Belinda Yen-Lieberman

Mononuclear Leukocytes Preferentially Bind via CD44 to Hyaluronan on Human Intestinal Mucosal Smooth Muscle Cells after Virus Infection or Treatment with Poly(I·C)

Pathological changes in inflammatory bowel disease include an increase in intestinal mucosal mononuclear leukocytes and hyperplasia of the muscularis mucosae smooth muscle cells (M-SMCs). Because virus infections have correlated with disease flare, we tested the response of cultured M-SMCs to respiratory syncytial virus, measles virus, and the viral analogue, poly(I·C). Adhesion of U937 cells and peripheral blood mononuclear cells was used to measure the leukocyte-interactive potential of M-SMCs. Untreated M-SMCs, only minimally adhesive for leukocytes, bound U937 cells after treatment with respiratory syncytial virus or measles virus. Mononuclear leukocytes also bound to poly(I·C)-treated M-SMCs. Although both vascular cell adhesion molecule-1 mRNA and protein increased 3–4-fold in poly(I·C)-treated M-SMC cultures, U937 cell adhesion was not blocked by an anti-vascular cell adhesion molecule-1 monoclonal antibody. However, hyaluronidase digestion of poly(I·C)- or virus-treated M-SMCs dramatically reduced leukocyte adhesion (∼75%). Fluorophore-assisted carbohydrate electrophoresis demonstrated a ∼3-fold increase in surface-bound hyaluronan on poly(I·C)-treated M-SMCs compared with untreated controls. In addition, pretreatment of mononuclear cells with a blocking anti-CD44 antibody, greatly decreased adhesion to poly(I·C)-treated M-SMCs. Recognition of this virus-induced hyaluronan/CD44 mechanism of mesenchymal cell/leukocyte interaction introduces a new avenue in the research of gut inflammation.

Assessment of Cytomegalovirus-Specific Cell-Mediated Immunity for the Prediction of Cytomegalovirus Disease in High-Risk Solid-Organ Transplant Recipients: A Multicenter Cohort Study

BACKGROUND Cytomegalovirus (CMV) disease remains an important problem in solid-organ transplant recipients, with the greatest risk among donor CMV-seropositive, recipient-seronegative (D(+)/R(-)) patients. CMV-specific cell-mediated immunity may be able to predict which patients will develop CMV disease. METHODS We prospectively included D(+)/R(-) patients who received antiviral prophylaxis. We used the Quantiferon-CMV assay to measure interferon-γ levels following in vitro stimulation with CMV antigens. The test was performed at the end of prophylaxis and 1 and 2 months later. The primary outcome was the incidence of CMV disease at 12 months after transplant. We calculated positive and negative predictive values of the assay for protection from CMV disease. RESULTS Overall, 28 of 127 (22%) patients developed CMV disease. Of 124 evaluable patients, 31 (25%) had a positive result, 81 (65.3%) had a negative result, and 12 (9.7%) had an indeterminate result (negative mitogen and CMV antigen) with the Quantiferon-CMV assay. At 12 months, patients with a positive result had a subsequent lower incidence of CMV disease than patients with a negative and an indeterminate result (6.4% vs 22.2% vs 58.3%, respectively; P < .001). Positive and negative predictive values of the assay for protection from CMV disease were 0.90 (95% confidence interval [CI], .74-.98) and 0.27 (95% CI, .18-.37), respectively. CONCLUSIONS This assay may be useful to predict if patients are at low, intermediate, or high risk for the development of subsequent CMV disease after prophylaxis. CLINICAL TRIALS REGISTRATION NCT00817908.

Congestive cardiomyopathy and illness related to the acquired immunodeficiency syndrome (AIDS) associated with isolation of retrovirus from myocardium.

Excerpt Most clinical signs and symptoms reported in persons infected with the human immunodeficiency virus (HIV) are due to opportunistic infections or malignancies that flourish in the presence o...

