Immunostimulant properties of full-length and truncated Marinobacter algicola flagellins, and their effects against viral hemorrhagic septicemia virus (VHSV) in trout.

Adjuvants that would help optimize fish vaccines against bacterial and viral pathogens are highly demanded by the aquaculture sector. Flagellin has been proposed as an immunostimulant and an adjuvant for more than a decade. However, the adjuvant ability of flagellins with hypervariable region deleted is still unclear in fish. In this study, we evaluated the immune-stimulating capacity of two recombinant flagellins, the wild-type flagellin F from Marinobacter algicola and a version with the hypervariable region deleted (FredV2), to induce the transcription of a wide range of immune genes using two rainbow trout cell lines: a monocyte/macrophage-cell line (RTS-11) and an epithelial cell line from intestine (RTgutGC). Additionally, we studied the capacity of both flagellins to limit the replication of viral hemorrhagic septicemia virus (VHSV) on the RTgutGC cell line. Our results demonstrated that both recombinant flagellins can significantly increase the transcription of IL-1ß1, IL-6, and IL-8 in both cell lines. However, other cytokines such as IFNγ1, and TNFα or antimicrobial peptides such as hepcidin were induced by both flagellins in RTgutGC but not in RTS-11 cells. Furthermore, both flagellins were capable of reducing the replication of VHSV in RTgutGC cells. Although the immunostimulatory and the antiviral capacities exerted by F were slightly more potent than those obtained with FredV2, the effects were retained after losing the hypervariable region. Our results provide new information on the immunostimulating and antiviral capacities of flagellins that point to their potential as suitable adjuvants for the future optimization of vaccines in aquaculture.

Bacillus subtilis Expressing the Infectious Pancreatic Necrosis Virus VP2 Protein Retains Its Immunostimulatory Properties and Induces a Specific Antibody Response.

Bacillus subtilis has been documented in the past years as an effective probiotic for different aquacultured species, with recognized beneficial effects on water quality, fish growth and immune status. Furthermore, its potential as a vaccine adjuvant has also been explored in different species. In the current work, we have used B. subtilis spores as delivery vehicles for the presentation of the VP2 protein from infectious pancreatic necrosis virus (IPNV). For this, the VP2 gene was amplified and translationally fused to the crust protein CotY. The successful expression of VP2 on the spores was confirmed by Western blot. We then compared the immunostimulatory potential of this VP2-expressing strain (CRS208) to that of the original B. subtilis strain (168) on rainbow trout (Oncorhynchus mykiss) leukocytes obtained from spleen, head kidney and the peritoneal cavity. Our results demonstrated that both strains significantly increased the percentage of IgM+ B cells and the number of IgM-secreting cells in all leukocyte cultures. Both strains also induced the transcription of a wide range of immune genes in these cultures, with small differences between them. Importantly, specific anti-IPNV antibodies were detected in fish intraperitoneally or orally vaccinated with the CRS208 strain. Altogether, our results demonstrate B. subtilis spores expressing foreign viral proteins retain their immunomodulatory potential while inducing a significant antibody response, thus constituting a promising vaccination strategy.

HLA in Las Alpujarras Mts., South-East Spain: A Renaissance process of population artificial substitution.

Spain was invaded in 711 CE by mostly Berber North Africans carrying Muslim religion to a mostly Christian/Catholic Kingdom. A fight to expel Muslims soon started and were apparently driven out of Iberia (Spain) starting in 1492 CE. However, many of these expelled people were of Iberian old ancestry that had become Muslims at Las Alpujarras Mts. (South-East Spain). Also, Muslim North Africans converted to Christianity either remained there or came back after they more definetively were expelled by 1609 CE. Las Alpujarras region was also repopulated by northern Spaniards mostly from Galicia. Our HLA study of present day Alpujarrans shows that typical North Spain and European Atlantic façade HLA extended haplotypes are very frequent in nowadays Las Alpujarras region, i. e.: HLA-(A*29-B*44)-DRB1*07:01-DQA1*02:01-DQB1*02:01 and (A*02-B*27)-DRB1*15:01-DQA1*01:02-DQB1*06:02. It is concluded that repopulation had a noticeable success even in today Alpujarran population.

Vulnerability of SARS-CoV-2 and PR8 H1N1 virus to cold atmospheric plasma activated media.

