Detection of phosphotyrosine in bcr-abl-positive cells with PY20 antibody and its clinical applications

Objective To explore the specificity of anti-phosphotyrosine monoclonal antibody PY20 in ber-abl~+ cells and its possible clinical applications.Methods ber-abl~+ cell lines(K562,MEG-01)and ber-abl~- cells lines(Jurkat,MCF-7)were stained with PY20.Phosphotyrosine protein of K562 and MEG-01 cells was detected by flow cytomely before and after treatment with imatinib.Phosphotyrosine protein in bone marrow cells from 49 patients with chronic myeloid leukemia(CML),Ph~+ acute lymphoblastic leukemia(Ph~+- ALL),Ph~- ALL,acute myeloid leukemia(AML-M_1,M_2,M_3,M_5,FAB classification),chronic lymphocytic leukemia(CML)and 3 normal donor.Positive cells over 5% of total cells was considered positive cases for phosphotyrosine protein.The level of tyrosine phosphorylation was determined by median fluorescence intensi- ty(MFI).Results ber-abl~+ cell lines and marrow cells from 10 CML patients and 8 ALL patients were all PY20-positive,while ber-abl~- cell lines and marrow cells from 18 leukemia patients and 3 normal donor were all PY20-negative.MFI decreased remarkably after blocked by imatinib in K562 cells and MEG-01 cells.The positive cell percent of marrow cells from 10 newly diagnosed CML patients and 9 imatinib-sensitive CML pa- tients was(54.20±19.82)% and(14.84±6.17)%(P0.05),while that of 2 cases of imatinib-resistant was 64.3% and 57.2%.There was significant difference of MFI between imatinib-resistant patients and ima- tinib-sensitive patients(99.42±4.87 vs 46.41±4.67,P0.01).Conclusion PY20 monoclonal antibod- y is highly specific for ber-abl~+ cells.It might be useful in rapid detection of ber-abl~+ cells and sensitivity to imatinib of CML patients.