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

BACKGROUND: 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. STUDY DESIGN AND METHODS: 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). RESULTS: 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. CONCLUSION: 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.     

Prevalence of serologic markers for hepatitis B and C viruses in Brazilian blood donors and incidence and residual risk of transfusion transmission of hepatitis C virus

BACKGROUND: We evaluate the current prevalence of serologic markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in blood donors and estimated HCV incidence and residual transfusion‐transmitted risk at three large Brazilian blood centers. STUDY DESIGN AND METHODS: Data on whole blood and platelet donations were collected from January through December 2007, analyzed by center; donor type; age; sex; donation status; and serologic results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti‐HBc), and anti‐HCV. HBV and HCV prevalence rates were calculated for all first‐time donations. HCV incidence was derived including interdonation intervals that preceded first repeat donations given during the study, and HCV residual risk was estimated for transfusions derived from repeat donors. RESULTS: There were 307,354 donations in 2007. Overall prevalence of concordant HBsAg and anti‐HBc reactivity was 289 per 100,000 donations and of anti‐HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% confidence interval, 0.77‐7.03) per 100,000 person‐years, and residual risk of HCV window‐phase infections was estimated at 5.0 per million units transfused. CONCLUSION: Improvement in donor selection, socioeconomic conditions, and preventive measures, implemented over time, may have helped to decrease prevalence of HBV and HCV, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of HBV and HCV markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening, and counseling strategies.     

Alloimmunization to transfused HOD red blood cells is not increased in mice with sickle cell disease

BACKGROUND: Increased rates of red blood cell (RBC) alloimmunization in patients with sickle cell disease may be due to transfusion frequency, genetic predisposition, or immune dysregulation. To test the hypothesis that sickle cell pathophysiology influences RBC alloimmunization, we utilized two transgenic mouse models of sickle cell disease. STUDY DESIGN AND METHODS: Transgenic sickle mice, which express human α and β^S globin, were transfused with fresh or 14‐day‐stored RBCs containing the HOD (hen egg lysozyme, ovalbumin, and human Duffy^b) antigen; some recipients were inflamed with poly(I : C) before transfusion. Anti‐HOD alloantibody responses were subsequently measured by enzyme‐linked immunosorbent assay and flow crossmatch; a cohort of recipients had posttransfusion serum cytokines measured by bead array. RESULTS: Both Berkeley and Townes homozygous (SS) and heterozygous (AS) mice had similar rates and magnitude of anti‐HOD RBC alloimmunization after fresh HOD RBC transfusion compared with control animals; under no tested condition did homozygous SS recipients make higher levels of alloantibodies than control animals. Unexpectedly, homozygous SS recipients had blunted cytokine responses and lower levels of anti‐HOD alloantibodies after transfusion of 14‐day stored RBCs, compared with control animals. CONCLUSIONS: In sum, homozygous β^S expression and the ensuing disease state are not alone sufficient to enhance RBC alloimmunization to transfused HOD RBCs in two distinct humanized murine models of sickle cell disease under the conditions examined. These data suggest that other factors may contribute to the high rates of RBC alloimmunization observed in humans with sickle cell disease.     

Transmission of cytomegalovirus (CMV) infection by leukoreduced blood products not tested for CMV antibodies: a single-center prospective study in high-risk patients undergoing allogeneic hematopoietic stem cell transplantation (CME)

