Hepatitis B, hepatitis C and HIV transfusion-transmitted infections in the 21st century

In the past, transfusion-transmitted virus (TTV) infections were not uncommon. In recent years with advanced technologies and improved donor screening, the risk of viral transfusion transmission has been markedly reduced. Hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) have all shown marked reduction in transmission rates. However, the newer technologies, including nucleic acid technology (NAT) testing, have affected the residual rates differently for these virally transmitted diseases. Zero risk, which has been the goal, has yet to be achieved. False negatives still persist, and transmissions of these viruses still occur, although rarely. It is known that HBV serological testing misses some infected units; likewise, HBV NAT-negative units have also been known to transmit the virus. Similarly, HIV minipool NAT-negative units have transmitted HIV, as recently as 2007; likely, these transmissions would have been prevented with single-unit NAT testing. Newer technologies, such as pathogen inactivation (PI), will (ideally) eliminate these falsely test negative components, regardless of the original testing method used for detecting the viruses.

Does donating blood for the first time during a national emergency create a better commitment to donating again?

BACKGROUND AND OBJECTIVES

Emergency situations often elicit a generous response from the public. This occurred after attacks on the US on September 11, 2001 when many new blood donors lined up to donate. This study was performed to compare return rates for first time donors (FTD) after September 11th, 2001 to FTD during a comparable period in 2000.

MATERIALS AND METHODS

A total of 3315 allogeneic whole blood donations from FTD at a regional blood centre were collected between September 11th and 30th, 2001. Subsequent donations by the FTD before March 31, 2002 were reviewed. This (test) group was compared to 1279 FTD (control group) donating during the same time period in September 2000 and to their return rate in the subsequent 6 months.

RESULTS

Following September 11, 2001, 1087/3315 (32.8%) FTD returned by March 31, 2002. This return rate was similar to the control group [427/1279 (33.4%)]. The deferral rate during the donor screening process for the control group was significantly higher than the deferral rate for the September 11-30, 2001 group (P < 0.01). The odds of an individual FTD returning increased with age, and the chance of a female donor returning was 1.13 times higher than a male (P = 0.06). There was a carryover effect after September 11, 2001 too.

CONCLUSION

A national emergency, September 11, 2001, inspired people to donate blood for the first time. However, the proportion of return donations amongst them was not increased. Females and males in certain age groups were more likely to become repeat donors due to the residual effect of September 11, 2001. Additional efforts are needed to retain eligible FTD in donor pools.

TRALI is due to pulmonary venule damage from leucocytes with cholesterol crystal formation

BACKGROUND

There are two presumed mechanisms for the pulmonary oedema in transfusion-related acute lung injury (TRALI). One is antibodies to leucocytes while the other is biologically active lipids. We evaluated the vascular injury due to the former.

METHODS

The pulmonary vasculature was studied by light microscopy (LM) and scanning electron microscopy (SEM) in three fatal cases of TRALI and compared with that of two autopsied control patients. Lung tissue from two of the TRALI cases and both controls was studied by gas chromatography-mass spectroscopy (GC-MS) to identify crystals present in the former.

RESULTS

All three TRALI cases exhibited massive pulmonary oedema by weight and light microscopy and extensive defects by SEM in the endothelium of venules of the lungs. Such endothelial defects were absent in controls. Thrombi, composed of crystals, were present in venules and small veins diffusely throughout the lungs in Case 1. Similar crystals were identified in Case 2. The crystals in the lung vessels were identified morphologically as cholesterol and were proximate to the cytoplasmic defects of the endothelial surfaces. By GC-MS, there were markedly elevated levels of cholesterol and fatty acids in the two TRALI lungs tested compared with the lungs of the two controls.

CONCLUSIONS

Pulmonary damage in TRALI is related to formation of cholesterol crystals that appear to pierce endothelial membranes of venules. The endothelial defects lead to plasma extravasation into the alveoli causing TRALI.

Clinical outcomes of ABO-incompatible RBC transfusions

Factors that predict outcome after ABO-incompatible RBC transfusions are not well defined. We studied whether the volume of incompatible blood transfused would determine the signs and symptoms and survival outcome for ABO-incompatible RBC transfusions. We reviewed ABO-incompatible RBC transfusions from our institutions and our consultations for 35 years and from a survey of America's Blood Centers' members regarding causes, volume, signs, symptoms, and outcomes of ABO-incompatible RBC transfusions in their service areas from 1995 through 2005. All ABO-incompatible transfusions were due to error; 26 (62%) of 42 occurred at the patient's bedside. Of 36 patients who received more than 50 mL of incompatible blood, 23 (64%) manifested signs or symptoms related to the incompatible transfusion, and 6 (17)% died. Only 3 (25%) of 12 patients who received 50 mL or less of incompatible blood had associated signs or symptoms, and none died. Hypotension, hemoglobinuria, and/or hemoglobinemia were the most frequent findings in survivors and patients who died.ABO-incompatible RBC transfusion does not inevitably mean death or even occurrence of symptoms. Prompt recognition and discontinuation of the transfusion are critical because transfusing less ABO-incompatible blood may minimize signs and symptoms and may prevent death.

Hepatitis B virus (HBV) DNA screening of blood donations in minipools with the COBAS AmpliScreen HBV test

BACKGROUND

The risk of hepatitis B virus (HBV) transmission by blood transfusion (estimated at 1 in 63,000-1 in 205,000 units in the United States) exceeds that of hepatitis C virus (HCV) or human immunodeficiency virus (HIV). Reduction of window-period HBV transmissions through detection of HBV DNA-positive units by minipool nucleic acid testing (MP NAT) would be expected to decrease this risk.

STUDY DESIGN AND METHODS

A large multicenter study of the COBAS AmpliScreen HBV test (Roche Molecular Systems) was conducted on minipools of 24 blood donation specimens. The yield of HBV DNA-positive, hepatitis B surface antigen (HBsAg)-negative window-period donations was determined relative to current and newly licensed HBsAg assays. Donors with selected HBV DNA, HBsAg, and anti-hepatitis B core antigen (HBc) results were further evaluated.

