Serological Groups Research Articles

Risk of Hepatitis-Related Mortality Increased Among Hepatitis C Virus/HIV-Coinfected Drug Users Compared With Drug Users Infected Only With Hepatitis C Virus

Progression of liver-related disease is accelerated in individuals coinfected with HIV and hepatitis C virus (HCV). Because the life expectancy of HIV-infected drug users (DUs) improved after the widespread use of highly active antiretroviral therapy (HAART), HCV-related death is likely to become more important. To disentangle the effects of HCV and HIV, we compared the overall and cause-specific mortality between HCV/HIV-infected DUs and HCV-infected DUs and DUs without HCV or HIV, followed up between 1985 and 2006. A total of 1295 participants in the Amsterdam Cohort Study were included. Cause-specific hazard ratios (CHRs) were estimated for the eras before (<1997) and since HAART (> or =1997) within and among serologic groups. The risk of dying decreased for most causes of death > or =1997; this decrease was not the same for the different serologic groups. Among HCV/HIV-coinfected DUs, the risk of hepatitis/liver-related death did not substantially change over time (CHR = 0.87, 95% confidence interval [CI]: 0.21 to 3.58), whereas the risk of AIDS-related mortality decreased. Compared with DUs solely infected with HCV, HCV/HIV-coinfected DUs were at increased risk of dying from hepatitis/liver-related disease (CHR = 7.15, 95% CI: 1.98 to 25.8), other natural causes (CHR = 3.09, 95% CI: 1.41 to 6.79), and nonnatural causes (CHR = 2.30, 95% CI: 1.07 to 4.95) in the HAART era. HCV/HIV-coinfected DUs remain at increased risk of dying from hepatitis/liver-related death in the HAART era compared with HCV-monoinfected DUs. This risk did not change in HCV/HIV-coinfected DUs after HAART was introduced, suggesting that in the HAART era, HIV continues to accelerate HCV disease progression. Efforts should be made to establish effective treatment for HCV infection in HCV/HIV-coinfected individuals.

Genetic Diversity of Infectious Hematopoietic Necrosis Virus from Feather River and Lake Oroville, California, and Virulence of Selected Isolates for Chinook Salmon and Rainbow Trout

Infectious hematopoietic necrosis virus (IHNV) is a significant pathogen of young salmonid fishes worldwide but particularly within the historical range of the Pacific Northwest and California. In the Sacramento and San Joaquin River drainages of California, IHNV outbreaks in juvenile Chinook salmon Oncorhynchus tshawytscha have been observed regularly at large production hatcheries, including Coleman National Fish Hatchery (established in 1941) and Feather River State Fish Hatchery (FRH; established in 1967), since facility operations began. Recent severe epidemics at the FRH in 1998 and 2000-2002 prompted investigations into the characteristics and potential sources of virus at this facility. Both phylogenetic analyses of a variable portion of the glycoprotein gene and serologic comparisons based on neutralization with three polyclonal rabbit sera were used to characterize 82 IHNV isolates from the Feather River watershed between 1969 and 2004. All isolates examined were in the L genogroup and belonged to one of three serologic groups typical of IHNV from California. The IHNV isolates from the Feather River area demonstrated a maximum nucleotide sequence divergence of 4.0%, and new isolates appeared to emerge from previous isolates rather than by the introduction of more diverse subgroups from exogenous sources. The earliest isolates examined from the watershed formed the subgroup LI, which disappeared coincidently with a temporal shift to new genetic and serologic types of the larger subgroup LII. Experimental challenges demonstrated no significant differences in the virulence for juvenile Chinook salmon and rainbow trout O. mykiss from selected isolates representing the principal types of IHNV found historically and from recent epidemics at FRH. While most isolates were equally virulent for both host species, one isolate was found to be more virulent for Chinook salmon than for rainbow trout.

