Apheresis donor safety--changes in humoral and cellular immunity

Total platelet donation count and donation frequency are determinants of plateletpheresis-associated lymphopenia

BACKGROUND

Plateletpheresis using a leukocyte reduction system (LRS) traps donor WBCs in the LRS chamber, which may lead to lymphopenia, especially in frequent plateletpheresis donors. It seems plausible that this might cause adverse effects. However, current knowledge about potential confounders and donor health impacts is incomplete.

DONORS AND METHODS

Recent platelet donors and donations collected at University Hospital Regensburg from 2016 to 2019 using the Terumo BCT Trima Accel LRS system were retrospectively analyzed and compared with historical platelet donors and donations collected mainly with Fresenius Kabi Amicus non-LRS system from 2010 to 2013. Additionally, recent donors were prospectively surveyed using a health-related topics questionnaire.

RESULTS

Analysis of 819 recent donors with 11,254 blood counts and 1464 questionnaires and 1011 historical donors with 12,848 blood counts revealed that increased annual platelet donation frequencies were associated with decreased lymphocyte counts in both groups. Median lymphocyte counts in recent donors with no versus ≥24 previous annual donations declined from 2.0 to 1.2 × 10³ /μL (p < 2.2 × 10^-16 ), and those in historical donors with no versus ≥24 previous annual donations decreased from 2.0 to 1.5 × 10³ /μL (p = 6 × 10^-4 ), respectively. The questionnaire results showed that donation frequency and lymphopenia were not associated with upper respiratory tract infection (URTI) incidence or duration, but platelet donors who concomitantly donated granulocytes had significantly shorter URTI durations than those who did not (p = .008).

CONCLUSION

This study confirmed that plateletpheresis-associated lymphopenia occurs in LRS and to a lesser degree in non-LRS platelet donors, but revealed no evidence of a negative impact on donor health.

CD4+ T-cell lymphopenia in frequent platelet donors who have ceased platelet donation for at least 1 year

BACKGROUND

We recently discovered that 30% of current frequent apheresis platelet donors in a study at our donor center had CD4+ counts below 200 cells/μL. How long CD4+ lymphopenia persists after ceasing plateletpheresis is unknown. Whether there are infectious or other complications in former frequent donors that could relate to CD4+ lymphopenia is also unknown.

STUDY DESIGN AND METHODS

We mailed a letter to former frequent apheresis platelet donors who had not donated platelets for at least 12 months. Frequent donation was defined as 20 to 24 plateletpheresis sessions in at least one 365-day period starting in 2011. Donors who expressed interest in the study were contacted to schedule a study visit. Participants in the study provided a blood sample and completed a health questionnaire that included questions about opportunistic infections and malignancies.

RESULTS

Of 50 potential study candidates who were mailed a letter, 15 participated in the study. There were 2 participants with CD4+ counts below 200 cells/μL, one of whom had prior counts that documented a small improvement with cessation of plateletpheresis. Three participants had counts between 200 and 300 cells/μL. No study participant had a history of an opportunistic infection or a malignancy associated with immune dysregulation.

CONCLUSION

We detected CD4+ lymphopenia in former frequent apheresis platelet donors who had ceased platelet donation for more than 1 year. There was no evidence that the CD4+ lymphopenia predisposes to opportunistic infections or to malignancies associated with immune dysregulation.

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.

Improvement of plateletpheresis via technical modification on the MCS+

BACKGROUND

With the advantage of easy operation and high reliability, Haemonetics multicomponent collection system (MCS+) is widely used as a blood cell separator in clinical application.

OBJECTIVES

The aim of this study was to evaluate the effect of technical parameter modification as utilised on the MCS+ to improve the quality of platelet yielded as well as donor comfort.

METHODS

After informed consent, a total of 118 donors, well matched for baseline parameters, were included in the study from December 2012 to April 2013. Sixty-one donors underwent single-dose plateletpheresis (SDP), and the other 57 donors underwent double-dose plateletpheresis (DDP) before and after technical modification on the MCS+, respectively, according to the manufacturer's instructions. The procedures were evaluated, focusing on whole blood processed (WBP), processing time (PT) and number of cycles were measured, as well as the quality of products.

RESULTS

No severe adverse reaction was found during donation. WBP, PT and number of cycles after modification were all reduced significantly in both SDP and DDP groups (P < 0·01). In addition, 80·51 % (95 in 118) of the total post-modification products were qualified, presenting with high quality. Besides, the comfort of donors was also improved probably because of the reduced PT.

CONCLUSION

Adjustment of the relevant technical parameters on MCS+ could produce a beneficial effect on the procedure measures and ensure a high-quality platelet production.

