The impact of HLA class I and EBV latency-II antigen-specific CD8(+) T cells on the pathogenesis of EBV(+) Hodgkin lymphoma

In 40% of cases of classical Hodgkin lymphoma (cHL), Epstein–Barr virus (EBV) latency‐II antigens [EBV nuclear antigen 1 (EBNA1)/latent membrane protein (LMP)1/LMP2A] are present (EBV⁺cHL) in the malignant cells and antigen presentation is intact. Previous studies have shown consistently that HLA‐A*02 is protective in EBV⁺cHL, yet its role in disease pathogenesis is unknown. To explore the basis for this observation, gene expression was assessed in 33 cHL nodes. Interestingly, CD8 and LMP2A expression were correlated strongly and, for a given LMP2A level, CD8 was elevated markedly in HLA‐A*02^–versus HLA‐A*02⁺ EBV⁺cHL patients, suggesting that LMP2A‐specific CD8⁺ T cell anti‐tumoral immunity may be relatively ineffective in HLA‐A*02^– EBV⁺cHL. To ascertain the impact of HLA class I on EBV latency antigen‐specific immunodominance, we used a stepwise functional T cell approach. In newly diagnosed EBV⁺cHL, the magnitude of ex‐vivo LMP1/2A‐specific CD8⁺ T cell responses was elevated in HLA‐A*02⁺ patients. Furthermore, in a controlled in‐vitro assay, LMP2A‐specific CD8⁺ T cells from healthy HLA‐A*02 heterozygotes expanded to a greater extent with HLA‐A*02‐restricted compared to non‐HLA‐A*02‐restricted cell lines. In an extensive analysis of HLA class I‐restricted immunity, immunodominant EBNA3A/3B/3C‐specific CD8⁺ T cell responses were stimulated by numerous HLA class I molecules, whereas the subdominant LMP1/2A‐specific responses were confined largely to HLA‐A*02. Our results demonstrate that HLA‐A*02 mediates a modest, but none the less stronger, EBV‐specific CD8⁺ T cell response than non‐HLA‐A*02 alleles, an effect confined to EBV latency‐II antigens. Thus, the protective effect of HLA‐A*02 against EBV⁺cHL is not a surrogate association, but reflects the impact of HLA class I on EBV latency‐II antigen‐specific CD8⁺ T cell hierarchies.

A comprehensive analysis of the cellular and EBV-specific microRNAome in primary CNS PTLD identifies different patterns among EBV-associated tumors

Primary central nervous system (pCNS) posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation characterized by poor outcome. In contrast to systemic PTLD, Epstein-Barr virus (EBV)-association of pCNS PTLD is almost universal, yet viral and cellular data are limited. To identify differences in the pattern of EBV-association of pCNS and systemic PTLD, we analyzed the expression of latent and lytic EBV transcripts and the viral and cellular microRNAome in nine pCNS (eight EBV-associated) and in 16 systemic PTLD samples (eight EBV-associated). Notably although 15/16 EBV-associated samples exhibited a viral type III latency pattern, lytic transcripts were also strongly expressed. Members of the ebv-miR-BHRF1 and ebv-miR-BART clusters were expressed in virtually all EBV-associated PTLD samples. There were 28 cellular microRNAs differentially expressed between systemic and pCNS PTLD. pCNS PTLD expressed lower hsa-miR-199a-5p/3p and hsa-miR-143/145 (implicated in nuclear factor kappa beta and c-myc signaling) as compared to systemic PTLD. Unsupervised nonhierarchical clustering of the viral and cellular microRNAome distinguished non-EBV-associated from EBV-associated samples and identified a separate group of EBV-associated pCNS PTLD that displayed reduced levels of B cell lymphoma associated oncomiRs such as hsa-miR-155, -21, -221 and the hsa-miR-17-92 cluster. EBV has a major impact on viral and cellular microRNA expression in EBV-associated pCNS PTLD.

