TYK2 and Alzheimer disease: As for upadacitinib, abrocitinib is a selective oral JAK1 inhibitor recently FDA-approved for patients ≥ 18 years old with moderate-to-severe AD (163), whereas baricitinib, recently approved in Europe and Japan for the treatment of AD in adult patients (164), is an oral inhibitor of JAK1 and JAK2 with modest activity against JAK3 and TYK2.