Can COVID-19 Increase the Risk of Herpes Zoster? A Narrative Review

Herpes zoster (HZ) is associated with substantial morbidity. It is caused by reactivation of the latent varicella zoster virus (VZV) following decline in cell-mediated immunity, which is commonly age-related, but also occurs in individuals with immunosuppressive diseases and/or treatment. Since coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has been associated with T cell immune dysfunction and there have been reports of HZ in COVID-19 patients, we have performed a review of available literature on whether COVID-19 could trigger HZ. We identified 27 cases of HZ following COVID-19, which most frequently occurred within 1–2 weeks of COVID-19, and the majority of cases had typical presentation. Atypical presentations of HZ were noted especially in patients with lymphopenia. It has been hypothesized that VZV reactivation occurs as a consequence of T cell dysfunction (including lymphopenia and lymphocyte exhaustion) in COVID-19 patients. Based on current evidence, which is limited to case reports and case series, it is not possible to determine whether COVID-19 increases the risk of HZ. Practitioners should be aware of the possible increased risk of HZ during the pandemic period and consider timely therapeutic and preventive measures against it.

Pre-Flight Calibration of the Mars 2020 Rover Mastcam Zoom (Mastcam-Z) Multispectral, Stereoscopic Imager

The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm ( 25.5 ∘ × 19.1 ∘ FOV ) to 110 mm ( 6.2 ∘ × 4.2 ∘ FOV ) and will acquire data at pixel scales of 148-540 μm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover's mast with a stereo baseline of 24.3 ± 0.1  cm and a toe-in angle of 1.17 ± 0.03 ∘ (per camera). Each camera uses a Kodak KAI-2020 CCD with 1600 × 1200 active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors' Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26 t h and May 9 t h , 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be < 10 % . Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows MTF Nyquist = 0.26 - 0.50 across all zoom, focus, and filter positions, exceeding the > 0.2 design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11214-021-00795-x.

The Mars 2020 Perseverance Rover Mast Camera Zoom (Mastcam-Z) Multispectral, Stereoscopic Imaging Investigation

Mastcam-Z is a multispectral, stereoscopic imaging investigation on the Mars 2020 mission's Perseverance rover. Mastcam-Z consists of a pair of focusable, 4:1 zoomable cameras that provide broadband red/green/blue and narrowband 400-1000 nm color imaging with fields of view from 25.6° × 19.2° (26 mm focal length at 283 μrad/pixel) to 6.2° × 4.6° (110 mm focal length at 67.4 μrad/pixel). The cameras can resolve (≥ 5 pixels) ∼0.7 mm features at 2 m and ∼3.3 cm features at 100 m distance. Mastcam-Z shares significant heritage with the Mastcam instruments on the Mars Science Laboratory Curiosity rover. Each Mastcam-Z camera consists of zoom, focus, and filter wheel mechanisms and a 1648 × 1214 pixel charge-coupled device detector and electronics. The two Mastcam-Z cameras are mounted with a 24.4 cm stereo baseline and 2.3° total toe-in on a camera plate ∼2 m above the surface on the rover's Remote Sensing Mast, which provides azimuth and elevation actuation. A separate digital electronics assembly inside the rover provides power, data processing and storage, and the interface to the rover computer. Primary and secondary Mastcam-Z calibration targets mounted on the rover top deck enable tactical reflectance calibration. Mastcam-Z multispectral, stereo, and panoramic images will be used to provide detailed morphology, topography, and geologic context along the rover's traverse; constrain mineralogic, photometric, and physical properties of surface materials; monitor and characterize atmospheric and astronomical phenomena; and document the rover's sample extraction and caching locations. Mastcam-Z images will also provide key engineering information to support sample selection and other rover driving and tool/instrument operations decisions.

Hemizygous amplification and complete Sanger sequencing of HLA-C*07:37:01:02 from a South European Caucasoid

The novel C*07:37:01:02 was completely sequenced after haplo-specific amplification from a European Caucasoid carrying B*07:02.

