Monozygotic twins concordant for idiopathic thrombocytopenic purpura and discordant for systemic lupus erythematosus and lupus nephritis.

We report on identical twin sisters with systemic lupus erythematosus and lupus nephritis after initial presentation as idiopathic thrombocytopenic purpura. The patients had diverse clinical signs, symptoms and pathological findings of lupus nephritis. The changes in antinuclear antibodies and anti-double-stranded DNA antibodies were quite different. We conclude that even with an identical genetic background and the same environment, the expression of systemic lupus erythematosus and subsequent progression to lupus nephritis in twins was distinct, and antinuclear antibodies and anti-double-stranded DNA antibodies are helpful for clinical monitoring.