Interleukin 6 levels after tocilizumab administration in transplant recipients with COVID-19
Authors: Akhil R. Gade, Harshitha Alavala, Sridhar R. Allam
Journal: Kidney International (2020)

It is with great interest that we read the article by Gautier-Vargas and colleagues that reported a favorable clinical response with tocilizumab in a kidney transplant recipient with severe coronavirus disease 2019 (COVID-19).1Gautier-Vargas G. Baldacini C. Benotmane I. et al.Rapid resolution of cytokine release syndrome and favorable clinical course of severe COVID-19 in a kidney transplant recipient treated with tocilizumab.Kidney Int. 2020; 98: 508-509Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar Our clinical experience has also been similar.2Allam S.R. Dao A. Madhrira M.M. et al.Interleukin-6 receptor antagonist therapy to treat SARS-CoV-2 driven inflammatory syndrome in a kidney transplant recipient.Transpl Infect Dis. 2020; 22: e13326Crossref PubMed Scopus (15) Google Scholar The authors reported a dramatic decrease of serum interleukin 6 (IL-6) levels from 430.8 pg/ml to 3.4 pg/ml within 2 days after the administration of tocilizumab. However, as previously published,3Shimamoto K. Ito T. Ozaki Y. et al.Serum interleukin 6 before and after therapy with tocilizumab is a principal biomarker in patients with rheumatoid arthritis.J Rheumatol. 2013; 40: 1074-1081Crossref PubMed Scopus (76) Google Scholar,4Nishimoto N. Terao K. Mima T. et al.Mechanisms and pathologic significances in increase in serum interleukin-6 (IL-6) and soluble IL-6 receptor after administration of an anti-IL-6 receptor antibody, tocilizumab, in patients with rheumatoid arthritis and Castleman disease.Blood. 2008; 112: 3959-3964Crossref PubMed Scopus (616) Google Scholar and in our own experience, IL-6 levels generally increase after the administration of tocilizumab. In our published case report,2Allam S.R. Dao A. Madhrira M.M. et al.Interleukin-6 receptor antagonist therapy to treat SARS-CoV-2 driven inflammatory syndrome in a kidney transplant recipient.Transpl Infect Dis. 2020; 22: e13326Crossref PubMed Scopus (15) Google Scholar the IL-6 level was 241 pg/ml before tocilizumab and increased to 1259 pg/ml after the administration of tocilizumab. Given that tocilizumab functions by acting as a competitive inhibitor of the IL-6 receptor (IL-6R), increased serum IL-6 levels after its administration are likely caused by inhibition of IL-6R–mediated clearance as well as the endogenous production of IL-6 with ongoing disease activity. Hence, we wonder if the rapid decline of serum IL-6 level after tocilizumab in the case reported by Gautier-Vargas and colleagues was due to spontaneous improvement of disease activity or factors not related to tocilizumab. Randomized controlled studies are necessary to confirm the benefit of tocilizumab in transplant recipients with COVID-19. Rapid resolution of cytokine release syndrome and favorable clinical course of severe COVID-19 in a kidney transplant recipient treated with tocilizumabKidney InternationalVol. 98Issue 2PreviewImmunomodulatory drugs, such as tocilizumab, hold promise for the management of cytokine release syndrome in coronavirus disease 2019 (COVID-19).1,2 However, its clinical utility in immunosuppressed patients is still lacking.3,4 Here, we describe the successful use of tocilizumab in a kidney transplant recipient with severe COVID-19. Full-Text PDF