Flow cytometry studies indicated comparable binding profiles of both light chain-purified (KS-IgE) and IgE class-specific affinity-purified CSPG4-IgE (CS-IgE) to rat basophilic leukemia cell line RBL-SX38 cells expressing the high-affinity human IgE receptor FcεRI [Figure 1H]. The gene discussed is IGHE; the disease is acute basophilic leukemia.