Linkage disequilibrium between HLA-G*0104 and HLA-E*0103 alleles in Tswa Pygmies

Nonclassical human leukocyte antigen (HLA)-G and -E loci are separated by approximately 660 kb on the short arm of chromosome 6. Interestingly, some functional and expression characteristics are relatively identical or associated for both molecules. For example, expression of HLA-E on the cell surface has been linked to preferential binding of nonameric leader peptides derived from the signal sequence of HLA-G. It has been suggested that these two molecules act synergistically in modulating susceptibility to infectious or chronic inflammatory diseases. A possible explanation for these observations is that HLA-E and HLA-G are evolving under analogous selective pressures and have functions that place them under selective regimes differing from classical HLA genes. The purpose of this study was to investigate the consistency of this hypothesis based on the characterization of the molecular polymorphism of these two genes and their linkage disequilibrium (LD) in three populations, i.e. Southeastern French (n = 57), Teke Congolese (n = 84) and Tswa Pygmies (n = 74). Allelic frequencies observed for HLA-G and HLA-E and for 14-bp ins/del polymorphism in the three populations were similar to those observed in the literature for populations from corresponding geographic areas. Only one of the recently described HLA-G polymorphisms (HLA-G*01:07-01:16) was found, i.e. HLA-G*01:15 in one individual from Congo. We showed that two haplotypes in Tswa Pygmies, i.e. HLA-G*01:04-E*01:03:01 and G*01:04-E*01:01, exhibited highly significant positive and negative D' values respectively. Although these LD could have functional implications, it is more likely because of the genetic drift as the two other populations did not display any significant LD.

[Reorganization of blood watch and transfusion safety activities in the Marseille public hospital system in partnership between the French Blood Institute Alps Mediterranean Division (EFS AM)]

The Marseille public hospital system (APHM) has expressed its willingness to pool its services of immunohematology and delivery of labile blood products with those of the French blood institute Alps Mediterranean division (EFS AM). An agreement setting out the terms of this partnership was signed between the two parties. The users of the APHM and EFS AM blood watch wished to preserve the channels of distribution. Implementation of this reorganization has focused on ensuring transfusional safety, reinforcing harmonization of APHM practices, and finding ways to reduce costs. Despite joint information campaigns (to medical and paramedical personnel) carried out by the APHM and EFS AM blood watch, problems have arisen during start-up and adjustments have been necessary on both sides. The success of this project hinges on the involvement of the EFS AM in our transfusional practices, deployment of a system for diffusion of information, and consolidation of physical and human resources at the level of the APHM blood watch.

HLA-DRB1 frequencies of the Comorian population and their genetic affinities with Sub-Saharan African and Indian Oceanian populations

BACKGROUND

Ethnic-historic sources have considered the Comorian population to be the result of an amalgamation of African, Arabian and Southeast Asian groups.

AIM

This study seeks to determine the genetic relationships and contributions from Sub-Saharan Africa and Indian Oceania and to reconstruct past migration events.

SUBJECTS AND METHODS

The human leukocyte antigen (HLA) polymorphism of a Comorian population was described and analysed.

RESULTS

Genetic distances and multidimensional scaling analyses showed complex patterns of genetic differentiation in the Indian Oceanian area as a result of continuous gene flow occurring within the past approximately 2500 years. Nevertheless, the Comorian genetic pool appears to be a mix of Bantu-speaking and Arab populations as testified to by admixture estimations of almost 50-60% and 27-33%, respectively.

CONCLUSION

The Comorian population may represent the eastern limit of the recent and massive eastward Bantu expansion. In contrast to the population from Madagascar (Merina), only a restricted influence of Austronesian populations was found.

Use of the PSA enhancer core element to modulate the expression of prostate- and non-prostate-specific basal promoters in a lentiviral vector context

Composite promoters combining the prostate-specific antigen (PSA) enhancer core element with promoter elements derived from gene coding for human prostate-specific transglutaminase gene, prostate-specific membrane antigen gene, prostate-specific antigen, rat probasin or phosphoglycerate kinase were characterized for their ability to specifically express the enhanced green fluorescent protein (EGFP) gene in prostate versus non-prostate cancer cell lines when transferred with a human immunodeficiency virus-1-based lentiviral vector. By themselves minimal proximal promoter elements were found to inefficiently promote relevant tissue-specific expression; in all the vectors tested, addition of the PSA enhancer core element markedly improved EGFP expression in LnCaP, a cancer prostate cell line used as a model for prostate cancer. The composite promoter was inactive in HuH7, a hepatocarcinoma cell line used as a model of neighboring non-prostate cancer cells. Among the promoters tested, the combination of the PSA enhancer and the rat probasin promoter showed both high specificity and a strong EGFP expression. Neither a high viral input nor the presence of the cPPT/CTS sequence affected composite promoter behavior. Our data suggest that composite prostate-specific promoters constructed by combining key elements from various promoters can improve and/or confer tissue specific expression in a lentiviral vector context.

