Viral Specific Factors Contribute to Clinical Respiratory Syncytial Virus Disease Severity Differences in Infants.

BACKGROUND: There is a wide range of severity of respiratory syncytial viral (RSV) disease in previously healthy infants. Host factors have been well demonstrated to contribute to disease severity differences. However the possibility of disease severity differences being produced by factors intrinsic to the virus itself has rarely been studied. METHODS: Low-passage isolates of RSV collected prospectively from infants with different degrees of RSV disease severity were evaluated in vitro, holding host factors constant, so as to assess whether isolates induced phenotypically different cytokine/chemokine concentrations in a human lung epithelial cell line. Sixty-seven RSV isolates from previously healthy infants (38 hospitalized for acute RSV infection (severe disease) and 29 never requiring hospitalization (mild disease)) were inoculated into A549, lung epithelial cells at precisely controlled, low multiplicity of infection to mimic natural infection. Cultures were evaluated at 48 hours, 60 hours, and 72 hours to evaluate area under the curve (AUC) cytokine/chemokine induction. RESULTS: Cells infected with isolates from severely ill infants produced higher mean concentrations of all cytokine/chemokines tested (IL-1α, IL-6, IL-8 and RANTES) at all-time points tested. RSV isolates collected from infants with severe disease induced significantly higher AUCIL-8 and AUCRANTES secretion in infected cultures than mild disease isolates (p=0.028 and p=0.019 respectively). IL-8 and RANTES concentrations were 4 times higher at 48 hours for these severely ill infant isolates. Additionally, 38 isolates were evaluated at all-time points for quantity of virus. RSV concentration significantly correlated with both IL-8 and RANTES at all-time points. Neither cytokine/chemokine concentrations nor RSV concentrations were associated with RSV subgroup. DISCUSSION: Infants' RSV disease severity differences may be due in part to intrinsic viral strain-specific characteristics.

Effect of Preexisting Serum and Mucosal Antibody on Experimental Respiratory Syncytial Virus (RSV) Challenge and Infection of Adults.

We studied preexisting respiratory syncytial virus (RSV)-specific serum and nasal antibodies and their correlation with infectivity, viral dynamics, and disease severity in a human experimental infection model. Higher preinoculation serum neutralizing antibody titers and nasal immunoglobulin (Ig) A predicted lower infectivity and lower measures of viral replication. However, once individuals were infected, no significant protective effect of preexisting antibodies was seen. Lack of correlation between serum and mucosal antibodies was observed, implying that they are independent co-correlates of protection against RSV infection. We suggest that protection from RSV infection is a function of a complex interplay between mucosal and serum humoral immune responses.

Mucosal immune responses predict clinical outcomes during influenza infection independently of age and viral load.

RATIONALE: Children are an at-risk population for developing complications following influenza infection, but immunologic correlates of disease severity are not understood. We hypothesized that innate cellular immune responses at the site of infection would correlate with disease outcome. OBJECTIVES: To test the immunologic basis of severe illness during natural influenza virus infection of children and adults at the site of infection. METHODS: An observational cohort study with longitudinal sampling of peripheral and mucosal sites in 84 naturally influenza-infected individuals, including infants. Cellular responses, viral loads, and cytokines were quantified from nasal lavages and blood, and correlated to clinical severity. MEASUREMENTS AND MAIN RESULTS: We show for the first time that although viral loads in children and adults were similar, innate responses in the airways were stronger in children and varied considerably between plasma and site of infection. Adjusting for age and viral load, an innate immune profile characterized by increased nasal lavage monocyte chemotactic protein-3, IFN-α2, and plasma IL-10 levels at enrollment predicted progression to severe disease. Increased plasma IL-10, monocyte chemotactic protein-3, and IL-6 levels predicted hospitalization. This inflammatory cytokine production correlated significantly with monocyte localization from the blood to the site of infection, with conventional monocytes positively correlating with inflammation. Increased frequencies of CD14(lo) monocytes were in the airways of participants with lower inflammatory cytokine levels. CONCLUSIONS: An innate profile was identified that correlated with disease progression independent of viral dynamics and age. The airways and blood displayed dramatically different immune profiles emphasizing the importance of cellular migration and localized immune phenotypes.

