Depleting Autologous Activated CD4⁺ t Lymphocytes Increased Generation of Colony-Forming-Cells(CFC) in Patients with Myelodysplastic Syndromes

Objective To investigate how autoimmune mechanism playing a role in generation of colony-forming-cells(CFC), bone mononuclear cells(BMNC) from MDS were removed of autologous activated CD4⁺ T cells in vitro and cultured to find out effect of T cells on MDS hemopietic progenitor.

Methods BMNC from 25 patients with low-grade MDS and 5 normal donors were depleted of CD4⁺CCR5⁺ T lymphocytes using magnetic sorting. Depleted and plused CD4⁺CCR5⁺ T BMNC were seeded onto methycellulose and the correlation of colony-forming-cell (CFC) number and the polarization of T cells were analyzed, the generation of CFC, the immunophenotype and the clonal cells(which had cytogenetic markers detected by FISH), was compared respectively.

Results ¢Å The capacity of BMNC from 5 healthy donors to generate CFC remained unchanged in the CD4⁺CCR5⁺ T lymphocyte-depleted and lymphocyte-plused BMNC. In contrast, cultures initiated with CD4⁺CCR5⁺ T lymphocyte-depleted BMNC from patients with low-grade MDS exhibited significantly increased generation of CFC compared with the corresponding lymphocyte-plused cultures, but the lymphocyte-plused cultures had no generation of CFC. ¢Æ The number of CFU-E from the CD4⁺CCR5⁺ T lymphocyte-depleted BMNC from patients with low-grade MDS showed significantly correlation with the percentage of Th1 (r=0.52, p≤¼ 0.05), but had no correlation with the percentage of Tc1 and the rate of Th1/Th2 and Tc1/Tc2 (p >0.05); The number of CFC, CFU-G and CFU-GE had no correlation with the polarization of T lymphocyte (P >0.05). ¢Ç The percentage of CD34 in bone nucleated cells of low-grade MDS was higher than that in healthy donors(1.8% vs. 1.0%, P >0.05), that of CD33 in nucleated cells of low-grade MDS was significantly higher than that in healthy donors[(20.3±5.8)% vs.(13.8±1.8)%(P≤¼0.05)], and that of CD13 in nucleated cells of low-grade MDS was significantly higher than that in healthy donors[(21.1±6.4)% vs. (11.6±1.8)%(p<0.05)]. After cultivation, the percentage of CD34 in low-grade MDS nucleated cells decreased to 1.4%(P >0.05), that of CD33 decreased to (12.1±3.7)%(p<0.05), and that of CD13 decreased to (17.1±5.4)%(p<0.05), but the percentage of CD34, CD33 and CD13 had no significantly changed in healthy donors between pre-culture and post-culture. ¢È FISH analysis in 6 patients revealed that +8 clone was increased(from 51% to 61%), but 20q- and -7 clone cell had no significantly changed.

Conclusion In certain subtypes of MDS, selectedly removement of autologous activated CD4T cells can increase the generation of colony-forming-cells(CFC) in vitro, and improve the differentiation of MDS medullary system, but the increased CFC consisting of residual normal hemopoiesis or conal hemopoiesis were still unconcluded.