An up-regulation of TIM3 and IDO1 has been described in the context of PRRSV- and CSFV-infected pigs, respectively (Hulst et al., 2013; Chaudhari et al., 2020), whereas LAG3 was reported to play a limited role during the pathogenesis of postweaning multisystemic wasting syndrome (Yue et al., 2015). This evidence concerns the gene IDO1 and postweaning multisystemic wasting syndrome.