A method for the prevention or treatment of an immunology-related disease, which is not rheumatoid arthritis or psoriasis, in a mammal in need thereof which involves administering to the mammal a pharmaceutically effective amount of a compound, a pharmacologically acceptable salt of the compound or a pharmacologically acceptable ester of the compound, wherein the compound is a compound having a formula (Ia): ##STR00001## wherein R.sup.1 and R.sup.2 are each a hydrogen, R.sup.3 is hydrogen; R.sup.4 is C.sub.1-C.sub.2 alkyl; n is 2; X is .dbd.N--D, wherein D is hydrogen C.sub.1-C.sub.4 alkyl or phenyl; Y is ethylene, ethynylene, --CO--CH.sub.2 or phenylene; Z is ethylene or trimethylene; R.sup.5 is an unsubstituted C.sub.3-C.sub.10 cycloalkyl, an unsubstituted C.sub.6-C.sub.10 aryl, or a C.sub.3-C.sub.10 cycloalkyl or a C.sub.6-C.sub.10 aryl substituted with 1 to 3 substituents selected from the group consisting of halogen, lower alkyl, halogeno lower alkyl and lower alkoxy; and R.sup.6 and R.sup.7 are each hydrogen.