A compound of formula I:wherein X is O, S, SO or SO2；R1 is halogen, trihalomethyl, —OH, C1-7alkyl, C1-4alkoxy, trifluoromethoxy, phenoxy, cyclohexylmethyloxy, pyridylmethoxy, cinnamyloxy, naphthylmethoxy, phenoxymethyl, —CH2—OH, —CH2CH2—OH, C1-4alkylthio, C1-4alkylsulfonyl, benzylthio, acetyl, nitro or cyano, or phenyl, phenylC1-4alkyl or phenyl-C1-4alkoxy each phenyl group thereof being optionally substituted by halogen, CF3, C1-4alkyl or C1-4alkoxy；R2 is H, halogen, trihalomethyl, C1-4alkoxy, C1-7alkyl, phenethyl or benzyloxy；R3 H, halogen, CF3, OH, C1-7alkyl, C1-4alkoxy, benzyloxy, phenyl or C1-4alkoxymethyl；each of R4 and R5, independently is H or a residue of formula (a)wherein each of R8 and R9, independently, is H or C1-4alkyl optionally substituted by halogen；and n is an integer from 1 to 4；or a pharmaceutically acceptable salt, hydrate, solvate, isomer or prodrug thereof；or a compound of formula IIwhereinR1a is halogen, trihalomethyl, C1-4alkyl, C1-4alkoxy, C1-4alkylthio, C1-4alkylsulfinyl, C1-4alkyl-sulfonyl, aralkyl, optionally substituted phenoxy or aralkyloxy；R2a is H, halogen, trihalomethyl, C1-4alkyl, C1-4alkoxy, aralkyl or aralkyloxy；R3a is H, halogen, CF3, C1-4alkyl, C1-4alkoxy, C1-4alkylthio or benzyloxy；R4a is H, C1-4alkyl, phenyl, optionally substituted benzyl or benzoyl, or lower aliphatic C1-5acyl；R5a is H, monohalomethyl, C1-4alkoxy-methyl, C1-4alkyl-thiomethyl, hydroxyethyl, hydroxypropyl, phenyl, aralkyl, C2-4alkenyl or -alkynyl；R6a is H or C1-4alkyl；R7a is H, C1-4alkyl or a residue of formula (a) as defined above,Xa is O, S, SO or SO2； andn3 is an integer of 1 to 4；or a pharmaceutically acceptable salt, hydrate, solvate, isomer or prodrug thereof,for use in a method of treatment, optionally of an autoimmune condition,wherein said compound of formula I or II is administered at a dosage lower than the standard daily dosage of said compound during the initial period of treatment and then is increased, optionally stepwise, up to the standar