Identification and characterization of three novel HLA alleles, HLA‐A*240214, HLA‐A*3215 and HLA‐DQB1*060302

We describe three novel human leukocyte antigen (HLA) alleles found in three different Caucasians, HLA-A*240214, HLA-A*3215 and HLA-DQB1*060302. As compared with HLA-A*24020101, HLA-A*240214 has a synonymous nucleotide (nt) exchange in codon 132. HLA-A*240214 may have arisen from intergenic recombination between HLA-A*24020101 and an HLA-B or HLA-C allele. The second novel allele, HLA-A*3215, has three nucleotide exchanges as compared with HLA-A*320101. These variations result in amino acid exchanges in codons 62 and 63, generating the public epitope of the serological HLA-A10 group. The third novel allele, HLA-DQB1*060302, has one synonymous nucleotide exchange within codon 38 as compared with HLA-DQB1*060301. In a family segregation study, we found that HLA-DQB1*060302, similar to the known HLA-DQB1*060301 allele, cosegregates with HLA-DRB1*1301.

Radiographic joint damage in early rheumatoid arthritis is highly dependent on body mass index

To investigate the association between body mass index (BMI) and radiographic joint damage (using the Ratingen Score [RS]) in early rheumatoid arthritis (RA). The study was carried out in 767 patients with early RA. Standard clinical data, RS, and BMI were evaluated at baseline and after 3 years. Multivariate logistic regression analyses were performed in rheumatoid factor (RF)-positive and RF-negative patients to determine the influence of BMI (<25 versus > or = 30 kg/m(2)) on considerable joint damage (RS > or = 7) after 3 years, adjusting for sex, age, disease duration, and disease activity (using the Disease Activity Scale in 28 joints [DAS28]). Patients of normal weight already had significantly more joint damage at study entry than obese patients (mean RS 4.5 versus 2.4; P = 0.004) and experienced significantly more progression than obese patients (RS 3.4 versus 1.3; P = 0.011). At 3 years, their RS score was twice as high as that of the obese patients (7.5 versus 3.7; P < 0.001). Multivariate regression analyses in both serologic groups revealed significantly higher odds of RS > or = 7 in RF-positive patients of normal weight than in RF-positive obese patients (odds ratio [OR] 3.3), but not in RF-negative patients. Male sex (OR 1.6), osteoporosis (OR 2.0), C-reactive protein levels >15 mg/liter versus <5 mg/liter (OR 2.6), and disease activity (DAS28 > or = 5.1 versus <3.2; OR 1.9) were independently associated with RS > or = 7. BMI provides a risk estimate of joint damage in RA patients. Further studies are needed to elucidate the association between BMI, RF, and joint damage in RA and the possible role of adipose tissue.

Phylogenetic relationships among sandfly fever group viruses (Phlebovirus: Bunyaviridae) based on the small genome segment

The phleboviruses are more diverse in terms of arthropod vectors and antigenic relationships than most other genera of arthropod-borne viruses. In this study, 30 sandfly fever group viruses from the Naples, Sicilian, Punta Toro, Icoaraci and Frijoles serocomplexes were sequenced. Phylogenetic analyses were performed based on the sequence of the open reading frame for the nucleoprotein (N) and non-structural (NSs) protein genes of the small (S) segment. The five resultant genotypic lineages correlated with the serological grouping and were similar to analysis of M segment sequences. The sequence identity for N and NSs genes within the Sicilian, Naples, Punta Toro, Icoaraci and Frijoles serocomplexes was determined. The results indicated that genetic divergence for the S segment is lower than that for the M segment, suggesting that the S segment is more stable during evolution.

