Effect of long-term platelet donation on lymphocyte subsets and plasma protein concentrations

Serial analysis of hematological, biochemical, and immunological parameters alterations in regular healthy voluntary donors during plateletpheresis donation

BACKGROUND AND OBJECTIVES

The long-term effect of regular plateletpheresis on donors has not been characterized. Hence, we planned to study the long-term alterations in hematological, biochemical, and immunological parameters in regular repeat platelet apheresis donors.

MATERIALS AND METHODS

Thirty-three healthy voluntary regular repeat apheresis donors presenting for platelet donation, fulfilling the requisite donor selection criteria, underwent sequential analysis of the hematological, biochemical, and immunological parameters over 1 year.

RESULTS

A total of 33 regular repeat donors were enrolled in the study; out of these, 22 could be followed up to 3 months, 12 up to 6 months, and 10 donors up to 12 months for their hematological, biochemical, and immunological parameters. Overall, there was no significant change in hematological profile except a rise in platelet count at 3 months (P = 0.023) with no significant difference at 6 and 12 months from the baseline. In addition, serum thrombopoietin levels at 3 months (P = 0.010) and serum erythropoietin at 6 months (P = 0.01) were significantly higher than baseline. Mean platelet volume was significantly higher from baseline at 12 months (P = 0.00). Serum protein, lymphocyte subpopulation, and serum ferritin did not show any significant change from baseline over 12 months of follow-up. However, there was a significant decline (P = 0.00) in serum calcium and an increase in serum magnesium from baseline (P = 0.03) at 12 months.

INTERPRETATIONS AND CONCLUSIONS

To conclude, apheresis platelet donation is a safe procedure. However, a complete hematological, biochemical, immunological profile and bone marrow density at regular intervals (3-6 months) are recommended to ensure the safety of regular repeat plateletpheresis donors.

Case Report: Serial Cases: Prolongation of High Immunoglobulin G Level in Repetitive COVID-19 Convalescence Plasma Donor in Saiful Anwar Hospital Malang, Indonesia

Background

Convalescent plasma therapy is expected to be a promising alternative to supportive therapy during the SARS-CoV-2 pandemic outbreak. Altered immune response in repetitive convalescent plasma donors has not been widely studied. This case series was reported to analyze the patterns of immune responses and the factors that might influence them in repetitive convalescent plasma donors and increase awareness of COVID-19 survivors to donate their convalescent plasma.

Cases Illustration

There were five repetitive donors who were eligible as convalescent plasma donor requirements. It was found two donors who showed increment of anti-SARS-CoV-2 IgG level after donation and two others who showed persistent anti-SARS-CoV-2 IgG level more than two months after recovered.

Discussion

There was a difference in immune response in survivors who have the probability of being exposed to same antigens with survivors who did not, where the group of survivors who are at risk of exposure to antigens after recovery could trigger anamnestic immune response that can increase antiSARS-CoV-2 IgG levels. The other factor that influence the prolongation of anti-SARS-CoV-2 IgG levels are the possibility of neutralizing antibodies in plasma upregulation.

Conclusion

Immunological phenomenon in SARS-CoV-2, both in survivors and convalescent plasma donors, have not been widely observed and studied. From the case series discussed above, it can be concluded that convalescent plasma donation does not yet have strong evidence of decreasing levels of specific antibodies against SARS-CoV-2 and plasmapheresis procedure is safe to be done without reducing the protective effect of donor antibody post-plasma donation.

Frequent plateletpheresis donations & its effect on haematological parameters: An observational study

Background & objectives:

The well-being of donors undergoing frequent plateletpheresis has been a matter of concern. The aim of this study was to analyze the effect of frequent plateletpheresis on the haematological parameters (HP) of repeat donors.

Methods:

The study was conducted during February 2016 to March 2017 on all the repeat plateletpheresis donors undergoing the 2^nd plateletpheresis within a month of the first in a tertiary care centre. Donors repeating plateletpheresis 3^rd and 4^th times were also studied. The values of the HP observed on follow up after plateletpheresis done on three different separators were compared.

Results:

HPs of the 98 donors were similar at follow up except mean platelet volume (P<0.05). Of the 98 donors, 35 were followed up within a week and 63 were followed up within 8-30 days. No significant alteration was found in the HPs except a significant difference in the variation of platelet counts of the two groups (P=0.025). In 34 donors who presented 3^rd time for plateletpheresis (mean gap between 1^st and 3^rd plateletpheresis=31 days), no significant differences in the HPs were found except the platelet distribution width (P<0.05). Minimal difference in the HP was found in the baseline and the follow up of 3^rd plateletpheresis i.e., at 4^th plateletpheresis donation. Plateletpheresis through all the three cell separators used had similar effects on the follow up HPs.

Interpretation & conclusions:

Repeated plateletpheresis can be done without any detrimental effects on the cell counts of the plateletpheresis donors. The three cell separators yielded similar post-donation follow up haematological parameters.

