Six studies used "single CD25-positive" cells as Tregs, which revealed a significant increase in AS patients compared with healthy blood donors [0.736, (0.138, 1.334), <i>p</i> = 0.016, <i>I</i><sup>2</sup> = 80.7%].
Genetic polymorphism (rs1800693) of TNFRSF1A (type 1 tumour necrosis factor receptor) encodes a potentially anti-inflammatory soluble truncated form of the p55 receptor, which is associated with predisposition to multiple sclerosis but protection against ankylosing spondylitis (AS).
This study suggests that FoxO1, but not miR-27a, miR-182, and IL2RA, contributes to the genetic susceptibility of AAU with AS, but none of the tested polymorphisms confer risk to AAU without AS.