Incidence of gammopathies in long-term plasmapheresis donors at Canadian Blood Services

BACKGROUND

To investigate the long-term consequences of repeated plasmapheresis on donor health, their donation histories and demographic data were reviewed to determine the frequency of development of monoclonal (Mc) gammopathies or other gamma globulin abnormalities (OGGAs).

STUDY DESIGN AND METHODS

Samples from apheresis plasma donors collected at Canadian Blood Services were tested initially and every 4 months for total protein (TP) followed by serum protein electrophoresis (SPE). Out-of-range samples or those showing abnormal band patterns were forwarded to a hospital laboratory for additional investigation.

RESULTS

Of 52,972 donors who donated 471,446 apheresis plasmas over 9 years, 89,490 samples were sent for TP and SPE testing. Of 3005 samples forwarded for further investigation, abnormal immunofixation electrophoresis (IFE) results were found in 209 (0.4%) donors, 85 from first-time (FT) and 124 from repeat (RPT) plasma donors during participation in the program. There were 167 donors with Mc gammopathies (73 FT, 94 RPT) and 42 with OGGAs (12 FT, 30 RPT). FT or RPT donors with Mc gammopathies or OGGAs were significantly older than those with normal SPEs. RPT donors with Mc gammopathies or OGGAs also had a longer donation period than donors with normal SPEs.

CONCLUSIONS

The incidence of Mc gammopathies (2.41 per 1000 donors) did not significantly increase from 2004 to 2012. Older donors had a higher incidence of Mc gammopathies and longer donation periods than their healthy counterparts. Overall, gammopathy rates were below those reported over the same age range in the general population.

Evaluation of the performance of Trima Accel® v5.2 for the collection of concentrated high-dose platelet products and concurrent plasma from high platelet count donors, in Germany

BACKGROUND AND OBJECTIVES

This study was undertaken to test the ability of Trima Accel® version 5.2 to simultaneously collect concentrated high-dose leukoreduced platelet products and double doses of plasma.

MATERIALS AND METHODS

Random volunteers (18-65 years of age) with preprocedure platelet counts above 270 × 10(3) /μl were recruited among the blood center's apheresis donors. All complied with the center's donor selection criteria.

RESULTS

One hundred fourteen (114) collections were performed. Depending on which definition of single platelet dose is used (2.0 × 10(11) as prevalent standard in most European countries, and 3.0 × 10(11) as prevalent standard in the United States and Canada) in 107/114 (single dose = 2.0 × 10(11) ) and 39/114 (single dose = 3.0 × 10(11) ) instances, a triple platelet product was obtained. In 87 cases (76%), a double plasmaproduct (>430 ml) was collected, and in seven cases (6%), a single plasma product (>220 ml) was collected. In 20 procedures, only platelets without concurrent plasma were collected (18%). Overall procedure time was 87 ± 13 min and average platelet yield per procedure was 8.5 ± 1.4 × 10(11) (final storage concentration, 1,279 ± 153 × 10(3) /μl). The median residual leukocyte content per transfusion dose was 0.13 × 10(6) (0.02-0.98 × 10(6) ) for a single dose of 2.0 × 10(11) and 0.14 × 10(6) (0.02-0.98 × 10(6) ) for a single dose of 3.0 × 10(11) .

CONCLUSIONS

Trima Accel® version 5.2 allows for collection of concentrated high yield platelet products. It offers high productivity and reliably achieves the configured yield targets. Leukoreduction performance complied with both US and EU legal requirements. Collection as hyperconcentrates furthermore allowed for concurrent collection of double dose plasma in the majority of the procedures.

One pathway to academic success: autobiography of Dr Ronald G. Strauss

Often, I have been asked by "junior faculty"-who are usually burdened by substantial responsibilities in service and teaching-how they can launch their career in research as a means to succeed in academic medicine. Obviously, the answers/solutions are as diverse as are the circumstances of each questioner. In the following article, I offer the approach that I applied to my career-acknowledging that "one shoe doesn't fit all" and that others will advise differently. However, one truism exists whenever one seeks excellence in anything-the opportunity must be present to commit uninterrupted time for thought/concentration, organization, training/mentoring/study, and effort/hard work. Without such an opportunity, success in research will be elusive.

Apheresis affects bone and mineral metabolism

BACKGROUND

Apheresis is a procedure to selectively obtain blood components. For the collection process citrate is routinely used. It inhibits coagulation by binding to ionized calcium and leads to metabolic alkalosis.

