Sirolimus exposure and the occurrence of cytomegalovirus DNAemia after allogeneic hematopoietic stem cell transplantation.

Sirolimus appears to protect against cytomegalovirus (CMV) in organ transplant recipients. The effect of this drug in allogeneic hematopoietic stem cell transplantation recipients remains unexplored. By means of multivariate continuous-time Markov model analyses, we identified 3 independent covariates that significantly impacted the risk of CMV DNAemia: recipient/donor CMV serostatus, tacrolimus exposure, and sirolimus exposure. CMV-seropositive recipients with CMV-seronegative donors had a significantly higher probability of having detectable CMV DNAemia. Increasing the tacrolimus trough concentration from 0 to 16 ng/mL increased the probability of patients having detectable CMV DNAemia by 40% (from 40% to 80%), whereas this probability decreased by 25% (from 40% to 15%) when trough concentrations of sirolimus increased from 0 to 16 ng/mL. Sensitivity analysis showed that sirolimus exposure between 0 and 6 ng/mL has no or negligible effect on CMV DNAemia, but levels >8 ng/mL significantly decreased the number of detectable CMV DNAemia cases (the risk ratios decreased from 0.68 to 0.21 when whole blood sirolimus concentrations changed from 8 to 18 ng/mL, P < .01). In conclusion, we used a pharmacometric statistical tool to provide the first clinical evidence that fewer CMV DNAemia events become detectable as sirolimus exposure increases.

Autochthonous Crimean-Congo haemorrhagic fever in Spain: So much to learn / Fiebre hemorrágica de Crimea-Congo autóctona de España: tanto que aprender

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Analysis of the genetic diversity and mRNA expression level in porcine reproductive and respiratory syndrome virus vaccinated pigs that developed short or long viremias after challenge.

Porcine reproductive and respiratory syndrome virus (PRRSv) infection alters the host's cellular and humoral immune response. Immunity against PRRSv is multigenic and vary between individuals. The aim of the present study was to compare several genes that encode for molecules involved in the immune response between two groups of vaccinated pigs that experienced short or long viremic periods after PRRSv challenge. These analyses include the sequencing of four SLA Class I, two Class II allele groups, and CD163, plus the analysis by quantitative realtime qRT-PCR of the constitutive expression of TLR2, TLR3, TLR4, TLR7, TLR8 and TLR9 mRNA and other molecules in peripheral blood mononuclear cells.

Prevalence of hepatitis C virus infection in the veteran population undergoing total joint arthroplasty.

Many orthopedic surgeons train or are employed at the Department of Veterans Affairs (VA) hospitals. We sought to determine the prevalence of hepatitis C antibody-positive and hepatitis C-viremic patients in the VA population undergoing total joint arthroplasty. In this prospective cohort study, 381 of 408 patients undergoing primary total joint arthroplasty for 22 consecutive months were tested for hepatitis C virus (HCV) infection preoperatively. Thirty-two (8.4%) of 381 patients were positive for hepatitis C virus antibody. Seventeen were actually viremic at the time of total joint arthroplasty (4.5%). The prevalence of detectable hepatitis C antibody in VA patients undergoing total joint arthroplasty is about 6 times the general population (1.3%). Surgeons practicing on populations with a high prevalence of hepatitis C such as this should do all they can to minimize the risk of sharps injury.

[Enterobacteria producers of extended-spectrum beta-lactamase in a hospital from Venezuela]. / Enterobatteri produttori di beta-lattamasi a spettro esteso in un ospedale in Venezuela.

The emergence of antimicrobial resistance due to extended-spectrum beta-lactamase (ESBL) has significant clinical impact and is a public health problem. The aim of the present study was to determine the frequency of infections by ESBL-producing enterobacteria in patients hospitalized in the "Ruiz y Paez" Hospital (CHRP) from Cuidad Bolivar, Venezuela, from January to July 2011. We determined the ESBL production from all isolates of E. coli, K. pneumoniae, K. oxytoca and P. mirabilis, using a double disk synergy test and combined disk method. Of the Enterobacteriaceae isolated, 20.3% (53) were ESBL producers, the main ones being K. pneumoniae and E. coli with 56.6% and 43.3% respectively: 15.7% of all E. coli and 47.6% of all K. pneumoniae were ESBL producers, and were more frequent in the purulent samples (43.3%) and blood (30.1%). The service with the greatest number of isolated ESBL-producing enterobacteria was medicine (26.4%) followed by perinatology (24.5%). We concluded that the CHRP has a high rate of ESBL-producing enterobacteria, mainly K. pneumoniae.

