RT-PCR analysis of FIP1L1-PDGFRA expression in cell fractions enriched for eosinophils or neutrophils.FIP1L1-PDGFRA fusion transcripts were detected in both eosinophils and neutrophils. PCR products of different sizes are observed, due to alternative splicing in FIP1L1, as observed previously.^10,23  Two alternatively spliced transcripts with the same intensity were detected in eosinophils, whereas 1 predominant splice variant is present in neutrophils.