RESULTS

The detection rate of window-period units was 1 in 352,451 (95% confidence interval, 1 in 2,941,176-1 in 97,561). Assay specificity was high (99.9964%). HBV DNA was detected in 84 percent of HBsAg-positive, anti-HBc-positive donations by MP NAT and in 94 percent when individual-donation (ID) NAT was added. HBV DNA was detected in 0.03 percent of HBsAg-negative, anti-HBc-positive donations by MP NAT and in 0.41 percent when ID NAT was added.

CONCLUSIONS

Implementation of HBV MP NAT will provide an increment in safety relative to HBV serologic screening, similar to that for HCV and in excess of that for HIV. Our data indicate that the implementation of HBV MP NAT would likely interdict 39 HBV window-period units and prevent 56 cases of transfusion-transmitted HBV infection annually. The current data indicate that HBV MP NAT should not lead to discontinuation of anti-HBc testing but that discontinuation of HBsAg testing with retention of anti-HBc testing may be possible.

Microchimerism in transfused trauma patients is associated with diminished donor-specific lymphocyte response

BACKGROUND

Blood transfusion can result in long-term survival of donor leukocyte subpopulations, or microchimerism, in the peripheral blood of injured patients. Neither injury severity nor the number of transfusions is associated with its occurrence. We sought to determine whether changes in general or antigen-specific lymphocyte activation may be associated with the subsequent development of microchimerism.

METHODS

We evaluated 63 transfused trauma patients, which we compared with 10 non-transfused trauma patients and 10 healthy control subjects. Of the 63 transfused patients, 31 were known to have evidence of microchimerism at hospital discharge with real-time quantitative PCR for non-recipient HLA DR alleles. We assessed lymphocyte response to phytohemagglutinin (PHA) using blood sampled upon arrival to the hospital (before transfusion) and at discharge. We performed one-way mixed leukocyte cultures (MLC) with pre-transfusion recipient specimens to assess recipient lymphocyte response to mitomycin-C treated donor cells and vice versa.

RESULTS

Lymphocyte response to PHA in microchimeric transfusion recipients was lower at admission (before transfusion) and discharge than in non-microchimeric recipients. Lymphocytes from microchimeric patients had less response to donor cells than did lymphocytes from non-microchimeric patients. Microchimeric patients also more frequently had diminished lymphocyte response to a single blood donor on MLC.

CONCLUSIONS

Transfusion-associated microchimerism is correlated with diminished response to mitogen challenge as well as to specific alloantigenic challenges. This microchimerism is predated by diminished lymphocyte response to a specific blood donor in many instances. The blood donor associated with this diminished alloantigenic lymphocyte response may be the source of microchimeric cells present in the recipient.

High-level long-term white blood cell microchimerism after transfusion of leukoreduced blood components to patients resuscitated after severe traumatic injury

BACKGROUND

Long-term white blood cell (WBC) microchimerism (MC), of at least 2 years, has been reported in trauma patients receiving fresh nonleukoreduced (non-LR) blood. It is unknown, however, whether this occurs with LR blood products that are nearly devoid of WBCs. Twenty-seven patients transfused with LR and non-LR blood products were studied after severe traumatic injury. A secondary aim was to explore donor-recipient mixed lymphocyte reactivity in vitro.

STUDY DESIGN AND METHODS

To quantify MC, allele-specific real-time polymerase chain reaction assays were developed targeting HLA Class II sequence polymorphisms. Extensive validation showed that these assays reliably detect a single copy of target sequence in a complex allogeneic background without false positivity.

RESULTS

At a median follow-up of 26 months (range, 24-39 months), long-term MC was observed in 3 of 20 patients (15%) who received non-LR blood products and 2 of 7 (29%) who received LR blood products. The maximum MC ranged from 0.40 to 4.90 percent of circulating WBCs and appeared, by Class II genotype analysis, to be attributable to a single donor.

CONCLUSION

It is concluded that robust levels of long-term MC, apparently traceable to a single donor, occur at similar frequency despite leukoreduction of transfused blood products. Exploratory analysis of donor-recipient mixed lymphocyte reactivity suggests that long-term MC may require a state of bidirectional tolerance before transfusion.

Blood Transfusion is Associated with Donor Leukocyte Microchimerism in Trauma Patients

INTRODUCTION

Blood transfusion can result in survival of donor leukocyte subpopulations in the recipient. Persistence of donor leukocytes in the transfusion recipient is termed microchimerism. Microchimerism likely reflects engraftment of the recipient with donor hematopoietic stem cells and is very uncommon with transfusion for elective surgery, sickle cell anemia, thalassemia, and HIV. We have found, however, that microchimerism may be more common in trauma patients.

OBJECTIVE

To determine how frequently transfusion after trauma is associated with microchimerism.

METHODS

We prospectively enrolled 45 trauma patients who were transfused > or =2 units of PRBCs. We sampled blood before hospital discharge and determined microchimerism by polymerase chain reaction (PCR) analysis of specimens using quantitative allele-specific HLA DR assays to detect non-recipient alleles. Data are expressed as median with interquartile range.

RESULTS

Patients had a median age of 38 (interquartile range 25, 58) years, ISS of 19 (13, 29), and mortality of 7%. Seventy-eight percent were men, and 84% had blunt trauma. Patients received a median of 6 (4, 16) (range 2, 87) units of PRBCs. Of the 45 patients, 24 (53%) had evidence of microchimerism. Compared with patients without evidence of microchimerism, these patients had no difference in mean age, gender, ISS, units of PRBCs transfused, time from transfusion to blood sampling, or proportion that underwent splenectomy. Twenty-one of the 24 patients with microchimerism had only 1 or 2 non-recipient DR alleles identified by PCR.

CONCLUSIONS

Transfusion after trauma is associated with over half of recipients having evidence of microchimerism. Age, sex, ISS, and splenectomy of the recipient and the number of transfused units did not correlate with microchimerism. Because the median time from transfusion to sampling for PCR analysis was not longer in the group without microchimerism, it is unlikely microchimerism is due merely to failure of the recipient to clear transfused donor leukocytes.