Características virológicas del VIH / Virological characteristics of HIV

El virus de la inmunodeficiencia humana tipo 1 (VIH-1) es el agente productor del sida una enfermedad reconocida desde hace 30 años que ha alcanzado proporciones pandémicas. Su origen se remonta a la transmisión a humanos de retrovirus que infectan a poblaciones de chimpancés en África central hace aproximadamente 100 años. Desde esta localización su expansión a todo el mundo ha sido espectacular principalmente en las últimas décadas. La intensa investigación realizada nos permite disponer de un tratamiento eficaz para controlar la replicación del virus y evitar la progresión de la enfermedad sin embargo no disponemos aún de una vacuna que impida la continua extensión de la pandemia. No es posible entender estos fenómenos sin un conocimiento detallado de la biología del VIH-1 y los mecanismos que se han seleccionado en este asombroso agente para infectar una célula clave como el linfocito T CD4+ y evadir la respuesta inmune (AU)

The human immunodeficiency virus type 1 (HIV-1) is the agent that causes AIDS, a disease known for 30 years that has reached pandemic proportions. Its origin dates back to human transmission of retroviruses infecting populations of chimpanzees in central Africa about 100 years ago. From this location its expansion to the whole world has been phenomenal, particularly in recent decades. Extensive research has led to an effective treatment for controlling virus replication and to prevent progression of the disease, but we do not yet have a vaccine to prevent the continuing spread of the pandemic. It is not possible to understand these phenomena without detailed knowledge of the biology of HIV-1 and the mechanisms that have been selected in this amazing agent to infect a key cell such as the CD4 + T cell and evade the immune response (AU)

[Genotypic resistance in HIV-1-infected patients with persistent low-level viremia]. / Resistencias genotípicas en pacientes con VIH-1 y grados de viremia persistentemente bajos.

INTRODUCTION: Highly active antiretroviral therapy (HAART) in HIV patients is considered successful when plasma viral load (VL) reaches < 50 copies/ml. However, many patients have a persistent VL of 50 to 1000 copies/ml, and treatment guidelines do not recommend genotypic resistance testing at these levels because of poor performance. The aim of this study was to evaluate the usefulness of a concentration technique for HIV-1 sequencing in samples with < 1000 copies/ml, and determine the virological consequences of HAART treatment changes guided by resistance testing in this scenario. METHODS: Observational study performed in 51 patients with plasma VL between 50 and 1000 copies/m; 27 patients had these levels for at least 12 consecutive months. Prior to RNA extraction, virions were concentrated from 3-ml plasma samples and then genotyped following standard procedures. RESULTS: Forty-seven of the 51 samples were successfully sequenced, resulting in a sensitivity of 92%. Among these 47 patients, 27 showed a persistent viral load of 50-1000 copies/ml for 12 months, and 20 patients achieved undetectable viral load following the genotype-guided HAART change (intention-to-treat analysis: NC = F; 20 of 27 [74.1%]; on-treatment analysis: 20 of 23 [86.9%]). CONCLUSIONS: We report a simple method for genotype sequencing in patients with persistent low-level viremia that allowed a modification of the HAART regimen leading to undetectable plasma viremia.

Macrophage inflammatory proteins in cytomegalovirus-related inner ear injury.

OBJECTIVE: Inner ear inflammation triggered by CMV infection may play a role in CMV-related auditory pathogenesis. The purpose of the study was to determine if a virally encoded macrophage inflammatory protein played a role in CMV-related hearing loss. DESIGN: Mutagenesis was performed with deletion of a guinea pig CMV macrophage inflammatory protein. Intracochlear inoculations were performed on three groups of animals (n = 18). Group 1 received sterile viral media, Group 2 received wild-type CMV virus, and Group 3 received "knockout" (KO) virus with a deleted immunomodulation gene. Baseline and postinoculation ABRs were obtained. ELISA and PCR were performed and temporal bones examined. SUBJECTS: Eighteen guinea pigs. RESULTS: The KO group had significantly better hearing than the WT group. There were no significant differences between the KO and sham groups. The WT group had significant hearing loss at all frequencies. Inflammation and fibrosis were noted in the WT temporal bones only. CONCLUSIONS: Virally encoded macrophage inflammatory proteins appear to play a significant role in CMV-related hearing loss.

Detection of GBV-C/HGV RNA in saliva and serum, but not in urine of infected patients.

