Low-dose IL-2 might be effective and tolerated in the treatment of systemic lupus erythematosus (SLE), say researchers writing in Annals of the Rheumatic Disease this month.
Patients with SLE have been shown to be deficient in IL-2, which contributes to an unbalanced immune system. Proof-of-concept studies and case reports have suggested that low-dose IL-2 might promotes regulatory T cells, and inhibits T helper 17 cells and follicular helper T cells, inducing of remission in SLE patients. Meanwhile, IL-2 treatment may increase virus-specific CD8+ T cell responses and promote the activity of natural killer cells against infections.
“Given that infection is a major cause of relapse, hospitalization and death in patients with SLE, and that low-dose IL-2 might increase anti-infectious immune response, we determined whether low-dose IL-2 treatment benefits SLE patients by inducing clinical improvement without increasing the incidence of infection,” wrote the authors, led by Jing He, M.D., Ph.D., of Peking University People's Hospital Beijing China.
This first randomized, double-blind, placebo-controlled study of low-dose IL-2 in the treatment of SLE included 60 patients, aged 18–65 years, who received IL-2 (n=30) or placebo (n=30) for 12 weeks. IL-2 at a dose of 1 million IU or placebo was administered subcutaneously every other day for two weeks and followed by a two-week break as one treatment cycle. The primary endpoint was the SLE Responder Index-4 (SRI-4) at week 12. Patients were followed up for additional 12 weeks. The secondary endpoints were other clinical responses, safety and dynamics of immune cell subsets.
At week 12, the SRI-4 response rates were 55.2 percent and 30 percent for IL-2 and placebo, respectively (p=0.052). At week 24, the respective SRI-4 response rates were 65.5 percent and 36.7 percent (p=0.027). The primary endpoint was not met at week 12. Low-dose IL-2 treatment resulted in a 53.9 percent complete remission rate in lupus patients versus 16.7 percent with placebo (p=0.036). No serious infection was observed with IL-2, but two occurred with placebo. Patients treated with low-dose IL-2 had greater expansion of regulatory T cells, no change in CD4+ and CD8+ T cells and an increase natural killer cells.
“Some severe manifestations such as nephritis were unable to be achieve complete remission in such a short period. Therefore, during the trial, neither of the groups achieved ‘Clinical Remission with No Treatment’ or ‘Clinical Remission On Treatment’ by the DORIS definition. Prolonged treatment should be considered in future studies to evaluate the efficacy of low-dose IL-2 to induce SLE disease remission by DORIS definition.”
“Clinically, in agreement with previous studies, we showed that low-dose IL-2 did not increase the incidence of infection, rather reduced the viral loads of BK and HPV viral loads in three SLE patients to undetectable level. Whether low-dose IL-2 treatment could decrease viral loads in infected patients should be carried out in the future,” the authors wrote.
He J, Zhang R, Shao M, et al. “Efficacy and safety of low-dose IL-2 in the treatment of systemic lupus erythematosus: a randomised, double-blind, placebo-controlled trial.” Annals of the Rheumatic Diseases. September 19, 2019. doi: 10.1136/annrheumdis-2019-215396