Neonatal lupus erythematosus with negative anti-Ro and anti-La antibodies: report of one case.

Since 1981 when anti-Ro (SS-A) and/or anti-La (SS-B) antibodies were described to be present in infants with neonatal lupus erythematosus (NLE) and their mothers, subsequent studies have demonstrated the almost universal association of NLE with either or both of these autoantibodies. To our best knowledge, three cases of NLE were reported to be negative in anti-Ro (SS-A) and anti-La (SS-B) antibodies. We report one infant born to a mother with systemic lupus erythematosus (SLE). He had neonatal pancytopenia (thrombocytopenia, anemia, and leukopenia) which got resolved after intravenous immunoglobulin (IVIG) administration. Both anti-Ro (SS-A) and anti-La (SS-B) antibodies were not detectable in his serum by immunodiffusion method while other such as RNP (nonspecific, including U1,U2,U3,...,U6), Sm and Scl-70 antibodies were all positive. This mother had all the above antibodies detectable in her serum. After excluding other possibilities, his pancytopenia was most likely to be attributed to neonatal lupus. We suggest that autoantibodies such as RNP and Sm antibodies may play an important role in the pathogenesis of thrombocytopenia of NLE.