Tocilizumab for the Treatment of Mevalonate Kinase Deficiency and TNF Receptor-Associated Periodic Syndrome: cases report and literature review

Abstract Background Mevalonate kinase deficiency (MKD) and TNF receptor-associated periodic syndrome (TRAPS) are systemic autoinflammatory diseases (SAIDs), which are rare diseases with early-onset, severe condition and difficult diagnosis and treatment. Although different SAIDs have standard treatments, some SAIDs are poorly controlled after routine treatment, which seriously affects the growth and development of children and their quality of life. The purpose of our study is to provide more treatment strategies for SAIDs. Cases presentation: We presented 2 Chinese patients with MKD and TRAPS who were resistant to TNF-α blockade. The patients with MKD and TRAPS still have periodic fever and rash after using etanercept, baricitinib and glucocorticoid. IL-1 antagonists are not available in Chinese Mainland, then they commenced intravenous tocilizumab (240mg every 3 weeks). After they were treated by one or two doses of tocilizumab, they were not suffered from fever and rash so far. Before treatment of tocilizumab in MKD patient, WBC and TNF-α were normal, ESR and CRP increased significantly, and IL-6 increased slightly. After treatment of tocilizumab, ESR and CRP fell to normal, however, IL-6 increased occasionally. In TRAPS patient, ESR, CRP, WBC, IL-6 and TNF-α were increased significantly. After treatment of tocilizumab, ESR, CRP, WBC, IL-6 and TNF-α fell to normal. Two patients were treated with tocilizumab for more than 6 months, and they achieved in clinical and serological remission. Two patients had no adverse reactions after injection of tocilizumab. Conclusions Without IL-1 antagonists in Chinese Mainland, tocilizumab is useful as an alternative drug to the treatment of SAIDs who are resistant to TNF-α blockade.