TGFB1 and autism: In the CNS, IL-1β levels appear to be unchanged, but they have increased in the periphery.293 TGF-β1 levels have been reported to be rising in one study, while the vast majority of data point to a decline in TGF-β1 levels in peripheral blood.287 Hence, additional studies with persuasive datasets are warranted to confirm whether higher blood IL-1β levels influence CNS levels and whether TGF-β1 has dual roles in the brain and periphery in autism.