medwireNews: Treatment with low-dose interleukin (IL)-2 appears to reduce disease activity without severe adverse effects in patients with systemic lupus erythematosus (SLE), researchers report in the Annals of the Rheumatic Diseases.
For the study, 60 individuals with active SLE were randomly assigned to receive standard treatment plus either subcutaneous IL-2 at a dose of 1 million IU (n=30) or placebo (n=30) every other day for 2 weeks followed by a 2-week break for three cycles. The patients were then followed up for an additional 12 weeks.
At week 12, the SRI-4 response rates were higher in the IL-2 group than in the placebo group, at 55.2% and 30.0%, respectively, but the difference between the two groups did not quite reach statistical significance (p=0.052).
However, by week 24, the SRI-4 response rate was significantly higher with IL-2 than with placebo, at 65.5% versus 36.7%, with significant differences in favor of IL-2 also observed at weeks 6, 8, 10, and 16.
Moreover, the patients who received IL-2 had greater reductions in median SELENA–SELDAI, BILAG, and physician’s global assessment scores at weeks 12 and 24, along with a greater number of corticosteroid dose reductions, than those who received placebo, but again the differences between the two groups were not statistically significant.
Nonetheless, low-dose IL-2 treatment resulted in a significantly higher rate of complete remission in patients with lupus nephritis at week 24 than placebo, at 53.9% of 13 patients in the former group and 16.7% of 12 patients in the latter.
Other improvements included greater reductions in autoantibody levels and proteinuria and greater increases in serum complement and albumin with IL-2 than with placebo.
Furthermore, infection rates were numerically lower in the IL-2 group than in the placebo group, at 6.9% versus 20.0%, as were the number of serious infections (0.0 vs 6.7%).
Immunologic analysis showed that that low-dose IL-2, but not placebo, induced a significant expansion of regulatory T cells and natural killer cells that occurred without affecting CD4+ and CD8+ T cells. The researchers say that this finding “may contribute to the restoration of immune homeostasis in SLE patients.”
Jing He (Peking University People’s Hospital, Beijing, China) and co-authors conclude that their study “provides supportive data to confirm the therapeutic effects of low-dose IL-2 in SLE treatment.”
They add that “future clinical studies for low-dose IL-2 therapy should recruit a larger cohort and stratify patients based on background treatments,” which would allow them to analyze “the therapeutic efficacy of low-dose IL-2 without the interference of background treatments.”
By Laura Cowen
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