OBJECTIVE

Whether regular apheresis affects bone and mineral metabolism is unknown. The intention of this study was to investigate 1) the acute effects of apheresis on acid-base balance, bone and mineral metabolism and 2) to compare bone mineral density (BMD) at the lumbar spine and hip of donors to matched control subjects.

DESIGN

In this open, observational, single-center, cross-sectional study we enrolled 102 regular plasma and thrombocyte donors to pursue objective 1) and compared those to 102 matched controls (CTR) for objective 2).

RESULTS

Platelet donation led to significant decreases in serum ionized calcium (-17%) and phosphate (-18%), to marked increases in base excess (57%) and PTH levels (192%) during apheresis. Baseline biochemical comparisons between donors and CTR revealed significantly lower values for donors for serum calcium, albumin, and 25-hydroxyvitamin D levels. Mean Z-score at the lumbar spine adjusted for BMI, average physical activity and daily calcium intake was lower for donors (-0.28+/-0.11) when compared to CTR subjects (0.06+/-0.11, P<0.05). Total and neck femoral BMD was also lower in the donor group, however, this difference was not significant.

CONCLUSIONS

Exposure to citrate during the apheresis procedure acutely affects mineral and bone metabolism. Regular donations of blood components compromised BMD at the lumbar spine. If confirmed, strategies to prevent long-term effects on bone need to be formulated.

The impact of different intensities of regular donor plasmapheresis on humoral and cellular immunity, red cell and iron metabolism, and cardiovascular risk markers

BACKGROUND AND OBJECTIVES

Major studies are still lacking on the impact of differing intensities of long-term donor plasmapheresis, not only on total serum protein, albumin and immunoglobulin G (IgG), but also on humoral and cellular immunity, red cell and iron metabolism, and biochemical cardiovascular risk markers.

MATERIALS AND METHODS

Three groups of donors, comprising 483 individuals undergoing differing intensities of long-term serial plasmapheresis, were entered into a cross-sectional study. A fourth control group consisted of 100 non-donors. In addition to measuring total protein, albumin and IgG levels, we determined parameters of humoral and cellular immunity, red cell and iron metabolism and recognized biochemical cardiovascular risk factors.

RESULTS

The median annual net amount of plasma donated by the three donor groups was 37, 16 and 10 l, respectively (P < 0.0001). Donors had significantly lower total serum protein, albumin and IgG levels than non-donors (P < 0.0001), but the intensity of plasmapheresis had no influence on those parameters. Like non-donors, all plasma donors had normal humoral and cellular immunity. No increased rates of iron store depletion were observed in the three groups of plasma donors. Plasma donors were not at increased cardiovascular risk.

CONCLUSIONS

Regular donor plasmapheresis of up to 45 l of plasma per year appears to be as safe as more moderate plasmapheresis programmes, with respect to the parameters analysed in this study. Individuals donating under these conditions did not develop impaired humoral and cellular immunity, iron store depletion, or increased cardiovascular risk with regard to established biochemical risk markers. Prospective studies are required to determine more exactly than in retrospective analyses the reasons why donors withdraw from plasmapheresis programmes.

Safety of donating multiple products in a single apheresis collection: Are we expecting too much?

Modern blood separators rapidly process many liters of donor blood and efficiently collect vast quantities of blood components from donors, who may be stimulated with potent recombinant hematopoietic growth factors or cytokines. Accordingly, the potential risks of modern multiple product/unit apheresis donations and recombinant growth factors is analyzed in this report. As is true for all medical procedures, risks are associated with apheresis donations. Risks of a "standard" apheresis donation, in which one unit of PLTs or plasma is collected, are comparable to the risks of whole blood donation. Risks of multiple unit apheresis donations, in which either vast quantities of a single blood component or multiple units of various components are collected, are incompletely understood, particularly, when donors are stimulated with recombinant hematopoietic growth factors to increase component yields. To minimize donor risks and to increase knowledge of multiple component apheresis donations, both short-term problems (e.g., donor reactions accompanying apheresis procedures and pre- vs. post-procedure changes in results of donor laboratory studies) and long-term problems (e.g., medical diagnoses/problems and abnormalities of donor blood counts and laboratory test results) should be monitored, ideally, by a repeat donor registry. When recombinant hematopoietic growth factors are prescribed, donors should give informed consent, and blood center professionals must be aware of 1) the effects of these drugs given at pharmacologic, rather than physiologic, doses; 2) the differences between the molecular structure of recombinant vs. natural/endogenous growth factors; 3) the fact that recombinant growth factors have both narrow/focused and broad biological activities; and 4) the probability that results of studies in sick/immunosuppressed patients may not be applicable to healthy/immunocompetent donors.

