3. Il genoma del CMV è di 240 Kb diviso in 2 regioni U L e U S fiancheggiate da: sequenze terminali ripetute o internamente invertite 0,8kb TR L TR S 2 Kb IR L IR S U L 175Kb 11Kb Il genoma presenta 200 ORF 134 nella regione UL 36 nella regione US
15. Slide Fasi delle infezioni opportunistiche nei riceventi HSCT Haemopoetic stem cell transplantation
16. Sequenza delle infezioni dopo trapianto d’ organo Fishman, J. A. et al. N Engl J Med 1998;338:1741-1751
17. Infezione latente Infezione attiva Effetti diretti Effetti indiretti Sindrome virale Invasione di organi Nefrite-epatite ecc immunosoppressione Infezioni opportunistiche Effetti sul trapianto Rigetto acuto o cronico Altri effetti
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23. pp65 su PMN Ab anti p65 Coniugati con Perossidasi Ab anti p65 marcati con Fluorescina > Sensibilità
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25. Relazione temporale tra comparsa dei sintomi e test diagnostici Storch: Diagnostic Virology, 2000
26. Effetto paradosso della ricerca della pp65 in corso di terapia Il monitoraggio della terapia mediante ricerca della p65 ha fatto erroneamente ipotizzare la comparsa di farmacoresistenza
27. CMV DNA: Real time PCR La Real Time PCR ha un ampio range diagnostico, una elevata sensibilità. False positività praticamente assenti
28. CMV DNA (Real Time PCR) e pp65 Mengelle C et al J Medical Virology 69:225–231 (2003) Gruppo 1: negativi Gruppo 2: <50/200 000 Gruppo 3: > 50/200 000
29. Quale compartimento ? La ricerca del CMV DNA sul sangue intero aumenta la sensibilità della metodologia Cut off più alto
38. Diagnosi di infezione da CMV in gravidanza IgM Le gravide IgM positive devono essere considerate a rischio I test diagnostici disponibili hanno circa il 30% di discordanza
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40. A confirmatory test for CMV-IgM New immunoblot 1) Contains both structural and nonstructural proteins 2) Agrees with consensus of different ELISAs 3) Is easy to standardize 4) Is easy to interpret rp150 rp52 rp130 CKS rp38 Purified native viral proteins Recombinant proteins Vp28 Vp65 Vp82 Vp150
41. Antibody affinity: the strength of a single antigen–antibody bond Antibody avidity: the strength with which a multivalent antibody binds a multivalent antigen high-affinity – high attraction low-affinity – low attraction Good fit Poor fit
42. Weeks after beginning of symptoms Avidity index (%) 70 0 60 50 40 30 20 10 0 5 10 15 20 25 30 35 Congenital CMV infections Low IgG avidity is linked to primary infection
43. Transmission of CMV through the placenta barrier and infection of the fetus Infected mother viraemia infection of placenta trophoblasts Infection of fetal endothelial cells Viral replication in target organs (kidney) Fetal viruria Virus in amniotic fluid Infection of the oropharynx Fetal viraemia
44. T. Lazzarotto et al. / Journal of Clinical Virology 41 (2008) 192–197 Rapporto tra CMV DNA nel LA ed esito della gravidanza
47. Le infezioni congenite da CMV si distinguono da quelle neonatali o perinatali se si dimostra l’assenza o meno di eliminazione virale ( PCR o coltura) nelle prime due settimane di vita Infezioni intrauterine,perinatali,neonatali: diagnosi
FIGURE 311-1. Phases of predictable opportunistic infections among HSCT recipients. Immune defects predisposing to infection are bordered by color (neutropenia = pink, lymphopenia = blue, and hypogammaglobulinemia = green). Barrier defects predisposing to infection are shaded in color (mucosal breakdown = yellow, skin breakdown = silver).Contribution of defects to infections occurring with high incidence are designated by border color (for immune defects) and/or shading (for barrier defects). (Adapted from Van Burik J-AH, Freifeld AG. Infection in the severely imunocompromised host. In: Abeloff MD, Armitage JO, Niederhuber JE, et al, eds. Clinical Oncology. 3rd ed. Philadelphia: Churchill Livingstone; 2004:942.)
Several tests for CMV monitoring have been introduced in the last decade. The most commonly used techniques are the antigenaemia assay and CMV DNA detection by PCR. More recently, detection of viral load has become increasingly common. It is also possible to detect mRNA for example by nucleic acid sequence-based amplification (NASBA).
The second landmark study to be published on pre-emptive therapy was performed by Einsele et al . The shell vial/rapid culture technique was compared with the PCR and it was shown that PCR could overcome the limitations of the less sensitive shell vial technique, allowing earlier initiation of antiviral therapy and thereby resulting in a lower risk for CMV disease and CMV associated death. Einsele H, Ehninger G, Hebart H, Wittkowski KM, Schuler U, Jahn G, et al . Polymerase chain reaction monitoring reduces the incidence of cytomegalovirus disease and the duration and side effects of antiviral therapy after bone marrow transplantation. Blood 1995; 86: 2815-2820.