White Blood Cell Antibodies Research Articles

WBC alloimmunization: effects on the laboratory and clinical endpoints of therapeutic granulocyte transfusions.

Although the subject of many previous studies, the importance of white blood cell (WBC) alloimmunization in granulocyte transfusion therapy has not been settled. In this study, we report the results of the effects of WBC antibodies in the RING (Resolving Infection in Neutropenia with Granulocytes) study, a randomized controlled trial comparing the efficacy of daily granulocyte transfusion therapy plus antimicrobials versus antimicrobials alone; the primary outcome results have been published previously. One hundred fourteen subjects were enrolled in the study. Serum samples for WBC antibody determination were obtained from each subject at baseline and at 2 and 6 weeks. One hundred subjects had at least one antibody test result. Samples were tested for human leukocyte antigen (HLA) Class I and Class II antibodies as well as for granulocyte-specific antibodies using granulocyte agglutination and immunofluorescence techniques. All testing was performed at a central laboratory. Baseline WBC alloimmunization was modest, depending somewhat on the assay. Seroconversion during the study was slightly higher in the granulocyte transfusion arm, but the differences were not statistically significant. There was no demonstrable effect of the presence of alloimmunization on the primary outcome (survival and microbial response at 42 days), the occurrence of transfusion reactions (either overall or pulmonary), or posttransfusion neutrophil increments. The presence or development of WBC antibodies had no demonstrable effect on any clinical aspect of granulocyte transfusion therapy. It appears that, at least in the patient population studied, there is no evidence suggesting need for concern about recipient WBC alloimmunization when prescribing granulocyte transfusions.

Differentiating pulmonary transfusion reactions using recipient and transfusion factors.

It is increasingly recognized that recipient risk factors play a prominent role in possible transfusion-related acute lung injury (pTRALI) and transfusion-associated circulatory overload (TACO). We hypothesized that both transfusion and recipient factors including natriuretic peptides could be used to distinguish TRALI from TACO and pTRALI. We performed a post hoc analysis of a case-control study of pulmonary transfusion reactions conducted at the University of California at San Francisco and Mayo Clinic, Rochester. We evaluated clinical data and brain natriuretic peptides (BNP) levels drawn after transfusion in patients with TRALI (n = 21), pTRALI (n = 26), TACO (n = 22), and controls (n = 24). Logistic regression and receiver operating characteristics curve analyses were used to determine the accuracy of clinical and biomarker predictors in differentiating TRALI from TACO and pTRALI. We found that pTRALI and TACO were associated with older age, higher fluid balance, and elevated BNP levels relative to those of controls and TRALI. The following variables were useful in distinguishing cases of pTRALI and TACO from TRALI: age more than 70 years, BNP levels more than 1000 pg/mL, 24-hour fluid balance of more than 3 L, and a lower number of transfused blood components. Using the above variables, our logistic model had a 91% negative predictive value in the differential diagnosis of TRALI. Models incorporating readily available clinical and biomarker data can be used to differentiate transfusion-related respiratory complications. Additional studies examining recipient risk factors and the likelihood of TRALI may be useful in decision making regarding donor white blood cell antibody testing.

Proposed revised nomenclature for transfusion-related acute lung injury.

A decade ago, definitions of "transfusionߚrelated acute lung injury (TRALI)" and "possible TRALI" were standardized for research and clinical diagnosis. Since then, evidence has confirmed that TRALI is often due to transfusion of white blood cell antibodies to at-risk patients, and the term "TRALI, antibody mediated" is appropriate for such cases. Other TRALI cases are non-antibody mediated. Because specific, nonantibody transfusion factors have not yet been confirmed to cause TRALI in humans, the general term "TRALI, non-antibody mediated" is appropriate for such cases. In contrast, evidence is against possible TRALI being due to transfusion with the more likely cause of the acute respiratory distress syndrome (ARDS) being the alternative ARDS risk factor present in these patients. We propose to drop the misleading term "possible TRALI" and to rename this category of cases as "transfused ARDS." These nomenclature updates will more accurately categorize ARDS cases that develop after transfusion.

