Increased antibody levels to desmogleins 1 and 3 after administration of carbamazepine

Desmoglein (Dsg) 1 and Dsg3 are recognized as the autoantigens in pemphigus foliaceus and pemphigus vulgaris. Pemphigus‐like syndromes have been reported to occur in individuals after exposure to a variety of drugs, but pemphigus caused by carbamazepine is not common. We found that anti‐Dsg1 and anti‐Dsg3 antibody titres were increased in three individuals administered carbamazepine. Antibody titres against Dsgs 1 and 3 were measured by enzyme‐linked immunosorbent assay (ELISA). Of 42 serum samples (25 patients administered carbamazepine, eight patients administered valproic acid and nine healthy volunteers) tested by ELISA, three patients administered carbamazepine showed positive reactivity against both Dsg1 and Dsg3. The patient with the highest titre against Dsg1 and Dsg3 (the index values of anti‐Dsg1 and anti‐Dsg3 were 79.3 and 86.4, respectively) was a 23‐year‐old woman (Case 1). The other two patients with positive reactivity were a 5‐year‐old boy (Case 2) and a 65‐year‐old man (Case 3). In addition, indirect immunofluorescence study showed intercellular antibodies to the cell surface of the whole epidermis with a titre of 1 : 64 in Case 1 and 1 : 2 in Cases 2 and 3. However, no skin or mucosal involvement was found in any of these cases. There was no difference in the serum concentrations of carbamazepine between the three positive cases and the 22 negative cases of carbamazepine administration. From these facts, the lack of skin diseases may be explained by relatively low values of anti‐Dsg 1 and 3 antibodies in Cases 2 and 3. However, it cannot be excluded that undefined exogenous and/or endogenous factors are involved in an outbreak of pemphigus. Furthermore, these findings might be helpful for preventing susceptible individuals from exposure to the suspect drugs.