The nature of recombination in HLA‐B*4207

The identification of the novel human leukocyte antigen (HLA)-B*4207 allele, which was found in a blood donor of Caucasian origin, is described. The sequence of the new allele differs from HLA-B*4201 in three nucleotide substitutions in exon 2, resulting in three consecutive amino acid (AA) exchanges at position 69, 70, and 71. AA positions 69 and 70 affect the peptide-binding site of the HLA molecule in the formation of pockets A, B, and C. Therefore, it is likely that the peptide-binding motif of HLA-B*4207 differs from the HLA-B*4201 motif. HLA-B*4207 exhibits a high level of structural homology to HLA-B*08 alleles as well as to HLA-B*4201. Rating of the AA variations of these alleles according to the AA distance matrix score gives the lowest overall matching score between the HLA-B*4207 and the HLA-B*0801 alleles, indicating a high functional similarity. To further address this, homology modeling was performed using B8 as the closest structural template. The portion of the molecule that is accessible to the T-cell receptor and antibodies is identical between B*4207 and B*0801. Under consideration of allele frequencies, close inspection of these sequences shows that the new allele is most likely a result of a recombination involving B*0702 and B*0801. Unfortunately, patient consent could not be obtained for retrospective serological typing to definitively determine whether B*4207 reacts in the B8 serological group.

Prenatal determination of the fetal RhD blood group by multiplex PCR: a 7‐year Portuguese experience

This is a retrospective study to evaluate the efficacy and accuracy of the multiplex polymerase chain reaction (PCR) amplification, for early detection of fetuses at risk for hemolytic disease, in the population living in Portugal, and to characterize the RhD-negative individuals at serologic and molecular level. 2030 uncultured amniotic fluid samples and 2012 blood samples from the respective RhD-negative pregnant women were studied by multiplex PCR of intron 3/intron 4, exon 7 and 3'UTR. Amniocentesis was performed for a variety of medical indications. For quality control, serologic RhD blood groups were determined in the cord blood, after birth. 1361 fetal amniotic samples were RhD-positive (67%), 669 were RhD-negative. The average time for diagnosis was 2 days for uncultured amniocytes and the molecular versus serologic RhD typing (n = 809) had 99.5% concordance. Among the 2012 serologic RhD-negative mothers, 26 had an RhD-positive allele. The multiplex PCR amplification used in this study was a rapid and accurate method to determine the RhD blood type in the population living in Portugal, being a great tool for management of pregnancies with fetuses at risk for alloimmune hemolytic disease. In this population, 1.3% of the serologic RhD-negative women have an RHD-positive allele.

Occult hepatitis B virus infection in the setting of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co‐infection: Clinically relevant or a diagnostic problem?

The clinical relevance of occult hepatitis B virus (HBV) infection, defined as detectable HBV DNA serum/liver, in the absence of hepatitis B surface antigen (HBsAg), is unclear. We determined the prevalence of serum occult HBV infection in HIV/HCV co-infected patients enrolled in APRICOT, a randomized multinational trial that investigated the efficacy and safety of peginterferon alfa-2a (40 kDa) plus ribavirin for treatment of HCV. We also examined the effect of prior HBV exposure to liver histology at baseline. Only HBsAg-negative patients were eligible. At screening, serum HBV DNA was assessed by commercial assay (detection limit = 200 copies/mL). Patients were divided into four serological groups: anti-HBs+/anti-HBc+; anti-HBs-/anti-HBc+; anti-HBs+/ anti-HBc-; anti-HBs-/anti-HBc-. Baseline liver biopsy grade and stage were compared among groups. Serum HBV DNA was undetectable in all patients, (n = 866). Results of anti-HBs and anti-HBc was available for 176 patients: 60 (34.1%) anti-HBs+/anti-HBc+; 60 (34.1%) anti-HBs-/anti-HBc+; 11 (6.3%) anti-HBs+/anti-HBc-; 45 (25.6%) anti-HBs-/anti-HBc-. There were no differences among the groups in the histological grade or stage at baseline liver biopsies. Occult HBV infection in serum was not detected in this large immunocompetent cohort. Moreover, prior exposure to HBV did not appear to have any affect on baseline liver histology.