Haplotype-Based Analysis of KIR-Gene Profiles in a South European Population-Distribution of Standard and Variant Haplotypes, and Identification of Novel Recombinant Structures

Inhibitory Killer-cell Immunoglobulin-like Receptors (KIR) specific for HLA class I molecules enable human natural killer cells to monitor altered antigen presentation in pathogen-infected and tumor cells. KIR genes display extensive copy-number variation and allelic polymorphism. They organize in a series of variable arrangements, designated KIR haplotypes, which derive from duplications of ancestral genes and sequence diversification through point mutation and unequal crossing-over events. Genomic studies have established the organization of multiple KIR haplotypes—many of them are fixed in most human populations, whereas variants of those have less certain distributions. Whilst KIR-gene diversity of many populations and ethnicities has been explored superficially (frequencies of individual genes and presence/absence profiles), less abundant are in-depth analyses of how such diversity emerges from KIR-haplotype structures. We characterize here the genetic diversity of KIR in a sample of 414 Spanish individuals. Using a parsimonious approach, we manage to explain all 38 observed KIR-gene profiles by homo- or heterozygous combinations of six fixed centromeric and telomeric motifs; of six variant gene arrangements characterized previously by us and others; and of two novel haplotypes never detected before in Caucasoids. Associated to the latter haplotypes, we also identified the novel transcribed KIR2DL5B^*0020202 allele, and a chimeric KIR2DS2/KIR2DL3 gene (designated KIR2DL3^*033) that challenges current criteria for classification and nomenclature of KIR genes and haplotypes.

Immunostaining in whole-mount lipid-cleared peripheral nerves and dorsal root ganglia after neuropathy in mice

Immunohistochemical characterization of primary afferent fibers (intact or after nerve damage) is traditionally performed in thin sections from dorsal root ganglia (DRGs) or in teased fibers, as light scattering in whole-mounts compromises visualization. These procedures are time-consuming, require specific equipment and advanced experimental skills. Lipid-clearing techniques are increasing in popularity, but they have never been used for the peripheral nervous system. We established a modified, inexpensive clearing method based on lipid-removal protocols to make transparent peripheral nerve tissue (inCLARITY). We compared retrograde-labeling and free-floating immunostaining with cryo-sections. Confocal microscopy on whole-mount transparent DRGs showed neurons marked with retrograde tracers applied to experimental neuromas (Retrobeads, Fluoro-ruby, Fluoro-emerald, DiI, and Fluoro-gold). After immunostaining with calcitonin gene-related peptide (peptidergic) or isolectin IB4 (non-peptidergic), nociceptors were visualized. Immunostaining in transparent whole-mount nerves allows simultaneous evaluation of the axotomized branches containing the neuroma and neighboring intact branches as they can be mounted preserving their anatomical disposition and fiber integrity. The goal of our study was to optimize CLARITY for its application in peripheral nerve tissues. The protocol is compatible with the use of retrograde tracers and improves immunostaining outcomes when compared to classical cryo-sectioning, as lack of lipids maximizes antibody penetration within the tissue.

Report from the Killer-cell Immunoglobulin-like Receptors (KIR) component of the 17th International HLA and Immunogenetics Workshop

The goals of the KIR component of the 17th International HLA and Immunogenetics Workshop (IHIW) were to encourage and educate researchers to begin analyzing KIR at allelic resolution, and to survey the nature and extent of KIR allelic diversity across human populations. To represent worldwide diversity, we analyzed 1269 individuals from ten populations, focusing on the most polymorphic KIR genes, which express receptors having three immunoglobulin (Ig)-like domains (KIR3DL1/S1, KIR3DL2 and KIR3DL3). We identified 13 novel alleles of KIR3DL1/S1, 13 of KIR3DL2 and 18 of KIR3DL3. Previously identified alleles, corresponding to 33 alleles of KIR3DL1/S1, 38 of KIR3DL2, and 43 of KIR3DL3, represented over 90% of the observed allele frequencies for these genes. In total we observed 37 KIR3DL1/S1 allotypes, 40 for KIR3DL2 and 44 for KIR3DL3. As KIR allotype diversity can affect NK cell function, this demonstrates potential for high functional diversity worldwide. Allelic variation further diversifies KIR haplotypes. We determined KIR3DL3 ∼ KIR3DL1/S1 ∼ KIR3DL2 haplotypes from five of the studied populations, and observed multiple population-specific haplotypes in each. This included 234 distinct haplotypes in European Americans, 191 in Ugandans, 35 in Papuans, 95 in Egyptians and 86 in Spanish populations. For another 35 populations, encompassing 642,105 individuals we focused on KIR3DL2 and identified another 375 novel alleles, with approximately half of them observed in more than one individual. The KIR allelic level data gathered from this project represents the most comprehensive summary of global KIR allelic diversity to date, and continued analysis will improve understanding of KIR allelic polymorphism in global populations. Further, the wealth of new data gathered in the course of this workshop component highlights the value of collaborative, community-based efforts in immunogenetics research, exemplified by the IHIW.