Cold Atmospheric Plasma (CAP) and Plasma Activated Media (PAM) are effective against bacteria, fungi, cancer cells, and viruses because they can deliver Reactive Oxygen and Nitrogen Species (RONS) on a living tissue with negligible damage on health cells. The antiviral activity of CAP against SARS-CoV-2 is being investigated, however, the same but of PAM has not been explored despite its potential. In the present study, the capability of Plasma Activated Media (PAM) to inactivate SARS-CoV-2 and PR8 H1N1 influenza virus with negligible damage on healthy cells is demonstrated. PAM acted by both virus detaching and diminished replication. Furthermore, the treatment of A549 lung cells at different times with buffered PAM did not induce interleukin 8 expression, showing that PAM did not induce inflammation. These results open a new research field by using PAM to the development novel treatments for COVID-19, influenza, and other respiratory diseases.

Differential Immune Transcriptome and Modulated Signalling Pathways in Rainbow Trout Infected with Viral Haemorrhagic Septicaemia Virus (VHSV) and Its Derivative Non-Virion (NV) Gene Deleted.

Viral haemorrhagic septicaemia virus (VHSV) is one of the worst viral threats to fish farming. Non-virion (NV) gene-deleted VHSV (dNV-VHSV) has been postulated as an attenuated virus, because the absence of the NV gene leads to lower induced pathogenicity. However, little is known about the immune responses driven by dNV-VHSV and the wild-type (wt)-VHSV in the context of infection. Here, we obtained the immune transcriptome profiling in trout infected with dNV-VHSV and wt-VHSV and the pathways involved in immune responses. As general results, dNV-VHSV upregulated more trout immune genes than wt-VHSV (65.6% vs 45.7%, respectively), whereas wt-VHSV maintained more non-regulated genes than dNV-VHSV (45.7% vs 14.6%, respectively). The modulated pathways analysis (Gene-Set Enrichment Analysis, GSEA) showed that, when compared to wt-VHSV infected trout, the dNV-VHSV infected trout upregulated signalling pathways (n = 19) such as RIG-I (retinoic acid-inducible gene-I) like receptor signalling, Toll-like receptor signalling, type II interferon signalling, and nuclear factor kappa B (NF-kappa B) signalling, among others. The results from individual genes and GSEA demonstrated that wt-VHSV impaired the activation at short stages of infection of pro-inflammatory, antiviral, proliferation, and apoptosis pathways, delaying innate humoral response and cellular crosstalk, whereas dNV-VHSV promoted the opposite effects. Therefore, these results might support future studies on using dNV-VHSV as a potential live vaccine.

HLA genes in Barranquilla (North Colombia): Searching for cryptic Amerindian genes.

America First Inhabitants population (Amerindians, Na Dene and Eskimos) underwent a drastic population reduction and gene exchange after Europeans and Africans arrival after 1492 AD. Barranquilla population may be a good model to study present day population admixture in South America. HLA-A, -B and -DRB1 DNA typing has been performed in 188 unrelated individuals originated in the area and speak Spanish language; they showed apparent European/African and mixed characters. HLA genetic European/African features were found and only 1.85% Amerindian one. This contrasts with neighboring Cuban population where 10% HLA Amerindian characters appear.

Identification of the functional regions of the viral haemorrhagic septicaemia virus (VHSV) NV protein: Variants that improve function.

Non-virion (NV) protein is essential for an efficient replication increasing the pathogenicity of the Salmonid novirhabdovirus (formerly IHNV), Piscine novirhabdovirus (formerly VHSV), and Hirame novirhabdovirus (HIRV). The interferon system, apoptosis, and other immune-related genes are modulated by NV to finally induce a deficient antiviral state in the cell. However, little is known about the VHSV NV regions involved in function and location. Here, eight different NV 07.71 fragments and eleven NV 07.71 mutants derived from the region between the two first α-helices have been studied in order to establish the mx and il8 transcript levels in ZF4 cells and the subcellular location. As a result, we determined that the N-terminal part of NV preserves the same ability as the wild-type (wt) NV in mx/il8 modulation and it also shares the subcellular location. Among NV mutants, some induced mx upregulation (N34A, C35A, D38A, and S40A) but maintained the il8 levels stable when compared to wt-NV in ZF4. Four NV mutants (D28A, N31A, L33A, and F37A) were not affected by the mutation and showed mx and il8 transcript levels similar to wt-NV. Surprisingly, mutants D36A, R39A, and D41A induced a stronger downregulation of both mx and il8 transcript levels than wt-NV, suggesting that a more stable structure and an improved interaction with ligands could be achieved through these mutations. Amino acids at positions 36 and 39 are conserved among known VHSV NV proteins whereas at position 41 two different amino acids have been described. To date, no natural NV proteins with alanine at positions 36, 39, and 41 have been found. In addition, wt-NV, all NV mutants, and one N-terminal NV fragment were located at cytoplasm with a characteristic pattern, which might support that cytoplasm is the site for interaction with candidate ligands such as PPM1Bb. Taken together, the data presented in this work indicated that NV function relies on the first part of the molecule and is dependent on tertiary structure rather than on the linear one. This study could lead to a better knowledge of VHSV escape from fish antiviral mechanisms as well as to future studies on immune targets.