BACKGROUND: Measures to prevent transfusion‐transmitted cytomegalovirus (TT‐CMV) infection after hematopoietic stem cell transplantation (HSCT) include transfusion of CMV antibody–negative blood units and/or transfusion of leukoreduced cellular blood products. We assessed the incidence of TT‐CMV in CMV‐seronegative patients receiving CMV‐seronegative HSC transplants, who were transfused with leukoreduced cellular blood products not tested for anti‐CMV. STUDY DESIGN AND METHODS: In a prospective observational study between 1999 and 2009, all HSCT patients received leukoreduced cellular blood products not tested for anti‐CMV. Patients were screened for CMV serostatus and CMV‐negative recipients of CMV‐negative transplants were systematically monitored for TT‐CMV clinically and by CMV nucleic acid testing. Anti‐CMV antibodies (immunoglobulin [Ig]G and IgM) were assessed after three time intervals (Interval 1, study inclusion to Day +30 after HSCT; Interval 2, Day +30‐Day +100; Interval 3, after Day +100). RESULTS: Among 142 patients treated with allogeneic HSCT, 23 CMV‐negative donor‐patient pairs were identified. These 23 patients received 1847 blood products from 3180 donors. All patients remained negative for CMV DNA and none developed CMV‐associated clinical complications. This results in a risk for TT‐CMV per donor exposure of 0% (95% confidence interval, 0.0%‐0.12%). However, 17 of 23 patients seroconverted for anti‐CMV IgG, but none for anti‐CMV IgM. CMV IgG seroconverters received significantly more transfusions per week than nonconverters. CONCLUSION: The risk of TT‐CMV is low in high‐risk CMV^neg/neg HSCT patients transfused with leukoreduced blood products not tested for anti‐CMV. The cause of anti‐CMV IgG seroconversion is most likely passive antibody transmission by blood products.     

Outcome of an optional HCV screening program for blood transfusion recipients in Ireland

BACKGROUND: An optional (general) HCV testing program for blood and blood component recipients before the introduction of routine donor anti-HCV screening (October 1991) was launched in Ireland in 1995 to complement the targeted lookback program in progress at that time and to identify transfusion-transmitted hepatitis C. STUDY DESIGN AND METHODS: The public were informed of the opportunity to avail of screening by widespread media coverage. Screening was by an initial ELISA (Abbott 3.0, Abbott Laboratories) at the transfusion center laboratories. Reactive samples were referred to a virus reference laboratory where two additional ELISAs (Ortho 3.0, Ortho Clinical Diagnostics; and Murex 3.0, Murex) were performed. Confirmation of ELISA-positive samples was by a RIBA (RIBA 3.0, Chiron Corp.). All patients found to be anti-HCV- seropositive were tested for HCV RNA by PCR and were referred to a hepatologist. RESULTS: A total of 14,917 persons have been tested for hepatitis C in this program to date (85% women). Sixty-one people were confirmed positive for HCV by RIBA 3.0 (0.4%). Excluding persons with other risk factors (n = 15), the HCV positivity rate for blood component transfusion recipients (n = 46) was 0.3 percent. Of the 46 confirmed hepatitis C-positive blood component transfusion recipients, 32 were women (70%), 24 of whom received transfusion for obstetric or gynecologic indications (75%). Thirty-eight of 46 (83%) anti-HCV seropositive transfusion recipients tested had detectable HCV RNA by PCR. CONCLUSION: This program identified 46 transfusion recipients and 10 coagulation factor concentrate recipients, all of whom were previously unaware of their infection. The majority of HCV-positive transfusion recipients identified were women. This may reflect that women are longer living survivors of transfusion therapy or alternatively, in our experience, that Irish women perceive themselves at greater risk of hepatitis C because of the well-publicized association of this virus with recipients (women) of Irish RhIG.     

Severe hemolytic disease of fetus and newborn caused by red blood cell antibodies undetected at first-trimester screening (CME)