An automatically curated MHC ontology for intelligent immunogenetic information retrieval (B42)

Abstract Accurate information retrieval of scientific articles is complicated by the intricacies of natural language. Ontologies are useful for formalizing scientific concepts and providing a foundation to mediate between formal, computationally accessible, representations and informal natural language expressions. The terminology associated with the MHC exemplifies the need for a sophisticated translation process between a natural language query and the relevant documents. For example, a researcher searching for “peptides that bind MHC” should be presented with a text containing “peptides were eluted from HLA-A2.” To achieve this goal, we have developed a multi-species MHC ontology which encompasses all human MHC alleles and serologic groups. Because of the rapid rate of new allele discovery, allele incorporation is automated using the IMGT/HLA and IPD-MHC databases. In the context of the StemNet knowledge management project, this MHC ontology contributes to machine-learning-driven text annotation, as well as to search-string interpretation and mapping. In this way, StemNet aims to offer researchers a platform to efficiently access the goldmine of clinically relevant immunogenetic information, which is otherwise inaccessible by standard search engines and databases. This work was financed by the Federal Ministry of Education and Research, Germany, funding number 01DS001C; the authors are solely responsible for content.

HLA Class II Polymorphisms Associated with The Physiologic Characteristics Defined by Traditional Chinese Medicine: Linking Modern Genetics with An Ancient Medicine

The aim of this study was to test whether human leukocyte antigen (HLA) polymorphism contributes to the physical constitutions classified in Traditional Chinese Medicine (TCM). Seven hundred six (706) individuals of the Han ethnic group inhabiting South China were classified into 7 TCM constitution groups, according to the criteria described in Theories of Physical Constitutions of Traditional Chinese Medicine, and the distributions of HLA-DRB1, DPB1, and DQB1 were investigated using the polymerase chain reaction-sequencing-based typing method. The allele frequencies of DPB1*0501 in the Yin-deficiency group, DRB1*09012 in the Phlegm-wetness group, and DQB1*03032 in the Qi-deficiency and Phlegm-wetness groups were significantly different from that of the corresponding alleles in the Normality constitution, suggesting those alleles might be group-specific alleles and thus related to a particular constitution. Based on our analysis of serological groups of HLA, the associations of DR*04 with the Blood-stasis group and DQ*09 with the Qi-deficiency and Phlegm-wetness groups were observed. This was the first study to systematically investigate the relationship between HLA and TCM constitution using a high-resolution typing technique. The results suggested a genetic basis for the classification of physical constitution in TCM. This study laid the foundation, for the first time ever, toward gaining insight into the theory of traditional medicine using modern biological approaches.

Évolution des formes moléculaires de l'antigène spécifique de la prostate chez des groupes sérologiques de patients atteints de pathologies prostatiques

The prostate-specific antigen (PSA) is a human tissular kallikrein used as serum tumoral marker of prostate cancer. The Total PSA and its molecular forms were detected at several different proportions in both patients with benign prostatic hyperplasia (BHP) and patients with prostate cancer (PCa). The purpose of the present study was to measure the total PSA in patients with these pathologies and to analyse the free PSA's evolution in each pathology group. Serums were taken from 90 patients with BHP and 23 with PCa. The DPC Immulite assays was used to determine total PSA and free PSA levels. The cut-off total PSA was 4 ng/ml. On a second hand were revelled that total PSA levels were variable in both BPH and PCa patients considering cut-off value. We showed that for BPH patients, 47 out of 90 present total PSA levels between 4–20 ng/ml, 6/90 between 20–100 ng/ml and 2/90 between 10–500 ng/ml. For PCa patients, 6 out of 23 present total PSA levels lower than 4 ng/ml. While, 2/23 of them between 4–20 ng/ml, 11/23 between 20–100 ng/ml and 4/23 between 100–900 ng/ml. Each serological group present a characteristic distribution of free molecular form of PSA, free PSA, marked by progressive free PSA level in related with total PSA. This individual concentration is variable in groups of patients having PSA levels higher than 20 ng/ml. The analysis of percentage free PSA/total PSA in each group of patient's showed characteristic percentages with a significant difference between BHP and PCa patients essentially in group with total PSA level between 4–20 ng/ml ( P = 0,0004), followed a less significant difference less for the group with total PSA between 0–4 ng/ml. Differences are not significant in groups patient's with total PSA higher than 20 ng/ml.

