Shaobing Li

Quantitative CSF PCR in Epstein–Barr virus infections of the central nervous system

Acute Epstein–Barr virus (EBV) infection of the central nervous system (CNS) is associated with meningoencephalitis and other neurological syndromes and with CNS lymphomas (CNSLs). Diagnosis is based on serological studies and more recently on detection of EBV DNA in cerebrospinal fluid (CSF) by polymerase chain reaction (PCR). We measured EBV DNA by quantitative PCR and EBV mRNA by RT‐PCR in the CSF in patients with EBV‐associated neurological disorders. EBV was identified as the cause of CNS infection in 28 patients: 14 with CNSL, 10 with encephalitis, and 4 with postinfectious neurological complications. CSF analysis showed that patients with CNSL had high EBV load (mean ± standard error of 4.8 ± 0.2 log10 DNA copies/ml) and low leukocyte counts (22 ± 7 cells/μl); encephalitis was characterized by high EBV load (4.2 ± 0.3 log10 DNA copies/ml) and high leukocyte counts (143 ± 62 cells/μl); and patients with postinfectious complications showed low EBV load (3.0 ± 0.2 log10 DNA copies/ml) with high leukocyte counts (88 ± 57 cells/μl). Lytic cycle EBV mRNA, a marker of viral replication, was identified in 10 CSF samples from patients with CNSL and encephalitis. These studies demonstrate the utility of quantitative CSF PCR and establish the presence of lytic cycle EBV mRNA in CSF of patients with EBV‐associated neurological disease.

Dual Infections of the Central Nervous System with Epstein-Barr Virus

We describe clinical and laboratory characteristics of 16 patients with central nervous system (CNS) infection caused by Epstein-Barr virus (EBV) and another pathogen. Seven of 10 immunocompromised patients had coinfection with viruses (3 with cytomegalovirus, 2 with JC virus, and 2 with varicella zoster virus) and 3 with nonviral pathogens (2 with pneumococcus and 1 with Cryptococcus species). Three of 6 immunocompetent patients had coinfections with viruses (1 each with herpes simplex virus, varicella zoster virus, and West Nile virus), and 3 had coinfections with nonviral pathogens (2 with Ehrlichia chaffeensis and 1 with Mycoplasma pneumoniae). The EBV load was similar in immunocompromised and immunocompetent patients and in patients with viral and nonviral coinfections. EBV lytic-cycle mRNA was detected in the cerebrospinal fluid of 5 of 6 tested samples, indicating EBV replication in the CNS during coinfection.

The value of polymerase chain reaction for the diagnosis of viral respiratory tract infections in lung transplant recipients.

BACKGROUND Respiratory viruses cause severe infections in lung transplant recipients, which require rapid and accurate diagnosis for appropriate management. OBJECTIVES To evaluate the added benefit of a multiplex PCR for respiratory viruses (influenza [FLU] A and B, respiratory syncytial virus [RSV] A and B and parainfluenza virus [PIV] 1, 2, and 3) complementing rapid respiratory viral culture (RRV) and FLU-A antigen detection (EIA) in this transplant population. RESULTS Over 6 months, 116 nasal washes and bronchoalveolar lavages, obtained from 72 lung transplant recipients with symptoms of upper or lower respiratory tract infections, were tested in real time by RRV and FLU-A EIA, and batched frozen by PCR. One or more methods recognized a respiratory virus in 31 (27%) specimens, including 15 FLU-A, nine RSV and seven PIV. PCR identified 26 of 31 positive samples demonstrating a sensitivity of 84%, higher than RRV (67%) or EIA (54%). PCR, RRV and EIA detected 60, 80 and 54%, respectively, FLU-A samples. PCR and RRV were equivalent for RSV-A, PIV-2 and 3, but PCR found a significantly higher number of RSV-B and PIV-1. CONCLUSIONS These data indicate that routine use of PCR will enhance the number and speed with which viral respiratory tract infections are diagnosed in lung transplant recipients.

How Evolution of Mutations Conferring Drug Resistance Affects Viral Dynamics and Clinical Outcomes of Cytomegalovirus-Infected Hematopoietic Cell Transplant Recipients

ABSTRACT Infection with cytomegalovirus (CMV) remains a significant cause of morbidity and mortality among hematopoietic cell transplant (HCT) recipients. We describe two pediatric HCT recipients who developed persistent and severe drug-resistant CMV infections. CMV resistance to foscarnet and ganciclovir was detected after only 6 and 11 weeks of therapy, respectively. Viral pol mutations associated with drug resistance in these patients included T838A (a novel mutation) and D588N, which were shown by marker transfer to confer foscarnet and multidrug resistance, respectively. Each of these mutations significantly reduced in vitro replication of CMV, suggesting that they may decrease viral fitness. This finding was further supported by the disappearance of mutations upon withdrawal of antiviral pressure in one patient. Novel antivirals or combination therapy may be required for the treatment of drug-resistant CMV in HCT recipients and perhaps in other severely immunocompromised patients.

