Successful treatment of a child with idiopathic multicentric Castleman disease associated with hemophagocytic lymphohistiocytosis using tocilizumab

Abstract

To the Editor: The combination of idiopathic multicentric Castleman disease (i-MCD) with hemophagocytic lymphohistiocytosis (HLH) is rare, with only a few cases reported in the English literature, all of which are in adults.1,2 Patients with i-MCD have been treated with combination chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP]). Recently, i-MCD patients have also been treated with immunotherapy, such as humanized anti-interleukin 6 (IL-6) antibody (siltuximab) and humanized anti-IL-6 receptor antibody (tocilizumab).3–5 There have been no previous reports on the application of tocilizumab to treat children with i-MCD. Here, we report a case in which tocilizumab was used for successful treatment of a child with i-MCD associated with HLH when chemotherapy alone was ineffective. In 2017, a 2-year-old male child initially visited Beijing Children’s hospital for recurrent fever over 20 days and edema of the extremities for 14 days. Laboratory tests revealed a normocytic anemia (Hb 6.0 g/dL, mean cell volume 75.8 fL) and thrombocytopenia (15 × 109 cells/L). Elevated levels of lactic dehydrogenase (329 U/L), ferritin (879.4 ng/mL), sCD25 (7226pg/mL), and IL-6 (507.92 pg/mL)were also observed. The fibrinogen level (1.37 g/L) and NK cell activity (13.06%) were below the normal range. Serological tests for humanherpesvirus8 and various parasites yielded negative results. A neck ultrasound