Among the mRNAs for CD6, several alternative splices have been identified by RT-PCR, and confirmed by sequencing (Figure 2): one lacking exon 5 (CD6ΔD3) in T cells, and at least four isoforms lacking exon(s) for the cytoplasmic domain of CD6: Δ8, Δ8-9, Δ8/Δ12 or Δ9/Δ12 in CLL [26]. The gene discussed is CD6; the disease is B-cell chronic lymphocytic leukemia.