IGHE and acute basophilic leukemia: Finally, cross-linking of receptor-bound IgE antibodies by polyclonal anti-IgE antibody, multimeric antigen, or antigen-expressing cancer cells triggered degranulation of human FcεRI-expressing rat basophilic leukaemia (RBL SX-38) mast cells [36,39,43,44,47,48,49].