An Observational Retrospective Study Provide Information on Hospitalization and Severe Outcomes of the 2009 A(H1N1) Infection in Italy.

BACKGROUND: The aim of this study was to try to ascertain whether, in the absence of a pre-organized programme, locally collected data might provide information about the epidemiological and clinical characteristics of the recent A(H1N1) pandemic in Italy. METHODS: The study was an observational retrospective analysis of the clinic-epidemiological features performed by reviewing medical charts from 141 hospitalized patients with laboratory confirmed pandemic A(H1N1) infection in Umbria, a region of central Italy, in the period July 2009 to March 2010. RESULTS: The pandemic virus was found capable of inducing severe illness requiring hospitalization or intensive care unit admission (ICU), or resulting in death. Age and comorbidity were found to be potential risk factors for severe disease. The mean age of the hospitalized patients was 37 years (range 0 - 93 yrs), however the mean age of ICU admitted patients, including people who did not survive, was higher as compared with those admitted to general medical ward (54 vs 35 yrs). The highest incidence of hospitalization was observed in the youngest group (0 - 17 yrs), the greatest rate of ICU admission in adults (18 - 64 years), and the risk of death in the oldest population (≥ 65 yrs). Comorbity conditions were present in some (55%), but not all hospitalized patients and increased with the age and the severity of the illness. CONCLUSIONS: The data obtained are compatible with the identified epidemiological characteristics of the A(H1N1) pandemic derived from partial information previously collected in Italy and from studies conducted in other European and non European countries. The results of our retrospective observational study suggest that locally organized data collection may give information on the epidemiological and clinical characteristics of a pandemic that are compatible with those obtained from more complex and complete studies.

Influenza viruses and cross-reactivity in healthy adults: humoral and cellular immunity induced by seasonal 2007/2008 influenza vaccination against vaccine antigens and 2009 A(H1N1) pandemic influenza virus.

We analyzed humoral and cellular immune responses against vaccine antigens and the new A(H1N1) virus in healthy adults before and after immunization with the 2007/2008 commercially available trivalent subunit MF59-adjuvanted influenza vaccine during the Fall 2007, prior to the emergence of the new virus. Antibody titers were significantly boosted only against the three vaccine antigens. Seasonal vaccination boosted pre-existing cellular responses upon stimulation of peripheral blood mononuclear cells not only with the homologous three vaccine antigens, but also with the heterologous new 2009 A(H1N1) and with a highly conserved peptide present in the stalk region of hemagglutinin (HA). These results show that cross-reactive cell responses against the new virus were present before the circulation of the virus and were boosted by seasonal vaccination. The cross-reactivity of cellular responses might, at least in part, explain the low pathogenicity of the new pandemic virus. The finding of cellular immunity, that can be increased by seasonal vaccination, against the conserved HA peptide, underline the potential use, in human vaccines, of conserved peptides of the stalk region of HA characterized by broad immunogenicity in experimental systems.

Pentraxin 3 protects from MCMV infection and reactivation through TLR sensing pathways leading to IRF3 activation.

Reactivation of latent human cytomegalovirus (HCMV) following allogeneic transplantation is a major cause of morbidity and mortality and predisposes to severe complications, including superinfection by Aspergillus species (spp). Antimicrobial polypeptides, including defensins and mannan-binding lectin, are known to block viral fusion by cross-linking sugars on cell surface. Pentraxin 3 (PTX3), a member of the long pentraxin family, successfully restored antifungal immunity in experimental hematopoietic transplantation. We assessed here whether PTX3 binds HCMV and murine virus (MCMV) and the impact on viral infectivity and superinfection in vivo. We found that PTX3 bound both viruses, reduced viral entry and infectivity in vitro, and protected from MCMV primary infection and reactivation as well as Aspergillus superinfection. This occurred through the activation of interferon (IFN) regulatory factor 3 (IRF3) in dendritic cells via the TLR9/MyD88-independent viral recognition sensing and the promotion of the interleukin-12 (IL-12)/IFN-gamma-dependent effector pathway.

Antibody responses and HIV-1 viral load in HIV-1-seropositive subjects immunised with either the MF59-adjuvanted influenza vaccine or a conventional non-adjuvanted subunit vaccine during highly active antiretroviral therapy.

OBJECTIVE: To study immunological and virological parameters in HIV-1-seropositive adults treated with highly active antiretroviral therapy (HAART) for at least 7 months after immunisation with MF59-adjuvanted (FLUAD, Chiron, Siena, Italy) or with non-adjuvanted (AGRIPPAL, Chiron) trivalent influenza vaccine. DESIGN: Blood samples, collected before and after vaccination, were analysed for the presence of antibodies against the vaccine antigens, for number of CD4+ T lymphocytes and HIV-1 RNA levels. RESULTS: Forty-four volunteers received FLUAD and 40 AGRIPPAL influenza vaccine. Thirty days after vaccination both adjuvanted and non-adjuvanted vaccines induced significant increases of anti-influenza virus antibodies. However, antibody titres found in volunteers receiving adjuvanted vaccine were in general significantly higher when compared with those found in the non-adjuvanted vaccine group. The requirements of the European Commission of influenza vaccine for a non-elderly adult population were always met by recipients of the adjuvanted vaccine, even in those with the lowest CD4+ cell counts (<200 cells/mmc). The subjects receiving the non-adjuvanted vaccine failed to met these requirements. The CD4+ T lymphocytes and plasma HIV-1 RNA levels remained stable in the long term, both in people receiving adjuvanted or non-adjuvanted vaccine. CONCLUSION: MF59-adjuvanted influenza induced a significant higher immune responses as compared with conventional vaccine in HIV-seropositive HAART-treated patients. Both vaccines were safe regarding HIV RNA viral replication and loss of CD4+ T lymphocytes.