Platelet function abnormalities in qualified whole-blood donors: effects of medication and recent food intake

BACKGROUND AND OBJECTIVES

Platelet function abnormalities have been reported in blood donors who have not consumed aspirin. Our objective was to identify factors other than aspirin that may contribute to impaired platelet function in qualified volunteer blood donors.

MATERIALS AND METHODS

Blood samples were obtained from 24 donors following routine blood donation. Donors completed a study questionnaire that included questions about recent food consumption, medication and medical history. Platelet activation was measured using monoclonal antibodies and flow cytometry. CD62P expression and PAC-1 binding on platelets were used as indicators of platelet activation. Platelet function was measured on a platelet function analyser (PFA-100) using both collagen/epinephrine (cEPI) and collagen/ADP (cADP) cartridges.

RESULTS

Fifty-four per cent of donors (13 of 24) had normal platelet function. Thirty-eight per cent (nine of 24) had prolonged cEPI closure times, of whom four (17%) had no cEPI closure (> 300 seconds). No closure was associated with aspirin use (two donors) or chocolate consumption (two donors) before donation. Two donors (8%) had either a shortened cEPI or cADP closure time.

CONCLUSIONS

Platelet dysfunction in qualified blood donors is underestimated. Platelet function screening can identify donors with diet-related platelet dysfunction or with poor recollection of aspirin use.

Visual assessment of hemolysis in red blood cell units and segments can be deceptive

BACKGROUND

Blood components that appear hemolyzed are discarded. However, visual inspection is subjective and criteria for excessive hemolysis are poorly defined.

STUDY DESIGN AND METHODS

Packed RBCs (10 CPDA-1, 10 Adsol) were collected. Half of each unit was leukoreduced. Plasma Hb was measured and compared in segments and units by three methods: 1) a HemoCue Plasma/Low Hb Photometer system; 2) a tetramethyl-benzidine (TMB) chemical method, and 3) a free Hb visual comparator.

RESULTS

Visual assessment tended to overestimate hemolysis. Chemical methods were comparable (r(2)= 0.894; HemoCue = 0.043 +[0.770]x TMB; n = 400; range, 0.01-0.5 g/dL), although the mean plasma Hb (g/dL) for the HemoCue method was higher than that of the TMB method (0.12 vs. 0.10 g/dL, respectively; p < 0.001). No units would have been discarded based on a hemolysis level of at least 0.6 g/dL (approx. 1%) if measured by a chemical method. However, 50 percent of CPDA-1 and 10 percent of Adsol units would have been discarded if only visual criteria were used. Leukoreduction did not increase plasma Hb levels. Discrepancies in plasma Hb levels were noted between units and their corresponding segments.

CONCLUSION

Visual assessment of hemolysis can result in unnecessary wastage of blood components. HemoCue offers an alternative, objective method to assess plasma Hb in the setting of blood collection and processing facilities for routine quality control and process validation, and may aid in the development of objective criteria for excessive hemolysis in blood components.

TRALI: correlation of antigen-antibody and monocyte activation in donor-recipient pairs

BACKGROUND

TRALI may be a severe reaction associated with transfusion of plasma-containing blood components. TRALI has usually been associated with antibodies against granulocytes and HLA class I antigens, but more recently with antibodies against HLA class II and monocytes. TRALI cases were investigated to determine correlation between antigen and antibody. Additionally, activation of monocytes by TRALI serums was studied.

STUDY DESIGN AND METHODS

Sixteen cases of TRALI were investigated. All patients were typed for HLA antigens. Implicated donors were screened for HLA antigens and antibodies against granulocytes and monocytes. In 6 cases, recipient monocyte activation was measured in vitro after incubation with TRALI and control serums. In four cases, monocyte activation was measured after incubation of TRALI serums against a panel of monocytes of known HLA antigen type.

RESULTS

In 14 of the 16 cases (87.5%), antigen-antibody correlation was identified. TRALI monocytes, incubated with implicated TRALI serum (n = 6), expressed significantly greater cytokine and tissue factor (p < 0.05, repeated-measures ANOVA) than controls. Panel monocytes incubated with TRALI serum showed increased expression of cytokine and/or tissue factor when corresponding antigen was present.

CONCLUSION

In most cases of TRALI, a correlation between antigen and antibody can be identified. Activation of monocytes and their subsequent release of cytokines may play a role in the pathogenesis of TRALI.

Early diagnosis and successful treatment of a patient with transfusion-associated GVHD with autologous peripheral blood progenitor cell transplantation

BACKGROUND

Transfusion-associated GVHD (TA-GVHD) is an uncommon complication of blood transfusion. Diagnosis of TA-GVHD is difficult, and it is usually rapidly fatal. There are few documented sur- vivors of TA-GVHD.

CASE REPORT

A 61-year-old woman with chronic lymphocytic leukemia (CLL) was treated with fludarabine followed by combination chemotherapy and high-dose radioimmunotherapy and peripheral blood progenitor cell (PBPC) rescue. She was transfused with nonirradiated blood components at an outside hospital and presented 10 days later with rash, elevated liver enzymes, and progressive pancytopenia. Skin biopsy was consistent with GVHD, and HLA typing of lymphocytes from the patient demonstrated mixed chimerism. The patient was treated with solumedrol and cyclosporin A, followed by high-dose cyclophosphamide and antithymocyte globulin and autologous PBPC infusion. She had rapid engraftment, resolution of skin rash, and normalization of liver function abnormalities. She is in good health with normal blood counts and no evidence of CLL 34 months after transplantation.

CONCLUSION

TA-GVHD occurs in the setting of an immunocompromised recipient receiving nonirradiated blood components. A typical presentation includes skin rash, liver function abnormalities, and pancytopenia. Demonstration of mixed chimerism by HLA typing facilitated diagnosis in this patient. High-dose immunosuppression, facilitated by the availability of autologous PBPCs, resulted in a successful outcome.