Benefit of transfusion‐related acute lung injury risk‐minimization measures – German haemovigilance data (2006–2010)

Based on the frequency of immune-mediated and non-immune-mediated transfusion-related acute lung injury (TRALI), the effect of risk-minimization measures was evaluated during a period of 5 years (2006-2010). Risk-minimization measures were implemented in 2008/2009, consisting of exclusion of female donors with a history of pregnancy or exclusion of female donors with human leucocyte antigen (HLA)/human neutrophil alloantigen (HNA) antibodies. TRALI was confirmed according to the criteria of the International Haemovigilance Network. Based upon the results of donor testing of white-blood-cell antibodies (WBC-Ab) against HLA or HNAs, confirmed cases were classified as immune- or non-immune-mediated TRALI. Reporting rates were calculated on the basis of the annually transfused blood components, and pre- and post-implementation periods were compared. In total, 60 immune-mediated (75%) and 20 non-immune-mediated (25%) TRALI reactions were confirmed. A total of 68 (64 women and four men) donors were involved: seven red-blood-cell concentrates donors (13%), six platelet concentrate donors (10%), and 48 fresh frozen plasma (FFP) donors (77%). The reporting rate of immune-mediated TRALI caused by FFP decreased continuously; from 12·71 per million units in 2006/2007 to 6·81 per million units in 2008/2009 and no case in 2010. The comparison of the pre- and the post-implementation period demonstrated a significantly reduced risk of TRALI events comparing 2006/2007 with 2010 (P-value: <0·01). Furthermore, no case of TRALI-induced fatality occurred after the implementation of risk-minimization measures.

Storage time of blood products and transfusion‐related acute lung injury

Besides white blood cell antibodies in plasma-rich products, another cause of transfusion-related acute lung injury (TRALI) could be release of biologically active substances during storage of cellular blood products. We aimed to investigate the association of storage time and risk of TRALI for different product types. We compared storage time of blood products transfused within 6 hours before the onset of TRALI to storage time of a representative sample of all blood products transfused in the Netherlands. Generalized linear models were used to correct for confounding variables. Platelets (PLTs) in plasma transfused to TRALI patients were stored for 0.7 (95% confidence interval [CI], 0.073 to 1.3) days longer than those transfused to controls. The relative risk of TRALI, after receiving PLTs stored for 4 or 5 days, compared to 3 days or less, was 5.8 (95% CI, 0.99 to 110) and increased to 6.3 (95% CI, 1.1 to 118) after more than 5 days (i.e., 6 or 7 days). While longer storage of buffy coat-derived PLTs was associated with an increased risk of TRALI, storage of plasma for up to 2 years and red blood cells for up to 35 days was not associated with the risk of TRALI.

Alloexposed blood donors and transfusion‐related acute lung injury: a case‐referent study

Donor white blood cell (WBC) antibodies are thought to increase the risk of transfusion-related acute lung injury (TRALI). WBC antibodies can be present in blood products from donors who have been alloexposed. Alloexposed donors are increasingly excluded from donating plasma, but can still donate plasma-poor products. We aimed to quantify the contribution of alloexposed donors to the occurrence of TRALI for different blood product types. We performed a case-referent study including all reported TRALI patients and all Dutch blood donors. Data on alloexposure status of donors of all TRALI cases reported between January 2004 and October 2008, in the Netherlands, were compared to information on the total donor population. Alloexposure status of all 223 involved donors was compared to the expected status. The overall percentage of TRALI cases that could have been prevented by the deferral of all alloexposed donors (i.e., population-attributable risk [PAR]) was 51% (95% confidence interval [CI], 14%-88%). In 19 recipients of exclusively plasma-poor products (mostly red blood cells [RBCs]), alloexposure of the donors was not associated with TRALI, while in 28 recipients of both plasma-poor and plasma-rich products (>200 mL plasma), the PAR was 94% (95% CI, 34%-100%). Alloexposed donors conferred an increased risk of TRALI in recipients of plasma-rich products, but not in recipients of plasma-poor products. Although WBC antibodies are an important risk factor for TRALI, among RBC recipients another risk factor must be more important.