Transmission of Toxoplasma gondii in an urban population of domestic cats ( Felis catus)

Toxoplasma gondii is a protozoan parasite that infects humans and animal species worldwide. The relative importance of each potential transmission route in the complex life cycle of this coccidia is largely unknown, due to the lack of studies taking into account all routes simultaneously. In this study, we analyzed the transmission of T. gondii in an urban population of stray cats captured between 1993 and 2004. Analyzing prevalence, our aim was to determine which factors influence transmission in this population. Specific anti- T. gondii IgG antibodies were detected using the modified agglutination test. Firstly, we analyzed the kinetics of antibody titers in cats captured several times, using mixed linear models and correspondence analysis. We showed that antibody titers did not vary significantly with time and that titer 40 was the best threshold to separate individuals into two serological groups. Overall, prevalence was only 18.6%, thus transmission of T. gondii is infrequent in this population. As expected, a highly significant association was detected between age and presence of IgG antibodies. Prevalence was lowest in kittens aged 3–4 months, suggesting that newborn kittens may carry maternal antibodies and that vertical transmission is rare. After taking into account the effect of age, logistic regression showed that antibody carriage was related to factors that possibly related to the survival of oocysts: localization in the study site, origin of the cats, maximal temperatures and rain. Our results suggest that in this population, vertical transmission is rare, low predation limits prevalence, and oocyst survival is a determining factor in the risk of infection. We discuss the more general importance of conditions determining oocyst survival in the life cycle of T. gondii.

Characterization of Edwardsiella tarda strains isolated from turbot, Psetta maxima (L.)

The biochemical, serological and molecular characteristics of a group of 21 Edwardsiella tarda strains isolated from turbot, Psetta maxima, in two different areas of Europe were analysed and compared with a total of 13 strains of this bacterial species with different geographical and host origins. All the turbot isolates were biochemically identical to the E. tarda strains included as reference. The use of different techniques including microagglutination, dot blot and Western blot of lipopolysaccharides allowed us to determine that all the turbot isolates constitute an homogeneous and distinctive serological group. Genetic analysis by randomly amplified polymorphic DNA (RAPD) analysis demonstrated that although the E. tarda strains from turbot were compiled in a unique group using the primers P3 and P6, two clonal lineages could be detected when oligonucleotides P4 and P5 were employed.

Clinical Relevance of Different IgG and IgM Serum Antibody Responses to Borrelia burgdorferi After Antibiotic Therapy for Erythema Migrans

To investigate the kinetics of anti-Borrelia burgdorferi antibodies for a minimum of 1 year after antibiotic therapy in patients with erythema migrans (EM) and to correlate antibody titer kinetics with clinical variables. Retrospective study of serial anti-B burgdorferi antibodies in correlation to clinical variables. University-based hospital. One hundred thirteen patients with EM. Pretreatment and a median of 4 consecutive posttreatment serum samples from median follow-up of more than 400 days were simultaneously investigated for anti-B burgdorferi IgG and IgM antibodies. Semiquantitative titers were plotted to identify different groups of antibody kinetics. Individual patients were then stratified to those groups according to their antibody development. A statistical comparison of clinical and therapy-related characteristics among the serologic groups was performed. Anti-B burgdorferi IgG and IgM antibody titers developed in 3 distinct courses: persistent positivity across follow-up (IgG: 12 patients, 11%; IgM: 14, 12%), persistent negativity (IgG: 63, 56%; IgM: 47, 42%), and decrease of a positive pretreatment titer to a negative titer approximately 5 months after therapy (IgG: 34, 30%; IgM: 49, 43%). Statistics revealed significant correlations only between persistent positive IgG titers and long disease duration or large EM lesions before therapy. Long duration or large size of EM before therapy correlates with persistence of a positive anti- B burgdorferi IgG antibody titer after therapy. Serologic profiles do not depend on the type or duration of therapy or the clinical course thereafter. Thus, antibody testing in the follow-up of patients with EM is inappropriate for the assessment of therapeutic response.