Comparative yield of HCV RNA testing in blood donors screened by 2.0 versus 3.0 antibody assays

BACKGROUND

Two HCV antibody tests (EIA 2.0 [EIA2], Abbott; and the Version 3.0 ELISA [EIA3], Ortho) are currently licensed for screening of US blood donors. Testing of donors for HCV RNA allows comparison of the sensitivities of the two antibody-screening assays.

STUDY DESIGN AND METHODS

All allogeneic blood donations at 13 US test sites were screened for HCV RNA by testing plasma minipools using an investigational assay (COBAS AmpliScreen HCV test, v2.0, Roche Molecular Systems). Some sites screened for HCV antibody by EIA2 and some used EIA3. The frequency of RNA-positive and antibody-negative (RNA-pos and Ab-neg) donations among donors screened by each antibody assay was compared. Antibody appearance was assessed in a donor follow-up study.

RESULTS

A total of 5.51 x 10(6) donations were screened for HCV RNA. Of these, 2.27 million were screened for antibody by EIA2, and 3.24 million by EIA3. Twenty-three donations were HCV RNA-pos and Ab-neg. The frequency of RNA-pos and Ab-neg donations was higher among donations screened by EIA2 (1 in 134,000), compared to those screened by EIA3 (1 in 540,000) (p = 0.001). Of the 17 RNA-pos and Ab-neg donations identified by test sites that used EIA2, 14 were retested by EIA3 and 10 (71%) were reactive. Most RNA-pos and Ab-neg donors appear to be in the process of seroconversion. Donors that were initially EIA2-negative and EIA3-reactive showed a more prolonged pattern of seroconversion compared to those that were initially nonreactive by both antibody assays. Four donors were EIA2-negative, EIA3-reactive, and RIBA-indeterminate (c33c) for at least 90 days, 1 for more than 317 days.

CONCLUSION

EIA3 would have detected the majority of RNA-positive donations missed by EIA2. Some RNA-positive donors are EIA2-negative and EIA3-reactive for a prolonged period of time.

Noninfectious serious hazards of transfusion

Serious, noninfectious transfusion complications include transfusion-related acute lung injury (TRALI), transfusion-associated graft-versus-host disease, anaphylaxis, hemolysis, and post-transfusion purpura. Prompt recognition and treatment are crucial, but prevention is preferable. Many transfusion reactions are not recognized as such, perhaps because signs and symptoms mimic other clinical conditions. However, any unexpected symptoms in a transfusion recipient should at least be considered as a possible transfusion reaction and be evaluated. Appropriate diagnosis is the key to treatment and may prevent additional reactions, not only in the patient, but possibly, as in the case of TRALI, in other patients.

Interpretation of atypical patterns encountered when using a flow cytometry-based method to detect residual leukocytes in leukoreduced red blood cell components

BACKGROUND

Universal leukoreduction of blood components is becoming the standard of care. Flow cytometry methods are being used for quality control of the leukoreduction process.

METHODS

We provide an atlas of atypical flow cytograms generated by a commercial LeucoCOUNT assay that was used to enumerate residual leukocytes in leukoreduced red blood cell components. Numeric results are derived from a flow cytogram generated by the assay.

RESULTS

Three types of atypical flow cytogram patterns were observed during process validation or routine quality control of leukoreduced red blood cell components. (a) Fixation artifact: Fixation of control or test samples can alter the staining intensity compared with fresh cells. (b) "Rain" pattern: Flow cytometry methods count slightly damaged leukocytes not removed during leukoreduction. Slightly damaged leukocytes appear on a flow cytogram like "rain" falling from a well-defined "cloud" of intact residual leukocytes. Discrepancies between automated flow cytometry results and subjective manual counting methods can occur. (c) Autofluorescence-debris pattern: Cell debris and age-related changes in the sample can cause shifts in the fluorescence staining pattern, resulting in erroneous test results.

CONCLUSION

Review of flow cytograms is essential for accurate reporting of flow cytometry-based methods for enumerating residual leukocytes in leukoreduced blood components.

Transfusion-related acute lung injury: report of a clinical look-back investigation

CONTEXT

Transfusion-related acute lung injury (TRALI) is a syndrome that includes dyspnea, hypotension, bilateral pulmonary edema, and fever. TRALI is the third leading cause of transfusion-related mortality, but it is probably underdiagnosed and underreported.

OBJECTIVE

To determine if blood products from a frequent plasma donor, whose blood product was implicated in a fatal case of TRALI, caused symptoms of TRALI in other recipients of her plasma.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective chart review (conducted from November 2000 through April 2001) of 50 patients who received blood components within 2 years (October 1998 through October 2000) from a donor linked to a transfusion-related fatality.

MAIN OUTCOME MEASURE

Occurrence of mild/moderate (dyspnea with fever, chills, hypotension, and/or hypoxemia) or severe (acute pulmonary edema or need for mechanical ventilation) reaction associated with transfusion.

RESULTS

Superimposed illness prevented assessment of TRALI in 14 patients. Of the 36 patient charts that could be reviewed, 7 mild/moderate reactions were reported in 6 patients (16.7%) and 8 severe reactions were reported in 8 patients (22.2%). Of 5 patients who received multiple transfusions from the same donor, 2 experienced 2 reactions: one had 2 mild/moderate reactions and the other had both a mild/moderate and a severe reaction. While 5 of the 7 mild/moderate reactions were reported to the hospital transfusion service, only 2 of the 8 severe reactions were reported. Only 2 reactions (1 mild/moderate and 1 severe) were reported to the regional blood collection facility.

CONCLUSIONS

TRALI was frequently underdiagnosed and underreported in recipients of blood products from a donor whose blood products may have caused TRALI in several transfusion recipients. Clinical education and awareness of this often-overlooked diagnosis are imperative for appropriate prevention and treatment.

