Neonatal lupus erythematosus: Maternal IgG antibodies bin to a recombinantNH2-terminal fusion protein encoded by human alpha-fodrin cDNA

IgG antibodies to a cleavage product of alpha-fodrin (120 kDa alpha-fodrin) have recently been identified as organ-specific autoantibodies in primary Sjogren's syndrome. In this study, we examined seroreactivity of mothers an d infants with neonatal lupus erythematosus (NLE) to a recombinant NH2-term inal protein (120 kDa alpha-fodrin) of human alpha-fodrin. Serum samples we re collected during the perinatal period in seven pregnancies of five mothe rs delivering offspring with NLE. Anti-120 kDa alpha-fodrin antibodies were identified by immunoblotting in six of seven perinatal maternal sera of of fspring with NLE: one of two congenital heart block offspring and all five offspring with cutaneous NLE. These antibodies were placentally transmitted to infants. One of the five mothers had primary Sjogren's syndrome, and fo ur were asymptomatic. One asymptomatic mother did not demonstrate anti-120 kDa alpha-fodrin activity at the time of the first delivery of a congenital heart block infant, but was found to be positive at the time of subsequent delivery of a second child with cutaneous NLE. We propose that maternal an tibodies to 120 kDa alpha-fodrin may be an additional serologic marker for the risk of NLE in anti-Ro/SS-A positive women.