Saliva and urine samples from six GB virus C (GBV-C)/hepatitis G virus (HGV)-infected renal transplant patients were tested by RT-PCR. Viral RNA was detected in all saliva samples, but the viral RNA titers in saliva were 100 to 10,000 lower than those in the corresponding sera. Comparative sequence analysis of the amplified 354 bp DNA from one patient revealed full identity of GBV-C/HGV variants present in serum and saliva. None of the urine samples from the six patients was found to contain GBV-C/HGV RNA. High prevalence of GBV-C/HGV RNA in saliva of infected individuals may contribute to a wide spread of GBV-C/HGV infection, at least in some settings.

Determination of hepatitis delta virus (HDV)-RNA in asymptomatic cases of HDV infection.

OBJECTIVES: To assess the frequency of hepatitis delta virus (HDV) viremia in asymptomatic cases of HDV infection and the clinical significance of the HDV viremia, we conducted a cross-sectional, community-based study. METHODS: Of 2207 examinees, 210 (9.5%) were found to be positive for hepatitis B surface antigen (HBsAg). Antibody to HDV was detected in 47 (22.4%) of the 210 examinees, and 43 of the 47 were further evaluated for serum HDV-RNA by polymerase chain reaction. RESULTS: Twenty-one (48.8%) of the 43 had detectable levels of HDV-RNA in serum, and 22 (51.2%) were negative for serum HDV-RNA. The majority (61.9%) of the HDV-RNA-positive HBsAg carriers had high levels of serum ALT. In contrast, the frequency of an abnormally high level of serum ALT was only 9.1% in the HBsAg carriers positive for HDV antibody but negative for HDV-RNA, and the frequency did not differ from that seen in the HBsAg-negative individuals. The semiquantified HDV-RNA levels did not correlate with the serum ALT levels. CONCLUSION: Seropositivity of HDV-RNA was strongly associated with liver cell damage, even in asymptomatic cases. The absence of a detectable level of serum HDV-RNA might be related to previous HDV infection.

A prospective study of rapid methods of detecting cytomegalovirus in the blood of renal transplant recipients in relation to patient and graft survival.

Eighty-five renal transplant recipients were prospectively monitored for CMV infection up to 4 months post-transplantation by virus isolation from leukocytes, CMV antigen detection (pp65) in peripheral blood leukocytes (PBL), polymerase chain reaction (PCR) of alkaline treated plasma (P-PCR), PCR of extracted DNA from PBL (L-PCR) and serology. Additionally univariate and multivariate analyses of risk factors for patient and graft survival up to 4 yr post-transplantation were performed. The incidence of CMV infection was 78% and of CMV disease 33%. Antigen detection in PBL was positive before or at onset of symptoms in 23/24 (96%) evaluable patients with CMV disease. The corresponding figures for virus isolation were 22/24 (92%), P-PCR 21/24 (88%) and for L-PCR 18/24 (75%). The percentage of negative samples in patients without CMV disease was 89% for the antigen test, 92% for L-PCR and 83% for virus isolation and P-PCR. One rapid test (antigen test, P-PCR or L-PCR) was positive at a median of 16 d before the onset of symptoms. The antigen test was generally the first rapid test to become positive. CMV disease did not affect graft survival in the multivariate analysis but was associated with decreased patient survival.

Treatment of woodchuck hepatitis virus infection in vivo with 2', -3'-dideoxycytidine (ddC) and 2',-3'-dideoxycytidine monophosphate coupled to lactosaminated human serum albumin (L-HSA ddCMP).

Dideoxycytidine (ddC) is a nucleoside analogue active against human immunodeficiency virus and with in vitro activity against human hepatitis B virus. We investigated the ability of ddC to inhibit one of the Hepadnaviridae, the woodchuck hepatitis virus and compared the results with the effect obtained by a conjugate of lactosaminated human serum albumin 2',-3'-dideoxycytidine monophosphate (L-HSA ddCMP). This compound specifically enters the hepatocyte via the asialoglycoprotein receptor. We treated five chronic woodchuck hepatitis virus carriers with intravenous injections of 0.5 mg/kg body weight of ddC for 5 consecutive days, and under the same protocol five woodchucks with 10.4 mg/ kg L-HSA ddCMP, a dose equivalent to 0.25 mg/kg of free ddC. A reduction of serum woodchuck hepatitis virus DNA (5-125 fold) was observed during therapy in three out of five animals receiving ddC and in two of the five animals treated with L-HSA ddCMP. In responding woodchucks, virus DNA levels rebounded immediately after stopping therapy. No signs of toxicity were observed during or after the course of therapy. These preliminary results of short-term treatment indicate that ddC has anti-viral activity against woodchuck hepatitis virus. When the dose was reduced by 50%, L-HSA ddCMP showed anti-viral activity to an even lesser degree.

Detection of Kaposi sarcoma associated herpesvirus in peripheral blood of HIV-infected individuals and progression to Kaposi's sarcoma.

