ABSTRACT
Background@#Platelet aggregation studies using conventional light transmission aggregometry (LTA) have several disadvantages and require strict pre-analytical measures for reliable results.We aimed to examine the utility of flow cytometric platelet aggregation (FCA) assay in detecting platelet function defects (PFDs) in patients with a history of bleeding symptoms. @*Methods@#Sixty-four participants (24 patients and 40 healthy controls) were included in this study.LTA and FCA assay were performed simultaneously in patients and healthy controls. In the FCA assay, two portions of platelets from the same individual were labeled separately with CD31-FITC and CD31-PE. After mixing and stimulation with agonists, the double-colored platelet aggregates were visualized using a flow cytometer. The results generated using the two techniques were compared and correlated. @*Results@#The patients’ median age was 17 years (range, 3‒72 yr) with a male-to-female ratio of 1:1.7. There was substantial agreement between LTA and FCA assay in detecting a PFD (κ=0.792). Four patients showing a Glanzmann thrombasthenia-like pattern on LTA exhibited an abnormal FCA. A functional defect in collagen binding was detected on the FCA assay conducted in two immune thrombocytopenic patients with severe bleeding. @*Conclusion@#FCA assay can be used to identify functional defects in platelets, with potential applications in thrombocytopenic individuals. It also facilitates the diagnosis of inherited bleeding disorders with platelet defects.
ABSTRACT
Background@#Platelet aggregation studies using conventional light transmission aggregometry (LTA) have several disadvantages and require strict pre-analytical measures for reliable results.We aimed to examine the utility of flow cytometric platelet aggregation (FCA) assay in detecting platelet function defects (PFDs) in patients with a history of bleeding symptoms. @*Methods@#Sixty-four participants (24 patients and 40 healthy controls) were included in this study.LTA and FCA assay were performed simultaneously in patients and healthy controls. In the FCA assay, two portions of platelets from the same individual were labeled separately with CD31-FITC and CD31-PE. After mixing and stimulation with agonists, the double-colored platelet aggregates were visualized using a flow cytometer. The results generated using the two techniques were compared and correlated. @*Results@#The patients’ median age was 17 years (range, 3‒72 yr) with a male-to-female ratio of 1:1.7. There was substantial agreement between LTA and FCA assay in detecting a PFD (κ=0.792). Four patients showing a Glanzmann thrombasthenia-like pattern on LTA exhibited an abnormal FCA. A functional defect in collagen binding was detected on the FCA assay conducted in two immune thrombocytopenic patients with severe bleeding. @*Conclusion@#FCA assay can be used to identify functional defects in platelets, with potential applications in thrombocytopenic individuals. It also facilitates the diagnosis of inherited bleeding disorders with platelet defects.
ABSTRACT
BACKGROUND: Chronic lymphoproliferative disorders (CLPDs) are heterogeneous group of disorders with variable clinical presentations and outcomes. Therefore, accurate classification is crucial for treatment planning. At present, flow cytometry immunophenotyping (FCM-IPT) is a useful tool for diagnosing these diseases. However, overlapping immunophenotypes do exist. Recently, differential expression of CD200 and variation in number of CD20 antibody bound per cell (ABC) in different CLPDs has been reported. MATERIALS AND METHODS: Seventy-seven CLPD cases were analyzed by FCM-IPT for CD200 expression, and Quantibrite bead was used to calculate CD20 ABC. RESULTS: Variability in CD200 expression can help in the differentiation of chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HCL) from other CLPDs. CD200 was brightly expressed in 100% CLL cases, having homogenous bright (2+) intensity. On the contrary, CD200 was uniformly negative in all Mantle cell lymphoma cases except 1, in which the intensity was dim, and the mean fluorescence intensity was significantly lower than CLL. Furthermore, all HCL cases showed bright expression of CD200, thereby making it useful in differentiation from other CLPD with villous lymphocytes. Evaluation of CD20 ABC showed that it differs among various CLPD and was significantly lowest in CLL and highest in HCL both on peripheral blood and bone marrow samples. CONCLUSION: Our results support the fact that CD200 can be added to routine CLPD panel as it is useful in subcategorizing them. However, inclusion of CD20 ABC to routine panel does not seem plausible but may be done for difficult diagnostic cases or where anti-CD20 therapy is planned.
