Influence of HLA-C environment on the spontaneous clearance of hepatitis C in European HIV-HCV co-infected individuals.

Natural killer (NK) cell functions are regulated by diverse inhibitory and activating receptors, including killer cell immunoglobulin-like receptors (KIR), which interact with human leukocyte antigen (HLA) class I molecules. Some KIR/HLA genetic combinations were reported associated with spontaneous clearance (SC) of hepatitis C virus (HCV) but with discordant results, possibly reflecting KIR and/or HLA gene polymorphism according to populations. KIR/HLA genetic combinations associated with both an exhaustive NK and T cell repertoire were investigated in a cohort of HIV-HCV co-infected individuals with either SC (n = 68) or chronic infection (CI, n = 163) compared to uninfected blood donors [controls (Ctrl), n = 100]. Multivariate analysis showed that the HLA C2C2 environment was associated with SC only in European HIV-HCV co-infected individuals [odds ratio (OR) = 4·30, 95% confidence interval = 1·57-12·25, P = 0·005]. KIR2D+ NK cell repertoire and potential of degranulation of KIR2DL1/S1+ NK cells were similar in the SC European cohort compared to uninfected individuals. In contrast, decreased frequencies of KIR2DS1+ and KIR2DL2+ NK cells were detected in the CI group of Europeans compared to SC and a decreased frequency of KIR2DL1/S1+ NK cells compared to controls. Regarding T cells, higher frequencies of DNAX accessory molecule-1 (DNAM-1)+ and CD57+ T cells were observed in SC in comparison to controls. Interestingly, SC subjects emphasized increased frequencies of KIR2DL2/L3/S2+ T cells compared to CI subjects. Our study underlines that the C2 environment may activate efficient KIR2DL1+ NK cells in a viral context and maintain a KIR2DL2/L3/S2+ mature T cell response in the absence of KIR2DL2 engagement with its cognate ligands in SC group of HCV-HIV co-infected European patients.

IMMUNOGENETIC FACTORS INFLUENCING CLINICAL COURSE OF HCV INFECTION (REVIEW).

Hepatitis C virus (HCV) infection remains one of the most important blood-borne diseases worldwide with about 130-170 million people chronically infected with hepatitis C virus, and more than 350 000 people die from hepatitis C-related liver diseases each year. Infection with HCV becomes chronic in approximately 80% of cases, while in up to 20% of cases hepatitis C virus is cleared from the human organism. Chronic infections of hepatitis C often leads to the end-stage liver diseases such as cirrhosis and hepatocellular carcinoma. The clinical course and the outcome of the HCV infection is determined by the complex interplay between the viral replication and the host defense mechanisms. Several recent studies have shown that MHC class I and class II as well as natural killer (NK) cell's immunoglobulin-like receptors (KIR) loci can be associated with the HCV protection and clearance as well as with disease progression and responsiveness to antiviral treatment. Current status of our knowledge about the influence of immunogenetic factors on the clinical course of HCV infection is presented in the paper. Plans to investigate these factors among HCV infected patients enrolled in the HCV Elimination Program (launched in April 2015 in Georgia) are discussed.

The novel HLA-B*15:180 allele appears to be a recombinant B*08/B*15 allele.

Human leukocyte antigen B-*15:180 is a B*08/B*15 recombinant allele similar to B*15:29 with substitutions positions at 97, 292, 538, 539.

Human leukocyte antigen class I and MICA haplotypes in a multicase family with Cladophialophora carrionii chromoblastomycosis.

Previous studies carried out in an endemic semiarid region northwest of Venezuela at Falcon State have shown a prevalence of 15.4/1000 of chromoblastomycosis following traumatisms with xenophile vegetation infected with Cladophialophora carrionii. We performed high-resolution DNA typing of human leukocyte antigen (HLA)-A, -B and -C and major histocompatibility complex class I chain related gene A (MICA) alleles and segregation analysis in 49 members of one extended family with 12 affected individuals, who have lived for approximately 70 years in this endemic zone. None of the alleles, haplotypes or genotypes is shared by all the patients. No deviation from the expected HLA haplotype distribution or association of chromoblastomycosis with HLA-A, -B and -C haplotypes was observed. Further, a haplotype-sharing transmission/disequilibria testing of 11 nuclear families did not give enough evidence to claim linkage (P = 0.398), suggesting that genes located in the short arm of chromosome 6 may not be relevant in the immune response toward infection with C. carrionii in this Venezuelan endemic zone. Deleted MICA alleles on HLA-B*4802 haplotypes were present among several members of the extended family, but only two of them were affected.

TNF-alpha-308A allele, a possible severity risk factor of hemorrhagic manifestation in dengue fever patients.

Among the several hypothesis postulated to explain the pathogenesis of severe dengue disease, the model of immunopathogenesis is the most supported one with a likely important role played by the cascade of cytokines. This work describes single-nucleotide polymorphism of tumor necrosis factor (TNF)-alpha, interferon-gamma, interleukin (IL)-6, transforming growth factor-beta1, and IL-10 in patients with dengue virus infections and analyzes their relation with clinical manifestations of the disease. Because cytokine gene polymorphisms affect cytokine production, the significant increase of the TNF-308A allele we have observed among patients with dengue fever (DF) with hemorrhagic manifestations compared to patients with DF only indicates that the former patients are genetically predisposed to express higher levels of TNF-alpha. This finding supports studies reporting a possible association between elevated levels of circulating TNF, vascular permeability, and hemorrhage in patients with dengue hemorrhagic fever.

Colonia Tovar: the history of a semi-isolated Venezuelan population of German ancestry described by HLA class I genes.

The history of Colonia Tovar is very complex, being the home of descendants of only a small fraction of immigrants arriving to the South American continent from a specific region of Germany, with a restricted number of founders, small population size and consanguineous mating, experiencing isolation for 100 years, with later migrations, a low rate of population growth and a high mean number of children per couple. How complex is its genetic structure? Do the highly polymorphic HLA genes reflect its history and confirm the story of this population described by other genes? Several studies have been made in this population, but we describe for the first time the HLA Class I variability in the population of Colonia Tovar using PCR-SSOP. Random genetic drift, founder effect and gene flow could explain the HLA allele and haplotype frequencies observed in this population but alleles at the class I loci were insufficient to identify the German origin of the community established through history. This agrees with findings obtained testing other genetic systems (ACP, AK, ESD, G6PD, GLO, PGM, PGD, ALB, CP, HP, TF), but the HLA-typing results indicate that the original gene pool has been diluted due to gene flow from the surrounding Mestizo population.

Inhibition of Crotalidae venom hemorrhagic activities by Didelphis marsupialis liver spheroids culture supernatants.

The main aim of this work was the development of a primary hepatocyte culture from Didelphis marsupialis, to determine the possible use of culture medium supernatants as a source of inhibitors of the Bothrops lanceolatus venom hemorrhagic activity. The cellular culture was carried out from isolated hepatocytes by the double perfusion technique, and digestion of the liver with collagenase and culturing the hepatocytes in a liquid media under continuous agitation at 37 degrees C in 5% CO2. The hemorrhagic activity inhibition assays were performed inoculating intradermically, a mixture of Bothrops lanceolatus venom plus a pool of liver spheroids culture supernatants, in mice. These liver Didelphis marsupialis spheroid cultures were adequate to obtain large supernatant volumes with inhibitors of hemorrhagic activity.