Distribution of hepatitis B virus genotypes among American blood donors determined with a PreS2 epitope enzyme-linked immunosorbent assay kit

We genotyped 418 sera from volunteer blood donors from two large, regional blood centers in the United States who were HBsAg positive by an enzyme-linked immunosorbent assay (ELISA). The HBV genotypes were determined by a serological method using a preS2 epitope ELISA kit (Institute of Immunology, Tokyo, Japan) with monoclonal antibodies. Of the 418 samples, the genotypes of 320 could be determined (76.6%). One hundred forty-three (34.2%) were genotyped as A (preS2 subtype su), 31 (7.4%) were genotyped as B (subtype m), 59 (14.1%) were genotyped as C (subtype ks), 83 (19.9%) were genotyped as D or E (subtype ksu), and 4 (1.0%) were genotyped as F (subtype k). This kit cannot differentiate genotypes D and E. For 98 (23.4%) of the 418 samples, the genotype could not be determined; 11 of these 98 samples were positive for at least one of the preS2 genotype-specific epitopes (m, k, s, and u), but the combinations of positive epitopes were different from those of samples that could be genotyped; 45 had only the common epitope (b). In the group with a high signal-to-cutoff (S/C) ratio, the HBV genotype could be determined for 199 (84%) of 237 samples; in contrast, in the low-S/C-ratio group, only 10 (20%) of 51 samples could be genotyped (P < 0.001). These findings may indicate the limitation of genotyping samples with low S/C ratios for HBsAg by ELISA or the existence of genotype G or other new HBV genotypes in HBsAg-positive blood donors in the United States. Of the genotyped samples, 201 were assayed for HBeAg; only 9 (4.5%) were positive for HBeAg. The frequency of genotype C in HBeAg-positive donor samples (5 of 9 or 56%) was higher than that in HBeAg-negative donor samples (33 of 192, or 17%) (P = 0.022).

Fluctuation of serum HCV-RNA levels in untreated blood donors with chronic hepatitis C virus infection

The hepatitis C virus (HCV)-RNA levels were measured in 281 serum samples from 32 untreated volunteer blood donors prospectively collected over a period of 14-73 months. The HCV-RNA levels were tested by the branched DNA signal amplification assay. The mean HCV-RNA levels of each donor ranged from 4.92 log10-6.36 log10 gene equivalents/mL (25%, median, 75% percentile; 5.51, 5.79, 6.12 log10 gene equivalents/mL). The fluctuations of HCV-RNA levels in individuals, represented by the ratio of the maximum value divided by the minimum value, ranged from a 1.7- to a 141-fold change. Fluctuations with more than a 10-fold change were observed in five subjects: 11-, 15-, 17-, 96- and 141-fold changes. Eleven subjects were followed for at least 5 years; all subjects had fluctuations of HCV-RNA levels greater than 3-fold during the observation period. No blood donor was observed whose HCV levels changed from a high-level phase to a low-level phase or from low to high. No subjects cleared HCV during follow-up, although two had undetectable HCV-RNA levels transiently. These findings reveal that changes in HCV-RNA levels occur which are unrelated to treatment with interferon and ribavirin.

The disappearance of transfusion-transmitted hepatitis C virus infections in the United States

Because of anti-HCV testing, rates of transfusion-transmitted HCV infections have dropped from a high level (approximately 1 per 200 units, even using volunteer, repeat donors) to an extremely low one (approximately 1 per 125,000 units). Moreover, preliminary data indicate that pooled- (and perhaps, eventually, single-) specimen NAT for HCV-RNA or EIA for HCV core antigen may reduce this risk even further. It is anticipated that implementation of one or more of these methods, coupled with one or more pathogen-inactivation steps, may functionally eliminate the risk of transmitting HCV by transfusions.

HLA class II antibodies in transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a serious, sometimes fatal, complication of transfusion. Granulocyte and HLA class I antibodies present in blood donors have been associated with TRALI. HLA class II antibodies have recently been described in a few cases of TRALI.

STUDY DESIGN AND METHODS

Donors involved in TRALI reactions reported to a blood center over an 18-month period were tested for HLA class I and II antibodies as well as granulocyte antibodies, if HLA antibodies were not identified.

RESULTS

HLA class II antibodies were identified, in at least one donor, in 7 (64%) of 11 cases of TRALI. HLA class I antibodies were identified in combination with HLA class II antibodies in 5 of these 7 cases. HLA class I antibodies were exclusively identified in 2 cases. Granulocyte antibodies were identified in 1 case, and no antibodies were identified in another.

CONCLUSION

In addition to HLA class I antibodies, HLA class II antibodies are associated with TRALI. Testing of donors for HLA class II antibodies as well as HLA class I and granulocyte antibodies is recommended as part of the investigation of suspected cases of TRALI.

HIV transmissions from a window-period platelet donation

Recently, blood centers began investigational testing for HIV RNA by pooled nucleic acid testing (NAT). A 35-year-old frequent platelet donor tested HIV p24 antigen positive, antibody negative before implementation of NAT. He made 2 platelet donations (day -4 and -11) immediately before testing positive for HIV. The donor's HIV seroconversion was monitored, and stored samples were tested retrospectively for HIV RNA. Platelet recipients were tested for HIV infection. The day -4 sample tested positive for HIV RNA by pooled and individual sample NAT. The day -11 sample tested negative for HIV RNA by both NAT tests. The 2 recipients of the day -4 platelets tested HIV RNA and p24 antigen positive. The recipient of the day -11 platelets could not be tested because he had died. HIV NAT would have prevented transmission of HIV had it been available at the time of this donor's HIV seroconversion.

Mechanisms of severe transfusion reactions

Serious adverse effects of transfusion may be immunologically or non-immunologically mediated. Currently, bacterial contamination of blood products, particularly platelets, is one of the most significant causes of transfusion-related morbidity and mortality. Septic transfusion reactions can present with clinical symptoms similar to immune-mediated hemolytic transfusion reactions and transfusion-related acute lung injury. Extremely high fever and/or gastrointestinal symptoms, in a transfusion recipient, may be indicative of sepsis. The diagnosis is based upon culturing the same organism from both the patient and the transfused blood component. Numerous organisms have been implicated as the cause of septic transfusion reactions. Due to different storage conditions, gram negative organisms are more often isolated from red blood cell components; gram positive organisms are more often isolated from platelets. Prevention of septic transfusion reactions is primarily dependent on an adequate donor history and meticulous preparation of the donor phlebotomy site. Visual inspection of blood components prior to transfusion is also vital to preventing these reactions. Several methods of detection of bacterial contamination and inactivation of pathogens are currently under active investigation.