BACKGROUND: The objective was to determine clinical consequences of anti‐D and non‐D antibodies undetected at first‐trimester screening for infant or fetus. STUDY DESIGN AND METHODS: This retrospective cohort study included all pregnant women with red blood cell (RBC) antibodies who were tested between 1993 and 2008. Data were obtained from the forms for tracking immunization at the transfusion department. Each form was analyzed for three data sets: the order of screening at which the antibodies were detected (initial or repeated screening), the order of pregnancy (first pregnancy or higher), and whether the antibodies caused severe hemolytic disease of fetus and newborn (HDFN). RESULTS: In D– women, anti‐D was detected in 1.3% of cases. The anti‐D was undetected in 72 (37%) cases on the first‐trimester screening, of which eight cases were complicated by severe HDFN. In this group, three patients were primigravidae. An overall non‐D incidence of 0.2% was observed. In 16 cases, non‐D were undetected on the first‐trimester screening (10 anti‐c, two anti‐E, two anti‐C, one anti‐S, and one case of anti‐Rh17). Non‐D antibodies undetected on initial screening caused 11 cases of severe HDFN (27% of all severe non‐D HDFN). Ten of them were in multiparous women. Seven of 11 cases with severe HDFN that were missed were caused by anti‐c. CONCLUSION: The third‐trimester screening may detect RBC antibodies that were not present or detected on the first‐trimester screening. Such screening may be especially relevant in D+ multiparous women due to the risk of HDFN.     

Electronic health record surveillance algorithms facilitate the detection of transfusion‐related pulmonary complications

BACKGROUND: Transfusion‐related acute lung injury (TRALI) and transfusion‐associated circulatory overload (TACO) are leading causes of transfusion‐related mortality. Notably, poor syndrome recognition and underreporting likely result in an underestimate of their true attributable burden. We aimed to develop accurate electronic health record–based screening algorithms for improved detection of TRALI/transfused acute lung injury (ALI) and TACO. STUDY DESIGN AND METHODS: This was a retrospective observational study. The study cohort, identified from a previous National Institutes of Health–sponsored prospective investigation, included 223 transfused patients with TRALI, transfused ALI, TACO, or complication‐free controls. Optimal case detection algorithms were identified using classification and regression tree (CART) analyses. Algorithm performance was evaluated with sensitivities, specificities, likelihood ratios, and overall misclassification rates. RESULTS: For TRALI/transfused ALI detection, CART analysis achieved a sensitivity and specificity of 83.9% (95% confidence interval [CI], 74.4%‐90.4%) and 89.7% (95% CI, 80.3%‐95.2%), respectively. For TACO, the sensitivity and specificity were 86.5% (95% CI, 73.6%‐94.0%) and 92.3% (95% CI, 83.4%‐96.8%), respectively. Reduced PaO₂/FiO₂ ratios and the acquisition of posttransfusion chest radiographs were the primary determinants of case versus control status for both syndromes. Of true‐positive cases identified using the screening algorithms (TRALI/transfused ALI, n = 78; TACO, n = 45), only 11 (14.1%) and five (11.1%) were reported to the blood bank by physicians, respectively. CONCLUSIONS: Electronic screening algorithms have shown good sensitivity and specificity for identifying patients with TRALI/transfused ALI and TACO at our institution. This supports the notion that active electronic surveillance may improve case identification, thereby providing a more accurate understanding of TRALI/transfused ALI and TACO epidemiology.     

The significance of repeat testing in Turkish blood donors screened with HBV,HCV and HIV immunoassays and the importance of S/CO ratios in the interpretation of HCV/HIV screening test results and as a determinant for further confirmatory testing

The purpose of this study was to investigate the intra‐assay correlations amongst initial reactive and repeat screening results used in enzyme immunoassays (EIAs) for hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV in blood donors. This study evaluated the value of using the power of the signal to cut‐off (S/CO) ratio index for confirming anti‐HCV/HIV reactive screening results, thereby touching upon the utility of S/CO indices in determining whether further confirmatory testing was necessary. Screening test results of the 72 695 blood donors were evaluated over a 1‐year period. Correlation analysis among each initial test and retests was done by Pearson r test. Appropriate S/CO values to determine the need of the confirmation testing was investigated by ROC analyses. EIA intra‐assay correlations were of statistical significance and were determined as follows: 0·948 for anti‐HCV, 0·827 for anti‐HIV and 0·948 for HBsAg. The threshold S/CO ratio values which predicted more than 95% of the confirmation test result were 3·8 for HCV and 5·6 for HIV. We were able to demonstrate a strong level of intra‐assay correlation amongst EIAs, thereby eliminating the need for repetition of the screening test. Hence, we suggest that repeat screening should only be limited to HBV and HIV tests with low EIA S/CO ratios. Thus, using the power of the S/CO ratio in determining the need for HCV confirmation testing can be a cost‐effective measure, especially if the S/CO value is ≥3·8.     