Interleukin-28B TT genotype is frequently found in patients with hepatitis C virus cirrhosis but does not influence hepatocarcinogenesis

Persistent hepatitis C virus (HCV) infection is associated with progressive hepatic fibrosis and ultimately hepatocellular carcinoma. The interleukin-28B (IL28B) rs12979860 polymorphism is associated with fibrosis progression in chronic HCV infection. IL28B encodes interferon-λ, which has both antiviral and anti-proliferative properties. This study aimed to determine whether IL28B rs12979860 polymorphism is also associated with development of hepatocellular carcinoma both in chronic HCV infection and in non-viral-related cirrhosis. Real-time polymerase chain reaction and melting curve analyses were used to genotype 311 patients who underwent liver transplantation for HCV cirrhosis (n = 202) or alcoholic cirrhosis (n = 109). HCV patients were older (p = 0.012) and less likely males (p < 0.001) than patients with alcoholic cirrhosis. IL28B rs12979860 TT genotype [OR 6.08, 95 % CI 2.11-17.53; p < 0.001] and T allele carriage (CT + TT; OR 2.3, CI 95 % 1.42-3.72; p = 0.001) were more frequent among HCV patients and, among them, more common in patients infected with HCV genotype 1 (CT + TT; OR 1.79, CI 95 % 1.03-3.09; p = 0.009). Incidence of hepatocellular carcinoma was higher in HCV cirrhosis (OR 2.7, CI 95 % 1.5-4.7; p < 0.001), with no differences according to HCV genotype. IL28B genotype distribution was similar among patients with or without hepatocellular carcinoma, in both HCV patients regardless viral genotype (p = 0.84) and alcoholic patients (p = 0.91). Multivariate analysis showed that older age (OR 1.06, CI 95 % 1.02-1.1; p = 0.003) and male gender (OR 2.49, CI 95 % 1.24-5; p = 0.01) were independent risk factors for hepatocellular carcinoma in HCV patients. In summary, the current study did not find a significant association between IL28B rs12979860 polymorphism and hepatocarcinogenesis.

Report From the First and Second Spanish Killer Immunoglobulin-Like Receptor Genotyping Workshops: External Quality Control for Natural Killer Alloreactive Donor Selection in Haploidentical Stem Cell Transplantation

An important factor affecting the success in the setting of related haploidentical hematopoietic stem cell transplantation (HSCT) is the graft-versus-leukemia effect mediated by natural killer (NK) cells when the donor displays NK alloreactivity versus the recipient. NK cell function is regulated by killer immunoglobulin-like receptors (KIR) and it has been described that donor KIR genotype influences transplantation outcome. This has led to a requirement of laboratories to have a quality assurance program for validation and control of their KIR genotyping methods. The goal of the 1st and 2nd Spanish KIR Genotyping Workshops was to provide an external proficiency testing program in KIR genotyping for Spanish immunology and transplant laboratories. These workshops were conducted during the years 2014-2016 and consisted of 17 participating laboratories typing a set of 20 samples. The presence/absence of 16 mandatory KIR loci (2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 2DS1, 2DS2, 2DS3, 2DS4, 2DS5, 2DP1, 3DL1, 3DL2, 3DL3, 3DS1, and 3DP1) was evaluated per sample. Methods for KIR genotyping included polymerase chain reaction with the use of sequence-specific primers and sequence-specific oligoprobes. Consensus typing was reached in all samples, and the performance of laboratories in external proficiency testing was satisfactory in all cases. The polymorphism detected in the small sample studied in both workshops is indicative of an ample variety of KIR gene profiles in the Spanish population.