Kaposi sarcoma-associated herpesvirus (KSHV) is consistently found in biopsy samples from patients with AIDS-related and "classical" Kaposi's sarcoma (KS). Although highly suggestive of a causal role of KSHV in the pathogenesis of KS, this observation does not exclude the possibility that KSHV, like other herpesviruses, is widely distributed and is a mere "passenger" in these lesions. Here we report that KSHV was detectable in peripheral blood mononuclear cells of 24/46 (52%) of KS patients, but in none of 134 blood donors or 26 HIV-uninfected hospital controls. KSHV detection increased with immunosuppression, as shown by a correlation with a reduced number of CD4-positive T-cells. Moreover, KSHV detection in peripheral blood cells of HIV-infected individuals without KS predicted the subsequent appearance of KS lesions. 143 patients who did not have KS at the time of their first (or only) blood sample were followed up for a median of 30 months. Of the 11 who had been KSHV positive 6 developed KS compared with only 12 out of 132 who were KSHV negative. These findings are compatible with a causative role of KSHV in KS. KSHV was rarely detected in sputum and throat swabs of HIV-infected patients, providing a potential explanation for the apparently limited spread of this virus.

Comparison of three different tests for assessment of hepatitis C virus in dialysis patients.

OBJECTIVE: To evaluate the relationship between hepatitis C virus antibodies (HCV-Ab) and viremia and to compare the prevalence of HCV-Ab and HCV viremia in hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: Cross-sectional study. SETTING: Dialysis unit of a nephrology division in a public university hospital. PATIENTS: All dialysis patients who came for routine clinic visits during the study period. None denied informed consent. Forty-eight patients on HD and 79 on CAPD were examined. INTERVENTION: Blood samples were tested by second-generation enzyme-linked immunosorbent assay (ELISA II) and recombinant immunoblot assay (RIBA II) to look for HCV-Ab and by the polymerase chain reaction (PCR) to look for HCV viremia. RESULTS: ELISA II was positive in 52% of HD patients and in 14% of CAPD patients. RIBA II was positive in 48% of HD patients and in 11% of CAPD patients. HCV viremia was positive by PCR in 41.6% of HD patients and in 12% of CAPD patients. Two of these PCR-positive patients did not show HCV-Ab by ELISA II and RIBA II. The sensitivity and specificity of ELISA II were 93% and 92%, the sensitivity and specificity of RIBA II were 86% and 94%. CONCLUSIONS: Our data confirm a higher prevalence of HCV viremia in HD than in CAPD patients. The absence of Ab against virus C in 2 patients positive with PCR might be due to recent HCV infection or to weak virus replication or to a poor immune response.

Evaluation of SHARP signal system for enzymatic detection of amplified hepatitis B virus DNA.

The sensitivity, specificity, reproducibility, detection level, and quantification potential of the SHARP Signal System for enzymatic detection of amplified hepatitis B virus (HBV) DNA in clinical samples were evaluated by testing 104 samples in parallel in a SHARP PCR, an in-house HBV PCR, and a dot blot hybridization assay for semiquantification. SHARP PCR showed a sensitivity of 100%, a specificity of 92.3% (resolved, 100%), a reproducibility of 92.3% (all discrepant serum samples involved very low levels of HBV DNA), and a detection level of at least 3.5 pg/ml. Clinically relevant quantification of the amplified products was not feasible.

Influence of exogenous interleukin-2 concentration on the isolation of human immunodeficiency virus.

A significant increase (P = 0.015) in the HIV isolation rate from plasma samples was achieved by use of 10 U/ml exogenous interleukin-2 compared to 20 U/ml. The sensitivity rose from 0% to 29% in patients negative for p24 core antigen (P = 0.031) and from 71% to 86% in patients positive for p24 core antigen in plasma (P > 0.05). Titration of infectious HIV revealed that 10 U/ml interleukin-2 is the optimal concentration to isolate low numbers of infectious particles of HIV.

Hepatitis C virus genotypes among blood donors and their recipients in Iceland determined by the polymerase chain reaction.

Eight antibody-positive individuals were detected among 12,000 blood donations during the first year of screening blood donors for hepatitis C virus (HCV) antibodies in Iceland. All 8 were found to have a history of intravenous drug abuse. Six of these 8 individuals had previously donated blood to 27 patients who could be traced and examined for HCV infection. The great majority (23/27, 85%) of the recipients had demonstrable HCV antibodies. Furthermore, RNA analysis with the polymerase chain reaction showed that all patients with HCV antibodies had HCV RNA in their serum and in one hemodialysis patient without HCV antibodies viral RNA could be demonstrated. Genotyping of the HCV strains showed that the genotype of the donor was also identified in all but one of the infected recipients of his/her blood or blood products. This study, therefore, substantiates high infectivity of the HCV by blood or blood factor donation and shows that viremic HCV antibody-negative individuals exist.