Genetic HLA Study of Kurds in Iraq, Iran and Tbilisi (Caucasus, Georgia): Relatedness and Medical Implications.

Kurds from Iraq (Dohuk and Erbil Area, North Iraq) have been analyzed for HLA genes. Their HLA genetic profile has been compared with that of other Kurd groups from Iran and Tbilisi (Georgia, Caucasus) and also Worldwide populations. A total of 7,746 HLA chromosomes have been used. Genetic distances, NJ dendrograms and correspondence analyses have been carried out. Haplotype HLA-B*52-DRB1*15 is present in all three analyzed Kurd populations. HLA-A*02-B*51-DRB1*11 is present in Iraq and Georgia Kurds. Haplotypes common to Iran and Iraq Kurds are HLA DRB1*11-DQB1*03, HLA DRB1*03-DQB1*02 and others in a lower frequency. Our HLA study conclusions are that Kurds most probably belong to an ancient Mediterranean / Middle East / Caucasian genetic substratum and that present results and those previously obtained by us in Kurds may be useful for Medicine in future Kurd transplantation programs, HLA Epidemiology (HLA linked diseases) and Pharmacogenomics (HLA-associated drug side effects) and also for Anthropology. It is discussed that one of the most ancient Kurd ancestor groups is in Hurrians (2,000 years BC).

Characterisation and functional implications of the two new HLA-G alleles found in Amerindian and Caribbean populations.

HLA-G polymorphism has been found to be relatively low in all world populations. In the present paper two new HLA-G molecules are described in ancient American natives. A new HLA-G molecule from a Ecuador Amerindian individual (male) showed four codon changes with respect to HLA-G*01:01:01. Silent changes at α1 domain (residue 57, Pro, CCG→CCA) and α2 domain (residue 93, His, CAC→CAT and residue 100, Gly, GGC→GGT) and one productive change in α3 domain (residue 219 changed from Arg to Trp). This α3 change may dramatically alter HLA-G interactions with beta-2 microglobulin, CD8, ILT-2 and ILT-4 ligands present in subsets of T, B, NK, monocytes, macrophages and dentritic cells. Another HLA-G new molecule was found in a woman from Hispaniola Island, Dominican Republic (Sto Domingo): it presented a silent change at α2 domain residue 107, Gly, GGA→GGT and non-silent change at residue 178, Met→Thr (with respect to HLA-G*01:01:01) which is close to class I molecule/clonotypic T cell receptor interaction sites. Functional implications of these findings are discussed.

Differential Modulation of IgT and IgM upon Parasitic, Bacterial, Viral, and Dietary Challenges in a Perciform Fish.

Three different immunoglobulin (Ig) isotypes can be found in teleost fish, IgM, IgD, and the teleost-specific IgT. IgM is considered to have a systemic activity, and IgT is attributed a mucosal role, similar to mammalian IgA. In this study, the complete sequence of gilthead sea bream IgM and IgT in their membrane (m) and soluble (s) forms are described for the first time in a perciform fish. Their constitutive gene expression is analyzed in different tissues, and their regulation upon viral, bacterial, parasitic, mucosal vaccination and dietary challenges are studied. GCB IgM and IgT have the prototypical structure when compared to other fish Igs. The constitutive expression of sIgM was the highest overall in all tissues, whereas mIgT expression was highest in mucosal tissues, such as gills and intestine. IgM and IgT were differentially regulated upon infection. IgT was highly upregulated locally upon infection with the intestinal parasite Enteromyxum leei or systemically after Nodavirus infection. Long-term intestinal parasitic infections increased the serum titer of both isotypes. Mucosal vaccination against Photobacterium damselae subsp. piscicida finely regulated the Ig response inducing a systemic increase of IgM titers in serum and a local IgT response in skin mucus when animals were exposed to the pathogen by bath challenge. Interestingly, plant-based diets inhibit IgT upregulation upon intestinal parasitic challenge, which was related to a worse disease outcome. All these results corroborate the mucosal role of IgT and emphasize the importance of a finely tuned regulation of Ig isotypes upon infection, which could be of special interest in vaccination studies.

