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.

The efficacy of a malarial antibody enzyme immunoassay for establishing the reinstatement status of blood donors potentially exposed to malaria.

BACKGROUND AND OBJECTIVES: The two key objectives of the study were, first, to evaluate the sensitivity and specificity of a recombinant antigen-based malarial enzyme-linked immunoassay (EIA) and, second, to estimate the risk associated with implementing this test with a shortened cellular component restriction period (6 months rather than the standard 12-36 months) for blood donors with a malarial risk exposure. MATERIALS AND METHODS: Blood donors were recruited into four distinct groups [non-exposed (control), malarial area 'visitors', 'residents' and 'previous infection') and screened by using the Newmarket malarial antibody EIA. Assay specificity was evaluated in unexposed blood donors, and sensitivity was determined in acute clinical samples. RESULTS: No parasitaemic donors were detected amongst 337 malarial 'visitors' who had returned from a malaria-endemic area less than 6 months previously, or for 402 'visitors' or 'residents' who had returned from a malaria-endemic area more than 6 months previously. The incidence of malarial antibodies within the exposed blood donor groups was 1.33% (10/751). In acute clinical non-donor samples, the Newmarket EIA detected 106/108 (98.1; 93.5-99.5%) 'film' positive Plasmodium falciparum infections and 12/12 (100, 75.7-100.0%) P. vivax infections. The estimated additional risk exposure of the proposed new strategy was one infectious P. falciparum donation per 175 years or 1 per 4.2 years for P. vivax. CONCLUSIONS: The study findings support the efficacy and safety of a targeted screening strategy combining antibody screening with a 6-month cellular component restriction period for donors with a declared malarial risk.

Geographical distribution of hepatitis C virus genotypes in blood donors: an international collaborative survey.

The frequency of infection with the six classified major genotypes of hepatitis C virus (HCV) was investigated in 447 infected volunteer blood donors from the following nine countries: Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan. Viral sequences in plasma from blood donors infected with HCV were amplified in the 5'-noncoding region and were typed by restriction fragment length polymorphism analysis. Electrophoresis of DNA fragments produced by cleavage with HaeIII-RsaI and ScrFI-HinfI allowed HCV types 1 (or 5), 2, 3, 4, and 6 to be identified. Further analysis with MvaI-HinfI allowed sequences of the type 5 genotype to be distinguished from sequences of the type 1 genotype. Types 1, 2, and 3 accounted for almost all infections in donors from Scotland, Finland, The Netherlands, and Australia. Types 2 and 3 were not found in the eastern European country (Hungary), where all but one of the donors were infected with type 1. Donors from Japan and Taiwan were infected only with type 1 or 2, while types 1, 2, and 6 were found in those from Hong Kong. HCV infection among Egyptians was almost always by type 4. Donors infected with HCV type 1 showed broad serological reactivity with all four antigens of the second generation Chiron RIBA-2 assay (Chiron Corporation, Emeryville, Calif.), while infection with divergent HCV genotypes elicited antibodies mainly reactive to c22-3 and c33c. Reactivities with antibodies 5-1-1 and c100-3 were infrequent and were generally weak, irrespective of the geographical origin of the donor. Because the envelope region of HCV is even more variable than the NS-4 region, it is likely that vaccines based on these proteins need to be multivalent and perhaps specifically adapted for different geographical regions.

Differences in gene copy number carried by different MHC ancestral haplotypes. Quantitation after physical separation of haplotypes by pulsed field gel electrophoresis.

We have examined the hypothesis that MHC ancestral haplotypes have a specific content of genes regulating the extent of autoimmune reactions. Gene copy number was quantitated by objective densitometry after PFGE was used to separate heterozygous AHs of different lengths. Initially we analyzed examples of known gene copy number at the C4 and 21 hydroxylase loci and showed that the approach provides predictable results. We then studied heterozygotes containing one characterized and one uncharacterized AH with particular attention to the gene copy number at the C4, Cyp21, and DRB loci. Each AH studied has a characteristic gene copy number at each locus studied. The same may be true of TNF, but other possibilities must be considered. AHs are markers for extensive chromosomal segments including particular numbers of several functional genes. Since AHs mark susceptibility to autoimmune disease, differences in gene copy number may be implicated.

Influence of C4 null genes on infection with human immunodeficiency virus.

The hypothesis that complement is important in the host response to human immunodeficiency virus (HIV) was tested. Complement C4 and Bf allotypes were determined in 26 patients who fulfilled the diagnostic criteria for persistent generalised lymphadenopathy due to HIV, 72 homosexuals who were negative for antibody to HIV, and 185 control subjects drawn from the local population. HLA-A, B, and DR were also typed and the phenotypes examined for the presence of supratypes and C4BQ0. Eleven patients (42%) had C4B null alleles compared with only 13 (18%) homosexuals who were negative for antibody and 28 (15%) controls. From estimates of gene frequencies the difference between the patients with lymphadenopathy and the controls was significant after conservative correction. In the patients only a minority (six) of the C4B null alleles were contained within ancestral haplotypes. Together with the fact that C4 null alleles result in partial deficiency of C4, this finding suggests that products of complement genes are important in infection with HIV or its consequences, or both. A role is proposed for complement and Fc receptors.

