Comparative analysis of T-cell turnover and homeostatic parameters in HIV-infected patients with discordant immune-virological responses to HAART

OBJECTIVE: Inadequate CD4 cell count recovery despite full HIV RNA control occurs in 30% of HAART-treated HIV-infected patients. A better understanding of the relationship between T-cell dynamics and the HIV intracellular reservoir in HIV-infected patients failing to recover CD4 cell count following long-term HAART, is required. METHODS: In a cross-sectional study T-cell turnover and homeostatic parameters featuring discordant responses were investigated in 27 immunologic non-responders (INR; CD4 count, < or = 200 cells/microl; HIV RNA, < or = 50 copies/ml), 15 virological non-responders (VNR; CD4 count, > or = 350 cells/microl; HIV RNA, > or = 10 000) and 22 full responders (FR; CD4 count, > or = 500 cells/microl; HIV RNA, < or = 50 copies/ml). RESULTS: INR displayed significantly higher activated CD38CD8 than FR (P < 0.05) and was comparable to VNR (P > 0.05). As compared with VNR and FR, INR displayed the highest level of proliferating Ki67CD4 and apoptotic CD4 cells (P < 0.05). VNR presented lower proliferation and apoptosis than FR and INR. INR displayed the lowest levels of naive T cells (P < 0.05) and a predominant memory pattern. Despite the memory/activated/apoptotic phenotype, INR showed a statistically non-significant reduction in T-cell receptor excision circles (TREC) compared to FR (P > 0.05), and substantially heightened interleukin (IL)-7 (P < 0.05), while VNR showed higher naive T-cell counts and TREC. Moreover, the reservoir of infected CD4 cells was increased in INR, with a trend toward highest intracellular HIV DNA within total, naive and memory CD4 cells. CONCLUSIONS: The lack of CD4 cell count recovery in INR seems to reflect a highly activated apoptotic T-cell compartment, with elevated IL-7 and thymic impairment. High levels of intracellular HIV-DNA in INR could be strictly involved in the lack of T-cell reconstitution. Immune correlates of an ultimate direction of the response to HAART, could be exploited in clinical practice for the most effective management of discordant patients, to amend immune imbalances and to improve clinical outcome.     

Analysis of natural killer cells isolated from human decidua: Evidence that 2B4 (CD244) functions as an inhibitory receptor and blocks NK-cell function

While during the first trimester of pregnancy natural killer (NK) cells represent the most abundant lymphocyte population in the decidua, their actual function at this site is still debated. In this study we analyzed NK cells isolated from decidual tissue for their surface phenotype and functional capability. We show that decidual NK (dNK) cells express normal surface levels of certain activating receptors, including NKp46, NKG2D, and 2B4, as well as of killer cell immunoglobulin-like receptors (KIRs) and CD94/NKG2A inhibitory receptor. In addition, they are characterized by high levels of cytoplasmic granules despite their CD56(bright) CD16- surface phenotype. Moreover, we provide evidence that in dNK cells, activating NK receptors display normal triggering capability whereas 2B4 functions as an inhibitory receptor. Thus, cross-linking of 2B4 resulted in inhibition of both cytolytic activity and interferon-gamma (IFN-gamma) production. Clonal analysis revealed that, in the majority of dNK cell clones, the 2B4 inhibitory function is related to the deficient expression of signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) mRNA. Moreover, biochemical analysis revealed low levels of SAP in the dNK polyclonal population. This might suggest that dNK cells, although potentially capable of killing, are inhibited in their function when interacting with cells expressing CD48.     

