Nef-specific CD45RA+ CD8+ T cells secreting MIP-1β but not IFN-γ are associated with nonprogressive HIV-1 infection

Background

Long-term survival of HIV-1 infected individuals is usually achieved by continuous administration of combination antiretroviral therapy (ART). An exception to this scenario is represented by HIV-1 infected nonprogressors (NP) which maintain relatively high circulating CD4+ T cells without clinical symptoms for several years in the absence of ART. Several lines of evidence indicate an important role of the T-cell response in the modulation of HIV-1 infection during the acute and chronic phase of the disease.

Results

We analyzed the functional and the differentiation phenotype of Nef- and Tat-specific CD8+ T cells in a cohort of HIV-1 infected NP in comparison to progressors, ART-treated seropositive individuals and individuals undergoing a single cycle of ART interruption. We observed that a distinctive feature of NP is the presence of Nef-specific CD45RA+ CD8+ T cells secreting MIP-1beta but not IFN-gamma. This population was present in 7 out of 11 NP. CD45RA+ IFN-gamma^neg MIP-1beta+ CD8+ T cells were not detected in HIV-1 infected individuals under ART or withdrawing from ART and experiencing a rebounding viral replication. In addition, we detected Nef-specific CD45RA+ IFN-gamma^neg MIP-1beta+ CD8+ T cells in only 1 out of 10 HIV-1 infected individuals with untreated progressive disease.

Conclusion

The novel antigen-specific CD45RA+ IFN-gamma^neg MIP-1beta+ CD8+ T cell population represents a new candidate marker of long-term natural control of HIV-1 disease progression and a relevant functional T-cell subset in the evaluation of the immune responses induced by candidate HIV-1 vaccines.     

Broad copy neutral‐loss of heterozygosity regions and rare recurring copy number abnormalities in normal karyotype‐acute myeloid leukemia genomes

We analyzed, by the latest high‐resolution SNP arrays, 19 Normal Karyotype (NK)‐AML patients at diagnosis (Dx) and remission (R) phases, to determine the number of tumor‐associated copy number abnormalities (CNAs) and copy neutral‐loss of heterozygosity (CN‐LOH) regions per patient and to identify possible recurring genomic abnormalities. The number of tumor‐associated CNAs was determined after comparison of matched Dx/R samples using stringent conditions able to reduce the number of false positive CNAs. With the exception of a single outlier case, a low number of CNAs per patient was detected (median value of 1 somatic loss or gain per patient). However, a high prevalence of CNAs (60–70% of the patients showed at least one tumor‐associated gain or loss) and few recurring CNAs were observed, thus providing new hints towards identification of cooperating mutations. An extensive search of all tumor‐associated CN‐LOH regions >1 Mb revealed only three broad regions (terminal 12Mb of 22q, terminal 27Mb of 1p and the whole chromosome 21) in three patients out of 19 (16%). CN‐LOH of the whole chromosome 21 was responsible for homozygosity of a missense mutation (R80C) of RUNX1/AML1. Our study suggests that a relative submicroscopic copy number stability NK‐AML genomes is associated with low recurrence of specific CNAs and CN‐LOH in NK‐AML patient population. Sequencing of candidate genes in the identified CNAs and CN‐LOH regions should be considered a priority in the search of novel driver mutations of AML. © 2010 Wiley‐Liss, Inc.     

Novel method for isolating untouched rat natural killer cells with higher purity compared with positive selection and fluorescence-activated cell sorting

The Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA1) is regularly expressed in all proliferating virus‐infected cells and is therefore an interesting target for immunotherapy. Alleles of the human leucocyte antigen (HLA) ‐A2 family are dominantly expressed in Caucasians so we sought to identify EBNA1‐specific cytotoxic T‐lymphocyte (CTL) responses restricted through this allele. We report on the characterization of the LQTHIFAEV (LQT) epitope. LQT‐specific memory CTL responses were reactivated in three of 14 healthy EBV seropositive donors (21%) whereas responses to HLA‐A2‐restricted epitopes, two derived from LMP2 and one from EBNA3A, were detected in 93%, 71% and 42% of the donors, respectively. The LQT‐specific CTL clones did not lyse EBV‐carrying lymphoblastoid cell lines and Burkitt’s lymphoma cell lines nor EBNA1‐transfected Burkitt’s lymphoma cells but specifically released interferon‐γ upon stimulation with HLA‐matched EBNA1‐expressing cells and this response was enhanced by deletion of the Gly‐Ala repeat domain that inhibits proteasomal degradation. The poor presentation of the endogenously expressed LQT epitope was not affected by inhibition of peptidases that trim antigenic peptides in the cytosol but full presentation was achieved in cells expressing a trojan antigen construct that releases the epitope directly into the endoplasmic reticulum. Hence, inefficient proteasomal processing appears to be mainly responsible for the poor presentation of this epitope.     

