Platelet Yield and Some Donor-Related Predictors in a Single Donor Apheresis: Report from a Nigerian Tertiary Hospital

BACKGROUND

Single-donor platelet transfusion is the preferred therapeutic option for patients with platelet insufficiency and its effectiveness is partly dependent on the yield.

AIM

To determine the platelet yield and predictors of platelet yield in single-donor apheresis.

MATERIALS AND METHODS

This was a five-year review of the data on single-donor apheresis using the Haemonetics Apheresis machine MCS+ at Alex Ekwueme Federal University Teaching Hospital Abakaliki Ebonyi state. Platelet donor related variable of interest included the pre-donation platelet count, donor's blood group, number of apheresis cycles and yield volume. Analysis was done using Graphpad Prism version 9.1.1.

RESULTS

A total of 153 platelet apheresis were studied. The mean (SD) values for pre-donation platelet count, number of cycles, platelet yield and volume of platelet concentrate were 279 ± 47 x 109/L, 6 ± 0.3, 4.5± 0.8 X 10 11/L, and 320 ± 78 mL respectively. In this study, volume of platelet concentrate predicted 61% of platelet yield while platelet count of donor predicted 41%. Neither ABO nor Rh blood groups was a determinant of platelet yield.

CONCLUSION

Pre-donation platelet count and volume of platelet concentrate are important predictors of platelet yield. There is need for proper platelet donor selection.

Quantile-Specific Heritability of Mean Platelet Volume, Leukocyte Count, and Other Blood Cell Phenotypes

INTRODUCTION

"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g., mean platelet volume, MPV) is high or low relative to its distribution.

METHODS

Offspring-parent regression slopes (βOP) were estimated by quantile regression, from which quantile-specific heritabilities (h2) were calculated (h2 = 2βOP/[1 + rspouse]) for blood cell phenotypes in 3,929 parent-offspring pairs from the Framingham Heart Study.

RESULTS

Quantile-specific h2 (±SE) increased with increasing percentiles of the offspring's age- and sex-adjusted MPV distribution (plinear = 0.0001): 0.48 ± 0.09 at the 10th, 0.53 ± 0.04 at the 25th, 0.70 ± 0.06 at the 50th, 0.74 ± 0.06 at the 75th, and 0.90 ± 0.12 at the 90th percentile. Quantile-specific h2 also increased with increasing percentiles of the offspring's white blood cell (WBC, plinear = 0.002), monocyte (plinear = 0.01), and eosinophil distributions (plinear = 0.0005). In contrast, heritibilities of red blood cell (RBC) count, hematocrit (HCT), and hemoglobin (HGB) showed little evidence of quantile dependence. Quantile-dependent expressivity is consistent with gene-environment interactions reported by others, including (1) greater increases in WBC and PLT concentrations in subjects who are glutathione-S-transferase Mu1 (GSTM1) null homozygotes than GSTM1 sufficient when exposed to endotoxin; (2) significantly higher WBC count in AA homozygotes than carriers of the G-allele of the glutathione S-transferase P1 (GSTP1) rs1695 polymorphism at low but not high benzene exposure in shoe factory workers; (3) higher WBC counts in TT homozygotes than C-allele carriers of the interleukin-1β (IL1B) c.315C>T polymorphism after undergoing surgery for infective endocarditis but not before surgery.

DISCUSSION/CONCLUSION

Quantile-dependent expressivity may explain several purported gene-environment interactions involving blood cell phenotypes.

Platelet indices and glucose control in type 1 and type 2 diabetes mellitus: A case-control study

BACKGROUND AND AIMS

The relationship between platelet indices and glucose control may differ in type 1 (T1DM) and type 2 (T2DM) diabetes. We aimed to investigate differences in mean platelet volume (MPV), platelet count, and platelet mass between patients with T1DM, T2DM, and healthy controls and to explore associations between these platelet indices and glucose control.

METHODS AND RESULTS

A total of 691 T1DM and 459 T2DM patients and 943 control subjects (blood donors) were included. HbA1c was measured in all subjects with diabetes and 36 T1DM patients further underwent 24 h-continuous glucose monitoring to estimate short-term glucose control (glucose mean and standard deviation). Adjusting for age and sex, platelet count was higher and MPV lower in both T1DM and T2DM patients vs control subjects, while platelet mass (MPV × platelet count) resulted higher only in T2DM. Upon further adjustment for HbA1c, differences in platelet count and mass were respectively 19.5 × 10⁹/L (95%CI: 9.8-29.3; p < 0.001) and 101 fL/nL (12-191; p = 0.027) comparing T2DM vs T1DM patients. MPV and platelet count were significantly and differently related in T2DM patients vs both T1DM and control subjects; this difference was maintained also accounting for HbA1c, age, and sex. Platelet mass and the volume-count relationship were significantly related to HbA1c only in T1DM patients. No associations were found between platelet indices and short-term glucose control.

