Memory precursor phenotype of CD8+ T cells reflects early antigenic experience rather than memory numbers in a model of localized acute influenza infection

The mechanistic basis of memory T‐cell development is poorly defined. Phenotypic markers that define precursors at effector stages have been characterized for acute systemic infections with high antigen load. We asked whether such markers can identify memory precursors from early effectors (d6) to late memory (>d500) for two immunodominant CD8⁺ responses during the course of a localized low‐load influenza infection in mice. CD8⁺ T cells stained with the D^bNP₃₆₆ and D^bPA₂₂₄ tetramers were characterized as IL‐7Rα^hi, IL‐7Rα^hiCD62L^hi or IL‐7Rα^hiKLRG1^lo. While the D^bNP₃₆₆‐ and D^bPA₂₂₄‐specific responses were comparable in size, decay kinetics and memory precursor frequency, their expansion characteristics differed. This correlated with a divergence in the IL‐7Rα^hi, IL‐7Rα^hiCD62L^hi and IL‐7Rα^hiKLRG1^lo phenotypes on effector, but not naïve, CD8⁺ populations. That effect was abrogated by priming with viruses engineered to present equivalent levels of NP₃₆₆ and PA₂₂₄ peptides, indicating that memory phenotypes reflect early antigenic experience rather than memory potential. Thus, the IL‐7Rα^hiKLRG1^lo phenotype had a poor predictive value in identifying memory precursors in the spleen and at the site of infection. Greater consistency in influenza‐specific IL‐7Rα^hiKLRG1^loCD8⁺ T‐cell numbers was found in draining lymph nodes, suggesting that this may be the preferential site for memory establishment and maintenance following localized virus infections.     

Primary hepatic marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type in a patient with primary biliary cirrhosis

Primary lymphoma of the liver is rare. Recently, marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type have been described in the liver. Most of these cases occurred without known underlying liver disease, while others were seen in patients with chronic hepatitis. A case of primary hepatic MALT lymphoma in a patient with primary biliary cirrhosis was reported recently. Some authors have proposed that chronic persistent immunogenic stimulation causes development of acquired MALT and subsequently MALT lymphoma, based on the observation of MALT lymphoma in association with infectious agents, such as Helicobacter pylori and hepatitis C virus, and autoimmune diseases, such as Hashimoto thyroiditis and Sj?gren syndrome. Primary biliary cirrhosis is a chronic, progressive, cholestatic liver disease characterized by destruction of intrahepatic small to medium-sized bile ducts; this disease is mediated by a cytotoxic T-cell reaction. The prolonged immune activation in primary biliary cirrhosis may play a role in the lymphomagenesis of hepatic MALT lymphoma. We describe another case of primary hepatic MALT lymphoma, which was found incidentally in a patient with end-stage primary biliary cirrhosis. This case further supports the role of immunogenic stimulation in the pathogenesis of this particular low-grade B-cell lymphoma.     

Increased hepatic iron deposition resulting from treatment of chronic hepatitis C with ribavirin

Increased levels of hepatic iron may impair the response of patients with chronic hepatitis C to treatment with interferon-alfa, but combination therapy with ribavirin has demonstrated efficacy in the treatment of hepatitis C. When used alone or with interferon-alfa, ribavirin may cause a dose-dependent reversible hemolytic anemia. We compared the extent and cellular localization of iron deposition in liver tissue from biopsy specimens obtained before and after 36 weeks of therapy with ribavirin or placebo for 59 patients with chronic hepatitis C. Paired slides were available for review from 26 ribavirin and 27 placebo recipients. Iron deposition was assessed using coded slides stained with Perls Prussian blue and was semi-quantitated in hepatocytes, Kupffer cells, and areas of fibrosis. The overall iron score fell by 0.96 in the placebo group and increased 1.69 in the ribavirin recipients. Iron was deposited mainly in hepatocytes; the hepatocyte iron score increased from 2.19 to 3.81 in the ribavirin group. The amount of iron staining in Kupffer cells declined in the placebo group and increased slightly in the ribavirin group. Iron changes in areas of fibrosis were minor and did not differ between groups. Increased total hepatic iron deposition occurred during a 9-month course of ribavirin. Ribavirin-associated hemolysis deposits iron preferentially in hepatocytes. This increased deposition of hepatic iron does not seem to affect the biochemical or histologic response to ribavirin therapy but may have implications for hepatocyte susceptibility to future injury.     

Fear and Missing Out: Youth Anxiety and Functional Outcomes

Anxiety disorders are prevalent and associated with functional impairments. Outcome research has focused on symptom reduction, rather than positive factors such as life satisfaction and improved functioning. We review the impact of youth anxiety disorders and elevated anxiety symptoms on academic, occupational, family, social, and legal functioning. Emphasis is placed on the degree to which developmental trajectories differ for youth with and without anxiety disorders. In some areas, psychopathology generally, rather than anxiety specifically, is associated with functional impairment. Other studies support youth anxiety as a unique predictor of functional impairment. In particular, social anxiety is associated with impairments in social functioning throughout development. The short‐ and long‐term impacts of anxiety treatment in youth are discussed. Last, research directions are suggested.     