The presence of KIR2DS5 confers protection against adult immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disorder of unknown aetiology, characterised by an isolated low platelet count in the absence of other identifiable causes. Genes influencing activation of the immune system have been identified as influencing predisposition. Killer cell immunoglobulin-like receptors (KIR) control T-cell and natural killer (NK) cell function via inhibitory and activating signalling pathways. The inhibitory KIR2DL3, KIR3DL2 and KIR3DL1 are up-regulated in the T-cells of patients with ITP in remission relative to those with active disease, and an association of KIR2DS2 and KIR2DL2 with ITP has also been reported. No comprehensive KIR analysis in ITP has been reported. We performed genotyping of all currently known KIR genes using sequence specific primer polymerase chain reaction (SSP-PCR) on a cohort of 83 adult patients with ITP (chronic/persistent or relapsed primary ITP identified by defined criteria) and 106 age matched healthy white volunteers. Non-white patients were not included in the analysis. There was an over-representation of KIR2DS3 (known to be in linkage disequilibrium with KIR2DS2 and 2DL2) and under-representation of KIR2DS5 (also protective against other immune mediated disorders) in adult ITP [odds ratio (OR) = 0.16, confidence interval (CI) 0.08-0.32, P < 0.001]. By multivariable binary logistic regression to adjust for age, sex and the effects of other KIR genes, the presence of KIR2DS2/2DL2 with KIR2DS5 abrogated the risk of KIR2DS2/2DL2 and the protective benefit of KIR2DS5. Further studies are required to establish the mechanistic basis for these observations and their potential impact on ITP therapy.

Does pre-dialysis care management reap rewards for patients, renal staff, and payers

This article describes one renal disease management organization's experience in implementing a pre-dialysis care management program to improve outcomes in patients who develop end-stage renal disease (ESRD). Optimal Renal Care, a national renal disease management company, has implemented care management programs for 600+ ESRD patients and 600+ pre-ESRD patients in Oregon (1998) and Hawaii (1999). This article describes our Oregon pre-ESRD program's start-up experience.

The heterocyclic substituted pyridine derivative (+/-)-2-(-3-pyridinyl)-1-azabicyclo[2.2.2]octane (RJR-2429): a selective ligand at nicotinic acetylcholine receptors

The present report describes in vitro studies demonstrating that the heterocyclic substituted pyridine compound (+/-)-2-(3-pyridinyl)-1-azabicyclo[2.2.2]octane (RJR-2429) is extremely potent in activating human muscle nicotine ACh receptor (nAChR) (EC50 = 59 +/- 17 nM; Emax = 110 +/- 09% vs. nicotine). RJR-2429 is markedly less potent in activating nAChRs in the clonal cell line PC12, with EC50 = 1100 +/- 230 nM and Emax = 85 +/- 20% when compared with nicotine. The activation of a putative alpha 3 beta 4-containing nAChR in PC12 by RJR-2429 reveals a potency intermediate between nicotine and epibatidine (EC50 of 20,000 nM for nicotine and 30 nM for epibatidine). Dose-response curves for agonist-induced ileum contraction indicate that RJR-2429 is equipotent with nicotine, having an EC30 of approximately 2 microM. RJR-2429 binds with high affinity to alpha 4 beta 2 receptor subtype (Ki = 1.0 +/- 0.3 nM), and chronic exposure results in significant up-regulation of the high-affinity [3H]nicotine binding sites. In addition, RJR-2429 does not activate nAChRs present in rat thalamic preparations but is a potent inhibitor of this receptor subtype. It antagonizes nicotine-stimulated ion flux in thalamic synaptosomes with an IC50 of 154 +/- 37 nM. It also is a potent partial agonist at nAChRs mediating dopamine release from rat synaptosomal preparations (EC50 = 2 +/- 1 nM; Emax = 40%; epibatidine and nicotine have EC50 values of 0.4 and 100 nM, respectively). A model for the structure-activity profile of RJR-2429, nicotine and epibatidine was derived by molecular forcefield and quantum mechanics calculations and may provide important clues for the development of ligands selective for nAChR subtypes as probes in the life sciences or as potential therapeutic tools.

Ischemic preconditioning: a long term survival study using behavioural and histological endpoints

In this study we sought to determine if ischemic preconditioning provided long term behavioral and histological protection. A second goal was to see if ischemic preconditioning conveys its protective effect on CA1 neurons by altering post-ischemic brain temperature. While preconditioning episodes of short duration ischemia (i.e. 1.5 min) provided significant histological protection of CA1 pyramidal cells against a subsequent severe ischemic insult (i.e. 5 min), this did not result in complete behavioural protection. Preconditioned ischemic animals initially displayed habituation deficits in an open field test that were comparable to untreated ischemic gerbils. A significant decline in CA1 preservation in preconditioned animals was observed when survival time was extended from 10 (81% protection) to 30 (53% protection) days. In addition, protection was not observed in the subiculum and CA2 sector of the hippocampus where consistent damage was observed in 21/22 gerbils. Ischemic preconditioning did not markedly affect post-ischemic brain temperature suggesting that the observed protection was not due to a reduction in temperature during or after the severe ischemic insult. The lack of functional protection within the first 10 days after ischemia, along with the decline of cellular preservation over time, suggests that this paradigm may not provide permanent protection.