Allelic Polymorphism Determines Surface Expression or Intracellular Retention of the Human NK Cell Receptor KIR2DL5A (CD158f)

KIR2DL5 (CD158f) is the most recently identified inhibitory member of human killer-cell Ig-like receptors (KIRs), which enable NK cells to sense self-HLA. Unlike KIR2DL1–3, recognizing HLA-C allotypes through Ig-like domains of the D1–D2 type, KIR2DL5 shares a D0–D2 configuration with KIR2DL4, and its ligands have not been identified. KIR2DL5 is encoded by two paralogous genes displaying copy number variation and allelic polymorphism—KIR2DL5A and KIR2DL5B. UP-R1 mAb, raised against the common allele KIR2DL5A*001, enables specific KIR2DL5 detection. However, not every KIR2DL5⁺ individual has NK cells staining with UP-R1, discrepancy explained in part by epigenetically silent KIR2DL5B alleles with a distinctive substitution in a promoter RUNX-binding site. Furthermore, we show here that the transcribed allele KIR2DL5A*005, second most common of its locus, fails to confer NK cells UP-R1 reactivity, phenotype explained by inefficacious transport of its product to the cell surface. Two amino acid substitutions distinguish the KIR2DL5A*005 and *001 coding regions. Western blot, flow cytometry, and confocal microscopy analyses of cells transfected with tagged constructs demonstrate that a serine substitution for glycine-174, conserved in most KIR, is mainly responsible for KIR2DL5A*005 intracellular retention, and it also affects mAb recognition. In contrast, substitution of aspartate for asparagine 152 has only a minor effect on surface expression, despite destroying an otherwise conserved N-glycosylation site. Our results help to explain the variable expression profile of KIR2DL5⁺ subjects and indicate that functional polymorphisms in both its promoter and its coding regions are critical for understanding the KIR2DL5 role in immunity and its importance for human health.

Activated Allogeneic NK Cells Preferentially Kill Poor Prognosis B-Cell Chronic Lymphocytic Leukemia Cells

Mutational status of TP53 together with expression of wild-type (wt) IGHV represents the most widely accepted biomarkers, establishing a very poor prognosis in B-cell chronic lymphocytic leukemia (B-CLL) patients. Adoptive cell therapy using allogeneic HLA-mismatched Natural killer (NK) cells has emerged as an effective and safe alternative in the treatment of acute myeloid and lymphoid leukemias that do not respond to traditional therapies. We have described that allogeneic activated NK cells eliminate hematological cancer cell lines with multidrug resistance acquired by mutations in the apoptotic machinery. This effect depends on the activation protocol, being B-lymphoblastoid cell lines (LCLs) the most effective stimulus to activate NK cells. Here, we have further analyzed the molecular determinants involved in allogeneic NK cell recognition and elimination of B-CLL cells, including the expression of ligands of the main NK cell-activating receptors (NKG2D and NCRs) and HLA mismatch. We present preliminary data suggesting that B-CLL susceptibility significantly correlates with HLA mismatch between NK cell donor and B-CLL patient. Moreover, we show that the sensitivity of B-CLL cells to NK cells depends on the prognosis based on TP53 and IGHV mutational status. Cells from patients with worse prognosis (mutated TP53 and wt IGHV) are the most susceptible to activated NK cells. Hence, B-CLL prognosis may predict the efficacy of allogenic activated NK cells, and, thus, NK cell transfer represents a good alternative to treat poor prognosis B-CLL patients who present a very short life expectancy due to lack of effective treatments.

Relationship of NKG2C Copy Number with the Distribution of Distinct Cytomegalovirus-Induced Adaptive NK Cell Subsets