Diversity of MICA and Linkage Disequilibrium with HLA-B in Two North American Populations

The MICA gene has a high degree of polymorphism. Allelic variation of MICA may influence binding of these ligands to the NK cell receptor NKG2D and may affect organ transplantation and/or disease pathogenesis. Knowledge of the population distribution of MICA alleles and their linkage disequilibrium (LD) with class I human leukocyte antigen (HLA) will enhance our understanding of the potential functional significance of the MICA polymorphism. In the present study, we characterized the MICA and HLA-B polymorphisms in two North American populations: European and African. The individual racial groups showed rather limited variation at the MICA locus, where the same set of three most common alleles, MICA*00201, *004, and *00801, account for 64 and 71% of the allele frequency in European-Americans and African-Americans, respectively. Other common alleles (allele frequency >5% in a population) include MICA*00901 and *010. MICA alleles showed strong linkage disequilibrium with HLA-B. Typically, a common MICA allele has strong LD with several HLA-B alleles, whereas most HLA-B alleles and their related serological groups are associated with a single MICA allele. The lack of evidence for an active diversification of the MICA gene after racial separation indicates an evolutionary history distinct from that of the classical HLA genes.

SARS Coronavirus, but Not Human Coronavirus NL63, Utilizes Cathepsin L to Infect ACE2-expressing Cells

Viruses require specific cellular receptors to infect their target cells. Angiotensin-converting enzyme 2 (ACE2) is a cellular receptor for two divergent coronaviruses, SARS coronavirus (SARS-CoV) and human coronavirus NL63 (HCoV-NL63). In addition to hostcell receptors, lysosomal cysteine proteases are required for productive infection by some viruses. Here we show that SARS-CoV, but not HCoV-NL63, utilizes the enzymatic activity of the cysteine protease cathepsin L to infect ACE2-expressing cells. Inhibitors of cathepsin L blocked infection by SARS-CoV and by a retrovirus pseudotyped with the SARS-CoV spike (S) protein but not infection by HCoV-NL63 or a retrovirus pseudotyped with the HCoV-NL63 S protein. Expression of exogenous cathepsin L substantially enhanced infection mediated by the SARS-CoV S protein and by filovirus GP proteins but not by the HCoV-NL63 S protein or the vesicular stomatitis virus G protein. Finally, an inhibitor of endosomal acidification had substantially less effect on infection mediated by the HCoV-NL63 S protein than on that mediated by the SARS-CoV S protein. Our data indicate that two coronaviruses that utilize a common receptor nonetheless enter cells through distinct mechanisms.

Allelic and haplotypic diversity of HLA‐A, ‐B, ‐C, ‐DRB1, and ‐DQB1 genes in the Korean population