A Standardized Plaque Reduction Assay for Determination of Drug Susceptibilities of Cytomegalovirus Clinical Isolates

ABSTRACT Twelve laboratories collaborated in formulating and testing a standardized plaque reduction assay for cytomegalovirus (CMV) cell-associated clinical isolates. Four characterized and plaque-purified CMV strains, as well as six coded clinical isolates obtained after antiviral therapy, were distributed and tested. Good agreement was obtained for four of the clinical isolates, but a broad distribution of results was obtained for two isolates. Analysis of these results indicates the problems associated with clinical isolates, including the large genetic variability and the highly cell-associated phenotype. This collaborative effort, by addressing these problems, represents a significant step toward the development of a standardized assay.

Analysis and Characterization of Antiviral Drug–Resistant Cytomegalovirus Isolates from Solid Organ Transplant Recipients

The development of cytomegalovirus (CMV) disease and subsequent emergence of drug-resistant strains was examined in a large group of solid organ transplant recipients; drug-resistant CMV was detected in a total of 30 transplant recipients (20 lung, 5 kidney, 4 heart, and 1 liver). Drug resistance was confirmed both phenotypically and genotypically. The sequences of drug-resistant CMV strains from the same patient differed from drug-susceptible baseline sequences only at single sites previously confirmed to confer drug resistance. At least 1 isolate from each patient had a mutation in the UL97 phosphotransferase coding sequence. Mutations in the DNA polymerase gene were found in 6 of 38 sequenced strains. Lung transplant recipients had the highest incidence of drug-resistant virus: of the 30 patients, 28 were CMV-seronegative transplant recipients of CMV-seropositive organs, which strongly supports the premise that drug resistance is most prevalent in that transplant population.

Interferon-β impairs induction of HLA-DR antigen expression in cultured adult human astrocytes☆

We studied the effect of interferons on the expression of class II histocompatibility (HLA-DR) antigens by cultured adult human astrocytes. Cultures were derived from brain tissue resected for surgical treatment of intractable epilepsy. Cultured astrocytes did not spontaneously display HLA-DR antigen as determined by immunocytochemistry and flow cytometry with antibody to HLA-DR. Astrocytes cultured for 72 h with recombinant or natural interferon-gamma (IFN gamma) demonstrated a dose-dependent increase in HLA-DR expression with optimal stimulation by 100 U/ml IFN gamma. HLA-DR expression was not detectable in astrocytes cultured with IFN gamma for less then 48 h, and peak HLA-DR expression (over 80% of cells) was seen at 120 h of culture. Optimal HLA-DR expression required continuous presence of IFN gamma. Exposure of astrocytes to recombinant or natural interferon-beta (IFN beta) did not induce HLA-DR and pretreatment of astrocytes with IFN beta or interferon-alpha (IFN alpha) significantly inhibited subsequent induction of HLA-DR expression by IFN gamma. These observations suggest that interferons may function in regulating human astrocyte HLA-DR expression within the central nervous system.

Detection of Legionella pneumophila by Real-Time PCR for the mip Gene

ABSTRACT A real-time PCR assay for the mip gene of Legionella pneumophila was tested with 27 isolates of L. pneumophila, 20 isolates of 14 other Legionella species, and 103 non-Legionella bacteria. Eight culture-positive and 40 culture-negative clinical specimens were tested. This assay was 100% sensitive and 100% specific for L. pneumophila.