Transcriptome analysis of rainbow trout in response to non-virion (NV) protein of viral haemorrhagic septicaemia virus (VHSV).

The non-virion (NV) protein of viral haemorrhagic septicaemia virus (VHSV), an economically important fish novirhabdovirus, has been implicated in the interference of some host innate mechanisms (i.e. apoptosis) in vitro. This work aimed to characterise the immune-related transcriptome changes in rainbow trout induced by NV protein that have not yet been established in vivo. For that purpose, immune-targeted microarrays were used to analyse the transcriptomes from head kidney and spleen of rainbow trout (Oncorhynchus mykiss) after injection of recombinant NV (rNV). Results showed the extensive downregulation (and in some cases upregulation) of many innate and adaptive immune response genes not related previously to VHSV infection. The newly identified genes belonged to VHSV-induced genes (vigs), tumour necrosis factors, Toll-like receptors, antigen processing and presentation, immune co-stimulatory molecules, interleukins, macrophage chemotaxis, transcription factors, etc. Classification of differentially downregulated genes into rainbow trout immune pathways identified stat1 and jun/atf1 transcription factor genes as the most representative of the multipath gene targets of rNV. Altogether, these results contribute to define the role and effects of NV in trout by orchestrating an immunosuppression of the innate immune responses for favouring viral replication upon VHSV infection. Finally, these transcriptome results open up the possibility to find out new strategies against VHSV and better understand the interrelationships between some immune pathways in trout.

Flagellin from Marinobacter algicola and Vibrio vulnificus activates the innate immune response of gilthead seabream.

Adjuvants have emerged as the best tools to enhance the efficacy of vaccination. However, the traditional adjuvants used in aquaculture may cause adverse alterations in fish making necessary the development of new adjuvants able to stimulate the immune system and offer strong protection against infectious pathogens with minimal undesirable effects. In this respect, flagellin seems an attractive candidate due to its ability to strongly stimulate the immune response of fish. In the present study, we have evaluated the ability of recombinant flagellin from Marinobacter algicola (MA) and Vibrio vulnificus (Vvul), a non-pathogenic and a pathogenic bacteria, respectively, to stimulate the innate immune system of gilthead seabream (Sparus aurata L.) and compare the effect with that of the classical flagellin from Salmonella enterica serovar Typhimurium (Salmonella Typhimurium, STF). Intraperitoneal injection of MA and Vvul resulted in a strong inflammatory response characterized by increased reactive oxygen species production and the infiltration of acidophilic granulocytes at the injection site. Interestingly, however, only flagellin from MA consistently induced the expression of the gene encoding pro-inflammatory interleukin-1ß. These effects were further confirmed in vitro, where a dose-dependent activation of macrophages and acidophilic granulocytes by MA and Vvul flagellins was observed. In contrast, STF flagellin was found to be less potent in both in vivo and in vitro experiments. Our results suggest the potential use of MA and Vvul flagellins as immunostimulants and adjuvants for fish vaccination.

Identification of multipath genes differentially expressed in pathway-targeted microarrays in zebrafish infected and surviving spring viremia carp virus (SVCV) suggest preventive drug candidates.

Spring viremia carp virus (SVCV) is a rhabdovirus seasonally affecting warm-water cyprinid fish farming causing high impacts in worldwide economy. Because of the lack of effective preventive treatments, the identification of multipath genes involved in SVCV infection might be an alternative to explore the possibilities of using drugs for seasonal prevention of this fish disease. Because the zebrafish (Danio rerio) is a cyprinid susceptible to SVCV and their genetics and genome sequence are well advanced, it has been chosen as a model for SVCV infections. We have used newly designed pathway-targeted microarrays 3-4-fold enriched for immune/infection functional-relevant probes by using zebrafish orthologous to human genes from selected pathways of the Kyoto Encyclopedia of Genes and Genomes (KEGG). The comparative analysis of differential expression of genes through 20 pathways in 2-day exposed or 30-day survivors of SVCV infection allowed the identification of 16 multipath genes common to more than 6 pathways. In addition, receptors (Toll-like, B-cell, T-cell, RIG1-like) as well as viral RNA infection pathways were identified as the most important human-like pathways targeted by SVCV infection. Furthermore, by using bioinformatic tools to compare the promoter sequences corresponding to up and downregulated multipath gene groups, we identified putative common transcription factors which might be controlling such responses in a coordinated manner. Possible drug candidates to be tested in fish, can be identified now through search of data bases among those associated with the human orthologous to the zebrafish multipath genes. With the use of pathway-targeted microarrays, we identified some of the most important genes and transcription factors which might be implicated in viral shutoff and/or host survival responses after SVCV infection. These results could contribute to develop novel drug-based prevention methods and consolidate the zebrafish/SVCV as a model for vertebrate viral diseases.

