The present application describes modulators of CCR3 of formula (Ia) and (Ib): ##STR00001## or pharmaceutically acceptable salt forms thereof, wherein Z, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.5', R.sup.6, a, b, c, d, and u are as defined herein in the specification. In addition, methods of treating and preventing inflammatory diseases such as asthma and allergic diseases, as well as autoimmune pathologies such as rheumatoid arthritis and atherosclerosis using modulators of formula (Ia) and (Ib) are disclosed.