Distribution of killer-cell immunoglobulin-like receptor (KIR) in Comoros and Southeast France

Killer-cell immunoglobulin-like receptors (KIRs) expressed by natural killer cells are cell surface molecules able to recognize groups of HLA class I alleles. The number and distribution of KIR genes vary among individuals and populations. The aim of this study is to analyse the KIR gene content in a Comorian population in order to investigate genetic relationships with other populations and to reconstruct past migration events. The Comorian population consisted of 54 unrelated immigrants living in France and a control population consisted of 38 individuals from Southeast France. We investigated the presence or absence of 15 KIR genes, two pseudogenes expressed and non-expressed forms of KIR2DL5 and the two major subtype full-length and deleted forms of KIR2DS4. All individuals were typed positive for the framework genes, i.e. KIR2DL4, KIR3DL2 and KIR3DL3, and the two pseudogenes KIR3DP1 and KIR2DP1. The frequencies of full-length KIR2DS4 (*00101/00102/002) were lower in the French population (F = 29%) than in the Comorian population (F = 72%) (P(c) < 0.05). No significant differences were found for other KIR genes. A total of 11 genotypes were identified in the Southeast French population and 22 genotypes in the Comorian population. The most common genotype (2DL1, 2DL3, 2DL4, 3DL1, 3DL2, 3DL3 and 2DS4) accounted for 41% in the Comorian population and 34% in the Southeast French population. Principal component analysis using KIR gene data from 20 populations was performed to determine genetic differences and relations between populations. The Comorian population exhibited closest kinship with Africans and Asians. As KIR gene content is heterogeneous among ethnic groups, it can probably be used to assess the genetic relationships among populations from different geographic areas.

Sequence family variant loss from the AZFc interval of the human Y chromosome, but not gene copy loss, is strongly associated with male infertility

BACKGROUND

Complete deletion of the complete AZFc interval of the Y chromosome is the most common known genetic cause of human male infertility. Two partial AZFc deletions (gr/gr and b1/b3) that remove some copies of all AZFc genes have recently been identified in infertile and fertile populations, and an association study indicates that the resulting gene dose reduction represents a risk factor for spermatogenic failure.

METHODS

To determine the incidence of various partial AZFc deletions and their effect on fertility, we combined quantitative and qualitative analyses of the AZFc interval at the DAZ and CDY1 loci in 300 infertile men and 399 control men.

RESULTS

We detected 34 partial AZFc deletions (32 gr/gr deletions), arising from at least 19 independent deletion events, and found gr/gr deletion in 6% of infertile and 3.5% of control men (p>0.05). Our data provide evidence for two large AZFc inversion polymorphisms, and for relative hot and cold spots of unequal crossing over within the blocks of homology that mediate gr/gr deletion. Using SFVs (sequence family variants), we discriminate DAZ1/2, DAZ3/4, CDY1a (proximal), and CDY1b (distal) and define four types of DAZ-CDY1 gr/gr deletion.

CONCLUSIONS

The only deletion type to show an association with infertility was DAZ3/4-CDY1a (p = 0.042), suggesting that most gr/gr deletions are neutral variants. We see a stronger association, however, between loss of the CDY1a SFV and infertility (p = 0.002). Thus, loss of this SFV through deletion or gene conversion could be a major risk factor for male infertility.

Analysis of ABO discrepancies occurring in 35 French hospitals

BACKGROUND

The risk of immunohemolytic reaction owing to ABO-mismatched mistransfusion is 100 to 1000 times higher than the risk of viral infection. Like analysis of incident reports, evaluation of near-miss events can provide useful insight into hazardous situations for mis-matched blood transfusion. The aim of this prospective study was to assess the incidence and root causes of all ABO discrepancies, detected by a central hematology laboratory, in blood samples referred from 35 district hospitals.

STUDY DESIGN AND METHODS

ABO discrepancies were detected by comparing either two current blood specimens or a current and historical specimen collected over a 5-year study period. Discrepancies were investigated by retyping new samples, checking sample identification, and reviewing previous hospital records.

RESULTS

A total of 118 ABO discrepancies were discovered in a series of 407,769 tests carried out during the study period. The incidence of ABO discrepancies was 1 per 3,400. This figure was 10 times higher than the incidence of ABO-mismatched transfusions. Most of these ABO discrepancies were due to phlebotomy errors, that is, collection from wrong patient. The second most common cause involved clerical errors during patient registration or identification.

CONCLUSION

ABO discrepancies can result from errors made not only by the medical staff during phlebotomy but also to by the clerical staff during registration and identification. These findings emphasize the need to standardize data transmission between health care personnel.