Correlation between surrogate markers, viral load, and disease progression in HIV-1 infection.

Surrogate markers generally used for observation of patients infected with human immunodeficiency virus (HIV) and their plasma and cellular viral load were assayed in a series of 40 patients before initiation of zidovudine therapy. Plasma viremia was positive in 62.5% of patients and was statistically correlated with clinical stage, CD4+ T cell count, CD8+ T cell count, beta 2-microglobulin level, neopterin level, and immunoglobulin A level. Cellular viremia was positive in 95% of patients and was correlated with clinical stage, CD4+ T cell count, beta 2-microglobulin, neopterin levels, and disease progression during the following months. A discordance was found between p24 antigenemia, even after acid dissociation of immune complexes, and plasma viremia. In fact, p24 antigenemia was correlated with only biological markers of immune activation as beta 2-microglobulin and neopterin levels. The measurement of anti-p24 antibodies did not appear discriminative in our staging. Plasma viremia, like CD4+ T cell count, reflects the patient's status at the time of assessment. Cellular viremia could be more informative for the prediction of future clinical progression.

Quantification of human immunodeficiency virus type 1-infected mononuclear cells in peripheral blood of seropositive subjects by newly developed flow cytometry analysis of the product of an in situ PCR assay.

The presence of human immunodeficiency virus type 1 (HIV-1) proviral DNA in peripheral blood mononuclear cells (PBMC) of three groups (group 1, more than 500 CD4+ T cells per microliter; group 2, between 200 and 499 CD4+ T cells per microliter; group 3, fewer than 200 CD4+ T cells per microliter) of HIV-1-infected patients, in different stages of the disease, was determined by using a newly developed flow cytometry analysis of the product of in situ PCR assay and compared with other markers of viral replication (HIV-1 p24 antigenemia and viral isolation). Results showed varied percentages of HIV-1-infected PBMC, ranging from 0.6 to 20%. Patients with more than 500 CD4+ T cells per microliter showed the lowest percentage of HIV-1-infected PBMC (2.1 +/- 1.7), compared with patients with CD4+ T-cell counts of between 200 and 499 per microliter (6.5% +/- 4.1%; P < 0.001) and patients with fewer than 200 CD4+ T cells per microliter (4.9% +/- 4.7%; P < 0.05). The difference in the percentage of HIV-1-infected PBMC between group 2 and group 3 patients may in part reflect the loss of CD4+ T lymphocytes in more advanced stages of the disease. However, the results clearly indicate a striking coincidence between the fall of the CD4+ T-cell count below 400/microliter and the sharp increase in PBMC virus loading and p24 antigenemia. Since the procedure is relatively easy to perform, it could be used to monitor the evolution of HIV-1 infection and may prove a useful adjunct in tailoring therapeutic strategies.

Stabilities of quantitative plasma culture for human immunodeficiency virus, RNA, and p24 antigen from samples collected in VACUTAINER CPT and standard VACUTAINER tubes.

We evaluated the stability of human immunodeficiency virus (HIV) load markers from blood samples collected in VACUTAINER CPT or standard VACUTAINER brand tubes using sodium heparin or sodium citrate as anticoagulants. Quantitative plasma culture and p24 antigen concentrations were determined, and HIV RNA levels in plasma were measured by both reverse transcription-PCR-enzyme-linked immunosorbent assay (RT-PCR-ELISA) and branched DNA methods. All tubes were stored at room temperature for analysis at 2, 24, 48, and 72 h after the blood samples were drawn. No difference was seen between tube types with respect to the HIV titer in plasma or the positivity rate for all samples that demonstrated a fall in titer over time. Unbound p24 antigen levels in plasma decreased during the initial 48-h period in both tube types. Immune complex-dissociated p24 antigen levels decreased in CPT tubes but not in standard VACUTAINER tubes. The HIV RNA copy number in plasma measured by RT-PCR-ELISA was stable in most subjects and was significantly higher in CPT tubes than in standard VACUTAINER tubes at 24 and 72 h after the blood samples were drawn. The branched DNA probe assay detected a significant decline in HIV RNA equivalent in plasma over 72 h in both collection tubes, the decline being more dramatic in the standard VACUTAINER tube than the CPT tube. Overall, interday variability suggests that samples collected for a particular assay should be processed at the same time after blood is drawn and that a particular tube type be used throughout a given study.