CD94/NKG2C and lack of FcεRγ (FcRγ) expression are considered markers of the adaptive NK cell response to human CMV (HCMV) infection. Despite the fact that FcRγ(-) and NKG2C(bright) NK cells share some phenotypic, epigenetic, and functional features, their relationship remains unclear. To address this issue, a systematic analysis of NKG2C(bright) and FcRγ expression was carried out in NK cells from a cohort of healthy young adults (n = 81) considering NKG2C copy number, previously related to the magnitude of NKG2C(+) NK cell expansion. NKG2C(bright) and FcRγ(-) NK cells coincided in a subgroup of HCMV(+) individuals, pointing to a common host-virus interaction pattern. Even though FcRγ loss was often confined to expanded NKG2C(bright) NK cells, both markers appeared occasionally dissociated, consistent with the existence of distinct adaptive NK cell subsets. Remarkably, FcRγ loss was mostly accumulated within the NKG2C(bright) subset in NKG2C(+/+) subjects, whereas NKG2C(-)FcRγ(-) NK cell subpopulations were more frequently detected in NKG2C(+/del) donors and also in NKG2C(del) (/del) individuals, independently of activating killer Ig-like receptor expression. The distribution of other NK receptors (i.e., killer Ig-like receptor, LILRB1, or CD57) supported a sequential differentiation from NKG2C(bright)FcRγ(+) to NKG2C(bright)FcRγ(-) NK cells. Noticeably, NKG2C(bright) NK cells produced more TNF-α in response to Ab-dependent activation, regardless of their FcRγ levels. Moreover, the TNF-α response of NKG2C(-)FcRγ(-) subpopulations was lower than that of concurrent NKG2C(bright)FcRγ(-) NK cells, further supporting that FcRγ levels and enhanced potential for cytokine production are uncoupled. Overall, our data extend the characterization of adaptive NK cell subsets that differentiate in response to HCMV, supporting a relationship between their distribution and NKG2C copy number.

CC genotype at rs12979860 of IL28B is associated with lower risk of new-onset diabetes after transplantation in adult patients with liver transplantation for hepatitis C cirrhosis

INTRODUCTION

New-onset diabetes mellitus after transplantation (NODAT) in patients undergoing liver transplantation (LT) for hepatitis C virus (HCV)-related cirrhosis is associated with more aggressive HCV recurrence on the graft, rapid progression of fibrosis, and lower rate of sustained viral response to antiviral therapy. The CC genotype at rs12979860 of the IL28B is associated with greater rates of spontaneous clearance of HCV and response to antiviral therapy. IL28B acts on the interferon-stimulated genes through the JAK-STAT pathway, which is related to the development of insulin resistance. The aim of this study was to investigate whether IL28B rs12979860 polymorphism is associated with the development of NODAT after LT for cirrhosis owing to HCV infection.

METHODS

We analyzed 99 patients (age, 52.7 ± 9.4 years; 70% male) who underwent LT for HCV-related cirrhosis, with ≥1 year of follow-up and with available DNA sample. NODAT was defined starting from the sixth month after LT, according to the international consensus guidelines. Genotyping was carried out by real-time polymerase chain reaction and analysis of the melting temperature with the LightCycler 480 system.

RESULTS

Twenty-eight patients (28.3%) developed NODAT. CC genotype at rs12979860 of IL28B was associated with a lesser incidence of NODAT versus non-CC genotypes (P = .05; odds ratio, 0.31; 95% CI, 0.11-0.92). We did not find any association between NODAT and age at transplantation, gender, pretransplant body mass index, presence of hepatocellular carcinoma, type of initial immunosuppression (cyclosporine, tacrolimus or corticosteroids) or acute rejection treated with steroids.

CONCLUSION

The CC genotype at rs12979860 of IL28B is a protective factor for NODAT in patients with LT for HCV-related cirrhosis.

Advancing allele group-specific amplification of the complete HLA-C gene--isolation of novel alleles from three allele groups (C*04, C*07 and C*08)

A variety of strategies have been designed for sequence-based HLA typing (SBT) and for the isolation of new human leucocyte antigen (HLA) alleles, but unambiguous characterization of complete genomic sequences remains a challenge. We recently reported a simple method for the group-specific amplification (GSA) and sequencing of a full-length C*04 genomic sequence in isolation from the accompanying allele. Here we build on this strategy and present homologous methods that enable the isolation of HLA-C alleles belonging to another two allele groups. Using this approach, which can be applied to sequence-based typing in some clinical settings, we have successfully characterized three novel HLA-C alleles (C*04:128, C*07:01:01:02, and C*08:62).

KIR typing by non-sequencing methods: polymerase-chain reaction with sequence-specific primers

The killer-cell immunoglobulin-like receptors (KIR), which enable NK cells to detect allogeneic target cells and abnormalities in the expression of self-HLA molecules, are encoded by genes that display extensive copy number variation. These variations in the KIR genotype are relevant for multiple aspects of human health, including therapy of cancer. PCR with sequence-specific primers (SSP) is simplest and most widely used among techniques for studying KIR genotypes. Here, we present a protocol that details the critical steps of a method for KIR genotyping by PCR-SSP.