Antibody screening in multitransfused patients: A prerequisite before each transfusion

Life-long red blood cell (RBC) transfusions remain the main treatment for severe thalassemia. We hereby report a case of anti S and anti Lu^a in a β-thalassemia major patient detected incidentally on antibody screening. The patient was a known case of β-thalassemia major and was on regular blood transfusion every 3 weeks from the institute from the age of 6 months. Subsequently, on one occasion, patient's crossmatch was compatible despite positive antibody screen using microcolumn gel technique. Autocontrol and direct antiglobulin test were negative on microcolumn gel. Anti S and anti Lu^a antibodies were identified. Blood unit found compatible was negative for S and Lu^a antigens. Antibody titers were 1:1 for both anti S and anti Lu^a in AHG phase using tube technique and antibodies were of IgG type. Blood unit was transfused uneventfully to the patient. Donors were traced back (last three donations) and called for repeat blood sample testing for S and Lu^a antigen. Two out of three donors were found to be S antigen positive and one out of these two was Lu^a antigen positive. Anti S and anti Lu^a antibodies were again identified on patient's subsequent visit for transfusion. The present case re-emphasize the importance of antibody screening at each visit in earlier detection of antibodies in multi transfused patients. Encouraging patients to receive transfusion from one center and dedicating donors could reduce alloimmunization rate but larger studies are required.     

Long-term follow-up among Danish transfusion recipients identified in the national hepatitis C lookback

BACKGROUND: In 1996, a national lookback study was performed in Denmark identifying 1018 patients exposed to hepatitis C virus (HCV) by transfusion before 1991. The objective of this study was to describe morbidity and mortality during extended follow‐up among patients in the Danish HCV lookback cohort alive in 1996. STUDY DESIGN AND METHODS: In a retrospective cohort study of 230 patients exposed to HCV by blood transfusion and alive in 1996 we extracted data from national registers and compared these with a matched group of unexposed transfusion recipients. RESULTS: Among 230 HCV‐exposed recipients alive in 1996, 124 (53.9%) had chronic hepatitis C, 43 (18.7%) were not infected, and 63 (27.4%) had incomplete HCV data. In 2009, 121 (52.6%) were still alive a median of 21.8 years after transfusion. The mortality rate among the HCV‐exposed recipients followed from 1996 was 4.9 per 100 person‐years (PY). The incidence of liver cirrhosis and decompensated cirrhosis was 1.0 per 100 PY and 0.4 per 100 PY, respectively; 16.5% had cirrhosis at death. Among HCV‐exposed recipients, no difference in all‐cause or liver‐related mortality was observed between HCV‐infected and HCV‐uninfected recipients. Further, there was no difference in mortality between HCV‐exposed and ‐unexposed transfusion recipients (mortality rate ratio [MRR], 1.06; 95% confidence interval [CI], 0.96‐1.17; p = 0.47), but liver‐related mortality was significantly higher among HCV‐exposed patients (MRR, 10.0; 95% CI, 7.20‐17.7; p < 0.001). CONCLUSION: Two decades after exposure to blood products from HCV‐infected donors, only 121(11.8%) of 1018 recipients remained alive. For HCV‐exposed recipients no excess all‐cause mortality was observed, but liver‐related mortality was significantly increased.     