CONCLUSION

By accounting for confounders and glucose control, our data evidenced higher platelet mass and different volume-count kinetics in subjects with T2DM vs T1DM. Long-term glucose control seemed to influence platelet mass and the volume-count relationship only in T1DM subjects. These findings suggest different mechanisms behind platelet formation in T1DM and T2DM patients with long-term glycaemic control being more relevant in T1DM than T2DM.

Using the mean platelet volume MPV for the quality assessment of apheresis procedures

INTRODUCTION

Referring to current standards the quality of an apheresis procedure is estimated by the quantity of collected cells. Nowadays a new kind of quality measurement could be found in the detection of cell volumina. Recent diagnostics have shown that stem cells and platelets - when separated - are likely to appear in a higher volume inside the cell product. Therefore, in this study the question should be discussed wether platelets of higher volume are more likely to be separated than platelets showing a lesser volume.

METHODS

Blood samples of three different apheresis procedures could be observed: allogenic platelet donations (n = 7) (Trima, Terumo), autologous (n = 5) and allogenic stem cell donations (n = 5) (Cobe Spectra, Terumo). To examine the blood samples the Sysmex hematology analyser (XT-2000) has been used.

RESULTS

During stem cell apheresis, the volume of the separated platelets was 1.2 fold increased compared to the platelet volume in the peripheral blood before separation. Before apheresis the mean platelet volume in the peripheral blood was found to be 6,21 fl, after apheresis 6,09 fl and inside the platelet concentrate 7,42 fl. The platelet number in the peripheral blood was also significantly decreased (before separation 180.1/nl and after separation 133.5/nl). In the blood products the concentration of platelets was nearly 8 fold higher than in the peripheral blood before separation.

CONCLUSION

Overall, the observed apheresis procedures are more likely to separate platelets showing a higher voulme than common in the peripheral blood. This might indicate that not only the amount of separated cells reflects the quality of the apheresis procedure but also that the volume of the separated cells can be used as a parameter for quality assessment.

Selection of P2Y12 antagonist, treatment initiation, and predictors of high on-treatment platelet reactivity in a "Real World" registry

OBJECTIVE

The present study aimed to compare characteristics related to selection of a P2Y₁₂ antagonist, investigate initiation of therapy with new-generation drugs, and identify predictors of high on-treatment platelet reactivity (HTPR) in patients with acute coronary syndrome treated with stent percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Data from 589 patients in the LAPCOR (Laboratory AntiPlatelet efficacy and Clinical Outcome Registry; ClinicalTrials.gov Identifier: NCT02264912) registry was analyzed. P2Y₁₂ receptor antagonist efficacy was measured by VASP phosphorylation 24 ± 4 hours after a loading dose of clopidogrel (600 mg, N=407), prasugrel (60 mg, N=106), or ticagrelor (180 mg, N=76) and expressed by platelet reactivity index (PRI). HTPR was defined as PRI ≥50%. Patients treated with prasugrel were significantly younger and had significantly higher hemoglobin levels than those who received clopidogrel or ticagrelor, while chronic kidney disease was significantly more prevalent in the ticagrelor group. Almost all invasively managed patients given new-generation drugs received a loading dose after coronary angiography. Mean residual PRI and HTPR were significantly higher after clopidogrel (44.2 ± 23.1% and 42.2%, respectively) vs. prasugrel (17.7 ± 18.0% and 9.4%, respectively) or ticagrelor (18.8 ± 17.0% and 7.9%, respectively; all p<0.001). Among multiple variables tested, HTPR in patients treated with the new agents significantly related only to platelet count (p=0.014) and mean platelet volume (p=0.03).

CONCLUSION

Safety is the most important aspect under consideration in choosing new agents for an individual patient. Other than platelet count and mean platelet volume, factors known as predictors of higher platelet reactivity, did not influence the efficacy of new-generation P2Y₁₂ receptor antagonists.

Cardiovascular correlates of platelet count and volume in the Framingham Heart Study

PURPOSE

Platelet count and volume are inexpensive, routinely assayed biomarkers associated with cardiovascular health, but specific relationships among platelet indices, cardiovascular risk factors, and disease warrant further investigation. The purpose of this study was to understand associations among platelet count, volume, and 20 cardiovascular health-related variables in the Framingham Heart Study (FHS).

METHODS

Cross-sectional analyses were performed on platelet count and volume associations with cardiovascular health indicators in three FHS cohorts (original n = 964, offspring n = 2699, and third generation n = 2419) using multivariate linear regression analysis. Time-to-event analysis was used for cardiovascular disease-related event incidences using Kaplan-Meier plots and Cox proportional hazards regression adjusted for age and sex.

RESULTS

Results were concordant with the hypothesis that higher platelet counts are associated with less favorable cardiovascular risk profiles, although mean platelet volume associations were weaker. In our analysis, increased platelet count across FHS cohorts was consistently associated with smoking, triglycerides, low-density lipoprotein, and total cholesterol levels. Some associations with platelet count appeared sex dependent.

CONCLUSIONS

Significant associations of common blood platelet measurements are observed with sex and cardiovascular risk factors, namely smoking and lipids. Research is warranted to confirm these relationships in other cohorts, evaluate differences by ethnicity, and examine longitudinal effects on disease risk.