Immune response to influenza A(H1N1)v in HIV-infected patients

Paola Sansonetti,Jesus Bermejo-Martin,Massimiliano Fabbiani,Matteo Morandi,Michela Sali,Rosa Martucci,David Kelvin,Giovanni Delogu,Ali Danesh,Maurizio Sanguinetti,Salvatore Rubino,Roberto Cauda,Giovanni Fadda

doi:10.3855/jidc.3147

Abstract

HIV infection is considered a risk factor for severe outcomes of influenza A(H1N1)v infection. However, data on immune response against influenza A(H1N1)v virus in HIV-infected patients are lacking. Data from seven HIV-positive and 14 HIV-negative patients infected with A(H1N1)v and from 23 HIV-positive and six HIV-negative asymptomatic controls were analyzed to evaluate the clinical picture, A(H1N1)v viral shedding, and the immune response against the virus. Patients displayed mainly upper respiratory tract diseases (57.1%), while pneumonia was diagnosed only in HIV-negative patients (23.8% of subjects, of which 4.8% required intensive care unit admission). At day seven, 29% of HIV-infected patients were still positive for A(H1N1)v by RT-PCR on nasopharyngeal swabs. Interestingly, a persistence of CXCL10 secretion at high level and lower IL-6 levels was observed in HIV-positive subjects. The geometric mean haemagglutination inhibition titer (HI-GMT) and anti-influenza IgM levels were lower in HIV-positive individuals while anti-influenza IgG levels remained similar in the two groups. The immune impairment due to HIV infection could affect A(H1N1)v clearance and could lead to a lower antibody response and a persistent secretion of CXCL10 at high levels. However, the lower IL-6 secretion and treatment with highly active antiretroviral therapy (HAART) could result in a milder clinical picture.

Highlights

HIV infection is considered a risk factor for severe outcomes of influenza A(H1N1)v infection
Experiments conducted in animal models indicated that (H1N1)v infection may result in more severe lung lesions in humans compared to mice, ferrets, and non-human primates infected with the seasonal human H1N1 virus [14], suggesting that (H1N1)v can cause distinctive clinical effects, especially in patients with a compromised immune system [15]
HIV infection, which is associated with anomalous humoral and T-cell–mediated immune responses, could result in increased susceptibility to viral respiratory infections [16]

Summary

Introduction

HIV infection is considered a risk factor for severe outcomes of influenza A(H1N1)v infection. Data on immune response against influenza A(H1N1)v virus in HIV-infected patients are lacking. A persistence of CXCL10 secretion at high level and lower IL-6 levels was observed in HIV-positive subjects. Conclusions: The immune impairment due to HIV infection could affect A(H1N1)v clearance and could lead to a lower antibody response and a persistent secretion of CXCL10 at high levels. Studies on SARS CoV and influenza A (H5N1) have previously identified specific host immune signatures [4] These studies included (H1N1)v and showed that in the early phase of the infection, most of the mild outcomes are characterized by the expression of systemic levels of chemokines, such as CXCL10, that are associated with the innate antiviral response [5]

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