KIR2DL5: An Orphan Inhibitory Receptor Displaying Complex Patterns of Polymorphism and Expression

A recently developed anti-KIR2DL5 (CD158f) antibody has demonstrated KIR2DL5 expression on the surface of NK and T lymphocytes, making it the last functional KIR identified in the human genome. KIR2DL5 belongs to an ancestral lineage of KIR with Ig-like domains of the D0-D2 type, of which KIR2DL4, an HLA-G receptor, is the only other human member. Despite KIR2DL4 and KIR2DL5 being encoded by genes with similar domain usage, several KIR2DL5 functions resemble more closely those of KIR recognizing classical HLA class I molecules - surface-expressed KIR2DL5 inhibits NK cells through the SHP-2 phosphatase and displays a clonal distribution on NK and T lymphocytes. No activating homolog of KIR2DL5 has been described in any species. The genetics of KIR2DL5 is complicated by duplication of its gene in an ancestor of modern humans living ∼1.7 million years ago. Both KIR2DL5 paralogs have undergone allelic diversification; the centromeric gene is most often represented by alleles whose expression is silenced epigenetically through DNA methylation, thus providing a natural system to investigate the regulation of KIR transcription. The role of KIR2DL5 in immunity is not completely understood, in spite of different attempts to define its ligand. Here we revisit the most relevant characteristics of KIR2DL5, an NK-cell receptor possessing a unique combination of genetic, structural, and functional features.

Increased risk of severe hepatitis C virus recurrence after liver transplantation in patients with a T allele of IL28B rs12979860

BACKGROUND

Polymorphisms of the IL28B gene (encoding interferon-λ3) determine the spontaneous course of hepatitis C virus (HCV) infection and its response to antiviral therapy. We investigated the influence of the IL28B rs12979860 (C>T) polymorphism on the risk of severe HCV recurrence after liver transplantation.

METHODS

Ninety patients who underwent transplantation because of HCV cirrhosis were retrospectively analyzed; forty-one (45.6%) of them with severe HCV recurrence. Forty-eight of their paired donors were available and were also analyzed. IL28B rs12979860 was genotyped by real-time polymerase chain reaction, and evaluated for association with severe HCV recurrence, along with other variables, by univariate and multivariate analyses.

RESULTS

The risk allele rs12979860-T was more common in transplanted patients (66.7%) than reported in healthy whites, and it was significantly overrepresented among patients with severe HCV recurrence, in comparison with patients without it (82.9% vs. 53.1%, odds ratio [OR]=4.30, etiologic fraction=63.6%; P=0.0028). Furthermore, separate analysis of the recipients' genotypes indicated that the risk of severe HCV recurrence increased with the dose of the T allele (linear trend, P=0.0068). Multiple logistic regression analysis confirmed the contribution of the IL28B genotype to the risk of severe HCV recurrence (OR=4.27; P=0.014), independently of other associated factors. Allele IL28B T in the donor seemed to have an opposite effect than that in the recipient (OR=0.46), but the study was underpowered to demonstrate this unforeseen effect (P=0.1995).

CONCLUSIONS

The recipient IL28B rs12979860 genotype has a major influence on the posttransplantation course of HCV infection, being a valuable biomarker for patient care in liver transplantation.

Analysis of exosome release and its prognostic value in human colorectal cancer

A significant proportion of extracellular nucleic acids in plasma circulate highly protected in tumor-specific exosomes, but it is unclear how the release of exosomes is modulated in carcinogenesis. We quantified by cytometry exosomes in plasma of 91 colorectal cancer patients to evaluate their potential as a tumor indicator and their repercussions on diagnosis and prognosis. We examined the involvement of TSAP6, a TP53-regulated gene involved in the regulation of vesicular secretion, in levels of circulating exosomes in plasma of colorectal patients and in HCT116 TP53-(wild-type and null) human colorectal cancer cell lines. The fraction of exosomes in cancer patients was statistically higher than in healthy controls (mean rank ¼ 53.93 vs. 24.35). High levels of exosomes in plasma of patients correlated with high levels of carcino-embryonic antigen (P ¼ 0.029) and with poorly differentiated tumors (P ¼ 0.039) and tended to have shorter overall survival than patients with low levels (P ¼ 0.056). Release of exosomes did not correlate with TSAP6 expression; and regulation of TSAP6 by TP53 was not shown either in tumor samples or in HCT116 cell lines. Although it was not suggested that the TP53/TSAP6 pathway regulates the release of exosomes into the plasma of colorectal cancer patients, the level of circulating exosomes may be used as a tumor indicator, because it correlates with poor prognosis parameters and shorter survival.