Male‐only fresh‐frozen plasma for transfusion‐related acute lung injury prevention: before‐and‐after comparative cohort study

Transfusion-related acute lung injury (TRALI) is one of the most serious complications of blood transfusion. It can be caused by incompatible white blood cell antibodies in transfused plasma. The objective of this study was to quantify the reduction of TRALI after introduction of male-only plasma for transfusion as a preventive measure, which took effect in 2007. In the Netherlands all cases of TRALI are reported to the national hemovigilance office. All reported cases of TRALI from 2002 to November 2009 were considered for inclusion. Those meeting the Canadian consensus clinical definition were included and subdivided according to whether or not the patient had received quarantine fresh-frozen plasma (Q-FFP) in the 6-hour period before the reaction. The numbers of TRALI cases involving plasma donated before the measure and of those involving plasma donated after the measure were compared to TRALI cases that did not involve Q-FFP to adjust for reporting bias. A total of 110 cases were included in the analysis. Of 68 cases before the measure, 36 involved Q-FFP. Thirty-one cases occurred after the measure of which eight involved Q-FFP. Eleven occurred in the transitional period, of which four involved Q-FFP. The population-attributable risk of premeasure plasma among TRALI cases occurring before the measure was 0.33 (95% confidence interval, 0.09-0.51). In the Netherlands the male-only Q-FFP measure was associated with a 33% reduction of TRALI cases.

Screening plateletpheresis donors for HLA antibodies on two high‐throughput platforms and correlation with recipient outcome

To determine the prevalence and impact of transfusing plasma containing white blood cell antibodies, we compared two high-throughput HLA antibody screening assays and prospectively examined the medical records of all platelet (PLT) recipients to detect subtle manifestations of transfusion-related acute lung injury and other transfusion reactions. Serum samples from 136 plateletpheresis donors were tested for HLA Class I and II antibodies using microbead (LABScreen PRA, One Lambda) and microchip (Dynachip, Invitrogen) assays. Electronic medical records of all recipients were reviewed for vital signs and nursing documentation before and after transfusion. In the microchip assay with a cutoff value of 0.25, 2.9% of samples were positive for Class I and 8.9% for Class II antibodies; with a cutoff value of 0.1, the results were 14.9 and 21.6%, respectively. In the microbead assay (normalized background ratio, 1.5), 15% were positive for Class I and 21% for Class II antibodies. The prevalence of HLA antibodies was 17% in donors without pregnancy or transfusion history and 47% in donors with such history. The PLTs were transfused in 265 episodes to 67 patients. There were no reported reactions; however, symptoms or vital sign changes were noted in seven transfusion episodes. The incidence of reactions was 2.7% (2/75) for antibody-positive units and 2.6% (5/190) for antibody-negative units. Microbead and microchip assays yielded similar results. The prevalence of HLA antibodies was greater in donors with a history of pregnancy or transfusion, but no increase in the incidence of transfusion reactions was noted in recipients of components from donors with HLA antibodies.

Impact of using different laboratory assays to detect human leukocyte antigen antibodies in female blood donors

HLA antibodies passively transferred to transfused recipients may cause transfusion reactions such as transfusion-related acute lung injury (TRALI), but in many of the reported TRALI incidents, no white blood cell antibodies have been identified. We investigated whether a higher number of anti-HLA would be detected in donor's plasma by using a method with potential higher sensitivity rate. Sera from 300 previously pregnant female blood donors were screened for anti-HLA using a solid-phase mixed-antigen assay (enzyme-linked immunosorbent assay [ELISA]). Samples from 60 women with three or more pregnancies with a negative ELISA were further tested using microbead-flow assays (LABScreen mixed, panel-reactive antibodies [PRA], and single antigen). Anti-HLA Class I and/or Class II were detected by ELISA in 26.7% (80/300) of all women and in 37.0% (37/100) of women with three or more pregnancies. The LABScreen assays detected additional anti-HLA specificities (44 Class I and 17 Class II) in 28.3% (17/60) of ELISA-negative donors with three or more pregnancies. HLA antibodies were detected in 8.3% (5/60), 18.3% (11/60), and 21.7% (13/60) of ELISA-negative women by LABScreen mixed, PRA, or single antigen, respectively. Our data showed that the microbead-flow detected more HLA antibodies than ELISA, but the clinical significance of these antibodies is currently unknown. Detecting anti-HLA is useful for donor management and could contribute to the decision to definitively defer blood donors involved in TRALI incidents. However, further studies are necessary to better determinate the relative risk of TRALI induced by anti-HLA detected only by techniques with higher sensitivity rate.

