Biomedical subjects

Bai-Qin Qian

Publications and source records attributed to Bai-Qin Qian.

5 recordsLinked to original sources

PubMed2006

[Reactivity of a novel monoclonal antibody ZCH-2B8a on normal hematopoietic cells and malignant cell lines and its significance].

ZCH-2B8a (IgG2a) is a novel monoclonal antibody (McAb) generated in laboratory of Children Hospital of Medical College, Zhejiang University recently using human myeloblastic leukemia cell line KG1a as immunogen. This antibody has been submitted to the 8th International Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA8) and the results showed that the antibody recognized an unknown molecule on the surface of some blood cells. The aim of this study was to investigate the reactivity of this antibody on normal blood cells and malignant cell lines and to explore its possible application in clinical practice. The multi-parameter flow cytometry was used to analyze the expression pattern of 2B8a antigen in triplicate on normal blood components including T cells, B cells, natural killers (NK), neutrophils, monocytes, dendritic cells (DC), red blood cells (RBC), platelets (Plt), hematopoietic stem/progenitor cells derived from either bone marrow or G-CSF mobilized peripheral blood CD34(+) cells and malignant cell lines including 14 hematopoietic, 5 neuroblastoma, 1 colon cancer and 1 amniotic epithelium cell lines. The amount of positive cells > or = 20% was considered as positivity. The results showed that 2B8a antibody reacted to 3/3 specimens of blood B cells with a positive rate of 26.29% and 2/3 specimens of monocytes with an average positive rate of 59.84%. 2B8a was weakly reactive to neutrophils (23.72%) and negative for T cells, NK, DC, RBC and Plt. The antibody reacted to all 3 marrow CD34(+) cells with an average positive rate of 39.33% while it was negative for G-CSF-mobilized CD34(+) peripheral blood stem/progenitor cells (PBSC, 1.25%). Cell line analysis showed that the antibody notably reacted to three out of 4 cell lines (Raji, SMS-SB, Nalm-6 and Nall-1) with the positive rates of 98.78%, 98.61%, 94.93% respectively and weakly to one of them with 5.68% in B lineage cell lines and monoblastic cell line (U937, 67.78%) while it was only weakly positive or negative for other myeloid leukemia cell lines including Meg01 (33.40%), HL-60 (29.70%), K562 (28.19%), KG1a (16.23%) and HEL92.1.7 (8.02%). Among 4 T lineage leukemia, 5 neuroblastoma and 1 colon cancer cell lines tested, only Molt-3 was found weakly positive (31.40%) for 2B8a, while the remaining 3 T cell lines (Molt4, JM and CCRF-CEM), 5 neuroblastoma cell lines (LA-N1, KCNR, BE, SK-N-SH, SK-N-AS) and the colon cancer cell line (HR8348) tested were negative. An amniotic epithelium cell line (FL) was showed positive for the antibody (45.03%). It is concluded that 2B8a antibody primarily reacts to B lineage and monocytic lineage cells which may bear the diagnostic and therapeutic applications among different types of hematopoietic malignancies.

Antibodies, Monoclonal↗

PubMed2005

[Application of flow cytometry to detect PP65 antigenemia for diagnosis and monitoring of human cytomegalovirus infection].

OBJECTIVES: To evaluate the clinical significance of flow cytometry (FCM) to detect the cytomegalovirus (CMV) PP65 antigen in patients with CMV infection. METHODS: Samples from 35 patients without CMV infection were used as negative control. The definite diagnosis of CMV infection was based on the national criteria for CMV infection. All 136 patients with CMV infection were examined with the FCM to detect CMV PP65 antigen, real-time fluorescence quantitative-polymerase chain reaction assay (RFQ-PCR) to detect CMV-DNA and ELISA to measure the serum level of IgM antibody against CMV. The results of these 3 assays in 2 groups (isolated organ involvement and disseminated diseases) were compared and the significance of PP65 antigenemia was evaluated. A short-term follow-up was undertaken in 18 patients. RESULTS: The percentages of PP65 positivity in blood mononuclear cells (MNC) and polymorphic nuclear leukocyte (PMNL) from 35 negative control patients were 0.21% +/- 0.09% with a range of 0 - 0.41% and 0.24% +/- 0.10% with a range of 0.12% - 0.48%, respectively, which were not significantly different (t = 0.425, P > 0.05). The 95(th) percentiles (P(95)) of PP65 in MNC and PMNL were 0.39% and 0.45%, respectively, so a cutoff value of >/= 0.50% was set. Of the 136 patients with CMV infection, 118 samples from 118 patients were positive for PP65 antigenemia with a positive rate of 86.8%, which was not statistically different from that (90.4%, chi(2) = 0.91, P > 0.05) of CMV-DNA detected by RFQ-PCR assay but it was significantly higher than that (45.6%, chi(2) = 51.50, P < 0.005) of the detection by IgM measurement. PP65 detection was correlated with urine CMV DNA amplification (chi(2) = 63.78, P < 0.01) while the different detection rates between the two assays were not statistically significant (chi(m)(2) = 1.78,P > 0.05). PP65 detection was not correlated with serum IgM measurement while the detection rates between the two were significantly different (chi(m)(2) = 52.92,P < 0.01). No significant difference was found between the detection rates of CMV infection in MNC (45/53, 84.9%) and PMNL (43/53, 81.1%) (chi(m)(2) = 0.25, P > 0.05). Higher PP65 antigenemia level was correlated with systemic CMV infection, while lower level of PP65 was either in the patients with isolated organ involvement by CMV (chi(2) = 38.51, P < 0.005) or less severe in patient's situation. PP65 antigenemia of CMV infection returned to lower level or negative in recovery stage and increased when condition of patients deteriorated. CONCLUSIONS: PP65 antigenemia detection by FCM is effective in the diagnosis of the active CMV infection. Quantitative monitoring of PP65 antigenemia is useful in the evaluation of patients with CMV infection.