Growth and Drug Resistance Phenotypes Resulting from Cytomegalovirus DNA Polymerase Region III Mutations Observed in Clinical Specimens

ABSTRACT Recombinant phenotyping of cytomegalovirus (CMV) pol region III mutations from clinical specimens showed that T813S and G841A each conferred foscarnet resistance and approximately threefold increased ganciclovir resistance; adding the UL97 mutation C592G increased ganciclovir resistance to approximately sixfold. Bacterial artificial chromosome CMV clones containing pol mutation L845P were nonviable unless repaired with the wild-type sequence.

Incidence and morbidity of human metapneumovirus and other community‐acquired respiratory viruses in lung transplant recipients

A. Weinberg, D.M. Lyu, S. Li, J. Marquesen, M.R. Zamora. Incidence and morbidity of human metapneumovirus and other community‐acquired respiratory viruses in lung transplant recipients
Transpl Infect Dis 2010: 12: 330–335. All rights reserved.

Kinetics of viral shedding and immune responses in adults following administration of cold-adapted influenza vaccine.

The optimal type and timing of specimens to study the immune responses to cold-adapted influenza vaccine (CAIV) and shedding of vaccine virus are not well established. Healthy adults were vaccinated with CAIV (n=10) or trivalent influenza vaccine (TIV) (n=5). Shedding of vaccine strain influenza B was detected by culture in 6 of 10 CAIV recipients; influenza A was also detected in one of these subjects. Viral shedding by quantitative RT-PCR was detected in 9 of 10 subjects. We detected a > or = 2-fold increase in influenza-specific IgA in nasal wash in 80-100% of CAIV recipients following vaccination, but specific IgG increased in neither nasal wash nor saliva. Recipients of TIV had significant increases in specific serum IgG antibodies. Recipients of both CAIV and TIV had significant increases in IFNgamma-secreting peripheral blood mononuclear cells (PBMCs). PBMCs from subjects receiving CAIV showed a higher proportion of functional, tissue-tropic T-cells (CD4+CD69+CD18+MIP1alpha+) specific for homotypic and heterosubtypic strains of influenza by flow cytometry.

Contrasting drug resistance phenotypes resulting from cytomegalovirus DNA polymerase mutations at the same exonuclease locus.

BACKGROUND Diverse mutations in the cytomegalovirus (CMV) DNA polymerase (pol) gene confer resistance to one or more of the antiviral drugs ganciclovir, foscarnet or cidofovir. The levels of resistance conferred by specific mutations are variable, ranging from insignificant resistance to triple-drug resistance. OBJECTIVES Three pol mutations, I521T, P522A and P522L, detected in patients who received antiviral therapy for CMV infection, were studied by recombinant phenotyping to characterize their associated drug resistance. STUDY DESIGN The individual mutations were transferred by homologous recombination into a reference CMV strain modified with a reporter gene and the drug concentrations required to reduce the reporter signal by 50% (IC50) were determined. RESULTS The mutations I521T and P522A each conferred 3- to 4-fold increases in IC50 to both ganciclovir and cidofovir, while mutation P522L conferred no significant resistance to either drug. None of these mutations conferred foscarnet resistance. CONCLUSIONS The resistance phenotypes of mutations I521T and P522A are as predicted from the known mutation P522S, but divergent results with P522L indicate that different amino acid substitutions at the same position may not have the same effect on drug resistance. New mutations must be individually validated for proper interpretation of genotypic resistance testing.

Human Herpesviruses 6 and 7 and Central Nervous System Infection in Children1

Human herpesviruses 6 and 7 were infrequently found in cerebrospinal fluid of children with central nervous system infection.

Reactivation of latent viruses in individuals receiving rituximab for new onset type 1 diabetes

BACKGROUND Rituximab has been successfully used as an experimental therapy in different autoimmune diseases. Recently, a double-blind placebo-controlled phase-2 study in early onset type 1 diabetes showed that rituximab delayed progression of the disease. However, like with any immunosuppressive therapy, there is a concern of opportunistic viral reactivations with the use of rituximab, including herpes and polyomaviruses. OBJECTIVES To study the incidence of new infections and reactivations with BK, JC, Epstein-Barr and cytomegalovirus (BKV, JCV, EBV and CMV) in T1D participants in the phase-2 rituximab study. STUDY DESIGN Subjects received 4 weekly doses of rituximab (N = 57) or placebo (N = 30) during the first month of study. Blood samples obtained at weeks 0, 12, 26, 56 and 78 were assayed for CMV, EBV, BKV and JCV by real-time DNA PCR and serology. RESULTS EBV reactivations were diagnosed by PCR in 25% of placebo, but none of rituximab recipients (p < 0.01). There were no episodes of CMV viremia in either treatment group. BKV viremias were significantly more common in the rituximab recipients (9%) compared with placebo controls (0, p < 0.01). No JCV reactivations were detected in this study, but among 6 rituximab and 2 placebo recipients who seroconverted for JCV during the study, only one rituximab recipient had detectable viremia. All infections were asymptomatic. CONCLUSIONS Four doses of rituximab administered to individuals with early onset T1D decreased the incidence of asymptomatic EBV reactivations, as predicted by the rituximab-mediated elimination of memory B-cells, but increased the frequency of asymptomatic viremias caused by polyomaviruses.