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.

Effect of Frequency of Platelet Apheresis on Coagulation Function in Donors: A Prospective Cohort Study

The maximum number of plateletpheresis donation was permitted up to 24 times every year for each donor in China. This study was investigated the effect of donation frequency on coagulation function of the plateletpheresis donors. A total of 96 plateletpheresis regular donors (splitted into A, B, C groups with 32 donors each group. A was 6–11 times donations, B with 12–17 times and C with 18–24 times) and 32 first time plateletpheresis donors (D group) were analyzed. The coagulation reaction time (R), blood clot formation time (K), α-Angle, normal maximum amplitude (MA) were tested using thromboelastography instrument. Platelet (PLT) count was measured using a hematology analyzer. The ratio of the male to female were 23:9, 24:8, 27:5 and 24:8, the mean age were 40.7 ± 7.6, 39.8 ± 8.3, 40.2 ± 7.9 and 37.0 ± 9.3, and the platelet collection amount were 1.55 ± 0.37 U, 1.58 ± 0.38 U, 1.61 ± 0.33 U and 1.46 ± 0.31 U in the A, B, C, D groups respectively. There were significant difference in the values of the R, K, α-Angle, MA and PLT count between before and after plateletpheresis donation in each group (p < 0.05). However, the values of R, K, α-Angle, MA and PLT count in the before donation were not difference among the A, B, C, D groups (p > 0.05). Similar results were found in the after plateletpheresis donation. The number of the PLT was significantly correlated with the values of the R, K, α-Angle and MA (p < 0.05). However, the frequency of plateletpheresis were not significantly correlated with R, k, α and MA parameters (p > 0.05) using Spearman correlation analysis. The regular donation of apheresis platelets and the frequency of annual blood donation had no adverse effect upon coagulation function of the donors in China.

Innate immune responses of equine monocytes cultured in equine platelet lysate

Platelet lysate (PL) has been extensively used for the laboratory expansion of human mesenchymal stem cells (MSC) in order to avoid fetal bovine serum (FBS) which has been associated with immune-mediated host reactions and transmission of bovine-origin microbial contaminants. Before suggesting the routine use of PL for MSC culture, we wanted to further investigate whether PL alone might trigger inflammatory responses when exposed to reactive white blood cells such as monocytes. Our objectives were to evaluate the inflammatory profile of equine monocytes cultured with equine PL (ePL) and to determine if ePL can modulate the expression of inflammatory cytokines in lipopolysaccharide (LPS)-stimulated monocytes. In a first experiment, equine monocytes were isolated and incubated with donor horse serum (DHS), FBS, six individual donors ePL or pooled ePL from all horses. In a second experiment, monocytes were stimulated with E. coli LPS in the presence of 1, 5 or 10% DHS and/or pooled ePL. After 6h of incubation, cell culture supernatants were assayed via ELISA for production of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) and Interleukin 1β (IL-1β) as well as for the anti-inflammatory Interleukin 10 (IL-10). Equine monocytes incubated with pooled ePL produced significantly less TNF-α and significantly more IL-10 than monocytes incubated in FBS. A statistically significant difference was not identified for the production of IL-1β. The second experiment showed that pooled ePL added to LPS-stimulated equine monocytes resulted in a significant reduction in TNF-α and IL-1β production. IL-10 production was not significantly upregulated by the addition of ePL to LPS-stimulated monocytes. Finally, the addition of ePL to LPS-stimulated monocytes in the presence of various concentrations of DHS resulted to statistically significant decrease of TNF-α and IL-1β compared to the control groups. This is the first study to demonstrate that ePL suppresses the release of pro-inflammatory cytokines from stimulated equine monocytes. These results encourage further exploration of PL as a homologous media substitute for FBS but also opens the possibility of investigating its use as means to suppress cell-mediated inflammation.

Successful management of intraperitoneal bleeding with platelet apheresis and von Willebrand factor supplementation in a patient with essential thrombocythemia and acquired von Willebrand syndrome

A 36-year-old woman with essential thrombocythemia (ET) was admitted to our hospital for acute lower abdominal pain. Given no family history of bleeding disorder, she was diagnosed with acquired von Willebrand syndrome. Despite having a medical history of venous thrombosis, she had never been treated for ET because of her preferences. On admission, CT scan revealed massive hemorrhage in the ascending colon with the leakage of a contrast agent. Furthermore, a delayed enhancement of fluid collection in the Douglas fossa followingcontrast CT indicated bloody ascites. Laboratory data revealed elevated platelets (1,569×10³/µl) and reduced von Willebrand factor (VWF) :RCo (32%) and VWF:Ag (48%). Platelet apheresis was initiated, combined with the infusion of VWF-containing concentrates and cytoreductive therapy with hydroxyurea. Three days after admission, her platelet count decreased to 992×10³/µl after the second round of platelet apheresis. CT scan revealed no hemorrhage, which implied hemostasis. Because of the absence of symptoms, she was discharged 23 days after admission. These results suggest that platelet apheresis, combined with infusion of VWF-containing concentrates and cytoreductive therapy with hydroxyurea, is an effective approach for the treatment of acquired von Willebrand syndrome characterized by emergent bleeding concomitant with ET.

Evaluation of store lesion in platelet obtained by apheresis compared to platelet derived from whole blood and its impact on the in vitro functionality

Platelet units for transfusion purposes are obtained manually from whole blood or by apheresis, in an automated process. In both methods, platelets during storage present a characteristics grouped under the name "storage lesion" that are associated with adverse effects on platelet units. Oxidative stress has been claimed to be one of major causes, leading to activation and apoptosis processes affecting their post transfusion functionality. In this work, we observed an association between apheresis and a reduced presence of oxidative stress and better results in functional markers in stored platelets, compared to manually obtained platelets. Then, apheresis which would ensure a greater number of functional platelets during the 5 days of storage, compared to concentrates obtained from whole blood.