Complement polymorphism in herpes gestationis: association with C4 null allele.

BACKGROUND

Herpes gestationis (HG) is a rare, pregnancy-related skin disease characterized by the production of an autoantibody to a component of the hemidesmosome. It is associated with the class II antigens HLA-DR3 and HLA-DR4, but its potential association with the "class III antigens" C2, C4, and factor B has not previously been studied.

OBJECTIVE

Our purpose was to study complement polymorphism in HG.

METHODS

Using electrophoresis and immunofixation techniques, we determined the allele frequencies of C4A, C4B, C3, and factor B in 42 patients with a history of HG.

RESULTS

Ninety percent of patients carried a C4 null allele (C4*QO). No statistically significant association with C3 or factor B alleles was seen.

CONCLUSION

HG is associated with the presence of a C4*QO. Whether the C4*QO is the primary genetic association, or whether the C4*QO is related to its linkage disequilibrium with DR3 and DR4 has yet to be determined.