Influenza A H5N1 and HIV co-infection: case report

Abstract

The role of adaptive immunity in severe influenza is poorly understood. The occurrence of influenza A/H5N1 in a patient with HIV provided a rare opportunity to investigate this.
A 30-year-old male was admitted on day 4 of influenza-like-illness with tachycardia, tachypnea, hypoxemia and bilateral pulmonary infiltrates. Influenza A/H5N1 and HIV tests were positive and the patient was treated with Oseltamivir and broad-spectrum antibiotics. Initially his condition improved coinciding with virus clearance by day 6. He clinically deteriorated as of day 10 with fever recrudescence and increasing neutrophil counts and died on day 16. His admission CD4 count was 100/microl and decreased until virus was cleared. CD8 T cells shifted to a CD27+CD28- phenotype. Plasma chemokine and cytokine levels were similar to those found previously in fatal H5N1.
The course of H5N1 infection was not notably different from other cases. Virus was cleared despite profound CD4 T cell depletion and aberrant CD8 T cell activation but this may have increased susceptibility to a fatal secondary infection.

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Fox et al. BMC Infectious Diseases 2010, 10:167
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Open Access
CASE REPORT
© 2010 Fox et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons At-
tribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.
Case report
Influenza A H5N1 and HIV co-infection: case report
Annette Fox*
1,2
, Peter Horby
1,2
, Nguyen Hong Ha
3
, Le Nguyen Minh Hoa
1
, Nguyen Tien Lam
3
, Cameron Simmons
2,4
,
Jeremy Farrar
2,4
, Nguyen Van Kinh
3
and Heiman Wertheim
1,2,5
Abstract
Background: The role of adaptive immunity in severe influenza is poorly understood. The occurrence of influenza A/
H5N1 in a patient with HIV provided a rare opportunity to investigate this.
Case Presentation: A 30-year-old male was admitted on day 4 of influenza-like-illness with tachycardia, tachypnea,
hypoxemia and bilateral pulmonary infiltrates. Influenza A/H5N1 and HIV tests were positive and the patient was
treated with Oseltamivir and broad-spectrum antibiotics. Initially his condition improved coinciding with virus
clearance by day 6. He clinically deteriorated as of day 10 with fever recrudescence and increasing neutrophil counts
and died on day 16. His admission CD4 count was 100/μl and decreased until virus was cleared. CD8 T cells shifted to a
CD27+CD28- phenotype. Plasma chemokine and cytokine levels were similar to those found previously in fatal H5N1.
Conclusions: The course of H5N1 infection was not notably different from other cases. Virus was cleared despite
profound CD4 T cell depletion and aberrant CD8 T cell activation but this may have increased susceptibility to a fatal
secondary infection.
Background
Influenza A/H5N1 infection is characterized by high viral
loads, overproduction of pro-inflammatory cytokines
and chemokines, direct lung tissue destruction, pulmo-
nary oedema and extensive inflammatory infiltration [1-
3]. The prevailing view is that alveolar damage is the pri-
mary pathology leading to acute respiratory distress,
multiple organ dysfunction syndrome and death [3].
Likewise, 2009 H1N1 infection can cause acute respira-
tory distress syndrome and death in previously healthy
young adults very similar to the clinical syndrome seen in
H5N1 [4].
It remains unclear whether lung pathology in severe
influenza is a direct consequence of high viral loads and/
or of ensuing inflammatory responses. The involvement
of innate versus adaptive immunity in inflammation or
controlling viremia is also poorly defined. Further under-
standing of the pathological processes is necessary to
develop interventions that prevent severe lung disease.
The occurrence of H5N1 infection in a patient with HIV
infection offered a unique opportunity to study the path-
ological and immunological process when adaptive
immunity is impaired.
Case presentation
In February 2009 a 30-year-old male was admitted to our
hospital with a four-day history of fever, cough and
increasing difficulty breathing. Three days prior to illness
onset he had slaughtered, prepared and consumed a duck
that was the last survivor of a household flock of ten
birds, which had died over the preceding week. Close
contacts did not report recent respiratory illness and the
patient had no known chronic health conditions. On
admission the patient was febrile, tachycardic, tachypneic
and hypoxemic (Figure 1). Chest x-ray showed bilateral
pulmonary infiltrates and an ultrasound revealed a right
pleural-effusion. A throat swab was positive for influenza
A/H5N1 by a real time RT-PCR protocol described else-
where [2] but the cycle threshold (CT) value was 35 (Fig-
ure 1), indicative of low viral loads. Viral RNA was not
detected in plasma. HIV antibody and/or antigen tests
were performed as per routine practice in the admitting
hospital. Determine®HIV-1/2 rapid test (Abbott Labora-
tories), Genscreen ULTRA HIV Ag-Ab (BioRad) and SFD
HIV 1/2 (Fujirebio) tests were positive. HIV branched
DNA load was 510 copies/ml (Quantiplex HIV RNA 2.0
Assay, Chiron Corporation, USA). The patient was com-
* Correspondence: afox@oucru.org
1 Oxford University Clinical Research Unit Viet Nam, Wellcome Trust Major
Overseas Program, National Hospital of Tropical Diseases, 78 Giai Phong Road,
Dong Da, Ha Noi, Viet Nam
Full list of author information is available at the end of the article