Antigens, Viral↗

PubMed2005

Comparison between CD19 and CD20 expression patterns on acute leukemic cells.

In order to provide the evidences for CD19 as a better antibody targeting molecule for B lineage acute leukemias than CD20 through the multi-parameter flow-cytometry analysis of leukemia cells, the samples from 321 patients with acute leukemia (AL) were immunophenotyped by multi-color flow cytometry and CD45/SSC gating strategy followed by the analysis of CD19 and CD20 expression. The results showed that the positive rate of CD19 (115/116, 99.1%) in 116 cases with B lineage acute lymphoblastic leukemia (B lineage ALL) was significantly higher than that of CD20 (33/116, 28.4%) (P < 0.01); in 17 patients with B lineage/Myeloid (B/My) acute mixed lineage leukemia (AMLL), the former positive rate (17/17, 100%) was also higher than the latter (5/17, 29.4%) (P < 0.01). Both of the two antigens were negative in 29 patients with acute T lymphoblastic leukemia and 7 patients with T/My AMLL. The positive rates of CD19 and CD20 in 152 patients with acute myeloid leukemia (AML) were 7.2% and 2.0%, respectively. The difference of the fluorescence intensity between the two antigens on the cells from each patient with B lineage ALL or B/My AMLL was statistically significant (t = 20.68, P < 0.001). The specificity of CD19 and CD20 in B lymphocytic lineage was 92.3% (132/143) and 92.7% (38/41), respectively, while the sensitivity was 99.2% (132/133) and 28.6% (38/133), respectively, the former sensitivity was significantly higher than the latter (chi(2) = 144.018, P = 0.001). It is concluded that CD19 continuously and steadily express on almost all subtypes of B lineage leukemic cells with homogeneous pattern while only a small number of leukemias express CD20. Both the specificity and sensitivity of CD19 were very high with a much broader reaction pattern than that of CD20 on this group of diseases. These indicate that CD19 may be a better antibody targeting molecule than CD20 for patients with B-lineage acute leukemia.

Acute Disease↗

PubMed2002

[Establishment of models for purging leukemic cells from the grafts in vitro].

Using a fluorochrome Calcein-AM, leukemia cells were labeled and seeded into cell lines or bone marrow cells to establish three cell-models of grafts with leukemia. These cell-models were engaged with CD34 immunomagnetic beads and the purging efficacy was evaluated using both fluorescence microscopy and flow cytometry. The results showed that the cell-models established in this study could be evaluated successfully not only with fluorescence microscopy but also flow cytometry. After CD34 positive selection, KG1a cells were removed by (0.98 +/- 0.09) log in model II and NALM-6 cells were removed by (1.82 +/- 0.51) log in model III, respectively. It is concluded that the models established in this study are stable and direct with an excellent reproducibility and an accuracy, which can be used to evaluate purging efficacy of leukemia cells in model graft using immunomagnetic selection and the experimental studies on tumorcidal effect in vitro.

Bone Marrow Purging↗

PubMed2002

[Expression of CD56 in acute leukemia and its clinical significance].

In order to investigate the expression of CD56 on acute leukemia cells and its clinical significance, samples from 70 patients with acute leukemia were analyzed with multicolor flow cytometry to determine the CD56 and other leukocyte differentiation antigens. The results showed that 16 of 70 cases (22.86%) were identified to express CD56, of which 1/35 (2.86%) patient with acute lymphocytic leukemia (ALL) and 15/31 (48.39%) with acute myelocytic leukemia (AML) were CD56 positive. The positive rate of CD56 in AML was significantly higher than that in ALL (P < 0.01). The expression of CD56 varied in AML subtypes. The positive rate (11/15) of CD56 in AML-M(0), -M(1) and -M(2) was significantly higher than that in AML-M(3), -M(4) and -M(5) (4/16) (P = 0.013). 13 of 15 AML with CD56 expression were also positive for HLA-DR (41.94%), and a significant positive correlation was found between the expression of CD56 and HLA-DR (r = 0.439, P = 0.014). It was concluded that CD56 mainly expressed in AML cells. The analysis of CD56 expression on acute leukemia is of great value in the diagnosis, prognosis prediction and monitoring of minimal residual disease in AML patients.

Adolescent↗