Angiotensin receptors as determinants of life span

Angiotensin II (Ang II), the central product of renin-angiotensin system, has a role in the etiology of hypertension and in pathophysiology of cardiac and renal diseases in humans. Other functions of Ang II include effects on immune response, inflammation, cell growth and proliferation, which are largely mediated by Ang II type 1 receptor (AT₁). Several experimental studies have demonstrated that Ang II acts through AT₁ as a mediator of normal aging processes by increasing oxidant damage to mitochondria and in consequences by affecting mitochondrial function. Recently, our group has demonstrated that the inhibition of Ang II activity by targeted disruption of the Agtr1a gene encoding Ang II type 1A receptor (AT_1A) in mice translates into marked prolongation of life span. The absence of AT_1A protected multiple organs from oxidative damage and the alleviation of aging-like phenotype was associated with increased number of mitochondria and upregulation of the prosurvival gene sirtuin 3. AT₁ receptor antagonists have been proven safe and well-tolerated for chronic use and are used as a key component of the modern therapy for hypertension and cardiac failure, therefore Ang II/AT₁ pathway represents a feasible therapeutic strategy to prolong life span in humans.     

Association of a wide invasive malignant thymoma with myastenia gravis and primary hyperparathyroidism due to parathyroid adenoma: case report and review of the literature

There are few cases described in the world literature reporting an association of thymoma (with myasthenia gravis or not) with hyperparathyroidism. In these cases the hyperparathyroidism was due to the presence of an adenoma or hyperplasic parathyroid tissue either in the cervical region or in an ectopic intrathymic location.(1-51, 5) In other cases the syndrome of hypercalcemia was due to the secretion of parathyroid-related protein (PTHRP) (6) or parathyroid hormone (PTH) (7) by the thymoma itself. We report the first case, at the best of our knowledge, of a wide invasive malignant thymoma (type B3), associated with myasthenia gravis and hyperparathyroidism caused by parathyroid adenoma.     

Hemispheric cerebellar rTMS to treat drug-resistant epilepsy: case reports

Electrical stimulation of the cerebellar cortex by implanted electrodes has been shown to ameliorate refractory epilepsy. We investigated the potential therapeutic role of high-frequency cerebellar rTMS in patients affected by refractory epilepsy due to single or multiple foci. Six patients, three with single and three with multiple epileptic foci, underwent 20 rTMS sessions. Each session was given daily, excluding weekends, and consisted of two trains of 50 stimuli (5 Hz frequency and 90% motor threshold intensity), separated by 50s interval. rTMS was delivered through a focal coil (2 cm below and lateral to the inion) bilaterally in patients with multiple foci (two trains for hemisphere: 100 stimuli each side) and contralaterally to the epileptic focus in the others. Seizure frequency was monitored four weeks before stimulation (pre-rTMS), during the four-week treatment (rTMS) and four weeks after the treatment (post-rTMS). The rTMS over the cerebellar cortex was associated with a significant decrease of rTMS versus pre-rTMS seizure frequency both in patients with single and multiple epileptic foci. However, during the post-rTMS period seizure frequency was back to the pre-rTMS frequency. Although the results are still preliminary, they encourage further studies on larger series of patients. In particular, this rTMS approach, as compared with others, might be more useful in patients with multiple epileptic foci.     

Immunohistochemical expression of p16(INK4a) is predictive of HR-HPV infection in cervical low-grade lesions.