Evidence that the mouse insulin receptor substrate-1 belongs to the gene family on which the promoter is activated by estrogen receptor alpha through its interaction with Sp1

In the present study, the molecular mechanism underlying the up-regulatory effect of estradiol (E2) on mouse insulin receptor substrate-1 (IRS-1) promoter was investigated in CHO cells on which the same promoter had first been functionally characterized. The mouse IRS-1 promoter bears four consensus half Estrogen Responsive Elements (ERE) sequences and thirteen AP-1- and ten Sp1-binding elements. We performed molecular dissection of this promoter gene providing 3' different deleted constructs, containing the same AP-1 rich region with a progressively increased number of ERE half sites located downstream. None of these constructs was responsive to E2, while a downstream region (nt -1420 to -160) rich in GC elements was induced by E2. However, the latter region lost its intrinsic E2 responsiveness when the whole IRS-1 promoter was mutated for deletion in all four ERE half sites. Deletion analysis of the ERE half sites demonstrated that only ERE located at the position -1500 to -1495, close to the GC-rich region, was able to maintain the induced activatory effect of E2 on the IRS-1 gene. Electrophoretic mobility shift and chromatin immunoprecipitation assays identified the region containing the half ERE/Sp1 (nt -1500 to -1477) as the one conferring E2 responsiveness to the whole promoter. This effect occurs through the functional interaction between E2/ERalpha and Sp1.     

Prevalence of HIV and other sexually transmitted infections among female commercial sex workers in Argentina

Sexually transmitted infections (STIs) have shown to enhance the transmission of human immunodeficiency virus (HIV) and to be more common among female commercial sex workers (FSWs). A cross-sectional study was conducted among 625 FSWs in six cities of Argentina in 2000-2002. The seroprevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell lymphotropic virus type I/II, and syphilis was 3.2%, 14.4%, 4.3%, 1.6%, and 45.7%, respectively. Syphilis was associated with older age (>/= 30 years, adjusted odds ratio [AOR] = 2.6 to 4.9), >/= 10 years in sex work (AOR = 2.2), use of illegal drugs (AOR = 2.1), and a prior history of an STI (AOR = 3.0). HBV and syphilis was the most common co-infection in 44 (7.5%) subjects. FSWs in Argentina are exposed to HIV and other STIs due to high-risk sexual and illegal drug use behavior. Renewed efforts are necessary to intervene effectively in this high-risk population.     

Gadolinium-based contrast agents and nephrotoxicity in patients undergoing coronary artery procedures.

OBJECTIVE: We tested whether gadolinium-based contrast agent is less nephrotoxic than iodinated-contrast media. BACKGROUND: Iodinated contrast agents are nephrotoxic. Some data suggest that gadolinium-based contrast agent may be less nephrotoxic than iodinated-contrast media. METHODS: Twenty-five consecutive patients with chronic renal insufficiency (creatinine concentration > or = 2.0 mg/dl and/or clearance < or = 40 ml/min), referred to our institution for coronary procedures, were assigned to receive gadolinium-based contrast agents, a solution of gadolinium chelates diluted 3:1 by iso-osmolality contrast media (Gadolinium-based group). A control group of 32 patients with comparable clinical characteristics and treated with iodinated iso-osmolality contrast agent alone (Iodinated-based group) was selected from our database and compared with the Gadolinium-based group. In all cases, prophylactic administration of 0.45% saline intravenously and NAC (1200 mg orally twice daily) was used. RESULTS: Baseline creatinine levels and creatinine clearance were similar in the 2 groups (Gadolinium-based group = 2.30 [IQR: 2.01-2.68] mg/dl and 33 +/- 13 ml/min; Iodinated-based group = 2.24 [IQR: 2.05-2.65] mg/dl and 30 +/- 10 ml/min; P > 0.05 for all). Increase of at least 0.5 mg/dl of the creatinine concentration 48 hr after the procedure occurred in 7/25 (28%) patients in the Gadolinium-based group and in 2/32 (6.5%) patients in the Iodinated-based group (P = 0.034; OR = 4.48; 95% CI = 1.01-19.17). Renal failure requiring temporary dialysis occurred in 2 (8%) patients in the Gadolinium-based group and in none in the Iodinated-based group (P = 0.19). CONCLUSIONS: The strategy of gadolinium-based contrast agent administration does not seem to reduce the rate of CAN, as compared to the iodinated iso-osmolality contrast agent in patients with chronic renal insufficiency.     