Frequency and severity of transfusion-related acute lung injury – German haemovigilance data (2006–2007)

In an observational cohort study (2006-2007) the Paul-Ehrlich-Institut collected epidemiological data to investigate the frequency and causes of TRALI. Diagnosis of TRALI was confirmed according to criteria of the European Haemovigilance Network. Subsequent testing of white blood cell antibodies (WBC-Ab) against HLA or human neutrophil alloantigens was performed. Of a total of 187 reported TRALI cases, 44 could be confirmed consisting of 35 cases of antibody-mediated TRALI and nine cases of non-immune-mediated TRALI. Eight of 44 affected patients (18%) had a fatal outcome, seven cases with WBC-Ab positive plasma donors and one case with red blood cell donors. WBC antibodies were found in one male and 39 female donors. In 34 female donors, a history of pregnancy was confirmed. WBC-Ab positive donors presented four HLA class I antibodies, 15 HLA class II antibodies, 13 HLA class I and class II antibodies, one HNA-2a, and seven HNA-3a antibodies. WBC antibodies matching with recipient antigens were found exclusively in 28 female donors; 26 FFP donors, one platelet donor and one red blood cell donor. Reporting frequency of immune-mediated TRALI was 1:66,000 for fresh frozen plasma, 1:2.86 million for red blood cell concentrates and 1:420,000 for platelet concentrates. Reporting frequency of TRALI-related fatalities was 1:285,000 for FFP. Haemovigilance data show the significance of female donors with a history of pregnancy for the development of antibody-mediated TRALI. Manufacturing of FFP from male plasma and female donor screening for WBC-Ab could represent preventive measures.

Ten years of hemovigilance reports of transfusion‐related acute lung injury in the United Kingdom and the impact of preferential use of male donor plasma

From 1996 through 2006, 195 cases were reported as transfusion-related acute lung injury (TRALI) to the Serious Hazards of Transfusion scheme and from 1999 onward classified by probability, using clinical features and HLA and/or HNA typing. From late 2003, the National Blood Service provided 80 to 90 percent of fresh-frozen plasma (FFP) and plasma for platelet (PLT) pools from male donors. Forty-nine percent of reports were highly likely/probable TRALI, and 51 percent possible/unlikely. Of 96 investigations, donor antibodies recognizing recipient antigens were found in 73 cases (65%), with HLA Class I in 25 of those (40%), HLA Class II antibodies in 38 (62%), and granulocyte antibodies in 12 (17%). A review in 2003 revealed that the TRALI risk/component was 6.9 times higher for FFP and 8.2 times higher for PLTs than for red blood cells, and that in donors of implicated FFP/PLTs, white blood cell antibodies were found 3.6 times more often than by chance (p <or= 0.0001), with all implicated donors being female. Provision of male plasma was associated with a reduction in TRALI reports from 36 in 2003 to 23 in each of 2004 and 2005 and 10 in 2006. Highly likely/probable cases reduced from 22 in 2003 to 13, 6, and 3 [corrected] in the 3 subsequent years, with cases implicating FFP or PLTs with positive donor serology [corrected] falling from 16 to 9, 3, and 1 respectively. The risk of highly likely/probable TRALI due to FFP has fallen from 15.5 per million units issued during 1999 through 2004 to 3.2 per million during 2005 through 2006 (p = 0.0079) and from 14.0 per million to 5.8 per million for PLTs.

How much residual plasma may cause TRALI?