Leukocyte-reduced red blood cell transfusions in patients with anemia and human immunodeficiency virus infection: the Viral Activation Transfusion Study: a randomized controlled trial

CONTEXT

Allogeneic blood transfusions have immunomodulatory effects and have been associated with activation of human immunodeficiency virus (HIV) and cytomegalovirus (CMV) in vitro and of HIV in small pilot studies. Retrospective studies suggest that transfusions adversely affect the clinical course of HIV. Data in selected non-HIV-infected patients requiring blood transfusion have suggested clinical benefit with leukocyte-reduced red blood cells (RBCs).

OBJECTIVE

To compare the effects of leukoreduced and unmodified RBC transfusions on survival, complications of acquired immunodeficiency syndrome, and relevant laboratory markers in HIV-infected patients.

DESIGN AND SETTING

Double-blind randomized controlled trial conducted in 11 US academic medical centers from July 1995 through June 1999, with a median follow-up of 12 months (24 months in survivors).

PATIENTS

A total of 531 persons infected with HIV and CMV, aged 14 years or older, who required transfusions for anemia; 259 received leukoreduced transfusions and 262 received unmodified transfusions (10 did not receive the planned transfusion).

MAIN OUTCOME MEASURES

Survival and change in plasma HIV RNA level 7 days after transfusion, compared by type of transfusion.

RESULTS

At entry, the groups were similar in demographic, clinical, and relevant laboratory characteristics. A total of 3864 RBC units were transfused. Two hundred eighty-nine deaths occurred (151 with leukoreduced transfusion; 138 with unmodified transfusion); median survival was 13.0 and 20.5 months, respectively (relative hazard [RH], 1.20; 95% confidence interval [CI], 0.95-1.51; log-rank P =.12). Analyses adjusted for prognostic factors suggested possible worse survival with leukoreduction (RH, 1.35; 95% CI, 1.06-1.72). There was no difference in time to new opportunistic event/death or frequency of transfusion reactions. No changes in plasma HIV RNA level were seen in either group at days 7, 14, 21, or 28, even in patients not taking antiretroviral drugs. There were no differences in trends between groups in CMV DNA, CD4 cell counts, activated (CD38% or human leukocyte antigen-DR) CD8 cell counts, or plasma cytokine levels.

CONCLUSIONS

We found no evidence of HIV, CMV, or cytokine activation following blood transfusion in patients with advanced HIV infection. Leukoreduction provided no clinical benefit in these patients. These data demonstrate the importance of conducting controlled studies of effects of leukoreduction in different patient populations, since smaller studies in other patient populations have suggested leukoreduction may be beneficial.

Old and new tests: where will it end?

Testing has improved the safety of the blood supply. We have excellent serologic tests in place now and are implementing nucleic acid based tests to identify asymptomatic carriers of viruses during the infectious part of the pre-seroconversion (window) period. However, the blood supply was already quite safe after a variety of other mechanisms had been put into place besides testing to screen out individuals at risk of carrying the most important transfusion transmissible agents. An important safety factor is the use of volunteer, unpaid (unremunerated) blood donors. The best alternative to implementing yet more tests to reduce, but not eliminate, the minute residual risks of transfusion transmission of such agents as HIV, HBV and HCV is the application of microbial inactivation technology to blood and blood components. Such microbially inactivated, cellular blood components should not have the risk of transmitting infectious agents, but may have other, different risks, since nothing has yet been shown to be one hundred percent safe (i.e., risk free). The use of a test to detect carriers of spongiform encephalopathies to prevent their theoretical transmission by transfusion may cause harm to donors and might increase risk for recipients by decreasing the available blood supply.

Universal leukocyte reduction

Leukocyte reduction of blood components, in the United States, is generally reserved for conditions in which a clinical indication has been documented. There is no evidence that either Creutzfeldt-Jakob disease or variant Creutzfeldt-Jakob disease are transmitted by transfusion in humans or that leukocyte reduction of blood components could reduce their transmission. A number of adverse outcomes following transfusion are alleged to be the result of white blood cells. At this point in time, there are insufficient clinical data to justify the universal leukocyte reduction of blood components.

Growth of bacteria in inoculated platelets: implications for bacteria detection and the extension of platelet storage

BACKGROUND

Recent reports from Europe have advocated the use of bacterial culturing of platelets on Day 2 or 3 of storage to extend the shelf life of platelets to 7 days, thereby reducing the outdating of platelets and preserving a limited medical resource. To assess the optimal timing, the necessary sensitivity, and the possible efficacy of bacterial detection, the bacterial growth characteristics were reviewed in 165 platelet units, each inoculated on the day of collection with one of the following organisms: Bacillus cereus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens, Staphylococcus aureus, and Staphylococcus epidermidis from four previously published studies.

STUDY DESIGN AND METHODS

Quantitative culture data from inoculated platelet concentrates from five sites and four studies were combined into one database and analyzed for bacterial concentration thresholds (> or =10(1), > or =10(2), > or =10(3), > or =10(4), > or =10(5) CFU/mL) by day of storage.

RESULTS

All examples of B. cereus, P. aeruginosa, K. pneumoniae, S. marcescens, and S. aureus had concentrations > or =10(2) CFU per mL by Day 3 after inoculation. By Day 4, all units with these organisms contained > or =10(5) CFU per mL. Units contaminated with S. epidermidis showed slower and more varied growth. By Day 3 after inoculation, 81.3 percent had 10(2) CFU per mL. By Day 4 after inoculation, 46 (95.8%) of 48 units had concentrations > or =10(2) CFU per mL.

CONCLUSION

These experiments suggest that an assay capable of detecting 10(2) CFU per mL on Day 3 of storage would detect the vast majority of bacterially contaminated platelet units, prevent many cases of platelet-associated bacterial sepsis, and provide a scientific basis for the extension of the current platelet storage time. It would be expected that a rare, slow-growing organism could escape such a detection scheme.

