Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple organ systems. Juvenile-onset SLE (jSLE) accounts for up to 20% of all SLE patients. Compared to adult-onset SLE, jSLE patients tend to show different manifestations of SLE and are often difficult to diagnose promptly. JSLE patients show severe disease conditions, and intensive treatments are therefore required to control disease activity. Thrombotic microangiopathy (TMA) is defined as a condition with vascular damage due to microvascular obstruction and endothelial cell injury. TMA is diagnosed through clinical features and pathological findings; clinical features include microangiopathic hemolytic anemia, thrombocytopenia, and multiple organ injury. Secondary TMA is associated with various causes such as drugs, organ transplants, and autoimmune diseases. SLE is one of the most common immune disorders accompanied by TMA, and the condition of the patients are usually severe. Although TMA occurring in jSLE patients is rare, it can be life-threatening. Because there are only a few reports of jSLE cases accompanied by secondary TMA, it is important to accumulate the data of each case. In this article, we would like to discuss the mechanisms of secondary TMA with jSLE and the treatment strategy, that we learned from our experience and previously reported cases. Combination therapy including immunosuppressants and plasma exchange is needed to control disease activity; in particular, suppressing complement pathways is important. Novel therapies such as eculizumab, rituximab, and belimumab require more data to determine whether they are effective in cases of TMA with SLE. The establishment of a treatment strategy based on evidence is needed for jSLE accompanied by TMA. The possibility of jSLE patients having a gene mutation, when they are resistant to treatment or when disease onset is at a young age, means we should consider performing gene analysis for those patients.

Juvenile systemic lupus erythematosus, Thrombotic microangiopathy, Life-threatening, Complement cascades, Gene mutation