[The immune effects of rituximab on dendritic cells derived from patients with primary immune thrombocytopenia].
OBJECTIVE
To explore the changes of surface antigen and function of rituximab on dendritic cells derived from patients with Primary immune thrombocytopenia (ITP) to further understand the effective mechanism of immunotherapy.


METHODS
The peripheral blood mononuclear cells (PBMCs) were isolated from remission patients with ITP before and after low-dose rituximab infusion, and the PMNCs were stimulated for 5 days by rhGM-CSF and rhlL-4 in 5% CO2 air at 37°C incubator. Then all of DCs were cultured with TNF-α for 48 hours. The morphology of DCs was monitored under inverted microscope daily, and the surface antigens of the DCs were analysed by flow cytometry, meanwhile the levels of IL-12p70 and TGF-β1 in supernatants were detected by ELISA, mix lymphocyte reaction was performed by MTT assay.


RESULTS
(1) Rituximab-treated-DCs showed no obvious tree-like protruding compared with untreated-DCs. The former cells were small and most of nucleus were centric. (2) The expressions of HLA-DR, CD80, CD83 and CD86 on rituximab-treated-DCs \[56.37 ± 3.95)%, (36.41 ± 2.82)%, (30.45 ± 4.61)% and (41.98 ± 4.17)%, respectively\] were significantly lower than those untreated-DCs \[(73.71 ± 7.61)%, (55.14 ± 7.30)%, (80.91 ± 7.09)% and (59.03 ± 3.43)%, respectively\](all P < 0.05), the concentration of IL-12p70 was significantly lower, \[(66.87 ± 4.29)% vs (50.17 ± 14.52)%\], while that of TGF-β1 \[(9.70 ± 0.31)%\] higher than the untreated-DCs \[(2.70 ± 0.36)%\] (P < 0.05). (3) The abilities to activate T cells proliferation of rituximab-treated-DCs reduced compared with untreated-DCs.


CONCLUSIONS
The surface antigen of ITP-DCs and the concentration of IL-12p70 reduced after the low-dose rituximab infusion. The abilities to activate T cells proliferation reduced while the concentration of TGF-β1 increased. Rituximab may achieve its therapeutic effect on ITP by downregulating the immunoreactivity of DCs.
Department of Hematology, the Second Affiliated Hospital of Lanzhou University, Lanzhou, China.
Guo-fa
GF
Xu
Lian-sheng
LS
Zhang
Li-juan
LJ
Li
Liang-cai
LC
Yi
Peng-yun
PY
Zeng
Chong-yang
CY
Wu
D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage / Q000627:therapeutic use*; D049109:Cell Proliferation; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D006801:Humans; D018664:Interleukin-12 / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D000069283:Rituximab; D013601:T-Lymphocytes / Q000276:immunology; D013921:Thrombocytopenia / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
D058846:Antibodies, Monoclonal, Murine-Derived; C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1; D018664:Interleukin-12; D000069283:Rituximab