Differentiation of hepatitis B virus genotypes D and E by ELISA using monoclonal antibodies to epitopes on the preS2-region product

An enzyme-linked immunosorbent assay (ELISA) has been described for serological determination of hepatitis B virus genotypes, using monoclonal antibodies (mAb) against seven distinct epitopes (b, m, k, s, u, f and g) on the preS2-region products of hepatitis B surface antigen (HBsAg). The usefulness of this method for serological detection of genotype E, however, was theoretical, because no HBsAg samples of this genotype were included in the original test panel. Moreover, the predicted serotype of genotype E (bksufg) closely resembled that of genotype D (bksu, bksuf or bksug). Four HBsAg samples of genotype E were tested by the original described ELISA. The epitope g, predicted to be present in these samples by amino acid sequences, was not detected when HBsAg of genotype E was captured on a solid phase by mAb to the common determinant 'a' of HBsAg and then reacted with mAb to g (5156) labeled with horseradish peroxidase. However, the four examples of HBsAg of genotype E were captured by mAb 5156 to g on a solid phase; they were then detected by labeled mAb to the common determinant 'a'. Since epitopes f and g co-occurred on HBsAg of genotype E, HBsAg samples of this genotype were also detected, by 'sandwiching' them between immobilized mAb to g and labeled mAb to f. By contrast, HBsAg of genotype D in 90 sera was not reactive when sandwiched between mAb to f and g. Thus, this modified ELISA enables the serological determination of all six genotypes of HBsAg and, by inference, of hepatitis B virus.

Improved survival with plasma exchange in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome

PURPOSE

Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome are uncommon disorders that are generally fatal if left untreated. Plasma exchange therapy is associated with high response rates and improved short-term survival, but most previous studies have been limited by small numbers of patients or short duration of follow-up.

METHODS

We performed a retrospective cohort analysis in 126 consecutive patients with thrombotic thrombocytopenic purpura/hemolytic uremic syndrome, most of whom were treated principally with plasma exchange at the Sacramento Medical Foundation Blood (Center and the University of California Davis Medical Center between 1978 and 1998. We measured the effect of therapeutic plasma exchange on 30-day mortality, response rate, and overall survival, and determined which factors were associated with 30-day mortality and relapse.

RESULTS

The overall 30-day mortality was 10% of the 122 patients who received plasma exchange as their principal treatment (a median of 9 exchanges and a mean cumulative infused volume of 43 +/- 77 L fresh frozen plasma); 56% were complete responders and 21% were partial responders. The relapse rate was 13%. The estimated 2-year survival was about 60%; among patients without serious underlying comorbid conditions, the estimated 2-year survival was about 80%. Each unit increase in clinical severity score (on a 0 to 8 scale) was associated with a 2.2-fold (95% confidence interval [CI]: 1.3 to 3.9) increase in the odds of 30-day mortality. Patients who were febrile at presentation were substantially less likely to suffer a relapse (odds ratio = 0.2; 95% CI: 0.03 to 0.9).

CONCLUSION

Plasma exchange therapy produced high response and survival rates in this large cohort of patients with thrombotic thrombocytopenic purpura/hemolytic uremic syndrome. The Clinical Severity Score may be useful in predicting 30-day mortality, whereas fever at onset was associated with a lesser risk of relapse. Prospective studies should stratify patients according to these prognostic factors.

Process improvement in transfusion medicine

Ongoing efforts to decrease costs in the clinical laboratory make continuous process improvement especially important in difficult economic times. Process improvement can result in decreased workload, cost savings, and increased customer satisfaction but is an abstract concept in and of itself. To illustrate the steps of process improvement, we applied them to our blood component retrieval policy. By identifying the problems with the current system, proposing and implementing solutions, and measuring the effects before and after revamping the process, we have been able to show impressive reductions in the number of component retrievals initiated, the number acted on, wasted components, and customer complaints, all of which translate into cost savings. Once the cycle is completed, it begins anew. There must always be continuous process improvement.

Survival of donor leukocyte subpopulations in immunocompetent transfusion recipients: frequent long-term microchimerism in severe trauma patients

We recently reported detection of a transient increase in circulating donor leukocytes (WBCs) in immunocompetent recipients 3 to 5 days posttransfusion (tx) (Blood 85:1207, 1995). We have now characterized survival kinetics of specific donor WBC subsets in additional tx populations. Eight female elective surgery patients (pts) were sampled pre-tx and on days 1, 3, 5, 7, and 14 post-tx. Ten female trauma pts transfused with a total of 4 to 18 U of relatively fresh red blood cells were sampled up to 1.5 years post-tx. WBC subsets from frozen whole blood were isolated using CD4, CD8 (T cell), CD15 (myeloid), and CD19 (B cell) antibody-coated magnetic beads. Donor WBCs were counted by quantitative polymerase chain reaction (PCR) of male-specific sex determining region (SRY) sequences. PCR HLA typing and mixed leukocyte reaction (MLR) between recipient and donor WBCs were performed on two of the trauma tx recipients who had long-term chimerism of donor cells post-tx. In 6 of 8 female surgery pts, circulating CD4(+) male donor cells peaked at day 3 or 5 (0.01 to 1 cell/microL), followed by clearance by day 14. In 7 of 10 female trauma pts, we observed multilineage persistence of male donor WBCs (CD4, CD8, CD15, CD19) for 6 months to 1.5 years post-tx at concentrations of 10 to 100 cells/microL. In 2 trauma recipients studied, MLR showed no, or very low, response to WBC of the single donor implicated as the source of microchimerism by HLA typing. Establishment of long-term multilineage chimerism in trauma recipients is probably caused by engraftment of donor stem cells and mutual tolerance between recipient and donor leukocytes. A better understanding of factors determining clearance versus chimerism of transfused leukocytes is critical to prevention of alloimmunization and transfusion-induced graft-versus-host disease, and, potentially, to induction of tolerance for transplantation.