Use of leflunomide in an allogeneic bone marrow transplant recipient with refractory cytomegalovirus infection

Summary:Ganciclovir-resistant cytomegalovirus (CMV) infection is an emerging problem in transplant recipients. Foscarnet resistance and cidofovir resistance have also been described, but no previous reports have suggested treatment regimens for patients with CMV refractory to all three of these drugs. Leflunomide, an immunosuppressive drug used in rheumatoid arthritis and in rejection in solid-organ transplantation, has been reported to have novel anti-CMV activity. However, its clinical utility in CMV treatment has not been described previously. We report an allogeneic bone marrow transplant recipient who developed CMV infection refractory to sequential therapy with ganciclovir, foscarnet, and cidofovir. The patient was ultimately treated with a combination of leflunomide and foscarnet. Both phenotypic and genotypic virologic analysis was performed on sequential CMV isolates. The patients high CMV-DNA viral load became undetectable on leflunomide and foscarnet, but the patient, who had severe graft-versus-host disease (GVHD) of the liver, expired with progressive liver failure and other complications. We concluded that leflunomide is a new immunosuppressive agent with anti-CMV activity, which may be useful in the treatment of multiresistant CMV. However, the toxicity profile of leflunomide in patients with underlying GVHD remains to be defined.

Utility of leflunomide in the treatment of complex cytomegalovirus syndromes.

Background. Cytomegalovirus (CMV) viremia that is resistant or refractory to the standard antiviral therapy still constitutes a major threat to high-risk transplant recipients. In addition, multiple CMV recurrences may lead to neutropenia because of repeated courses of therapy with ganciclovir derivatives. Leflunomide, a drug for rheumatoid arthritis, has been reported to have anti-CMV activity. This study reports on its use in 17 transplant recipients with complex CMV syndromes who had failed or were intolerant to other therapies. Methods. Single-center, retrospective study. Clinical data were extracted from the electronic medical record. CMV DNA viral loads were performed by quantitative hybrid capture assay. Results. Leflunomide was initiated after a median of three episodes of CMV viremia, with a mean peak viral load of 245,826 copies/mL. Initial clearance of CMV viremia was observed in 14 of 17 patients (82%), and 9 of 17 (53%) patients achieved a long-term suppression of CMV recurrences. Higher peak viral load and higher viral load at the start of leflunomide therapy were associated with failure to suppress viremia. The duration of leflunomide therapy ranged from 1 to 24 months (median 3.5 months, interquartile range 2.6–7 months), and the mean time to an undetectable CMV-DNA was 1.9 months. Adverse effects included diarrhea (35%), anemia (18%), and increased liver function tests (12%). Conclusions. Leflunomide, alone or in combination, has potential utility in treatment of complex CMV syndromes and in long-term suppression of viremia. The optimal duration of therapy and the balance of risks and benefits are not yet known.

Challenges of Interferon-γ Release Assay Conversions in Serial Testing of Health-care Workers in a TB Control Program

BACKGROUND Clinical data with use of serial interferon-γ release assay (IGRA) testing in US health-care workers (HCWs) are limited. METHODS A single-center, retrospective chart review was done from 2007 to 2010 of HCWs who underwent preemployment QuantiFERON-TB Gold In-Tube testing. Demographic data, bacille Calmette-Guérin history, prior tuberculin skin test result if done, and baseline and serial IGRA values were obtained. The number of IGRA converters and reverters and their subsequent management by infectious disease physicians were reviewed. Quantitative IGRA-negative values were not available. RESULTS A total of 7,374 IGRAs were performed on newly hired HCWs. Of these tests, 486 (6.6%) were positive at baseline, 305 (4.1%) were indeterminate, and 6,583 (89.3%) were negative. From 2007 to 2010, 52 of 1,857 HCWs (2.8%) with serial IGRA tests were identified as converters, with a serial IGRA median value of 0.63 IU/mL. Seventy-one percent of HCWs with IGRA conversion had values ≤ 1 IU/mL. None of the converters had active TB or were part of an outbreak investigation. CONCLUSIONS Clinical significance of most QuantiFERON-TB Gold In-Tube conversions in serial testing remains a challenging task for clinicians. The use of a single cutoff point criterion for IGRA may lead to overdiagnosis of new TB infections. Clinical assessment and evaluation may help to prevent unnecessary therapy in these cases. The criteria for defining conversions and reversions by establishing new cutoffs needs to be evaluated further, especially in HCWs.