High-resolution human leukocyte antigen (HLA) typing exposes the unique patterns of HLA allele and haplotype frequencies in each population. In this study, HLA-A, -B, -C, -DRB1, and -DQB1 genotypes were analyzed in 485 apparently unrelated healthy Korean individuals. A total of 20 HLA-A, 43 HLA-B, 21 HLA-C, 31 HLA-DRB1, and 14 HLA-DQB1 alleles were identified. Eleven alleles (A*0201, A*1101, A*2402, A*3303, B*1501, Cw*0102, Cw*0302, Cw*0303, DQB1*0301, DQB1*0302, and DQB1*0303) were found in more than 10% of the population. In each serologic group, a maximum of three alleles were found with several exceptions (A2, B62, DR4, DR14, and DQ6). In each serologic group exhibiting multiple alleles, two major alleles were present at 62-96% (i.e. A*0201 and A*0206 comprise 85% of A2-positive alleles). Multiple-locus haplotypes estimated by the maximum likelihood method revealed 51 A-C, 43 C-B, 52 B-DRB1, 34 DRB1-DQB1, 48 A-C-B, 42 C-B-DRB1, 46 B-DRB1-DQB1, and 30 A-C-B-DRB1-DQB1 haplotypes with frequencies of more than 0.5%. In spite of their high polymorphism in B and DRB1, identification of relatively small numbers of two-locus (B-C and DRB1-DQB1) haplotypes suggested strong associations of those two loci, respectively. Five-locus haplotypes defined by high-resolution DNA typing correlated well with previously identified serology-based haplotypes in the population. The five most frequent haplotypes were: A*3303-Cw*1403-B*4403-DRB1*1302-DQB1*0604 (4.2%), A*3303-Cw*0701/6-B*4403-DRB1*0701-DQB1*0201/2 (3.0%), A*3303-Cw*0302-B*5801-DRB1*1302-DQB1*0609 (3.0%), A*2402-Cw*0702-B*0702-DRB1*0101-DQB1*0501 (2.9%), and A*3001-Cw*0602-B*1302-DRB1*0701-DQB1*0201/2 (2.7%). Several sets of allele level haplotypes that could not be discriminated by routine HLA-A, -B, and -DRB1 low-resolution typing originated from allelic diversity of A2, B61, DR4, and DR8 serologic groups. Information obtained in this study will be useful for medical and forensic applications as well as in anthropology.

Tetragametic chimerism detected in a healthy woman with mixed‐field agglutination reactions in ABO blood grouping

The case of a healthy woman with serologic blood group AB and her biologic father showing blood group O was investigated. Further analysis, including blood, buccal swabs, and nail clippings, revealed a tetragametic chimerism. Blood grouping was performed with standard gel centrifugation test cards, ABO genotyping by sequence-specific primers (SSPs) and sequence-based typing, and HLA Class I and II typing by standard NIH cytotoxicity testing and SSP. Additionally, short-tandem-repeat (STR) and variable-number tandem-repeat (VNTR) typing was performed on blood, nail clippings, and buccal swab samples. The karyotype was analyzed by G-banded chromosomes. The proposita's RBCs were typed AB with a mixed-field agglutination whereas in molecular typing A, B, and O alleles were found. One paternal and two maternal haplotypes were determined by use of HLA typing. Interestingly, both paternal alleles were detected in 4 of 23 tested STR and VNTR loci only, with whole blood, nail clippings, and buccal swabs. The karyotype was identified as 46XX. The family members including the proposita's healthy twin children displayed no abnormal findings in tests performed. By investigation of DNA polymorphisms, it was possible to determine a rare case of tetragametic chimerism being the result of double parental contribution of nuclei.

Nomenclature for factors of the HLA system, 2004

Nomenclature for factors of the HLA system, 2004

Usefulness of a new immuno‐radiometric assay to detect hepatitis C core antigen in a community‐based population

A new immuno-radiometric assay (IRMA) to detect hepatitis C virus (HCV) core antigen (HCVcAg) has been developed. The aim of the present study was to investigate the sensitivity and specificity of this IRMA to measure HCV antigenemia, based on the detection of HCV RNA as the gold standard, and to assess the utility of the IRMA in a community-based population. Anti-HCV positive residents in a hyperendemic area of HCV infection in Japan were studied. Serum levels of HCVcAg were measured using IRMA, and the presence of HCV RNA was determined by a qualitative reverse transcription-polymerase chain reaction (RT-PCR) assay. The sensitivity and the specificity of the IRMA were 96.4 and 100%, respectively. The sensitivity of the IRMA was similar between serological HCV group I (HCV genotypes 1a and 1b) (97.6%) and group II (HCV genotypes 2a and 2b) (94.0%). There was a strong correlation between serum HCVcAg level and HCV-RNA measured by a quantitative RT-PCR (r = 0.832, P < 0.0001). There also was a very strong correlation of HCVcAg level between IRMA measurements performed on serum and those performed on plasma (r = 0.984, P < 0.0001). In conclusion, this new IRMA is useful for the detection of HCV core antigen in a community-based population.