Optimization of fixed-permeabilized cell monolayers for high throughput micro-neutralizing antibody assays: application to the zebrafish/viral hemorrhagic septicemia virus (vhsv) model.

A new high throughput centrifugation-free method to estimate viral neutralizing antibody levels in low volumes and large numbers of plasma blood samples is described. Cell monolayers were, (i) plated on poly-d-Lys coated 96-wells, (ii) infected with viruses previously incubated with fish plasma containing antibodies, (iii) fixed with formaldehyde to increase cell recovery and avoid centrifugation steps, (iv) permeabilized with Saponin, (v) immunostained in the presence of Saponin by using a monoclonal antibody (MAb) to viral protein, (vi) digested with trypsin to detach cells from the monolayer, in the absence of Saponin to reduce damage of intracellular MAb-antigen complexes, and (vii) gated by flow cytometry using automatic 96-well batch analysis. The method was applied to the determination of plasma neutralizing antibodies from zebrafish (Danio rerio) surviving infections with viral hemorrhagic septicemia virus (VHSV) (an important rhabdovirus of salmonids). This semi-automatic, rapid and practical assay detected anti-VHSV neutralizing antibodies in the plasma (∼3 µl per fish) of 95.1% of the zebrafish surviving VHSV infections. The fixed-permeabilized monolayer (FIXPERM) micro-neutralization method might help to analyze sera/plasma from small fish under standarized high throughput conditions.

In vitro neutralization of viral hemorrhagic septicemia virus by plasma from immunized zebrafish.

We studied humoral long-term adaptive viral neutralization responses in zebrafish (Danio rerio), an increasingly useful vertebrate model for viral diseases actually limited by the absence of standardized anti-zebrafish immunoglobulin M (IgM) antibodies. We established an alternative method, similar to those used in other fish, to achieve a first estimation of zebrafish anti-viral antibody-like responses. We used the viral hemorrhagic septicemia virus (VHSV) model because, although protection after this non-natural infection was demonstrated in cold-acclimatized zebrafish, little is known about their induced anti-VHSV antibody-like responses. Therefore, we first optimized a micro-neutralization method based on immunostaining VHSV-infected fish cell monolayers to detect zebrafish neutralizing activity in plasma samples in one day. We then used the method to measure the specific anti-VHSV neutralization in plasma obtained from individual zebrafish under various VHSV challenges or immunization protocols. The neutralizing activity was inhibited by protein A-sepharose and rabbit anti-zebrafish IgM antibodies, suggesting the implication of IgM zebrafish antibodies in such responses. To our knowledge, this is the first report to demonstrate detectable and significant VHSV neutralization titers in zebrafish surviving VHSV infections. This micro-method might be useful, not only for the follow-up of infection/vaccine development in the zebrafish/VHSV model in particular, but also for similar work involving other in vitro neutralizable zebrafish pathogens. This technique might also further the development of alternative ELISA assay methods to measure specific immunoglobulins in zebrafish.

Antibodies against Marinobacter algicola and Salmonella typhimurium flagellins do not cross-neutralize TLR5 activation.

Flagellins evoke strong innate and adaptive immune responses. These proteins may play a key role as radioprotectors, exert antitumoral activity in certain types of tumor and reduce graft-versus-host disease in allogeneic hematopoietic stem cell transplant recipients. Notwithstanding, flagellins are highly immunogenic, and repeated use leads to their neutralization by systemic antibodies. This neutralization is not prevented by using functional deleted flagellins. These observations led us to explore the possibility of preventing initial neutralization by means of another functional flagellin that does not belong to common pathogenic bacteria but that has the capacity to activate TLR5. Here we characterized the functional capacity of the two-phase Marinobacter algicola (MA)-derived flagellins (F and FR) as systemic and mucosal adjuvants and compared their performance with that of Salmonella typhimurium (STF) flagellins (FljB and FliC). We also report for the first time on the in vitro and in vivo capacity of various flagellins to trigger TLR5 activation in the presence of species-specific anti-flagellin antibodies, the cross-neutralization mediated by these antibodies, and the sequential use of these flagellins for TLR5 activation. Our results showed that MA flagellins behave in a similar way to STF ones, inducing pro-inflammatory cytokines (IL8, CCL20, CCL2) and evoking a strong in vivo antibody response against a model epitope. More importantly, MA flagellins were fully functional, in vitro or in vivo, in the presence of a high concentration of neutralizing anti-flagellin STF antibodies, and STF flagellin was not inhibited by neutralizing anti-flagellin MA antibodies. The use of active flagellins from distinct bacteria could be a useful approach to prevent systemic neutralization of this group of adjuvants and to facilitate the rational design of flagellin-based vaccines and/or other therapeutic treatments (against ischemia, acute renal failure, tumors, ionizing radiations and also to improve the outcome of bone marrow transplants).

