Searching for unknown transfusion-transmitted hepatitis viruses: a binational cohort study of 1.5 million transfused patients

BACKGROUND

Both hepatitis B and C viruses were transmitted through blood transfusion before implementation of donor screening. The existence of additional, yet unknown transfusion transmittable agents causing liver disease could have important public health implications.

METHODS

Analyses were based on the Scandinavian Donations and Transfusions (SCANDAT2) database. Cox regression models were used to estimate the hazard ratio (HR) of developing chronic liver disease in recipients of blood from donors who later developed any chronic liver disease compared to recipients who received blood transfusion from healthy donors. We also studied whether the risk of liver disease was increased in patients who received units from 'high-risk' donors, defined as donors who had a higher than expected occurrence of liver disease amongst their previous recipients. All analyses were stratified before and after 1992 to account for the effect of screening for hepatitis C virus.

RESULTS

A total of 1 482 922 transfused patients were included in the analyses. Analyses showed evidence of transfusion transmission of liver diseases before, but not after the implementation of hepatitis C virus screening in 1992, with HRs for any liver disease of 1.38 [95% confidence interval (CI), 1.30-1.46] and 0.99 (95% CI, 0.91-1.07), before and after 1992, respectively. Similarly, blood components from 'high-risk' donors conferred increased risks before, but not after 1992.

CONCLUSIONS

Our data provide no evidence for transfusion transmission of agents causing liver disease after the implementation of screening for hepatitis B and C, and suggest that if such transmission does occur, it is rare.

One-year period prevalence of blood transfusion

Transfusion practice is reported to differ considerably between countries. Comparisons often rely on transfusion rates, incidence - or prevalence rates. In this paper, the one-year period prevalence rate (1-YPPR) of transfusion of red cells (RBC) is presented. Transfusion data, demographic data and patient data were retrospectively combined to calculate sex and diagnosis specific and age standardized 1-YPPR s of RBC transfusion for the complete population in a Danish county. During the calendar year of 2006, 4427 patients received RBC transfusion in Funen County. The crude 1-YPPR of RBC transfusion was 9.2/1000 citizens. Most of the transfused patients had a main diagnosis of neoplasm (22% of recipients), diseases of the circulatory system (15%), the digestive system (15%), injuries (13%) and diseases of the blood (8%). Age standardization reversed the relation between sex specific 1-YPPRs, yielding a statistically significantly higher 1-YPPR in males (6.8/1000) vs. females (6.3/1000). The method for calculating a diagnosis specific 1-YPPR of transfusion of RBC is presented and proposed as an option for comparison of transfusion practice with other transfusion centres. The crude and the diagnosis specific 1-YPPR s are found to increase with age. Thus, age standardization of crude prevalence rates is necessary for meaningful comparisons between populations.

A survey of the demographics of blood use

Epidemiological information was obtained by a series of questions to experts in the field of epidemiology of transfusion from the United States, England, Australia and Denmark. Although it became clear that the methods for collecting the data had differed between the countries, useful information was obtained for all questions. The data highlighted some major differences between the countries: the incident rate for red cell transfusion varied from 44.7 to 54.1 units, for platelets from 2.0 to 6.0 units and for plasma from 4.8 to 13.8 units transfused per 1000 population per year. Age and sex distribution of transfused patients was similar in all countries. Most of the red cell products are transfused to older recipients, and the distribution between men and women is approximately equal. The distribution for platelets is over a wider age range, and the difference between men and women is marked, with men predominating in all countries. The distribution for plasma is also directed to the elderly, and there is a predominance of men. The relationship between the disease or surgical procedure and the use of blood products was similar between countries. The use of red cells in cardiovascular surgery predominated. Neoplasms and digestive disorders were also prevalent. Neoplasms, including those relating to haematology, were the main use for platelets, but cardiovascular surgery was also important. In all countries, plasma is largely used in cardiovascular surgery. Two countries provided data relating to the number of units per transfusion episode including information relating to massive transfusion. In Australia, red cell use of >or=50 units per episode was largely associated with multiple traumas. In Denmark, it was associated with gastrointestinal bleeding and various medical requests.

A population-based binational register for monitoring long-term outcome and possible disease concordance among blood donors and recipients

BACKGROUND AND OBJECTIVES

Even with appropriate donor deferrals and advanced screening tests, the risk of disease transmission through blood transfusion cannot be completely disregarded. Efficient monitoring of possible disease transmission between blood donors and recipients should be an important component of a comprehensive haemovigilance system.

MATERIALS AND METHODS

We assembled the Scandinavian Donations and Transfusions (SCANDAT) database, with data on virtually all blood donors and recipients who have been registered at least once in any of the computerized local blood bank databases in Sweden and Denmark since the start of computerized registration in 1966. The records of these individuals, with their entire computerized donation and/or transfusion histories and all donor-component-recipient connections, were linked to nationwide population and health registers to attain essentially complete follow-up for up to 36 years regarding reproduction, hospital morbidity, cancer, and death.

RESULTS

After data cleaning, the database contained 1,134,290 blood donors who contributed 15,091,280 records of donations and 1,311,079 recipients who received 11,693,844 transfusions. The data quality in the existing data sources was satisfactory. From the data obtained from local blood banks, 4.6%, 1.6%, and 6.4% of the person, donation, and transfusion records, respectively, had to be discarded after review of the legitimacy of recorded values, and comparisons with independent, external databases.