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menced on supplemental oxygen by face mask, Oseltami-
vir phosphate (150 mg bd), broad-spectrum antibiotics
(Table 1) for suspected bacterial co-infection and high
dose co-trimoxazole for possible Pneumocystis jiroveci
infection. Methylprednisolone was given 40 mg once a
day from days 5 to 8 and 20 mg on days 9 and 10 of illness.
At admission, clinical and laboratory signs were similar
in severity to those reported previously for fatal H5N1
patients (Figure 1). The patient's condition improved over
the next days coinciding with virus clearance but began to
deteriorate again from day 10 of illness with a recrudes-
cence of fever (Figure 1). Deterioration coincided with
increasing neutrophil counts and CRP levels (Figure 1).
Fluconazole was given from day 10 and the supplemental
oxygen flow rate increased. Sputum and blood obtained
on day 4 and 10 were assessed by smear and/or culture
for bacteria and fungi but pathogenic organisms were not
detected (Table 2). Aspergillus fumigatus was cultured
from tracheal aspirate obtained on day 14, and flucon-
azole was replaced with itraconazole. Chest x-ray on day
14 showed marked bilateral infiltrates and pleural effu-
sions (Figure 2). The patient was intubated and ventilated
on day 15 of illness. The patient died on day 16 with
respiratory and renal failure.
Blood samples were available for immunological assess-
ment until day 7 of illness. CD4 lymphopenia was marked
(Figure 1) with a CD4 count of 100/μl and a CD4:CD8
ratio of 0.16 at admission, which is lower than previously
reported for any H5N1 case [2]. CD4 and CD8 counts
decreased until virus was cleared (Figure 1). The percent-
age of CD8 T cells expressing activation markers includ-
ing HLA-DR (Figure 1) increased to reach levels at least
10 times higher than normal [5]. At admission 50% of
CD8 T cells had a fully differentiated (CD27-CD28-) phe-
notype but this decreased with a concomitant increase in
the percentage with an intermediate differentiation
(CD27+CD28-) phenotype (Figure 1).
Chemokine and cytokine levels were measured using
cytometric bead array kits (Becton Dickinson). MIG
Table 1: Antibiotics and antifungals given
Drug name Days of illness
Ceftazidine 4-10
Levofloxacin 4-14
Cotrimoxazole 5-16
Imipenem/Cilastatin 10-14
Fluconazole 10-14
Itraconazole 14-16
Cefperazone-sulbactam 14 -16
Figure 1 Clinical and laboratory findings by day of illness. Dashed
and solid lines represent reported values for fatal and surviving H5N1
patients, respectively [2,8,9]. %HLADR+ is for the the CD8 T cell subset.
Cytokines and chemokines are reported as Log 10 pg/ml.

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(CXCL9), IL-8 (Figure 1), IP-10 (CXCL10), MCP-1
(CCL2), IL-6 and IFN-γ (not shown) concentrations were
increased to levels similar to those found previously in
patients with fatal H5N1. IL-8, MCP-1 and IL-6 levels
declined from day 5 to 7 whereas MIG and IP-10
increased.
Conclusions
To our knowledge only one other patient with docu-
mented HIV and H5N1 co-infection has been reported
and details of the clinical course in this patient have not
been published [6].
Patients with immune compromise including those
with HIV are at higher risk of complications associated
with seasonal influenza [7]. This may not translate to
highly pathogenic H5N1 which has been fatal in the
majority of previously healthy patients. Although early
clinical and laboratory findings were similar to those of
other fatal H5N1 patients [2,6,8,9], the patient showed a
transient clinical improvement and a relatively delayed
time to death, which was accompanied by signs of sec-
ondary pneumonia. In addition, viral loads were relatively
low with no virus detection in plasma, unlike some fatal
cases described previously [2,6,8,9] suggesting that H5N1
viral clearance was not compromised by HIV co-infec-
tion. H5N1 can be cleared without antivirals and there is
little benefit of Oseltamivir after day 6 of illness [9,10].
However early control of viral load appears to be impor-
tant because survival rates are highest in patients treated
earliest [10]. Thus, the contribution of Oseltamivir may
have been negligible in this patient because viral loads
were relatively low prior to administration. Lymphopenia
is common in H5N1 patients [2,6,9] and low CD3 counts
and CD4:CD8 ratios have been reported [2]. We can not
determine if immune compromise preceded influenza A/
H5N1 infection in this patient. Investigation of AIDS
defining illnesses was not exhaustive because the patient
was reported to have been healthy and the presenting
symptoms and rapid onset of illness were consistent with
the confirmed diagnosis of H5N1. We can not exclude the
possibility of P. jirovecci or mycobacterial co-infection.
CD4 counts and CD4:CD8 ratios were lower than we
have seen in other H5N1 patients (unpublished findings).
This suggests that CD4 T cells may not be required for
viral clearance consistent with findings that CD8 T cells
are more important for survival from highly virulent
influenza infection in mice [11]. The patient maintained
substantial numbers of peripheral CD8 T cells and a large
fraction became activated, but the concomitant shift to a
CD27+CD28- phenotype raises doubts about their antivi-
ral function. This phenotype is associated with CD8 T
cells that proliferate but lack cytotoxic function and accu-
mulate in progressive HIV infection [12]. Chemokine and
cytokine levels were high as in other fatal H5N1 cases and
may account for the severity of the early pneumonia. The
prevailing view is that excessive cytokine and chemokine
Table 2: Laboratory tests for co-infection
Illness Day Specimen Test Result
4 blood culture negative after 5 days
4 sputum smear and Ziehl-Neelsen stain negative
culture for bacteria and fungi Candida albicans
4 N/A Mantoux/PPD skin test negative
10 blood culture negative after 5 days
10 sputum culture for bacteria and fungi Candi da albicans
13 blood culture negative after 5 days
14 tracheal aspirate smear for fungi positive
smear and Ziehl-Neelsen stain negative
culture for bacteria and fungi Candida albicans Aspergillus fumigatus