Antibody recognition of the glycoprotein g of viral haemorrhagic septicemia virus (VHSV) purified in large amounts from insect larvae.

BACKGROUND: There are currently no purification methods capable of producing the large amounts of fish rhabdoviral glycoprotein G (gpG) required for diagnosis and immunisation purposes or for studying structure and molecular mechanisms of action of this molecule (ie. pH-dependent membrane fusion). As a result of the unavailability of large amounts of the gpG from viral haemorrhagic septicaemia rhabdovirus (VHSV), one of the most dangerous viruses affecting cultured salmonid species, research interests in this field are severely hampered. Previous purification methods to obtain recombinant gpG from VHSV in E. coli, yeast and baculovirus grown in insect cells have not produced soluble conformations or acceptable yields. The development of large-scale purification methods for gpGs will also further research into other fish rhabdoviruses, such as infectious haematopoietic necrosis virus (IHNV), spring carp viremia virus (SVCV), hirame rhabdovirus (HIRRV) and snakehead rhabdovirus (SHRV). FINDINGS: Here we designed a method to produce milligram amounts of soluble VHSV gpG. Only the transmembrane and carboxy terminal-deleted (amino acid 21 to 465) gpG was efficiently expressed in insect larvae. Recognition of G21-465 by ß-mercaptoethanol-dependent neutralizing monoclonal antibodies (N-MAbs) and pH-dependent recognition by sera from VHSV-hyperimmunized or VHSV-infected rainbow trout (Oncorhynchus mykiss) was demonstrated. CONCLUSIONS: Given that the purified G21-465 conserved some of its most important properties, this method might be suitable for the large-scale production of fish rhabdoviral gpGs for use in diagnosis, fusion and antigenicity studies.

Different evolutionary pathway of B*570101 and B*5801 (B17 group) alleles based in intron sequences.

Two theories about MHC allele generation have been put forward: (1) point mutation diversification and/or (2) gene conversion events. A model supporting the existence of both of these mechanisms is shown in this paper; the possible evolution of the HLA-B*570101 and HLA-B*5801 alleles (which belong to the HLA-B17 serology group) is studied. The hypothesis favoured is that gene conversion events have originated these alleles, because intron sequences are also analysed. Evolution by point mutation should only be accepted if flanking introns have also been sequenced.

HLA genes in the Chuvashian population from European Russia: admixture of Central European and Mediterranean populations.

HLA alleles have been determined for the first time in individuals from the Chuvashian population by DNA typing and sequencing. HLA-A, -B, -DR, and -DQ allele frequencies and extended haplotypes have also been determined, and the results compared to those for Central Europeans, Siberians and other Asians, Caucasians, Middle Easterners, and Mediterranean peoples. Genetic distances, neighbor-joining dendrograms, and correspondence analysis have been performed. Present-day Chuvash speak an Altaic-Turkic language and are genetically related to Caucasians (Georgians), Mediterraneans, and Middle Easterners, and not only to Central or Northern Europeans; Chuvash contain little indications of Central Asian-Altaic gene flow. Thus, present-day Chuvash who speak an Altaic-Turkic language are probably more closely related to ancient Mesopotamian-Hittites and northern European populations than to central Asia-Altaic people.

An unusual expression of hyperplastic gastropathy (Menetrier type) in twins.

Menetrier's disease is an uncommon condition of unknown aetiology. We describe two cases of male identical twins with haematemesis aged 29 and 35 years that exhibited a similar and particular form of this hyperplastic gastropathy. Their stomachs showed confluent polypoid mucosal projections affecting mainly the gastric fundus and the antrum. To the best of our knowledge, only four previous cases have been reported in a familial setting, and this is the first documented example of an occurrence in twins. These two cases suggest the possibility of a genetic predisposition for this condition.