Significance of detecting anti‐HBc among Egyptian male blood donors negative for HBsAg*

Background: Screening for hepatitis B virus surface antigen (HBsAg) reduces the risk of transfusion‐transmitted hepatitis B viral (HBV) infection. However, the absence of HBsAg in the blood of apparently healthy individuals may not be sufficient to ensure the lack of circulating HBV. Blood containing anti‐hepatitis B core antibody (anti‐HBc) without detectable presence of HBsAg might be infectious; therefore, screening for anti‐HBc has been implemented in some countries resulting in a decrease in the risk of post‐transfusion HBV infection. Aim: To study the seroprevalence of anti‐HBc. The relationship between anti‐HBc positivity and the presence of circulating HBV among healthy blood donors negative for HBsAg will be helpful to decide whether supplemental testing may bring additional safety to blood products. Material and methods: A total of 1026 serum samples collected from HBsAg‐negative Egyptian healthy male donors were tested for the presence of anti‐HBc (both IgM and IgG types) using the competitive enzyme‐linked immunosorbent assay technique. Anti‐HBc‐positive samples were subjected to real‐time polymerase chain reaction to confirm the presence of HBV DNA. Results: Of the 1026 samples tested, 80 (7·8%) blood samples were found to be reactive to anti‐HBc. Of those, HBV DNA was detected in five of the samples (6·25%). The levels of detected viraemia were variable among the five donors. Conclusion: This study shows the insufficient effectiveness of HBsAg screening in protecting blood recipients from HBV infection. Inclusion of anti‐HBc testing should be considered in the screening of blood donors.     

Risk factors in individuals with a positive HCV test

One thousand and fifty-five indivuduals with a positive hepatitis C virus (HCV) antibody test were asked about the following risk factors for HCV infection: blood transfusion, iv drug use, haemophilia, dialysis treatment, occupation, multiple (>5) sex partners per year. Five hundred and thirty-one (50.3%) individuals indicated one, 106 (10%) two, and three (0.3%) three factors respectively, however 415 (39.3%) did not indicate any risk factor at all. Transfusion was often combined with dialysis or haemophilia and drug abuse with multiple sex partners. In total transfusion was indicated in 61.5%, iv drug use in 16.5%, dialysis in 8.1%, profession as healthcare worker in 7.3%, multiple sex partners in 3.4% and haemophilia in 3.0%. The relatively high amount of cases without any risk factor is suspected to be caused by an unspecific (false positive) HCV test. A few cases, however, may be explained by tatooing, visits to tropical countries and vertical transmission. Cases in the age group 0–20 yr were mainly caused by children with leukaemia or other malignancies, one peak in the age distribution curve was at the age of 31–40, which obviously was caused by drug users. The remaining cases fell into the older age groups and peaked at 61–70 yr.     

The incidence of hepatitis C in patients with thalassemia after screening in blood transfusion centers: a fourteen-year study

BACKGROUND: Blood safety is important in all transfusion centers. The aim has always been to try to guarantee the recipient's safety through careful screening and examination of donors' blood samples. In Iran the hepatitis C virus (HCV) screening test became mandatory for blood donations from 1996. We decided to determine the incidence of new cases of HCV in patients with thalassemia, after screening of blood bags was initiated. STUDY DESIGN AND METHODS: The study was done on patients with complete files for anti‐HCV test results. Only cases that had a confirmed positive anti‐HCV result after a negative result were considered as new cases. The incidence rate was estimated and expressed in person‐years (PY). Also, for increased accuracy and comparison of incidence in recent years, the incidence rate was calculated at two 7‐year intervals (1996‐2002 and 2003‐2009). RESULTS: A total of 395 files were studied with a mean age of 27.5 years (SD ± 7.99 years). We had 109 (27.5%) anti‐HCV positive, of which 21 (19.2% of positive cases) were exposed after 1996 and considered as new cases. The incidence of HCV cases in 14 years (1996‐2009) was 4.2/1000 PY. The incidence in the first 7‐year period (1996‐2002) was 6.2/1000 PY and 1.3/1000 PY in the second 7‐year period (2003‐2009). CONCLUSION: The incidence of HCV is on the decline in Iran, both in blood donors and in recipients. We owe this to the improved blood safety in our transfusion center that has taken up better strategies. Even though the residual risk will never reach zero and we may still have new cases of HCV, it will definitely be with a lower rate. The fact that we have had no new cases among our patients with thalassemia since 2005 bears witness to this matter.     

