A case of pandemic 2009 influenza A (H1N1) in a patient with HIV infection

HIV-1 and its gp120 inhibits the influenza A(H1N1)pdm09 life cycle in an IFITM3-dependent fashion

HIV-1-infected patients co-infected with A(H1N1)pdm09 surprisingly presented benign clinical outcome. The knowledge that HIV-1 changes the host homeostatic equilibrium, which may favor the patient resistance to some co-pathogens, prompted us to investigate whether HIV-1 infection could influence A(H1N1)pdm09 life cycle in vitro. We show here that exposure of A(H1N1)pdm09-infected epithelial cells to HIV-1 viral particles or its gp120 enhanced by 25% the IFITM3 content, resulting in a decrease in influenza replication. This event was dependent on toll-like receptor 2 and 4. Moreover, knockdown of IFITM3 prevented HIV-1 ability to inhibit A(H1N1)pdm09 replication. HIV-1 infection also increased IFITM3 levels in human primary macrophages by almost 100%. Consequently, the arrival of influenza ribonucleoproteins (RNPs) to nucleus of macrophages was inhibited, as evaluated by different approaches. Reduction of influenza RNPs entry into the nucleus tolled A(H1N1)pdm09 life cycle in macrophages earlier than usual, limiting influenza's ability to induce TNF-α. As judged by analysis of the influenza hemagglutin (HA) gene from in vitro experiments and from samples of HIV-1/A(H1N1)pdm09 co-infected individuals, the HIV-1-induced reduction of influenza replication resulted in delayed viral evolution. Our results may provide insights on the mechanisms that may have attenuated the clinical course of Influenza in HIV-1/A(H1N1)pdm09 co-infected patients during the recent influenza form 2009/2010.

Clinical characteristics of critical patients with pandemic influenza A (H1N1) virus infection in Chengdu, China

OBJECTIVE

The critical illness of pandemic influenza A (H1N1) virus infection may be associated with relatively poor outcomes. The objective of this study is to describe clinical features and factors associated with the deaths of critical patients.

METHODS

Medical records of 26 critical patients with H1N1 infection admitted from Sept. 1 to Dec. 31, 2009, were retrospectively reviewed. Diagnosis was established by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

RESULTS

The mean age of the patients was (40.4 ± 18.4) years and 73.1% of them were male. Clinical manifestations included fever, cough, and sputum production. The laboratory findings included leukocytosis, lymphopenia, C-reaction protein, and lactic dehydrogenase elevation. In this series, 17 subjects survived and 9 died. The parameters between the deaths and survivors were compared, which included acute physiology and chronic health evaluation II (APACHE II) scores (23.8 ± 10.1 vs. 14.3 ± 6.6, P<0.05), sequential organ failure assessment (SOFA) scores (13.3 ± 3.0 vs. 6.6 ± 3.3, P<0.05), and multiple organ dysfunction syndrome (MODS) scores (7.4 ± 2.5 vs. 3.3 ± 1.7, P<0.05). The cases of deaths had higher incidences of cardiovascular failure (100% vs. 41.2%, P<0.05), renal failure (55.6% vs. 11.7%, P<0.05), encephalopathy (44.4% vs. 5.9%, P<0.05), hepatic failure (33.3% vs. 5.9%, P<0.05), and septic shock (33.3% vs. 17.6%, P<0.05).

CONCLUSIONS

The critical patients with H1N1 infection have high APACHE II, SOFA, and MODS scores, which may be associated with an increased risk of death and complex clinical courses.