CONCLUSION

It is possible to use existing computerized data, collected in routine health care, in haemovigilance systems for monitoring long-term outcome and disease concordance in blood donors and transfusion recipients.

Monitoring transfusion practice--a computerized procedure

As the description of transfusion practice over time requires the handling of massive amounts of data, and because the majority of records have until now been paper-based, little is known about the epidemiology of blood transfusion. Furthermore, most previous studies have collected data manually from patient records or from computerized registers created solely for study purposes. We describe a procedure for monitoring transfusion practices based exclusively upon the collection of data from the existing computerized registers. During the calendar years 1997 and 1998, more than 750 000 data records were collected from the blood transfusion registers, diagnosis and procedure registers, and clinical biochemistry registers at two university hospitals. Linking of the data required a unique and consistent identification of all data records. This was made possible by the national Personal Identification Number. In this way more than 98% of all transfusions could be identified and approximately 95% (77 950) could be connected to a principal diagnosis. The described procedure creates new opportunities for studies of transfusion practices both on a large scale and in richness of detail, and we propose to establish a network where transfusion practices data are available and comparable for individual departments, hospitals, whole regions, and possibly nations.

Monitoring transfusion practices at two university hospitals

BACKGROUND AND OBJECTIVES

Considering the clinical importance of blood transfusions, the limited knowledge of transfusion practices is remarkable. New methods are needed to elucidate the observed variation of transfusion practices.

MATERIALS AND METHODS

All patients transfused or pretransfusion tested (i.e. at risk for blood transfusion) at two tertiary teaching hospitals during the full years of 1997 and 1998 were included in the study.

RESULTS

The observed practices contained substantial variance at the level of hospitals. The contributions to the total variance of the different specialities were highly significant, as was the contribution of hospitals to the variance in plasma and platelet transfusions. Significant interactions between hospitals and specialities were observed in transfusion of red cells, plasma and platelets.

CONCLUSION

To our knowledge this is the first survey of this size to combine transfusions, diagnoses and biochemical tests, exclusively based on an existing computerized register. The aim is to establish a basis for comparison of local transfusion practices with other commensurate hospitals and regions at a national (and international) level.

Detection of irregular red cell antibodies: more than 3 years of experience with a gel technique and pooled screening cells

BACKGROUND AND OBJECTIVES

The purpose of this study was to evaluate more than 3 years of experience with a gel technique in combination with pooled screening cells for the detection of irregular red cell antibodies.

MATERIALS AND METHODS

Conventional serologic methods were used for blood typing, antibody screening and cross-matching until the end of 1992. We introduced the gel technique as a routine assay for antibody detection and identification in 1993.

RESULTS

After the tube technique had been abandoned, the number of false-positive antibody screening tests was reduced by 71%, positive antibody screening tests by 33%, enzyme agglutination by 100% and rouleaux reactions and cold-reacting antibodies by more than 50%. There was a 40% increase in first-time detection of clinically relevant antibodies. We saw no increase in delayed haemolytic transfusion reactions.

CONCLUSIONS

For the detection of irregular red cell antibodies, pooled screening cells in combination with a gel technique are at least as efficient and safe as a conventional tube technique with unpooled test cells.

The isolation and characterization of an insulin-releasing tetrapeptide from urines of patients with lipoatrophic diabetes

The tetrapeptide pyroGlu-Glu-Asp-GlyOH and its gamma-amide have been isolated from the urines of lipodystrophic patients with insulin-resistant diabetes. Both peptides induce insulin release only at high blood glucose levels.

A synthetic hexadecapeptide derived from allergen M imposing allergenic and antigenic reactivity

A solid phase synthesis (SPPS) hexadecapeptide corresponding to residues 49-64 of allergen M from cod was found to bind specifically IgE antibodies from sera of cod-allergic individuals. The SPPS peptide was similarly reactive in IgG-mediated reactions; it could interfere with Allergen M line precipitate in rocket-line immunoelectrophoresis, giving a distinct deflection. It is the only reported synthetic polypeptide imposing allergenic and antigenic reactivity. The hexadecapeptide is composed of two homologous tetrapeptides located at its terminai, tentatively concluded to be mutually critical for the immunological specificity. The data obtained confirmed the predicted reactivity of the Ca2+-binding CD loop of the intact Allergen M.

Patterns of peptides and protein-associated-peptide complexes in psychiatric disorders

Peptidic neurones may be considered as multisignal intergrators and transducers. When formation or release of peptide outstrips genetically determined breakdown capacity, overflow of peptides to the body fluids and urine may be expected. In this paper, pathological urinary chromatographic patterns of peptides are shown for genetic, functional and mixed disorders. Part symptoms of the disorders may be induced with the biologically isolated and purified peptides as well as with chemically synthesized peptides.

Cyclic peptides of sarcosine. Syntheses and conformation

A series of cyclic peptides of sarcosine with the general formula c-Sar-n, n=2-8, has been synthesized and conformational studies carried out both in solution and in the solid. The rings are conformationally very homogeneous and contain both cis and trans amide bonds. Their barriers to ring inversion are high; in the smaller rings this is attributed to steric hindrance, caused by the N-methyl-groups, whilst in the larger rings the folding of the chain in helical segments plays an important role.