The p16(INK4a) is a cyclin-dependent kinase inhibitor that decelerates the cell cycle by inactivating the cyclin-dependent kinases involved in the phosphorylation of the retinoblastoma protein (RB). Expression of E6 and E7 oncogenes of high-risk (HR) human papillomavirus (HPV), affecting the RB-p16 pathway, leads to p16 upregulation. Although it is widely reported that p16 is overexpressed in a high percentage of preneoplastic lesions and in almost all carcinomas of the uterine cervix, protein upregulation and its correlation with HPV infection in low-grade lesions is still being debated. In this study, we investigated in parallel, p16 expression and HPV infection in 100 cervical biopsies (17 normal tissues, 54 CIN1, 10 CIN2, 11 CIN3, eight invasive squamous cancers). Results obtained demonstrated that none of the 17 normal cervical tissues, evaluated by immunohistochemistry, presented p16 positivity whereas, starting from CIN1 (31%) to CIN2 (90%), CIN3 (100%) and carcinomas (100%), a constant and significant increase of protein overexpression (P<0.0001) was observed. In addition, p16 overexpression consistently showed elevated sensitivity (84%) and specificity (98%) in detecting HR-HPV infection with a high positive predictive value (97%) and negative predictive value (86%). Of interest, 93% of the p16-positive CIN1 were also HR-HPV infected. Our findings confirmed that p16 overexpression is associated to high-grade precancerous lesions and cervical carcinomas, and further demonstrated that immunohistochemical evaluation of p16 may be a useful biomarker in identifying HR-HPV-infected low-grade lesions.     

Glutathione S-transferase T1 status and gastric cancer risk: a meta-analysis of the literature

To clarify the risk of gastric cancer associated with glutathione S-transferase T1 (GSTT1) status, a meta-analysis of published studies was performed. Eligible studies included all reports investigating an association between GSTT1 status and gastric cancer published before October 31, 2005. A qualitative scoring of papers was applied to evaluate the quality of the published data. The principal outcome measure was the odds ratio (OR) for the risk of gastric cancer associated with GSTT1 deletion status using a random effects model. Eighteen case-control studies detailing a possible association between the GSTT1 null genotype and gastric cancer were selected. Combining data from these studies, totalling 2508 cases and 4634 controls, a non-statistically significant OR for gastric cancer risk associated with GSTT1 deficiency emerged [OR = 1.09; 95% confidence interval (CI): 0.97-1.21; I(2) = 0%]. When only high-quality scored studies were considered, a statistically significant increased risk appeared (OR = 1.23; 95% CI: 1.04-1.45; I(2) = 0%), as well as considering only Caucasians (OR = 1.23; 95% CI: 1.03-1.56; I(2) = 0%). By pooling data from seven studies (319 cases and 656 controls) that considered combinations of GSTT1 and GSTM1 genotypes, a statistically significant increased risk for gastric cancer (OR = 1.95, 95% CI: 1.42-2.67; I(2) = 0%) was detected for individuals with deletion mutations in both genes compared with wild-types. In conclusion, this meta-analysis suggests that the GSTT1 null genotype may slightly increase the risk of gastric cancer and that interaction between unfavourable GST genotypes may exist. Greater attention should, therefore, be paid to the design of future studies; the investigation of interactions among multiple genotypes and environmental exposures are justified to clarify GSTT1 null status influence on gastric cancer risk.     

Phylogenetic analysis of the gag region encoding the matrix protein of small ruminant lentiviruses: comparative analysis and molecular epidemiological applications

Little sequence information exists on the matrix-protein (MA) encoding region of small ruminant lentiviruses (SRLV). Fifty-two novel sequences were established and permitted a first phylogenetic analysis of this region of the SRLV genome. The variability of the MA encoding region is higher compared to the gag region encoding the capsid protein and surprisingly close to that reported for the env gene. In contrast to primate lentiviruses, the deduced amino acid sequences of the N- and C-terminal domains of MA are variable. This permitted to pinpoint a basic domain in the N-terminal domain that is conserved in all lentiviruses and likely to play an important functional role. Additionally, a seven amino acid insertion was detected in all MVV strains, which may be used to differentiate CAEV and MVV isolates. A molecular epidemiology analysis based on these sequences indicates that the Italian lentivirus strains are closely related to each other and to the CAEV-CO strain, a prototypic strain isolated three decades ago in the US. This suggests a common origin of the SRLV circulating in the monitored flocks, possibly related to the introduction of infected goats in a negative population. Finally, this study shows that the MA region is suitable for phylogenetic studies and may be applied to monitor SRLV eradication programs.