Donor cell induced CD69 expression and intracellular IL-2 and IL-4 production by peripheral blood lymphocytes isolated from kidney transplant recipients

Flow cytometry assays, which measure CD69 activation and intracellular cytokine production, have been used to measure peripheral blood lymphocyte (PBL) responses to in vitro antigen exposure. In the present study, we show that, in healthy individuals and immunosuppressed kidney transplant recipients, CD69 expression and intracellular cytokine production by peripheral blood T cells compare favorably to thymidine uptake as a measure of PBL response to alloantigen in mixed leukocyte culture (MLC). Heparinized whole blood from 23 healthy individuals was incubated for 24-48 h with 3rd party allogeneic monocytes; blood from twelve kidney transplant recipients was incubated with monocytes from their kidney donor and with monocytes from unrelated individuals. The percentage of T cells expressing surface CD69 or intracellular IL-2 or IL-4 was determined by 3-color flow cytometry. We identified 5 donor-specific response patterns in our kidney transplant group. One transplant recipient was hyporesponsive; his cells did not express CD69 or produce IL-2 in response to either donor or 3rd party allogeneic cells. All other transplant recipients expressed CD69 and IL-2 in response to 3rd party allogeneic cells. Two had no response to donor cells (donor-specific hyporesponsiveness), three had donor-specific anergy (CD69 expression without cytokine production in response to donor cells), five had a donor-specific Thl response (CD69 expression and IL-2 production in response to donor cells), and one had a donor-specific Th2 response (CD69 expression and IL-4 but not IL-2 production in response to donor cells). Rapid measures of donor-specific hyporesponsiveness such as CD69 activation antigen expression and intracellular cytokine production may prove valuable in monitoring lymphocyte function and aid in the long-term management of kidney transplant recipients.

Post-transfusion hepatitis: current risks and causes

Viral hepatitis which follows transfusions (post-transfusion hepatitis) may be due to those transfusions, i.e., transfusion-transmitted hepatitis (TTH), or may be incident to the reason for the transfusion and, thus, may be transfusion-associated, but not transfusion-transmitted. The current risks of TTH, today, are extremely small, but are still due, primarily, to the hepatitis B virus (HBV) and the hepatitis C virus (HCV), the latter, formerly being known as "non-A, non-B hepatitis." The residual, now, of TTH which is non-A, non-B, and non-C is extremely small and may be due to a variety of agents. Using volunteer (unpaid), repeat, blood donors, who are carefully screened for hepatitis risk factors and then tested for evidence of HBV infection, the risk of HBV being transmitted by a transfusion today is in the order of 1 per 63,000 units of blood. For transfusion-transmitted HCV, with the same repeat, volunteer (unpaid) donors, careful screening and a sensitive assay for anti-HCV, the risk is in the order of 1 in 125,000 units. These risks of HBV and HCV due to transfusions are so small that other means of acquiring these viruses should be sought when patients develop hepatitis following blood transfusions. However, efforts to further reduce the current risks of HBV and HCV transmission by transfusions should continue; these include restricting transfusions to those which are necessary or appropriate, utilizing alternatives to transfusion, employing novel assays to detect viral nucleic acids, and, finally, implementing various microbial inactivation techniques on blood, blood components and plasma derivatives.

Current risks of viral hepatitis from blood transfusions

The incidence of transfusion-associated hepatitis in the United States has fallen dramatically since the late 1960s. Where once the risks were so great that as many as one in three transfused patients contracted hepatitis, now they are infinitesimal. Many factors share responsibility for this accomplishment; however, two stand above the rest: (i) improved donor selection and screening criteria, especially elimination of paid blood donations; and (ii) major advances in testing for viral hepatitis carriers. Currently, four tests are used for the prevention of transfusion-associated hepatitis: (i) hepatitis B surface antigen; (ii) hepatitis C virus antibody; (iii) hepatitis B core antibody; and (iv) alanine aminotransferase. The first two tests are largely responsible for the current low risks of transfusion-associated hepatitis due to hepatitis B virus and hepatitis C virus of 1 in 63,000 and 1 in 125,000, per unit, respectively. To further reduce the risks of transfusion-associated hepatitis will require the enhanced sensitivity provided by nucleic acid amplification techniques (e.g. polymerase chain reaction). Currently, however, no such tests are licensed and practical, automated, or inexpensive enough for individual blood donor screening. We have made such great strides in the prevention of transfusion-transmitted hepatitis that background rates of viral hepatitis now greatly exceed the risk of transmission via transfusion. For this reason, while it may still be reasonable to consider a transfusion as a possible cause for hepatitis, it is imperative that many other possibilities (e.g., iatrogenic and other risk factors) be ruled out.

Evaluation of assays for antibody to hepatitis E virus by a serum panel. Hepatitis E Virus Antibody Serum Panel Evaluation Group

Few data are available to evaluate the performance of existing assays for antibody to the hepatitis E virus (anti-HEV). A panel of 164 randomized and coded sera was tested for anti-HEV by 12 different assays. The panel included a dilution series of an early convalescent human serum, known-positive sera (undiluted human sera obtained 2 months to 13 years after acute hepatitis E, and postinoculation chimpanzee sera), known-negative sera (preinoculation chimpanzee sera; sera from chimpanzees with hepatitis A virus, hepatitis B virus, or hepatitis C virus infection; and normal human sera), and sera obtained from previously tested U.S. blood donors without a history of hepatitis. Six tests detected anti-HEV in > or =90% of undiluted known-positive sera. The sensitivity of all of the assays with known-positive sera ranged from 17% to 100%, and the limit of detection by endpoint dilution ranged from 1:5 to 1:160. Ten tests were nonreactive for all of the 22 known-negative sera, one test was reactive for one serum, and one test was reactive for 5 sera. In pairwise comparisons of different tests in blood donor sera, the overall concordance ranged from 49% to 94% (median, 69%) and the concordance among reactive sera ranged from 0% to 89% (median, 32%). Several of these tests performed well in detecting anti-HEV in known positive sera. However, highly discrepant results among U.S. blood donor sera indicate that anti-HEV seroprevalence data in non-HEV-endemic countries may be unreliable and should be interpreted with caution.