Plateletpheresis-associated lymphopenia in frequent platelet donors

More than 1 million apheresis platelet collections are performed annually in the United States. After 2 healthy plateletpheresis donors were incidentally found to have low CD4+ T-lymphocyte counts, we investigated whether plateletpheresis causes lymphopenia. We conducted a cross-sectional single-center study of platelet donors undergoing plateletpheresis with the Trima Accel, which removes leukocytes continuously with its leukoreduction system chamber. We recruited 3 groups of platelet donors based on the total number of plateletpheresis sessions in the prior 365 days: 1 or 2, 3 to 19, or 20 to 24. CD4+ T-lymphocyte counts were <200 cells per microliter in 0/20, 2/20, and 6/20 donors, respectively (P = .019), and CD8+ T-lymphocyte counts were low in 0/20, 4/20, and 11/20 donors, respectively (P < .001). The leukoreduction system chamber's lymphocyte-extraction efficiency was ∼15% to 20% for all groups. Immunophenotyping showed decreases in naive CD4+ T-lymphocyte and T helper 17 (Th17) cell percentages, increases in CD4+ and CD8+ effector memory, Th1, and regulatory T cell percentages, and stable naive CD8+ and Th2 percentages across groups. T-cell receptor repertoire analyses showed similar clonal diversity in all groups. Donor screening questionnaires supported the good health of the donors, who tested negative at each donation for multiple pathogens, including HIV. Frequent plateletpheresis utilizing a leukoreduction system chamber is associated with CD4+ and CD8+ T-cell lymphopenia in healthy platelet donors. The mechanism may be repeated extraction of these cells during plateletpheresis. The cytopenias do not appear to be harmful.

Comparison of plateletpheresis on three continuous flow cell separators

INTRODUCTION

Platelet concentrate (PC) remains one of the most important support measures in thrombocytopenic patients. An efficient cell separator is a prerequisite for an optimally functioning apheresis setup. Donor blood count may undergo a temporary reduction after the procedure.

AIM

The aim was to find the extent of reduction in donor blood count (hemoglobin, hematocrit, white blood cell, and platelet) after plateletpheresis and to evaluate the cell separator for collection efficiency, processing time, and leukoreduction.

STUDY DESIGN AND METHODS

Two hundred and thirty seven procedures performed on the Amicus (N = 121), Fenwal CS-3000 Plus (N = 50) and Cobe spectra (N = 66) in a one year period were evaluated. The procedures performed on the continuous flow centrifugation (CFC) cell separators and donor blood counts (pre and post donation) done were included in the study.

RESULTS

The percent reduction in hemoglobin (HB), hematocrit (HCT), white blood cell (WBC) and platelet count ((PLT ct) was 2.9, 3.1, 9, 30.7 (Mean, N = 237) respectively after the procedure. The post donation PLT ct reduced to < 100x109/L (range 80-100) in five donors (N = 5/237, Amicus). The pre donation PLT ct in them was 150-200x109/L. Collection efficiency (percent) of Amicus (79.3) was better as compared to the other two machines (CS: 62.5, Cobe: 57.5). PC collected on Cobe spectra had <1x106 WBC. The donor pre donation PLT levels had a positive correlation to the product PLT yield (r = 0.30, P = 0.000).

CONCLUSION

Monitoring donor blood counts helps to avoid pheresis induced adverse events. A cautious approach is necessary in donors whose pre donation PLT ct is 150-200x109/L. The main variable in PLT yield is donor PLT ct (pre donation). High collection efficiency is a direct measure of an optimally functioning cell separator.

Complications of donor apheresis

A decreasing blood donor pool in the presence of increasing blood transfusion demands has resulted in the need to maximally utilize each blood donor. This has led to a trend in the increasing use of automated blood collections. While apheresis donation shares many reactions and injuries with whole blood donation, because of the differences, unique complications also exist. Overall, evidence in the literature suggests that the frequency of reactions to apheresis donation is less than that seen in whole blood donation, though the risk of reactions requiring hospitalization is substantially greater. The most common apheresis-specific reaction is hypocalcemia due to citrate anticoagulation, which, while usually mild, has the potential for severely injuring the donor. Other reactions to apheresis donation are uncommon (e.g., hypotension) or rare (e.g., air embolism). More worrisome, and in need of additional study, are the long-term effects of apheresis donation. Recent evidence suggests that repeated apheresis platelet donations may adversely effect thrombopoiesis as well as bone mineralization. Granulocyte donation has also been implicated in unexpected long-term consequences.

Volunteer donor apheresis

Volunteer donor apheresis has evolved from early plasmapheresis procedures that collected single components into technically advanced multicomponent procedures that can produce combinations of red blood cells, platelets, and plasma units. Blood collection and utilization is increasing annually in the United States. The number of apheresis procedures is also increasing such that single donor platelet transfusions now exceed platelet concentrates from random donors. Donor qualifications for apheresis vary from those of whole blood. Depending on the procedure, the donor weight, donation interval, and platelet count must be taken into consideration. Adverse effects of apheresis are well known and fortunately occur in only a very small percentage of donors. The recruitment of volunteer donors is one of the most challenging aspects of a successful apheresis program. As multicomponent apheresis becomes more commonplace, it is important for collection centers to analyze the best methods to recruit and collect donors.