[Suspicious pigmented skin lesions. Screening campaign by occupational physicians in the Provence-Alpes-Côte d'Azur region]

OBJECTIVE

Cutaneous melanoma prevention has become a public health issue. The incidence of this cancer has been steadily growing for 50 years, and the related death ratio is not decreasing. Today, the surgical resection of a thin lesion is the only validated curative treatment. The early detection of melanoma represents a major line in the management of such tumours.

METHODS

Occupational physicians of the PACA area were invited to participate in a campaign for the screening of pigmented suspect cutaneous lesions for 2 years. Voluntary physicians were trained to use the ABCDEF diagnostic criterion. Lesions were detected during regular yearly consultations (1998/1999) and the data concerning the development and care of these lesions was collected during consultations over the following year (1999/2000).

RESULTS

Two hundred and fifty occupational physicians of the PACA area participated in the campaign. Two pre-cancerous lesions and 10 cancers (5 melanoma and 5 pigmented basocellular carcinoma) were found among the 487 suspect lesions detected. Each melanoma had a Breslow score of less than 0.9 mm and were of good or even excellent prognosis.

CONCLUSION

The cutaneous examination, although rapid, during the occupational medicine consultations, is an effective means of detecting the early onset tumoral lesions which, at that stage may potentially be cured. The ABCDEF criterion is a useful diagnostic tool and should be taught to the all the medical and paramedical staff.

[External quality evaluation]

Since ten years, the immunohaematology working group of the French Society of Blood Transfusion has organized a quality control. Tests concern essentially the screening and identification of irregular antibodies, direct antiglobulin tests and elutions.

[Problem-solving in immunohematology: direct compatibility laboratory test ]

Cross-matching between the serum of a patient and the red blood cells to be transfused is most important for the prevention of hemolytic transfusion reactions in allo-immunized or new-born patients found positive with direct antiglobulin test. Cross-matching is a time-consuming and complex laboratory test. In order to obtain valid results, it is necessary to abide by some technical rules detailed in this article. The choice of the blood units to be cross-matched depends on the patient's clinical story and on the specificity of anti-erythrocyte antibodies present in the serum. The identification and the management of most frequent difficulties met by using the cross-match technique are discussed hereby.

[Impact of the removal of A2 test erythrocytes and the anti-AB reactant on the interpretation of the ABO blood grouping]

This work evaluates the impact of the removal of the anti-AB reagents and A2 test-red blood cells on the interpretation of ABO blood grouping. The first step of the work was a multicentric study concerning the interpretation of "all coming" blood groupings, reporting the results of 105 195 ABO blood groupings of donors and patients carried out on microplates using an automated or a half-automated technique. Their interpretation was performed following four different methods, in order to appreciate the impact on the results of the removal of either anti-AB test-serum, A2 test-red blood cells, or the combination of both. Moreover, a qualitative and quantitative analysis of the interpretations of the blood groupings that were initially not performed (rejections), was carried out in order to determine the most often implied reagent and to quantify a possible gain in interpretation after removing it. A complementary study of the same type concerning more specifically weak ABO phenotypes was carried out to evaluate, in terms of sanitary risks, the consequences of a possible non-interpretation of these phenotypes in patients who would be potential receivers of blood cell products, and in blood donors.

[Immune safety in blood transfusions]

Immune security of blood donation is defined by all means aiming at reducing or eliminating the immune risk related to blood donation. It concerns the whole transfusion process from the blood donor to the receiver. The immune risk of blood donation is directly related to the polymorphism of molecular and cellular blood groups systems. Immune security consists in avoiding the meeting of antigens and augmented by the direct baneful consequences of the immune conflict. This requires the previous immune characterisation of blood products and of the patients and of their compatibility, which must be strongly maintained along the transfusion process. To control this process, which is still too much deficient, represents the true guarantee of immune security of blood donation.

[Methodology for the development of a program for following and maintaining the competency of human resources]

The progressive introduction of a management program for the maintenance and assessment of staff competence has also focussed attention on the human factor, a major consideration in risk management and quality control. This article has examined the relevant tools and practical means of application, and proposes a methodology combining a methodical analysis of processes with the determination of the minimal knowledge required for participation in the practical and theoretical training programs that provide a means of objective evaluation. The results obtained in terms of technical, organizational and cultural impact have also been analyzed.

Decision aides in immunohematology: detection of anti-erythrocyte antibodies

Detection and identification of irregular red-cell antibody in the serum or plasma of a patient is of prime importance for the prevention of hemolytic transfusion reactions and the biological supervision of the hemolytic disease of the foetus or the newborn. Practice in these tests is replete with complex biological problems. Using problem solving strategies, we discuss the recognition and resolution of the most frequent difficulties encountered in red cell antibody identification.

