Human HLA-B27 typing using the BD™ HLA-B27 kit on the BD FACSVia™ system: A multicenter study.

The BD FACSVia™ system is a novel flow cytometer with improved workflow efficiencies. To evaluate the HLA-B27 application developed on the BD FACSVia system utilizing the BD™ HLA-B27 kit, we conducted a concordance study at three centers to compare with the BD FACSCalibur™ system. Prepared donor samples (n = 594) were analyzed on both the BD FACSVia and BD FACSCalibur for the HLA-B27 assay. Adjudication of HLA-B27 discordant results was performed using the reverse sequence-specific oligonucleotide (rSSO) DNA typing method (LABType® SSO, One Lambda). On the BD FACSVia system 80 B27 positive, 499 B27 negative and 15 "Inconclusive" samples were observed. The corresponding BD FACSCalibur results were 73 B27 positive, 502 B27 negative and 19 "gray zone" samples. The overall concordance of HLA-B27 determination was 98% between the two systems with seven more positives identified on BD FACSVia as compared to BD FACSCalibur. The equivocal zone between positive and negative on BD FACSVia (named "Inconclusive") and on BD FACSCalibur (named "gray zone") is due to antibody cross reactivity of HLA-B27 clone GS145.2. One negative sample verified with the rSSO DNA method was reported as HLA-B27 positive by the BD FACSVia system leading to a false positive result. Our study demonstrated concordance results between the BD FACSVia system and BD FACSCalibur. Intersite reproducibility of BD HLA-B27 assay remained within the limits of acceptability. © 2018 The Authors. Cytometry Part B: Clinical Cytometry published by Wiley Periodicals, Inc. on behalf of International Clinical Cytometry Society.

Comparison of Flow Cytometric Methods for the Enumeration of Residual Leucocytes in Leucoreduced Blood Products: A Multicenter Study.

The BD FACSVia™ System features novel designs in hardware, software, and instrument QC. We compared the performance of the BD FACSVia System using the BD Leucocount™ kit with the BD FACSCalibur™ flow cytometer. Leucoreduced platelet (PLT, n = 252) and red blood cell (RBC, n = 278) specimens were enrolled at four sites. Each specimen was stained in four tubes using the BD Leucocount kit reagents and acquired on the two systems. BD Leucocount Control cells (high and low) were used to evaluate the inter-site reproducibility on the BD FACSVia System at three sites over 20 days. Deming regression and Bland-Altman analysis were performed to determine the WBC absolute counts on the BD FACSVia System vs. the BD FACSCalibur system. Assay accuracy for the range of 0-350 WBCs/µl was adequate. For samples with <25 WBCs/µl, the bias with 95% limits of agreement was 0.136 (-1.897 to 2.169) WBC/µl for PLTs (n = 184) and 0.170 (-2.025 to 2.365) WBC/µl for RBCs (n = 193). For inter-site reproducibility, the CV% was 6.46% (upper 95% CI 7.16%) for the PLT high control and 9.49% (10.52%) for the PLT low control. The CV% was 7.51% (8.32%) for the RBC high control and 10.76% (11.92%) for the RBC low control. The BD FACSVia System reported equivalent results of WBC absolute counts for leucoreduced PLT and RBC samples compared to the BD FACSCalibur system. The inter-laboratory reproducibility of the BD FACSVia System met study specifications. © 2018 The Authors. Cytometry Part A Published by Wiley Periodicals, Inc. on behalf of ISAC.

Premature senescence of T lymphocytes from patients with beta-thalassemia major.

Several researches have demonstrated a suppressed cell mediated immunity in patients with beta-thalassemia major. To know whether the premature aging of T cells is involved in abnormalities of cell mediated immunity, the biomarkers of immunosenescence including telomerase activity, apoptosis, and the expression of CD28 and CD95 were evaluated in T lymphocytes from beta-thalassemia major patients. The ex vivo spontaneous apoptosis in CD4(+) or CD8(+) T cells from patients and healthy subjects was assessed by an in situ TdT mediated dUTP-biotin nick end labelling (TUNEL) assay after 24h incubation in medium. Flow cytometric data revealed that lymphocytes from beta-thalassemia patients were resistant to spontaneous apoptosis compared to the normal lymphocytes. Moreover, the percentages of TUNEL(+)CD4(+) or TUNEL(+)CD8(+) T cells from patients were significantly lower than those control cells. Quantitative determination of telomerase activity in resting and activated T cells was performed using the Telomeric Repeat Amplification Protocol (TRAP). The results showed a decreased telomerase activity of activated T cells in patients with thalassemia major compared to that in healthy controls. However, the percentages of CD8(+)CD28(-) and CD3(+)CD95(+) T lymphocytes were significantly higher in thalassemia patients, indicating the phenotypes associated with senescent T lymphocytes. These data provide evidences for the occurrence of accelerated aging of T cells in beta-thalassemia major; possibly result in abnormal T cell function leading to suppressed cell mediated immunity.

A study on stress, depression and NK cytotoxic potential in women with recurrent spontaneous abortion.

It has been recognized that acute and chronic stress has an impact on the immune system. Acute stress may have a stimulating effect on the immune system, while in the case of chronic stress specially depression, the immune system could be down-regulated. However, an association between depression and a higher number of circulating white blood cells with increased activity has been reported. Elevation in immune cell numbers and alteration in cytokine profiles are documented for women suffering sporadic spontaneous abortion with a high stress score. In spite of these contradictory results and to make a new approach in immunological (NK activity) as well as psychological parameters (stress/depression) in women suffering from recurrent spontaneous abortion (RSA) the present study was planned. Forty-five women with a history of RSA and a matched control group were participated in this study. A questionnaire for life events known as life change units (LCU) and the Beck Depression Inventory (BDI) outlines were used and the socio-psychological events were recorded after visiting and interview. Fresh peripheral blood lymphocytes were taken as a source of NK activity and K562 cell line were used as NK sensitive target. The experiments were performed and the cells were analyzed with a flow-cytometer. The stress and the depression scores were determined 245+/-83.6 and 27.6+/-8.8 for women with RSA and 224+/-79.6 and 19.4+/-7.1 for non-RSA group respectively. There was an association between life stress scores and depression scores with r=0.65 and P=0.000 for RSA women. A correlation with r =-0.34 and P = 0.02 was found between depression scores and NK cytotoxicity. The Pearson correlation test showed a lack of relationship between high stress score and NK activity with the r=0.011 and P=0.95, but r=-0.30 and P=0.072 was obtained for high depression scores and NK cytotoxicity. Therefore, it could be suggested that in the case of women with a history of recurrent spontaneous abortion, modulation for immunological parameters (i.e immunotherapy) concurrently with managing psychological aspects (stress/depression) could be modified for the benefit of the patients.