PDCD1LG2 and multiple sclerosis: PD‐L1 expression was found to be upregulated by IL‐10 signaling, while this cytokine did not influence PD‐L2 expression.29 A recent mRNA expression analysis in peripheral blood leukocytes of patients with multiple sclerosis revealed significantly decreased PD‐L1 expression compared to healthy controls.30 However, there was no difference in PD‐L2 expression observable.30 This indicates that PD‐L1 might be more relevant for mediating peripheral immune tolerance than PD‐L2.