Host genetic factors in susceptibility to herpes simplex type 1 virus infection: contribution of polymorphic genes at the interface of innate and adaptive immunity

HSV-1 establishes life-long latency that can result in clinical relapses or in asymptomatic virus shedding. Although virtually all adults have been exposed to HSV-1, the clinical course varies remarkably. Genetic host variability could be related to this clinical diversity. In this study, we analyzed the contribution of gene families in chromosomes 1, 6, 12, and 19, which encode key regulators of the innate and adaptive immunity, in a cohort of 302 individuals. Class I and class II alleles of the HLA system, the copy-number variation of NK cell receptor genes (KIR and NKG2C), the combinations of killer cell Ig-like receptor and their HLA ligands, and CD16A and CD32A allotypes of variable affinity for IgG subclasses were all studied. Although no major susceptibility locus for HSV-1 was identified, our results show that the risk of suffering clinical HSV-1 infection is modified by MHC class I allotypes (B*18, C*15, and the group of alleles encoding A19), the high-affinity receptor/ligand pair KIR2DL2/HLA-C1, and the CD16A-158V/F dimorphism. Conversely, HLA class II and CD32A polymorphisms and NKG2C deletion did not seem to influence the clinical course of herpetic infection. Collectively, these findings support an important role in host defense against herpetic infection for several polymorphic genes implicated in adaptive immunity and in surveillance of its subversion. They confirm the crucial role of cytotoxic cells (CTL and NK) and the contribution of genetic diversity to the clinical course of HSV-1 infection.

A method for simple and accurate identification of the multiple sclerosis associated allele HLA-DRB1*1501 in neuroscience research laboratories

Research on multiple sclerosis (MS) frequently requires typing for allele HLA-DRB1*1501, which the complexities of the HLA system can restrict to specialised histocompatibility laboratories. To overcome this limitation, we have implemented a simple, robust and highly specific method for DRB1*1501 detection. One single-tube polymerase-chain reaction (PCR) per DNA sample allows for detecting DR2 individuals. The spare PCR products of these are then sequenced to identify allele DRB1*1501 by comparison with the official, publicly accessible HLA database. This approach, much simpler than previously available methods, should facilitate research on MS by making accurate identification of DRB1*1501 accessible to neuroscience laboratories.

Cerebrospinal fluid cyclic guanosine 3'5' monophosphate levels in Parkinson's disease

We measured CSF and plasma levels of cGMP in 22 patients with Parkinson's disease (PD) and in 28 age and sex-matched controls. PD patients had similar plasma cGMP levels than those of controls, although they showed a non-significant trend towards higher CSF cGMP levels (P=0.07). PD patients treated with levodopa showed significantly higher CSF cGMP levels than those not treated with this drug (P<0.01), and controls (P<0.01). However, treatment with dopamine agonists did not influence CSF cGMP levels. Plasma and CSF levels of cGMP did not correlate with age at onset, duration, and severity of PD. These results suggest that changes in the concentration of cGMP in CSF of patients with PD are not related with the disease, but rather with levodopa therapy.

