Background/Purpose: Current therapy for rheumatoid arthritis (RA) often leads to excessive immunosuppression induced by glucocorticoids and DMARDs. Low-dose Interleukin 2 (IL-2) has been showed to induce Treg cell expansion and activation, which is expected to control the development of RA. We studied the clinical efficacy and safety of IL-2 treatment in RA.

Methods: Total 41 RA patients with low Treg cells, who had been treated with glucocorticoids and DMARDs for over 6 months, were divided into two groups randomly. Patients in Non-IL-2 group (n=15) were still given traditional glucocorticoids and DMARDs treatment. Patients in IL-2 group (n=26) were not only given traditional treatment, but also injected subcutaneously IL-2 at 50 WIU per day for a 5 day course. The demographic features, clinical manifestations and laboratory indicators were compared before and after the treatment.

Results: There was no difference between Non-IL-2 group and IL-2 group in gender, age and course of the disease (P>0.05). The ratios of Th1/Th2 and Th17/Treg were significant correlated with ESR, the number of tender or swollen joints and DAS28-ESR (P<0.05) in all two groups of patients. After IL-2 treatment, the number of Th17 cells (16.51±19.06 vs 19.00±11.38, P=0.01) or Treg cells (18.67±14.08 vs 78.55±44.67, P=0.001) were significantly increased. Due to increased Treg cells were much more than the Th17, leading to a decrease in their ratio (1.36±1.49 vs 0.28±0.20, P=0.024). Before the IL-2 treatment, there was no difference in clinical manifestations between two groups (P>0.05), but in IL-2 group, there was a significantly decrease after the treatment in the number of tender joints (3.73±2.79 vs 0.94±1.00, P=0.001) or swollen joints (1.40±1.64 vs 0.42±0.70, P=0.011) and DAS28-ESR (3.60±0.96 vs 2.85±0.67, P=0.005). There was no difference in blood routine, liver and renal functions both before and after the treatment between two groups (P>0.05).

Conclusion: IL-2 can effectively up-regulate the level of Treg as well as that of Th17 to some degree and maintain the balance of Th17 and Treg cells. IL-2 subcutaneous injection combined with traditional antirheumatic drugs may help for RA patients’ symptoms remission without over-treatment and evaluated side effect. IL-2 could be used as a novel therapeutic candidate for RA treatment but long term benefits of IL-2 therapy are required to further study.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-efficacy-and-safety-of-low-dose-il-2-therapy-in-over-treated-patients-with-rheumatoid-arthritis-a-preliminary-study/