Pulmonary arteriovenous malformations, hereditary hemorrhagic telangiectasia, and brain abscess

Hereditary hemorrhagic telangiectasia (HHT) is a systemic angiodysplasia inherited as an autosomal dominant disease. Patients with HHT and pulmonary arteriovenous malformations (PAVMs) are at increased risk for brain abscess (BA), a potentially preventable condition as effective treatment for PAVMs is available. In a center dedicated to HHT, a history of BA was found in 6 out of 128 patients with a definite diagnosis: herewith, their histories are reported focusing on mistakes in the diagnosis and management of the disease. Patients with PAVMs and BA had a higher mean hemoglobin concentration (15.1 g/dl vs. 12.2 g/dl, p < 0.006 by Student's t test) compared to patients with PAVMs alone. Other clinical features (genetics, bacteriology, types of PAVMs, treatments, outcomes) are also discussed. Prompt diagnosis and screening for visceral involvement is pivotal for HHT patients and their relatives.     

Early outcome of treatment of ostial de novo left anterior descending coronary artery lesions with drug-eluting stents

We investigated early and mid-term clinical and angiographic outcomes of patients who had de novo ostial left anterior descending coronary artery (LAD) lesions that were treated with drug-eluting stents (DESs) or bare metal stents (BMSs). We identified 43 consecutive patients who underwent percutaneous intervention for isolated de novo ostial LAD lesions with implantation of DESs and compared them with 43 patients who had similar lesions that were treated with BMSs. All stents were successfully implanted. There were no significant differences with respect to major in-hospital complications between the 2 groups. One patient in the BMS group died during hospitalization. Non-Q-wave myocardial infarction occurred in 2 patients (4.7%) in the DES and in 1 patient (2.3%) in the BMS group. At 9-month follow-up, 3 patients (7%) in the DES group and 11 (25.6%) in the BMS group underwent target lesion revascularization (p = 0.038); major adverse cardiac events were less frequent in the DES than in the BMS group (9.3% vs 32.6%, p = 0.015). Angiographic follow-up was available in 82% of patients in the DES group and 75% of those in the BMS group (p = 0.6) and showed lower binary restenotic rates (5.7% vs 31.3%, p = 0.01) and smaller late loss (0.30 +/- 0.81 vs 1.23 +/- 0.93 mm, p = 0.0001) in the DES group. In conclusion, DES implantation in de novo ostial LAD lesions appears safe and effective and is associated with a significant decrease in restenotic rates compared with historical experience with BMSs.     

Changes in calcium responsiveness and handling during keratinocyte differentiation. Potential role of the calcium receptor.

Extracellular calcium concentrations (Cao) > 0.1 mM are required for the differentiation of normal human keratinocytes in culture. Increments in Cao result in acute and sustained increases in the intracellular calcium level (Cai), postulated to involve both a release of calcium from intracellular stores and a subsequent increase in calcium influx through nonspecific cation channels. The sustained rise in Cai appears to be necessary for keratinocyte differentiation. To understand the mechanism by which keratinocytes respond to Cao, we measured the acute effects of Cao on Cai and calcium influx in keratinocytes at various stages of differentiation. We then demonstrated the existence of the calcium receptor (CaR) in keratinocytes and determined the effect of calcium-induced differentiation on its mRNA levels. Finally, we examined the role of Cai in regulating both the initial rise in Cai after the switch to higher Cao and the activity of the nonspecific cation channel through which calcium influx occurs. Our data indicate that the acute Cai response to Cao is lost as the cells differentiate and increase their basal Cai. These data correlated with the decrease in CaR mRNA levels in cells grown in low calcium. However, calcium influx as measured by 45Ca uptake increased with differentiation in 1.2mM calcium, consistent with the increase in CaR mRNA in these cells as well as the calcium-induced opening of the nonspecific cation channels. We conclude that the keratinocyte contains a CaR that regulates both the initial release of Cai from intracellular stores and the subsequent increase in calcium flux through nonspecific calcium channels. A rising level of Cai may turn off the release of calcium from intracellular stores while potentiating the influx through the nonspecific cation channels. Differentiation of keratinocytes appears to increase the CaR, which may facilitate the maintenance of the high Cai required for differentiation.