HLA targeting efficiency correlates with human T-cell response magnitude and with mortality from influenza A infection.

Experimental and computational evidence suggests that HLAs preferentially bind conserved regions of viral proteins, a concept we term "targeting efficiency," and that this preference may provide improved clearance of infection in several viral systems. To test this hypothesis, T-cell responses to A/H1N1 (2009) were measured from peripheral blood mononuclear cells obtained from a household cohort study performed during the 2009-2010 influenza season. We found that HLA targeting efficiency scores significantly correlated with IFN-γ enzyme-linked immunosorbent spot responses (P = 0.042, multiple regression). A further population-based analysis found that the carriage frequencies of the alleles with the lowest targeting efficiencies, A*24, were associated with pH1N1 mortality (r = 0.37, P = 0.031) and are common in certain indigenous populations in which increased pH1N1 morbidity has been reported. HLA efficiency scores and HLA use are associated with CD8 T-cell magnitude in humans after influenza infection. The computational tools used in this study may be useful predictors of potential morbidity and identify immunologic differences of new variant influenza strains more accurately than evolutionary sequence comparisons. Population-based studies of the relative frequency of these alleles in severe vs. mild influenza cases might advance clinical practices for severe H1N1 infections among genetically susceptible populations.

Non-homologous end-joining gene profiling reveals distinct expression patterns associated with lymphoma and multiple myeloma.

Repair of DNA strand breaks induced during lymphoid antigen receptor rearrangement involves non-homologous end-joining (NHEJ). We investigated NHEJ in the aetiology of lymphoproliferative disorders (LPDs) and the disease subtypes therein through real-time quantitative RT-PCR gene expression analysis. Lower expression of XRCC6 and MRE11A was observed in all tumours, with higher expression of both XRCC4 and RAD50 observed only in multiple myeloma (MM). Hierarchical clustering enabled tumours to be clearly distinguished from controls, and by morphological sub-type. We postulate this identifies targets worthy of investigation in the genetic predisposition, pathogenesis and prognosis of lymphoid malignancies.

Efficient and reproducible large-scale isolation of human CD4+ CD25+ regulatory T cells with potent suppressor activity.

CD4+ CD25+ regulatory T cells have been the subject of intense investigation and have been shown to modulate immune responses in the settings of autoimmunity, cancer and transplantation. The assessment and optimization of purification schemes for specific cellular subtypes such as CD4+ CD25+ regulatory T cells is a critical consideration in developing cell-based therapies in the clinical setting. In the following studies, different strategies for magnetic isolation are compared and the parameters which affect the overall potency of purified human CD4+ CD25+ regulatory T cells are discussed. The data demonstrate that large-scale magnetic isolation can be used to efficiently and reproducibly purify human CD4+ CD25+ regulatory T cells capable of modulating alloreactive T cell responses. The ability to rapidly purify the desired cells from peripheral blood suggests that magnetic isolation may be a suitable alternative to cell sorting for clinical settings, where large numbers of CD4+ CD25+ regulatory T cells may be necessary.

A global expression-based analysis of the consequences of the t(4;14) translocation in myeloma.

PURPOSE: Our purpose in this report was to define genes and pathways dysregulated as a consequence of the t(4;14) in myeloma, and to gain insight into the downstream functional effects that may explain the different prognosis of this subgroup. EXPERIMENTAL DESIGN: Fibroblast growth factor receptor 3 (FGFR3) overexpression, the presence of immunoglobulin heavy chain-multiple myeloma SET domain (IgH-MMSET) fusion products and the identification of t(4;14) breakpoints were determined in a series of myeloma cases. Differentially expressed genes were identified between cases with (n = 5) and without (n = 24) a t(4;14) by using global gene expression analysis. RESULTS: Cases with a t(4;14) have a distinct expression pattern compared with other cases of myeloma. A total of 127 genes were identified as being differentially expressed including MMSET and cyclin D2, which have been previously reported as being associated with this translocation. Other important functional classes of genes include cell signaling, apoptosis and related genes, oncogenes, chromatin structure, and DNA repair genes. Interestingly, 25% of myeloma cases lacking evidence of this translocation had up-regulation of the MMSET transcript to the same level as cases with a translocation. CONCLUSIONS: t(4;14) cases form a distinct subgroup of myeloma cases with a unique gene signature that may account for their poor prognosis. A number of non-t(4;14) cases also express MMSET consistent with this gene playing a role in myeloma pathogenesis.