Although passive infusion of plasma-rich components containing white blood cell (WBC) antibodies are responsible for majority of the reported transfusion-related acute lung injury (TRALI) cases, the minimum volume of residual plasma, which might trigger TRALI, is not known. We report three cases of TRALI where the implicated donor component contained between 10 and 20 mL of residual plasma. Two cases were related to transfusion of red blood cells prepared in optimal additive solution, and the other was related to transfusion of pooled buffy coat platelets. In the latter case, WBC antibodies that matched the patient's human leucocyte antigen (HLA) antigens were only found in one buffy coat donor (female) who contributed a buffy coat for pooled platelets preparation. Plasma prepared from pooling platelets was collected from a male donor. Laboratory investigation confirmed that in all three cases, the donors' serum contained three to four different HLA class 1-specific and class 11-specific antibodies that matched with the patient's HLA type. Our cases suggest that the residual plasma volume as small as 10-20 mL containing donor derived WBC antibodies may cause TRALI. The risk of TRALI remains, despite providing pooled platelets suspended in male donor plasma. The significance of multiple HLA antigen/antibody matching between donor and recipient in immune TRALI warrants further study.

Ninety-six suspected transfusion related acute lung injury cases: Investigation findings and clinical outcome

Transfusion related acute lung injury (TRALI) is one of the complications of blood transfusion and can result in major morbidity or mortality. The diagnosis depends upon the application of strict clinical criteria defining acute lung injury (ALI) and a temporal relationship to blood transfusion. We present the clinical and immunogenetic findings of 96 suspected TRALI cases investigated between 1996 and 2004. During this time period the national haemovigilance scheme (UK) defined TRALI as a reaction occurring either during or within 24 h of blood transfusion. Using clinical, laboratory and post mortem evidence, 64/96 cases could be defined as TRALI in our series. Sensitive techniques were employed to screen for HLA class I, class II and granulocyte specific antibodies in donor serum. Donor derived antibodies were detected in 58/64 (90%) of cases. Recipient derived DNA or cells were not always available but incompatibility was confirmed by the presence of the cognate antigen on recipient leucocytes or by crossmatching in 47/64 (73%) of cases. Cases referred prior to 2001 were not tested for HLA class II antibodies. By applying strict clinical criteria and using sensitive techniques a white blood cell antibody mediated immunological pathophysiology can be implicated in the majority TRALI cases.

Donor risk factors for white blood cell antibodies associated with transfusion‐associated acute lung injury: REDS‐II Leukocyte Antibody Prevalence Study (LAPS)

Donor risk factors for white blood cell antibodies associated with transfusion‐associated acute lung injury: REDS‐II Leukocyte Antibody Prevalence Study (LAPS)

Transfusion‐related acute lung injury surveillance (2003‐2005) and the potential impact of the selective use of plasma from male donors in the American Red Cross

American Red Cross surveillance data on transfusion-related acute lung injury (TRALI) fatalities were analyzed to evaluate the association with components from donors with white blood cell (WBC) antibodies and to examine the potential impact of the selective transfusion of plasma from male donors. Suspected TRALI reports in 2003 through 2005 were identified and all fatalities were reviewed and classified by three physicians as "probable TRALI" or of "unrelated etiology," with independent review of the associated serologic investigation. Hospital investigational and reporting biases could not be fully controlled in this retrospective study. A total of 550 reports of suspected TRALI, including 72 fatalities, were investigated. The number of reports increased each year and the rate varied by geographic region. Retrospective review of fatalities revealed 38 cases of probable TRALI, the majority (24 of 38 [63%]) after plasma transfusion. A female, WBC antibody-positive donor was involved in 71 percent (27 of 38) of cases and in 75 percent (18 of 24) of cases involving plasma transfusion. Female antibody-positive donors were more likely to be associated with probable TRALI than with unrelated cases (p = 0.0001; odds ratio [OR], 9.5; 95% confidence interval [CI], 2.9-31.1]. The rate of probable TRALI among recipient fatalities was higher for plasma components (1:202,673; OR, 12.5; 95% CI, 5.4-28.9) and apheresis platelets (PLTs; 1:320,572; OR, 7.9; 95% CI, 2.5-24.8) compared to red cells (1:2,527,437). Male donors contributed 64.5 and 52.0 percent of distributed apheresis PLTs and plasma components, respectively, in 2005. Plasma components linked to female donors with WBC antibodies were responsible for the majority of probable TRALI fatalities. Prudent measures to limit transfusion of WBC antibody-containing plasma components may prevent as many as six fatalities per year in the Red Cross system.