C4 allotyping on plasma or serum: application to routine laboratories.

Allotypes of the fourth component of complement (C4) can be detected by electrophoresis and immunofixation after treatment of EDTA plasma with neuraminidase (NAse). We have assessed the value of additional treatment with carboxypeptidase B (CPseB). Following treatment with CPseB + NAse, each allele is resolved into a single band, permitting clear definition of overlapping bands seen following treatment with NAse alone. More importantly, C4 allotypes can be determined using stored heparinized plasma or serum. Most C4 null alleles can be assigned without requiring family studies. The approach described is suitable for routine use by tissue typing laboratories.

Comparison and standardization of measurement of anti-acetylcholine receptor antibody between laboratories.

The presence of autoantibodies to the acetylcholine receptor (anti-AChR) is useful in the diagnosis of myasthenia gravis, and their titre correlates with severity of the disease. Standardization of their measurement is therefore clinically important. Six laboratories world-wide were asked to determine anti-AChR under local conditions in coded samples and to repeat the measurement on the same samples recorded. There was a high degree of consensus over rank order of the samples but a wide systematic variation in the titres obtained. Standardization of units is an important next step in improving the comparability of anti-AChR data between laboratories.

The immunological detection of a 21-OH deficiency mutation HLA supratype.

Previous studies have shown that the late-onset and cryptic forms of 21-hydroxylase deficiency are highly associated with the HLA supratype HLA-B14,C4A2,C4B1/2,DR1. Since cells from a number of unrelated normal individuals from different ethnic backgrounds expressing the DR1 associated with this supratype failed to stimulate two different DR1-restricted T-cell clones that proliferated in the presence of most other DR1 cells, we decided to test the hypothesis that cells with this supratype express "abnormal" DR1 molecules that have been affected in some way by the chromosomal mutation responsible for B14,DR1-associated 21-hydroxylase deficiency (21-OH-defL). The results showed an association between "abnormal" DR1 and 21-OH-defL (elevated rates of 17 alpha-hydroxyprogesterone [17-OHP] increase and elevated peak 17-OHP values following ACTH stimulation). The presence of the B14,DR1 supratype can be used to predict the presence of "abnormal" DR1 and the clinical status of individuals not previously known to be 21-OH-defL carriers.

Family studies of IgA deficiency.

Seventeen immunoglobulin A (IgA)-deficient subjects and other members from 13 families were examined at HLA-A, B and DR, C4A, C4B, and Bf loci. Of the 29 independent haplotypes in the IgA-deficient subjects, 22 included deletions, duplications, or defects at the C4 or 21-hydroxylase loci. It is suggested that there may be a gene regulating serum IgA concentrations in this same region of chromosome 6. Three main supratypes explain most of the previously reported HLA associations with IgA deficiency. These are A1, Cw7, B8, C4AQ0, C4B1, BfS, DR3, Bw65(14), C4A2, C4B1/2, BfS, and Bw57(17), C4A6, C4B1, BfS. All three are proposed to carry a gene for IgA deficiency, while other supratypes carrying the same B allele generally do not. Other supratypes possibly associated with IgA deficiency were also identified. A survey of about 150 individuals with at least 1 of the 3 main supratypes revealed only 2 IgA-deficient subjects, and these were among the 20 that had 2 of these supratypes. This suggests the possibility of a recessive mode of inheritance, with penetrance determined by another factor which is not major histocompatibility complex-linked. All the supratypes found in this group of IgA-deficient subjects would then carry the putative recessive allele for IgA deficiency.

Association of IgA deficiency with HLA A28 and B14.

HLA typing was performed in two groups of individuals with low serum IgA concentrations. These consisted of 44 individuals identified from a blood donor clinic and 37 individuals attending an Immunology clinic with disorders associated with IgA deficiency. Both groups showed an increase in the frequency of HLA B14 (p less than 0.0001), HLA-A28 (P = 0.0007) and the combinations HLA-A1, B14 and HLA-A28, B14. The previously reported increase in HLA-A1, B8 was not apparent in either group. These data suggest that there is a gene within the human major histocompatibility complex which is relevant in IgA deficiency.

Arthritis associated with a crystallizing cryoprecipitable IgG paraprotein.

A crystallizing IgG-lambda cryoprotein was found in the synovial fluid of a patient with peripheral erosive arthritis and tenosynovitis. The same crystallizing paraprotein could be demonstrated in serum incubated at 4 degrees C, but its formation could be inhibited by the in vitro addition of D-penicillamine. Crystals were present in synovial tissue and appeared to be initiating an inflammatory reaction via complement activation. Slit lamp examination showed crystals in Bowman's membrane. Plasmapheresis led to temporary improvement in the synovitis and tenosynovitis.