Ruxolitinib Penetrates Blood Brain Barrier and Reduces the Cytokine Storm in Patients With Haemophagocytic Lymphohistiocytosis.

Haemophagocytic lymphohistiocytosis (HLH), complicated by the involvement of the central nervous system (CNS), contributes to high morbidity and mortality with rapid development and violent cytokine storms in the CNS. Consequently, intrathecal dexamethasone and methotrexate must be administered in a timely manner to treat CNS inflammation. No effective pharmacotherapy targeting cytokine pathways is available to suppress cytokine storms that occur in the CNS. Ruxolitinib, a JAK1/2 inhibitor, has been recommended for the treatment of HLH by multiple guidelines. Conventional studies have reported that ruxolitinib cannot penetrate the blood brain barrier (BBB), thereby impeding the implementation of numerous therapies. Our team previously identified the efficacy of ruxolitinib in patients with CNS-HLH. Ten patients with secondary HLH (two with CNS involvement and eight without) received ruxolitinib, and BBB permeability was evaluated. Ruxolitinib exhibited BBB penetrability, ranging from 5.31% to 18.08%, suggesting its promising potential in CNS therapy.