HLA-DRB1 and DQB1 polymorphisms in southern France and genetic relationships with other Mediterranean populations

This study presents the results of HLA-DRB1 and DQB1 sequence-specific oligonucleotide probe (SSOP) typing for a population sample of 181 individuals originating from southern France. On the basis of allele and haplotype frequencies, we compared our population with others from the Mediterranean area. Allele frequencies are comparable to those found in other western European populations (France, Portugal, Spain) and indicate neighboring exchanges. The haplotype frequencies showed relationships with North Africans and Jewish populations, as well as the common origin of Moroccan and Lebanese Jews. Therefore, allele frequencies seem to be more able to show recent exchanges while haplotype frequencies might show ancestral relationships. These results may serve as references for future studies of HLA and disease in southern France.

[Analytical validation in erythrocyte immunohematology]

In a transfusional or foeto-maternal context, hemolysis by incompatibility due to anti-erythrocyte antibodies (regular or irregular) remains the most frequent and most serious immunological risk in the receiver. In order to prevent this risk, a number of actions must be taken, such as the realization of the immunohematologic analyses for which the methodological practices have been legislated because of their serious clinical consequences. Several elements play a role in the reliability of the analyses and their results: the selection of the reagents and their validation in the routine technique used; the validation of reception; the controls involved in secondary preparations (e.g., blood cells reagent); and the daily internal controls. All this requires the choice of adapted controls and the management of possible anomalies.

[Evolving methods in immunohematology]

The immunogenic nature of erythrocyte polymorphism is in variance with the incompatible transfusion. Indeed, the fixing of an antibody on the corresponding antigen generally condemns the cell concerned with its destruction. Therefore, in order to ensure the immunohemolytic safety of the transfusions, it is necessary to avoid an in vivo encounter between antigens and antibodies, whose feasibility study in vitro is a determining element. Because of the requirement standards of such analyses and the preoccupation with the continuous improvement of transfusion safety, the evolution of the methods used in immunohematology is a constant concern for all those involved in the process. Thus, during the last few years, new technologies have been introduced which aim at improving performance and sometimes implementing alternatives to agglutination. This improvement is not limited to the search for an overall increase in specificity-sensitivity; it also takes into account the capability to detect "the clinically significant" as well as the limitations of human reliability, which justifies the introduction of automation and computerization. The whole of these methodological evolutions associated with that of the performance of reagents, legitimate the need to reconsider the realization of erythrocyte typing and the search for anti-erythrocyte antibodies.

[Problem-solving in immunohematology: interpretation of ABO typing and its difficulties]

Practice in immunohematology is replete with complex problems that require practitioners' problem-solving performance. In immunohematology, the acquisition of the reasoning process and necessary skills for making clinical decisions is based on teaching problem-solving strategies which potentially reduce errors and improve patient outcome. We discuss the recognition and resolution of the common causes of discrepancies in ABO typing results using problem-solving strategies.

[Data interchange in blood transfusion: the impact of a new standard on the evolution of health electronic data exchange in France]

The sanitary and social data interchange within care establishments or networks is today the subject of many national or international considerations. Electronic data interchange in the health field has characteristics linked to ethical and deontological principles of care staff. Used daily, this tool contributes to the quality of care, to the optimization of patient treatment and to the organization of the system care. In the transfusion field, the standardization of messages related to the traceability of blood products in now required by the No. 2 instruction of French Blood Agency, which rules the using of national norms elaborated by the French Agency of Normalization. If the technicality is the greater part of these regulated and formalized messages, this standardization systematizes and justifies the nominative and ciphered data interchange in an open environment, opening a new dimension in the interoperability of data system between care establishments. This article analyzes the characteristics and the potential impact of this normalization on the evolution of the electronic data interchange in the health field.

[Numeric terminology of erythrocyte blood group antigens]

Since the discovery of the first human blood groups, the terminology for erythrocyte blood group antigens has evolved and become inconsistent. In some cases, a single letter is used (eg, A/B, E/e), in some others a symbol with a superscript to denote allelic products is used (eg, Fya/Fyb, Jka/Jkb) while in still others, a numerical notation is used (eg, Fy3, Lu4, K11). Even within the same blood group system, antigens have been named by different terminology (eg, K/k, Kpa/Kpb, K11/K17) and the same antigen was given different names in different laboratories. Therefore a necessary alternative 'popular' terminology was suggested by the ISBT (International Society of Blood Transfusion) Working Party; In its last monograph, published in 1995 and reviewed in 1996, erythrocyte blood group antigens are classified into 23 systems, 5 collections and 2 series. The Working Party also suggested guidelines for establishing new blood group systems and including new specificities into the nomenclature.