Flow‐Cytometric Method for Counting Very Low Numbers of Leukocytes in Platelet Products<sup>1</sup>

Dzik, Walter H.; Ragosta, Annette; Cusack, William F.

doi:10.1111/j.1423-0410.1990.tb00850.x

Cited by 53 publications

(36 citation statements)

References 5 publications

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“…In addition, 2 min are necessary to input samples/reagent and agitate them, and 5 min for the measurement of each sample. As a result, the measurement of 10 samples takes 105 min [8, 9]. A capillary volumetric cytometry system (IMAGN 2000, Biometric Imaging, Mountain View, Calif., USA) has been developed and widely used in blood centers.…”

Section: Discussionmentioning

confidence: 99%

Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

et al. 2000

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Background and Objectives: Leukocytes remaining in platelet concentrates may be responsible for side effects caused by platelet transfusion. A simple method of high sensitivity for determining trace numbers of leukocytes is currently needed. Materials and Methods: An automated leukocyte counter, the LD-1000, the principle of which is a combination of spinning down on the observation field of stained nuclei derived from a 100 μl neat sample and image digitization with a charge coupled device camera, was newly developed and tested for sensitivity and reproducibility. Results: While the theoretical lower limit of detection was 0.01 cells/μl, the limit of detection of the LD-1000 was verified to be 0.2 cells/μl. A good correlation (r = 0.86) was observed between the results obtained using the Nageotte method and the LD-1000. Repeated measurements also confirmed satisfactory reproducibility. Conclusions: The instrument provides a new method of enumerating residual leukocytes in platelet products with better sensitivity and easier procedure compared to the Nageotte method and will be useful for quality assurance purposes at blood centers.

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Section: Discussionmentioning

confidence: 99%

Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

et al. 2000

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“…Postfiltration WBCs were measured by flow cytometry using propidium iodide as a DNA marker [23]. This simple method offers lower detection limits, 1 or 2 log below those obtained by the Nageotte chamber.…”

Section: Methodsmentioning

confidence: 99%

Benefit of Prestorage Leukocyte Depletion of Single–Donor Platelet Concentrates

et al. 1999

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Background and Objectives: The presence of contaminating white blood cells (WBCs) in platelet concentrates is associated with transfusion reactions and may adversely alter the quality of platelets during storage. Leukocyte depletion by filtration of platelets has been increasingly used to avoid these complications. However, the best time for filtration and the benefits of filtering single–donor platelet concentrates (thrombapheresis, TH) have yet to be clearly defined. Methods: In a randomized study of 202 TH collected with an Autopheresis C system, we determined whether prestorage filtration (preSF) of WBCs from TH as compared with poststorage (bedside) filtration (postSF) resulted in a better product. Levels of cytokines and C3a accumulating in the medium during storage, platelet activation state, in vivo platelet recovery, and transfusion reactions were compared in pre– and poststorage products. Results: As compared to preSF, significantly more postSF TH had detectable levels of tumor necrosis factor–α (TNF–α; 47 vs. 15%; p<0.0001) and interleukin 6 (13 vs. 3%; p = 0.02), lower pH (p<0.0001) and decreased levels of C3a (910 vs. 2,000 pg/ml; p<0.0001). Furthermore, platelet activation was increased in postSF TH (p = 0.022). PostSF TH tended to plug the bedside filter (27% of postSF TH delivered) from day 3 onward. There was also a significant difference in platelet recovery, postSF TH showing a lower corrected count increment (CCI; p = 0.0055) when taking into account the postSF TH that plugged filters (CCI = 0), but no difference when plugged TH were excluded. A correlation could be established between TNF–α levels and poor in vivo recovery (p<0.0001). Febrile nonhemolytic transfusion reactions were low in both groups (4 and 9%). Conclusion: These results indicate a benefit of preSF TH as compared with postSF TH based on the following parameters: decrease in cytokine levels, less platelet activation, maintenance of higher pH, and more efficient use of stored platelets (27% of postSF TH were lost because of plugging of filters). These results apply particularly to the Autopheresis C systems with its high initial WBC content.

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“…These two parameters indicated that for Cobe products it was necessary to test every pack prior to release as failures could easily be expected, but for the Haemonetics procedure the parameters indicated that failures were extremely unlikely and that 100% testing was not warranted. White cell counts (WCC) were performed using flow cytometry and propidium staining of DNA as previously described (Dzik et al, 1990).…”

Section: Methodsmentioning

confidence: 99%

Pilot study of HLA alloimmunization after transfusion with pre‐storage leucodepleted blood products in aplastic anaemia

Killick

N²,

Marsh

et al. 1997

Br J Haematol

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Summary.We have performed a pilot study to examine the incidence of alloimmunization using pre-storage leucocytedepleted blood products (PLDP) in 16 previously transfused aplastic anaemia (AA) patients with no detectable HLA antibodies. A further eight AA patients with HLA antibodies received HLA-matched PLDP. Leucodepleted apheresed platelets were obtained using either Cobe spectra or Haemonetics system with an integral pall filter. Pall BPF4 filters were used for red cell preparation. Patients' sera were tested for HLA antibodies using lymphocytotoxicity (LCT). Patients who were HLA antibody negative by LCT at study entry were further tested with enzyme-linked immunoassay (ELISA). Out of 16 patients, two (12%) formed anti-HLA antibodies with a median follow-up of 9 months (range 1-15), but did not display platelet refractoriness to random donor platelets. Two patients were inadvertently transfused with non-leucodepleted blood products when later referred back to their local hospital. Both subsequently demonstrated HLA antibodies by LCT and became platelet refractory. These results contrast with a 50% incidence of HLA alloimmunization in a control group of AA patients transfused prior to this study with non-PLDP. HLA antibodies could no longer be detected by LCT in follow-up of three out of eight patients with HLA antibodies at study entry. Only one patient experienced non-haemolytic febrile transfusion reactions (NHFTR). We conclude that PLDP reduce the risk of alloimmunization even in previously transfused AA patients, PLDP are associated with a low incidence of NHFTR, and all new AA patients should receive PLDP from diagnosis.

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Flow‐Cytometric Method for Counting Very Low Numbers of Leukocytes in Platelet Products¹

Cited by 53 publications

References 5 publications

Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

Benefit of Prestorage Leukocyte Depletion of Single–Donor Platelet Concentrates

Pilot study of HLA alloimmunization after transfusion with pre‐storage leucodepleted blood products in aplastic anaemia

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Flow‐Cytometric Method for Counting Very Low Numbers of Leukocytes in Platelet Products1

Cited by 53 publications

References 5 publications

Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

Benefit of Prestorage Leukocyte Depletion of Single&ndash;Donor Platelet Concentrates

Pilot study of HLA alloimmunization after transfusion with pre‐storage leucodepleted blood products in aplastic anaemia

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Flow‐Cytometric Method for Counting Very Low Numbers of Leukocytes in Platelet Products¹

Benefit of Prestorage Leukocyte Depletion of Single–Donor Platelet Concentrates