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

A donor safety evidence literature review of the short- and long-term effects of plasmapheresis

Many blood establishments are expanding plasmapheresis collection capacity to achieve increasing plasma for fractionation volume targets, driven by immunoglobulin product demand. Some adverse events occur in both apheresis and whole blood collection, such as venepuncture-related trauma and vasovagal reactions. Others are specifically related to the apheresis procedure, such as citrate reactions, haemolysis, infiltration and air embolism. Whilst plasmapheresis procedures are generally well tolerated, theoretical longer term donor health considerations, such as the effects on donor plasma protein levels, bone mineral density, iron deficiency and malignancy also require consideration. An evidence-based framework that supports a safe and sustainable increase in the collection of plasma is essential. Our review demonstrates a lack of high-quality evidence on risks and outcomes specifically in plasmapheresis. Whilst conservative procedural controls and donor harm minimization policies will mitigate risk, high-quality evidence is needed to facilitate practice change that is safe and sustainable and maximizes the potential of individual donor differences.

Safety and protection of plasma donors: A scoping review and evidence gap map

BACKGROUND AND OBJECTIVES

As part of a large-scale project to safely increase plasma collection in Europe, the current scoping review identifies the existing evidence (gaps) on adverse events (AEs) and other health effects in plasmapheresis donors, as well as factors that may be associated with such events/effects.

MATERIALS AND METHODS

We searched six databases and three registries. Study characteristics (publication type, language, study design, population, outcomes, associated factors, time of assessment, duration of follow-up, number and frequency of donations, convalescent plasma [y/n], setting and location) were synthesized narratively and in an interactive evidence gap map (EGM).

RESULTS

Ninety-four research articles and five registrations were identified. Around 90% were observational studies (57 controlled and 33 uncontrolled), and most of them were performed in Europe (55%) or the United States (20%). Factors studied in association with donor health included donor characteristics (e.g., sex, age) (n = 27), cumulative number of donations (n = 21), donation frequency (n = 11), plasma collection device or programme (n = 11), donor status (first time vs. repeat) (n = 10), donation volume per session (n = 8), time in donation programme (n = 3), preventive measures (n = 2) or other (n = 9).

CONCLUSION

The current scoping review provides an accessible tool for researchers and policymakers to identify the available evidence (gaps) concerning plasmapheresis donation safety. Controlled prospective studies with long-term donor follow-up are scarce. Furthermore, additional experimental studies comparing the health effects of different donation frequencies are required to inform a safe upper limit for donation frequency.

Paraprotein implicated in hardware failures in nucleic acid testing of blood donors

BACKGROUND AND OBJECTIVES

Analyser blockage due to gel formation by paraproteins leading to invalid results is a rare problem in viral nucleic acid testing (NAT) at New Zealand Blood Service (NZBS) despite many blood samples tested without problems from individuals with known paraproteins. This study aimed to identify common factors in samples causing blockages.

METHOD

Retrospective data were gathered on blood samples known to have blocked analysers at NZBS testing sites. Patients with plasma cell dyscrasia undergoing haematopoietic stem cell (HSC) harvest formed the comparator arm. These patients were identified from registry data of individuals undergoing autologous stem cell transplantation at Auckland City Hospital between 2013 and 2017.

RESULTS

Four individuals were identified as having blocked analysers between 2010 and 2018. A total of 184 HSC transplant patients were identified, with contemporaneous paraprotein levels available for 177 (96%). Patients with intact immunoglobulin subtypes (134, 73%) were further analysed. Of these, 119 patients (65%) also had total protein and globulin levels available. Mean paraprotein (37.5 g/l), total protein (95.3 g/l), globulin levels (51.5 g/l) and proportion of lambda subtype (75%) were higher in the blocker group compared with non-blocking comparators (4.7 g/l, 66.8 g/l, 27.7 g/l, 36.6% respectively) (P = 0·03, 0·02, 0·007, 0·12). The highest paraprotein and total protein levels from the non-blocking cohort overlapped with the lowest of the blocker group.

DISCUSSION

High protein levels (paraprotein >20 g/l, total protein >75 g/l) and a trend towards lambda subtype were associated with NAT analyser blockage. The overlap with non-blocking donor samples suggests factors in addition to protein quantity that are also important.