A perspective on transfusion‐related acute lung injury two years after the Canadian Consensus Conference

A perspective on transfusion‐related acute lung injury two years after the Canadian Consensus Conference

White blood cell–reactive antibodies are undetectable in solvent/detergent plasma

Transfusion-related acute lung injury (TRALI) is a life-threatening complication of transfusion. Although all types of blood products have been associated with TRALI, fresh-frozen plasma (FFP) is the most commonly implicated component. It has been postulated that TRALI is an immune-mediated event, because white blood cell (WBC)-reactive antibodies in the donor's plasma are frequently associated with the syndrome. In contrast to single donor-derived FFP, solvent/detergent (S/D) plasma is produced from multiple donations, leading to an at least 500-fold dilution of a single plasma unit. It was hypothesized that WBC-reactive antibodies are undetectable in S/D FFP. Twenty batches of S/D FFP (5 of each ABH group) were analyzed with well-established routine techniques to detect WBC antibodies. All samples tested negative for granulocyte-specific as well as HLA Class I and Class II antibodies. Different strategies to reduce the risk of TRALI are currently discussed. These include screening of all potentially immunized donors for WBC-reactive antibodies and exclusion of multiparous or all women from donating FFP. Here, it is demonstrated that neither granulocyte- nor lymphocyte-reactive antibodies are detectable in S/D FFP. Thus, S/D FFP may represent a potential alternative to reduce the risk of TRALI associated with the transfusion of FFP.

Immune response, udder health and productive traits of machine milked and suckling ewes

Twenty Comisana ewes, with no history of mastitis, were divided into 2 groups of 10 and housed separately in 2 rooms within the same building. Ewes in the machine milked (MM) group were removed from their lambs 48 h postpartum and subjected to machine milking twice daily thereafter. Lamb suckled (LS) ewes were suckled by their lambs throughout the trial. The concentrations of the main microbial groups (mesophilic bacteria, pyogenic streptococci, total coliforms, total staphylococci, yeasts and moulds) were measured weekly from both the air and potential sources of udder contamination such as room surfaces, lambs’ mouths, milking operators and milking equipment. The cell-mediated immune response in vivo of ewes to phytohemagglutinin (PHA) injection was evaluated at days 7, 21 and 35 of the study period. At days 7 and 21, ewes were intravenously injected with chicken egg albumin (OVA). Antibody titers were determined immediately before the first antigen injection and then again at days 21 and 35. On each sampling day, an aliquot of blood was analyzed for white blood cell (WBC) differentials. Individual milk samples were analyzed weekly for somatic cell (SCC) and polymorphonuclear neutrophil leukocyte count (PMNLC), and for bacteriological characteristics and composition. The main carriers of milk contamination were the hands of milking operators and mouth of suckling lambs. The MM ewes displayed a lower ( P<0.05) immune response to PHA than the LS animals at day 21. However, no significant differences were found in WBC differentials and antibody titers to OVA. The MM ewes had higher concentrations of PMNL ( P<0.05) and staphylococci ( P<0.01) in their milk than the LS ewes. Milk yield and protein content were not affected by treatment, whereas the fat content was lower ( P<0.01) in the milk of the LS ewes. Results suggest that early transition to machine milking may impair the responsiveness of the ewe immune system. Maximum care should be taken to control the hygiene of the udder, milking equipment and personnel in order to minimize the risk of intramammary infections.

Systemic disease and neuro-ophthalmology: annual update 2000 (Part I).

Multiple sclerosis (MS) is a common demyelinating disease of the central nervous system (1–86), with substantial long-term neurologic consequences (1,4,9,25,34, 52,54,55,57,60,63,65). After 10 years with MS, 50% of patients are unable to perform household and occupational responsibilities; after 15 to 20 years, 50% are unable to walk without assistance; after 25 years, 50% are unable to ambulate. The average annual cost of MS in the United States is greater than 6.8 billion dollars (1). There are three main subtypes of the disease: relapsing remitting (RR), secondary progressive (SP), and primary progressive (PP). This update reviews the current status of MS therapy (1–86). We have chosen to focus on the new and emerging immunomodulatory therapies for disease relapses and the treatments to prevent disease progression. We do not review the treatments for common MS-related sensory and motor symptoms, fatigue, or depression (35).