Distinct cytokine profile in juvenile systemic lupus erythematosus-associated macrophage activation syndrome.

Macrophage activation syndrome (MAS) has been observed in patients with systemic lupus erythematosus (SLE). Recognition of MAS in patients with SLE may be particularly challenging because it may mimic the clinical features of the underlying disease or be confused with an infectious complication. Massive hypercytokinemia is strongly associated with the pathogenesis of systemic lupus erythematosus-associated macrophage activation syndrome (SLE-MAS) but the pathogenesis and kinetics of cytokine release in SLE-MAS patients is not well studied. We present a case of SLE-MAS. The patient showed the distinct cytokine profile of SLE-MAS compared to systemic juvenile idiopathic arthritis associated MAS and Epstein-Barr virus-induced hemophagocytic lymphohistiocytosis. The observed TNF-α dominant increase appears to be characteristic of SLE-MAS. IgM type antilymphocyte antibody (ALAB) was detected on the surface of lymphocytes during the acute phase and disappeared when the patient was in remission. The patient had a heterozygous P369S-R408Q mutation in the MEFV gene. Our results suggest that ALAB and a MEFV mutation might play important roles in the pathogenesis of SLE-MAS. Furthermore, the cytokine profile of SLE-MAS differs from that of S-JIA-MAS: the TNF-α dominant increase appears to be characteristic.