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release are secondary to high viral loads [2], whereas viral
loads were low in this patient. Although HIV infection is
also associated with increased expression of proinflam-
matory cytokines [13,14], levels tend to be lower than
found here [15], even with co-presentation of pneumo-
cystis pneumonia, bacterial pneumonia or mycobacterio-
sis, and IFN-γ expression is often decreased [13]. Levels
of IL-8, MCP-1, and IL-6 also decreased with H5N1 viral
load indicting that they are primarily induced by H5N1
infection. There has been no conclusive report of second-
ary infection accompanying H5N1 whereas secondary
pneumonia may have caused a considerable fraction of
the deaths from the highly pathogenic 1918 H1N1 strain
and the current H1N1 2009 strain [16]. Findings in this
patient including recrudescence of fever, rising CRP lev-
els and neutrophilia were consistent with a secondary
infection despite being treated with broad-spectrum anti-
biotics. A. fumigatus was detected in a tracheal aspirate
suggestive of invasive pulmonary aspergillosis. Corticos-
teroid adminsitration may have contributed to the pre-
sumed development of invasive pulmonary aspergillosis
[17], but there have been numerous reports of invasive
pulmonary aspergillosis developing after influenza A
infection in which T cell lymphopenia occurred [18,19].
None these patients had HIV and few received corticos-
teroids indicating the influenza A associated immune
suppression may be sufficient for the development of
invasive pulmonary aspergillosis. In conclusion the
course of H5N1 infection in this case was not notably dif-
ferent in the presence of HIV co-infection but it is possi-
ble that HIV co-infection and profound CD4 T cell
depletion increase susceptibility to secondary infection.
The findings suggest that CD4 T cells may not be
required for H5N1 virus clearance.
Consent
The admitting hospital approved the use of patient sam-
ples and data and written informed consent was obtained
from the next of kin for publication of this case report. A
copy of the written consent is available for review by the
Editor-in-Chief of this journal.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
AF designed and conducted immunological assessments and drafted the
manuscript; PH coordinated the collection of clinical information and helped
draft the manuscript; NHH and NTL were the reference physicians during the
in-hospital management of this case; LNMH carried out molecular diagnostics
and immunological assessments; CS and JF participated in study design and
analysis; NVK helped coordinate the collection of patient information; HW
coordinated virology and helped draft the manuscript. All authors read and
approved the final manuscript.
Acknowledgements
This work was funded by the Wellcome Trust UK Major Overseas Programme
and The South East Asia Infectious Diseases Clinical Research Network. We
thank Ngoc Nghiem My and Rogier Van Doorn for performing the HIV viral
load determination.
Figure 2 Chest X-ray images. The illness day is shown in the bottom
left corner of each image.
5
7
14

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Author Details
1Oxford University Clinical Research Unit Viet Nam, Wellcome Trust Major
Overseas Program, National Hospital of Tropical Diseases, 78 Giai Phong Road,
Dong Da, Ha Noi, Viet Nam, 2Centre for Tropical Medicine, Nuffield Department
of Clinical Medicine, University of Oxford, Churchill Hospital, Old Road, Oxford
OX3 7LJ, UK, 3National Hospital of Tropical Diseases, 78 Giai Phong Road, Dong
Da, Ha Noi, Viet Nam, 4Oxford University Clinical Research Unit Viet Nam,
Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, 190
Ben Ham Tu Street, District 5, Ho Chi Minh City, Viet Nam and 5South East Asia
Infectious Diseases Clinical Research Network, JI Diponegoro no 69, Jakarta,
10430, Indonesia
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Cite this article as: Fox et al., Influenza A H5N1 and HIV co-infection: case
report BMC Infectious Diseases 2010, 10:167
Received: 1 March 2010 Accepted: 14 June 2010
Published: 14 June 2010
This article is available from: http://www.biomedcentral.com/1471-2334/10/167© 2010 Fox et al; licens ee BioMed C entral Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.BMC Infectious Diseases 2010, 10:167