Recent reports have provided conflicting evidence on the stability of CCR3 expression on the surface of basophils. Hence we wanted to independently evaluate the diagnostic usefulness of CCR3 as a surrogate marker of basophil activation and function.
We examined the correlative relationship between CCR3 expression on the surface of donor basophils and histamine release after donor basophils were treated with agonistic antibodies directed against the high-affinity IgE-Fc receptor and serum samples from 80 individuals displaying symptoms of chronic urticaria (CU).
We observed that CCR3 was significantly downregulated on donor basophils treated with the agonistic antibody and CU-patient serum that demonstrated positive "histamine-releasing activity" (HRA scores >10). However, CCR3 downregulation was also observed on donor basophils incubated with more than 40% of CU-patient serum samples with HRA scores less than or equal to 10.
Overall our data show that CCR3 demonstrates adequate sensitivity (83%) but weak specificity (59%) in its ability to reliably identify histamine-releasing activated basophils.