High-throughput association testing on DNA pools to identify genetic variants that confer susceptibility to acute myeloid leukemia.

We have evaluated the use of allele-specific PCR (AS PCR) on DNA pools as a tool for screening inherited genetic variants that may be associated with risk of adult acute myeloid leukemia (AML). Two DNA pools were constructed, one of 444 AML cases, and another of 823 matched controls. The pools were validated using individual genotyping data for GSTP1 and LTalpha variants. Allele frequencies for variants in GSTP1 and LTalpha were estimated using quantitative AS PCR, and when compared to individual genotyping data, a high degree of concordance was seen. AS primer pairs were designed for nine candidate genetic variants in DNA repair and cell cycle/apoptotic regulatory genes, including Cyclin D1 [codon 870 splice site variant (A>G)]; BRCA1, P871L; ERCC2, K751Q; FAS -1377 (G>A); hMLH1 -93 (G>A) and V219I; p21, S31R; and the XRCC1 R194W and R399Q variants. For six of these assays, there was at least 95% concordance between AS PCR genotyping and an alternative approach carried out on individual samples. Furthermore, these six AS PCR assays all accurately estimated allele frequencies in the pools that had been calculated using individual genotyping data. A significant disease association was seen with AML for the -1377 variant in FAS (odds ratio 1.76, 95% confidence interval 1.26-2.44). These data suggest that quantitative AS PCR can be used as an efficient screening technique for disease associations of genetic variants in DNA pools made from case-control studies.

Functional FAS promoter polymorphisms are associated with increased risk of acute myeloid leukemia.

The FAS (TNFRSF6/CD95/APO-1) gene is silenced in many tumor types, resulting in an inability to respond to proapoptotic signals. The FAS promoter is polymorphic, including a G to A substitution at -1377 bp and an A to G substitution at -670 bp, which occur within SP1 and signal transducers and activators of transcription 1 transcription factor binding sites, respectively. In a case-control study of adult acute myeloid leukemia (AML), we show a significantly increased risk of AML associated with heterozygotes (GA) and homozygote variants (AA) at position -1377 bp (32.3% in cases versus 22.0% in controls; odds ratio, 1.69; 95% confidence interval, 1.32-2.16). Extended haplotype analysis revealed that the -1377A/-670A haplotype was significantly associated with disease (3% versus 0.5%; odds ratio, 6.72; 95% confidence interval, 3.13-14.51). These data suggest that variation in the FAS gene promoter may affect FAS gene expression and modulate apoptotic signaling, contributing to an increased risk of AML.

Polymorphic variation in GSTP1 modulates outcome following therapy for multiple myeloma.

Glutathione S-transferase P1 (GSTP1) is a phase 2 drug metabolism enzyme involved in the metabolism and detoxification of a range of chemotherapeutic agents. A single nucleotide polymorphism (Ile105Val) results in a variant enzyme with lower thermal stability and altered catalytic activity. We hypothesized that patients with the less stable variant have a decreased ability to detoxify chemotherapeutic substrates, including melphalan, and have an altered outcome following treatment for multiple myeloma. We have assessed the impact of GSTP1 codon 105 polymorphisms in 222 patients entered into the Medical Research Council (MRC) myeloma VII trial (comparing standard-dose chemotherapy with high-dose therapy). In the standard-dose arm, patients with the variant allele (105Val) had an improved progression-free survival (PFS) (adjusted hazard ratios for PFS were 0.55 for heterozygotes and 0.52 for 105Val homozygotes, compared with 105Ile homozygotes; P for trend =.04); this was supported by a trend to improved overall survival, greater likelihood of entering plateau and shorter time to reach plateau in patients with the 105Val allele. No difference in outcome by genotype was found for patients treated with high-dose therapy. However, the progression-free survival advantage of the high-dose arm was seen only in patients homozygous for 105Ile (P =.008).

