Amyotrophic Lateral Sclerosis Transcriptomics Reveals Immunological Effects of Low-Dose Interleukin-2.

Neuroinflammation is one of the hallmarks of ALS. Regulatory T cells (Tregs) are immune-suppressive cells which physiologically regulate the immune system preventing the onset of autoimmune disorders. These cells are dramatically and progressive reduced in ALS patients, with lower levels correlated with shorter survival. Low-dose interleukin-2 (IL-2) has been roposed as an immune-modulatory strategy to boost Tres in ALS patient and to dampen neuroinflammation. Thirty-six patient were included in the IMODALS clinical trial and randomly assigned to three treatment arms: 1MIU IL-2, 2MIU IL-2 and placebo. They underwent subcutaneous injections once daily for 5 days every 28 days for a total of three administration cycles. The aim of this study was to assess transcriptomic changes occurring in the blood of ALS patients following low-dose IL-2 administration. Peripheral blood was collected and, using LeukoLOCK TM filters, white blood cells were isolated at different time points (day(D)1 or baseline; D8 three days after the first injection cycle; D64 three days after the last treatment cycle; D85 24 days after the last treatment). Total RNA was extracted using LeukoLOCK TM Total RNA isolation kit (AmbionTM). This was hybridized to Affymetrix Clariom D human microarrays and data was analysed using Transcriptome Analysis Console (TAC) software or Linear Models for Microarray Data (Limma) software package in R. Genes were considered differentially expressed if they showed a 1.2-fold changes (1.2≤FC≤-1.2) and if their p-value was less than 0.05. A total of 107 microarrays were generated: 24 arrays from samples at D1 (12 placebo and 12 2MIU-IL-2-treated patients), 23 from D8 (12 placebo and 11 2MIU-IL-2), 36 from D64 (12 placebo, 12 1MIU and 12 2MIU-IL-2) and 24 from D85 (12 placebo and 12 2MIU-IL-2). Peripheral blood transcriptomic profiling of ALS patient included in the IMODALS clinical trial by microarrays