Osmotically induced response in representatives of halophilic prokaryotes: the bacterium Halomonas elongata and the archaeon Haloferax volcanii

Haloferax volcanii and Halomonas elongata have been selected as representatives of halophilic Archaea and Bacteria, respectively, to analyze the responses to various osmolarities at the protein synthesis level. We have identified a set of high-salt-related proteins (39, 24, 20, and 15.5 kDa in H. elongata; 70, 68, 48, and 16 kDa in H. volcanii) whose synthesis rates increased with increasing salinities. A different set of proteins (60, 42, 15, and 6 kDa for H. elongata; 63, 44, 34, 18, 17, and 6 kDa for H. volcanii), some unique for low salinities, was induced under low-salt conditions. For both organisms, and especially for the haloarchaeon, adaptation to low-salt conditions involved a stronger and more specific response than adaptation to high-salt conditions, indicating that unique mechanisms may have evolved for low-salinity adaptation. In the case of H. volcanii, proteins with a typical transient response to osmotic shock, induced by both hypo- and hyperosmotic conditions, probably corresponding to described heat shock proteins and showing the characteristics of general stress proteins, have also been identified. Cell recovery after a shift to low salinities was immediate in both organisms. In contrast, adaptation to higher salinities in both cases involved a lag period during which growth and general protein synthesis were halted, although the high-salt-related proteins were induced rapidly. In H. volcanii, this lag period corresponded exactly to the time needed for cells to accumulate adequate intracellular potassium concentrations, while extrusion of potassium after the down-shift was immediate. Thus, reaching osmotic balance must be the main limiting factor for recovery of cell functions after the variation in salinity.

Neurotransmitter amino acids in cerebrospinal fluid of patients with Parkinson's disease

We measured the CSF and plasma levels of glutamate, glutamine, aspartate (only in plasma), asparagine, glutamine, glycine and GABA in 31 patients with Parkinson's disease and in 45 matched controls. We used an ion-exchange chromatography method. When compared to controls, PD patients had similar CSF levels of glutamate, glutamine, asparagine, and glycine higher CSF GABA levels higher plasma levels of glutamine, asparagine, and glycine, and lower plasma levels of aspartate. The CSF levels of the amino acids measured were not correlated with the clinical features of PD. Our results that CSF GABA levels are not decreased in PD as previously suggested.

Cerebrospinal fluid nitrate levels in patients with Parkinson's disease

It has been suggested that nitric oxide could be implicated in the neuronal degeneration of substantia nigra compacta in patients with Parkinson's disease. Recently, it has been reported decreased CSF nitrate levels (oxidation product that provides an indirect estimation of nitric oxide) in Parkinson's disease patients, assessed with a colorimetric method. We studied the CSF and plasma levels of nitrate with a kinetic cadmium-reduction method in 31 Parkinson's disease patients and 38 matched controls. The CSF and plasma nitrate levels were not correlated either in patient or in the control group, and they did not differ significantly between the two study groups. They were not influenced significantly by antiparkinsonian drugs in patients, although there was a trend for CSF nitrate levels to be higher in patients treated with levodopa or with dopamine agonists. CSF and plasma nitrate levels did not correlate with age at onset, duration, scores of the unified Parkinson's disease rating scales and Hoehn & Yahr staging in the patients group. These date suggest that CSF and plasma levels of nitrate are apparently unrelated with the risk for PD.

Restriction end-converting vectors with tandem repeated multiple cloning sites

The construction, characterization and uses of four vectors with novel multiple cloning sites (MCS) are described. The MCS consist of a central zone with unique restriction sites, flanked by two zones in which four sites are repeated in a direct sense. These vectors allow the insertion of fragments with the same or different restriction ends and their rescue with a multiple combination of ends, identical or different. This system conserves the XGal blue-white selection characteristics of the pUC plasmids, as well as their use as sequencing vehicles.

Distribution of insertion sequence IS1 in multiple-antibiotic resistant clinical Enterobacteriaceae strains

The presence of insertion sequence IS1 in 70 multiple-antibiotic resistant clinical strains was determined. This 70-strain collection comprised 46 Escherichia coli, 18 Salmonella and 6 Shigella strains. The presence of IS1 was detected in the chromosome and plasmids of 73% and 63% of the strains, respectively, and 51% of the strains carried IS1 in both. The frequency of IS1 was higher in Salmonella than in E. coli and Shigella strains. A total of 31 strains carried large plasmids with IS1; 10 of these strains (32.3%) were able to transfer all or some of the antibiotic resistance markers to E. coli K12 or S. typhimurium recipient strains. Resistance markers of all clinical strains were maintained stably after several generations of growth. The presence of IS1 in a relatively high percentage of plasmids of multiple-antibiotic resistant clinical isolates, suggests a role for this sequence in the dissemination of genes which code for antibiotic resistance.