Gastric marginal zone lymphoma is associated with polymorphisms in genes involved in inflammatory response and antioxidative capacity.

Gastric marginal zone lymphoma (GMZL) is strongly associated with Helicobacter pylori infection, which induces a chronic inflammatory response. Inflammation can result in DNA damage related to its severity, the cellular antioxidant capacity, and the integrity of DNA repair mechanisms. Interleukin-1 (IL-1) polymorphisms have been shown to be important mediators of inflammation, while glutathione S-transferase GST T1 and GST M1 polymorphisms are believed to affect cellular antioxidant capacity. We aimed to determine whether polymorphisms at the IL-1 and GST T1 and GST M1 loci modulate the risk of developing GMZL. Blood and biopsy samples were obtained for a historical series of 66 GMZL cases, whereas blood samples were available from 163 healthy controls. Genotypes were obtained for GST T1, GST M1, IL-1 RN, and IL-1B-31 using PCR-based techniques. H pylori infection was found in 86.0% of cases, whereas in the control population only 37.4% tested positive. The IL-1 RN 2/2 genotype was significantly associated with risk of GMZL (odds ratio [OR], 5.51; 95% confidence interval [CI] 2.16-14.07), but not the IL-1B-31 genotype. Likewise, the GST T1 null genotype was strongly associated with risk of GMZL (OR, 9.51; 95% CI 4.57-19.81), but not the GST M1 genotype. Evidence was found of effect modification between the IL-1 RN and GST T1 genotypes (P =.02). The combination of the IL-1 RN 2/2 and GST T1 null genotype was most strongly associated with risk of GMZL (OR, 32.29; 95% CI 6.92-150-63). These results support the hypothesis that the risk of developing GMZL is influenced by inter-individual variation in the cellular inflammatory immune responses to H pylori infection, and to antioxidative capacity.

CYP1A1*2B (Val) allele is overrepresented in a subgroup of acute myeloid leukemia patients with poor-risk karyotype associated with NRAS mutation, but not associated with FLT3 internal tandem duplication.

The etiology of acute myeloid leukemia (AML) is largely unknown. Biologic and epidemiologic data implicate exogenous toxicants, including cytotoxic drugs, benzene, radiation, and cigarette smoking. Allelic variation in genes encoding enzymes such as NADP(H) quinone oxidoreductase (NQO1) and glutathione S-transferase T1 (GSTT1) that metabolize environmental toxicants predispose to subtypes of AML, including therapy-related AML. We assayed NRAS oncogene mutation and FLT3 internal tandem duplication in 447 AML patients with an abnormal karyotype treated in Medical Research Council (MRC) AML clinical trials. Functional allelic variant frequencies in genes encoding carcinogen-metabolizing enzymes GSTT1, GSTM1, CYP1A1, CYP2D6, CYP2C19, SULT1A1, and NQO1 were previously determined for this cohort. FLT3 internal tandem duplication (ITD) frequency was 17%, and NRAS mutation 12% for the entire cohort. The 2 mutations were found together in only 4 patients. No association was found between enzyme allelic variant frequencies and the presence of FLT3 ITD for the entire cohort or within cytogenetic subgroups. CYP1A1*2B (Val) high-inducibility variant allele was overrepresented in patients with NRAS mutation compared with no mutation, for (1) the entire AML cohort (n = 8/53 vs 26/371; odds ratio [OR] = 2.36; 95% confidence interval [CI] 1.01-5.53) and (2) the poor-risk karyotype group (n = 6/14 vs 4/89; OR = 15.94; 95% CI 3.71-68.52) comprising patients with partial/complete deletion of chromosome 5 or 7, or abnormalities of chromosome 3. The CYP1A1*2B allele may predispose to the development of these subgroups of AML by augmented phase 1 metabolism to highly reactive intermediates of CYP1A1 substrates, including polycyclic aromatic hydrocarbons, or by generation of oxidative stress as a metabolic by-product.