Hemolytic transfusion reaction due to anti-IH

BACKGROUND: Anti‐IH is usually a clinically insignificant antibody that may complicate a serologic workup. However, it can occasionally cause hemolysis. We report a rare case of acute hemolysis caused by anti‐IH. CASE REPORT: A 60‐year‐old man with a long history of chronic myelomonocytic leukemia and anemia, blood group A, D+ was found to have an unidentified antibody on serologic workup. He received an A, D+ red blood cell (RBC) unit that was crossmatch compatible by immunoglobulin G indirect antiglobulin test and then experienced an acute hemolytic transfusion reaction with fever, hemoglobinuria, and acute renal failure. The antibody was later identified as an anti‐IH with a wide thermal amplitude. The transfused RBCs were later typed as A₂. The patient was subsequently typed as an A₁ individual. The patient recovered completely from the effects of this reaction and was transfused with A₁ RBCs over the next few days with no adverse effect. CONCLUSION: Anti‐IH, which is usually clinically insignificant and often found in A₁, B, and A₁B individuals, can, on rare occasions, cause acute hemolytic transfusion reactions, especially when an A₂ unit is transfused to an A₁ patient.     

Maternal red blood cell alloimmunisation in south western Uganda

Aims/Objectives: To identify the frequency and nature of maternal red blood cell (RBC) alloimmunisation in Uganda and to determine the prevalence of RhD negativity and the rate of RBC alloimmunisation in Ugandan pregnant women. Background: Haemolytic disease of the foetus and newborn (HDFN) results from maternal alloimmunisation following exposure to allogeneic RBCs during pregnancy or blood transfusion. The prevalence of maternal RBC alloimmunisation in Ugandans is not known. Materials and Methods: Pregnant women at Mbarara Hospital, South Western Uganda, were investigated in a cross‐sectional study. Demographics, transfusion and obstetric histories were recorded. Maternal RBC alloimmunisation was demonstrated using immunohaematological techniques. Results: A total of 2001 pregnant women were recruited; 3·6% of them being RhD negative. Forty‐five women (2·2%; 95% CI: 1·6–2·9) were found to be alloimmunised to RBC antigens. There were 38 RBC alloantibodies of known specificity including anti‐S, 12; anti‐M, 11; anti‐Le^a, 6; anti‐D, 4 and 1 each of anti‐K, anti‐Fy^b, anti‐Jk^a, anti‐Lu^a and anti‐Kp^a. In two women (4·4%), there were antibody combinations (anti‐M+S and anti‐K+Kp^a). Obstetric history, gestational age and previous immunising events were not significantly associated with the rate of alloimmunisation. Conclusions: This study revealed a maternal RBC alloimmunisation rate of 2·2% which was comparable with findings from a Zimbabwean study where the prevalence was 1·7%. Given the 6·0% prevalence of anti‐D among RhD‐negative women in our study and the high immunogenicity of the D antigen, programmes for preventing anti‐D alloimmunisation and HDFN in Uganda should be considered seriously.     

Platelet transfusions from D+ donors to D- patients: a 10-year follow-up study of 1014 patients

