Although IL-9 has been recognized as a classical Th2-related cytokine, recent studies have indicated that IL-9-producing cells contribute to a group of autoimmune disorders including systemic lupus erythematosus (SLE), multiple sclerosis (MS), inflammatory bowel diseases (IBD), rheumatoid arthritis (RA) and psoriasis.
The results showed that the plasma concentration and mRNA levels of IL-9 were significantly elevated in SLE patients compared with the healthy controls.
In RA patients, we found a reduction at T5 compared to T0 in serum levels of both TGFβ (p = 0.0016) and IL-9 (p = 0.0007); serum IL-9 levels were also reduced in SLE patients at T5 with respect to T0 (p = 0.03).
Ustekinumab, a fully human IgG1κ monoclonal antibody directed towards the p40 shared subunit of IL-12 and IL-23, has been recently investigated in SLE, suggesting a potential novel therapeutic strategy in SLE.