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

Previous studies of changes in immune function in platelet donors have investigated subjects who were undergoing plateletpheresis using older equipment that is no longer in general use. Therefore, the purpose of this study was to determine the effect of long-term platelet donation on lymphocyte numbers and subsets and plasma protein concentrations in platelet donors using newer cell separators. Three groups included in the study were nondonor controls (n = 27), long-term whole blood donors (n = 29), and long-term platelet donors (n = 20). Using a cross-sectional analysis, lymphocyte numbers and subsets were determined and compared among the three groups. Plasma concentrations of total protein, globulin, albumin, and IgG were also compared. Among the three groups there were no significant differences in total white blood cell counts, percentage or absolute number of lymphocytes, or percentage or absolute number of lymphocyte subsets. Serum total protein, globulin, albumin, and IgG concentrations of platelet donors were within normal ranges. These data support the current Food and Drug Administration (FDA) and American Association of Blood Banks' standards for the frequency of platelet donation allowed and monitoring required for plateletpheresis donors. Furthermore, these data indicate that the FDA could eliminate the requirement for the warning in informed consents about lymphocyte depletion in platelet donors.

The collection of platelets by apheresis procedures

Collection of platelets by apheresis has been a major advance in transfusion medicine. It has allowed the supply of a therapeutically beneficial component to grow with medical needs. Donors find fulfillment in more frequent donations than are possible with whole blood and know that their donation fills a special need. New technology allows leukocyte reduction in the collection of the component with or without the use of filtration. Matching for refractory patients is possible. However, platelets collected by apheresis have not been shown to be hemostatically different from platelets separated from whole blood donations, and thus, do not represent an advance in therapeutic efficacy. The use of apheresis platelets does reduce donor exposure, but this has not been shown to be a safety advance, although it seems intuitively obvious that transfusion risk is statistically reduced in some patients requiring only a few platelet transfusions. Support of patients by apheresis platelets may or may not reduce the risk of alloimmunization. Apheresis platelets from some equipment have less white blood cell contamination even in the absence of filtration, which may be an advantage. Apheresis platelets could be a major step in the ultimate customization of blood collection, in which some donors would preferentially donate red blood cells, whereas others would donate platelets or plasma depending on their blood type and ability to donate frequently, and the current medical need of their donation. Perhaps this would be the most significant advance from the medical progress initiated by Cohn almost 50 years ago.

Effects on donors of repeated leukocyte losses during plateletpheresis

All blood components collected by automated cytapheresis contain donor leukocytes. The possibility that repeated cytapheresis donation might lead to clinically important leukocyte losses and immunodeficiency has been a long-standing concern. Although convincing data do not exist to substantiate this concern, it is common practice to limit the number of annual cytapheresis donations per donor and to monitor donors for developing lymphocytopenia. Clinically significant immunodeficiency is unlikely to occur unless donors lose > 1 x 10(11) lymphocytes within a few weeks period of time or unless donor lymphocyte counts fall persistently to < 0.5 x 10(9)/L. Each plateletpheresis procedure, when performed using modern cell separators that are designed to produce a relatively "pure" platelet concentrate, leads to the loss of 1.0 x 10(6) to 5.0 x 10(7) leukocytes. Thus, automated plateletpheresis as performed in 1994 is extremely unlikely to cause clinically significant lymphocyte depletion and consequent immunodeficiency.

Effects of plasmapheresis on peripheral blood mononuclear cell populations from patients with macroglobulinemia

Effects of plasmapheresis on peripheral blood T-cell, B-cell, monocyte, and natural-killer-cell populations were studied in ten macroglobulinemia patients with hyperviscosity syndrome. Following plasmapheresis, there was a transient decrease in the number of T4+ helper cells and a longer-lasting decrease in the number of Leu-7+ natural killer cells and Mo2+ monocytes. In addition, there was a greater than 50% decrease in the in vitro ingestion capacity of monocytes. Although no significant changes in the numbers of IgM+, B1+, B4+, or PCA+ B cells (P greater than .05) were detected, there was a highly significant (P less than .01) increase in I2 antigen density on the surface of IgM+ B cells and in the bromodeoxyuridine uptake by these cells 7-9 days after plasmapheresis. These findings suggest that following plasmapheresis, IgM+ B cells are activated. Using flow cytometry to determine when maximum IgM+ B cell activation occurs by measuring I2 antigen density on the cell surface may be useful in determining the postplasmapheresis timing of chemotherapy in macroglobulinemia patients with hyperviscosity syndrome who require more aggressive treatment.