Successful treatment with tofacitinib for anti-melanoma differentiation-associated gene 5 antibody-positive juvenile dermatomyositis: case reports and review of the literature.

Although the clinical efficacy of tofacitinib has been reported in adult patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive (Ab+) dermatomyositis, data on its use in refractory juvenile dermatomyositis (JDM) are scarce. We describe two female Japanese patients with anti-MDA5 Ab + JDM and rapidly progressive interstitial lung disease who achieved remission by adding tofacitinib to existing immunosuppressive drugs and present a literature review. While both patients received various immunosuppressive or anti-inflammatory treatments for induction therapy, remission could not be achieved. Subsequently, tofacitinib was administered to reduce the Krebs von den Lungen-6 level 5 months after diagnosis in one patient; the other patient received tofacitinib 4 months after diagnosis to reduce ferritin levels and skin manifestations. Subsequently, both patients achieved remission, and prednisolone was withdrawn. Tofacitinib reduced the interferon signature associated with dermatomyositis/JDM disease progression and exerted a therapeutic effect on dermatomyositis/JDM. We found six published cases from five articles of tofacitinib for refractory anti-MDA5 Ab + JDM. Except for one case of herpes simplex meningitis, the other cases, including ours, had improved disease activity without severe adverse events, and steroids and immunosuppressive medicines could be tapered. Tofacitinib could be considered an available therapy for refractory anti-MDA5 Ab + JDM.

The dynamics of laboratory markers reflecting cytokine overproduction in macrophage activation syndrome complicated with systemic juvenile idiopathic arthritis.

OBJECTIVES: To validate the correlation between laboratory markers reflecting disease activity of macrophage activation syndrome (MAS) and serum cytokine levels and identify the valuable laboratory markers that change over time for a prompt MAS diagnosis. METHODS: Serum cytokine levels were determined by enzyme-linked immunosorbent assay and compared with laboratory markers reflecting MAS disease activity.The changes in values were evaluated from the acute phase of systemic juvenile idiopathic arthritis (s-JIA) to MAS diagnosis. RESULTS: CXCL9 was significantly correlated with aspartate aminotransferase (AST), lactate dehydrogenase (LDH), D dimer, and urine ß2 microglobulin levels. sTNF-RII was significantly correlated with platelet counts, AST, LDH, D dimer, and ferritin levels. Significant changes in platelet count, LDH, and D dimer levels were observed. Decreased platelet counts were the most valuable indicator for MAS diagnosis. CONCLUSION: Monitoring the laboratory markers that change over time, particularly decreased platelet counts, was valuable for the prompt MAS diagnosis in s-JIA.