Macrophage activation syndrome associated with neonatal lupus erythematosus.

Neonatal lupus erythematosus (NLE) is a multi-organ systemic inflammatory disease caused by passively transmitted maternal autoantibodies including anti-SSA/Ro antibody. NLE is clinically characterized by skin symptoms, atrioventricular block, liver dysfunction, and cytopenia. In addition, NLE can cause fever and is a rare cause for fever of unknown origin in the neonatal period. Furthermore, although rare, macrophage activation syndrome (MAS) can complicate NLE. However, the pathogenesis of MAS associated with NLE is still unknown. We report a case of NLE-associated MAS along with the results of serum cytokine profile analysis. A feature of the serum cytokine profile at the onset of disease in our patient was significant increase of serum IL-6 and sTNF-RII levels. Furthermore, in MAS phase, serum sTNF-RII level was massively increased and serum IFN-α level was persistently elevated. MAS complicating NLE might have similar "pathophysiology to MAS secondary to systemic lupus erythematosus.