BACKGROUND: Current guidelines recommend that platelets (PLTs) from D? donors should be given to D? patients. However, such evidence comes from studies with a limited number of included patients that reported an incidence of anti‐D alloimmunization to be up to 19%. We thus decided to extend these findings by examining anti‐D alloimmunization at our institution, where PLT transfusions from D+ donors are transfused to D? patients because of logistic constraints. STUDY DESIGN AND METHODS: From April 1999 to December 2009, we retrospectively reviewed the clinical and transfusion records of all D? patients who received PLT transfusions from D+ donors at our hospital. PLT concentrates (PCs) were obtained from apheresis and from whole blood donations. RhIG was not administered after the transfusion of PCs from D+ donors. The antibody screen test to detect anti‐D was performed by low‐ionic‐strength solution indirect antiglobulin test using the gel test. RESULTS: Our series comprises 1014 D? patients who received 5128 PLT transfusions from D+ donors (89% were pooled PCs). We had 315 (31.1%) patients who had a blood sample to analyze the presence of anti‐D 4 or more weeks after the first D+ PLT transfusion with a median follow‐up of 29 weeks (range, 4‐718 weeks). Anti‐D developed in 12 (3.8%) of these 315 patients. CONCLUSIONS: The frequency of anti‐D alloimmunization of D? patients after receiving pooled PCs from D+ donors is low. The transfusion of D‐incompatible pooled PCs without immunoprophylaxis to D? men or D? women without childbearing potential seems a reasonable and safe alternative.     

High antibody level: an accurate serologic marker of viremia in asymptomatic people with hepatitis C infection

BACKGROUND: The screening and diagnosis of hepatitis C virus (HCV) infection is initiated by testing for antibody to HCV (anti‐HCV). A positive anti‐HCV test in blood donors represents ongoing infection in only a variable proportion of individuals. Because a high anti‐HCV level has been associated with viremia, a study was conducted to determine whether a high antibody level is an accurate serologic marker for viremia in asymptomatic anti‐HCV–positive persons. STUDY DESIGN AND METHODS: In a diagnostic test study, we included 856 anti‐HCV–positive blood donors in a blood bank at Guadalajara, Jalisco, Mexico, between 2002 and 2007. A third‐generation amplified chemiluminescence assay (ChLIA HCV) was used to detect anti‐HCV. A positive result of the qualitative nucleic acid test (HCV RNA) was considered the gold standard for viremia. RESULTS: By receiver operating characteristic analysis, the signal‐to‐cutoff (S/CO) ratio of 20 or more was chosen as optimal to identify viremia and so was defined as high anti‐HCV level. There was a significant difference in the proportion of viremia between subjects with high antibody level and those with lower levels (93.7% vs. 1.8%, respectively; p < 0.001). A high antibody level showed a sensitivity for viremia of 96.6% (95% confidence interval [CI], 93.8%‐98.1%), a specificity of 96.6 % (95% CI, 94.8%‐97.8%), and a likelihood ratio of 28.6 (95% CI, 18.4%‐44.6%). CONCLUSION: A high antibody level (S/CO ratio ≥20 by ChLIA HCV) clearly divides the viremic from the nonviremic blood donors and functions as an accurate serologic marker to guide the use of routine HCV RNA testing to confirm hepatitis C infection.     

Comparison of demographic and donation profiles and transfusion-transmissible disease markers and risk rates in previously transfused and nontransfused blood donors

BACKGROUND: Increasing concern about transfusion transmission of variant Creutzfeldt-Jakob disease has resulted in indefinite deferral of transfused donors in France and the UK. Little is known, however, about the impact of indefinite deferral of transfused donors on blood safety and availability in the US. STUDY DESIGN AND METHODS: Data were collected on allogeneic donations at five US blood centers during 1991 through 2000. Donation characteristics, prevalence, and incidence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were compared between transfused and nontransfused donors. Unreported deferrable risk (UDR) and reasons to donate were evaluated with data from a mail survey. RESULTS: Transfusion history was reported by 4.2 percent of donors. Prevalence and incidence of HIV and HBV were comparable between transfused and nontransfused donors. Although HCV incidence was similar in both groups, HCV prevalence was nearly three times higher in transfused than in nontransfused first-time donors. UDR and reasons to donate were similar in the two groups, except transfused donors were less likely to donate for screening test results (odds ratio, 0.5; 95% confidence interval, 0.3-0.8). CONCLUSION: Transfused and nontransfused donors had similar viral incidence and comparable UDR, suggesting that indefinite deferral of transfused donors would unlikely improve blood safety. Until more is known about the prevalence and transfusion transmissibility of emerging agents, indefinite deferral of previously transfused donors in the US does not appear warranted.