Macrophage accumulation in gut mucosa differentiates AIDS from chronic SIV infection in rhesus macaques

The relationship between recruitment of mononuclear phagocytes to lymphoid and gut tissues and disease in HIV and SIV infection remains unclear. To address this question, we conducted cross‐sectional analyses of dendritic cell (DC) subsets and CD163⁺ macrophages in lymph nodes (LNs) and ileum of rhesus macaques with acute and chronic SIV infection and AIDS. In LNs significant differences were only evident when comparing uninfected and AIDS groups, with loss of myeloid DCs and CD103⁺ DCs from peripheral and mesenteric LNs, respectively, and accumulation of plasmacytoid DCs and macrophages in mesenteric LNs. In contrast, there were fourfold more macrophages in ileum lamina propria in macaques with AIDS compared with chronic infection, and this increased to 40‐fold in Peyer's patches. Gut macrophages exceeded plasmacytoid DCs and CD103⁺ DCs by ten‐ to 17‐fold in monkeys with AIDS but were at similar low frequencies as DCs in chronic infection. Gut macrophages in macaques with AIDS expressed IFN‐α and TNF‐α consistent with cell activation. CD163⁺ macrophages also accumulated in gut mucosa in acute infection but lacked expression of IFN‐α and TNF‐α. These data reveal a relationship between inflammatory macrophage accumulation in gut mucosa and disease and suggest a role for macrophages in AIDS pathogenesis.     

High-throughput gene mapping in Caenorhabditis elegans

Positional cloning of mutations in model genetic systems is a powerful method for the identification of targets of medical and agricultural importance. To facilitate the high-throughput mapping of mutations in Caenorhabditis elegans, we have identified a further 9602 putative new single nucleotide polymorphisms (SNPs) between two C. elegans strains, Bristol N2 and the Hawaiian mapping strain CB4856, by sequencing inserts from a CB4856 genomic DNA library and using an informatics pipeline to compare sequences with the canonical N2 genomic sequence. When combined with data from other laboratories, our marker set of 17,189 SNPs provides even coverage of the complete worm genome. To date, we have confirmed >1099 evenly spaced SNPs (one every 91 +/- 56 kb) across the six chromosomes and validated the utility of our SNP marker set and new fluorescence polarization-based genotyping methods for systematic and high-throughput identification of genes in C. elegans by cloning several proprietary genes. We illustrate our approach by recombination mapping and confirmation of the mutation in the cloned gene, dpy-18.     

Autosomal dominant SCA5 and autosomal recessive infantile SCA are allelic conditions resulting from SPTBN2 mutations

Although many genes have been identified for the autosomal recessive cerebellar ataxias (ARCAs), several patients are unlinked to the respective loci, suggesting further genetic heterogeneity. We combined homozygosity mapping and exome sequencing in a consanguineous Egyptian family with congenital ARCA, mental retardation and pyramidal signs. A homozygous 5-bp deletion in SPTBN2, the gene whose in-frame mutations cause autosomal dominant spinocerebellar ataxia type 5, was shown to segregate with ataxia in the family. Our findings are compatible with the concept of truncating SPTBN2 mutations acting recessively, which is supported by disease expression in homozygous, but not heterozygous, knockout mice, ataxia in Beagle dogs with a homozygous frameshift mutation and, very recently, a homozygous SPTBN2 nonsense mutation underlying infantile ataxia and psychomotor delay in a human family. As there was no evidence for mutations in 23 additional consanguineous families, SPTBN2-related ARCA is probably rare.     

Individual and environmental correlates of dietary fat intake in rural communities: A structural equation model analysis

Total dietary fat and saturated fat intake are associated with obesity, elevated cholesterol, and heart disease. This study tested a multi-group structural equation model to explore differences in the relative influence of individual, social, and physical environment factors on dietary fat intake amongst adults aged 40–70 years. Participants from four rural Georgia, U.S., counties (n = 527) completed a cross-sectional survey that included questions about eating patterns and individual and social influences on healthy eating. Observational measures of nutrition environments in stores and restaurants in these counties also were completed. Models for both women and men found significant positive relationships between self-efficacy for healthy eating and perceived nutrition environments and family support for healthy eating. The association between self-efficacy for eating a low-fat diet and frequency of eating out and grocery shopping was negative for both genders. The home nutrition environment was associated with dietary fat intake for women but not men. The results indicate that the influence of individual and environmental factors on dietary fat intake differs for men and women, with the home environment playing a larger role for women in rural communities.