 rather than against DSG3. DSG1 may bind IgG more efficiently than DSG3 since DSG1 has a longer cytoplasmic region compared to that of DSG3.