# 4643
Despite the occasional `Eureka!’ moment, most of our scientific knowledge is gained incrementally, and over months or even years of research. A single case study, such as the one presented below, doesn’t necessarily tell us a whole lot.
But it does provide a puzzle piece. And once you’ve gathered enough pieces, you can then begin to put the puzzle together.
Human H5N1 infections remain rare, with only about 500 recorded over the past dozen or so years. HIV , while more common, affects less than 1% of the global population (although in some countries, that number is as high as 15%).
Accordingly, there have been few opportunities for scientists to observe HIV positive patients with an H5N1 co-infection.
We’ve one such case study out of Vietnam, published today in BMC Infectious Diseases. A hat tip to Tetano on FluTrackers for this link.
Influenza A H5N1 and HIV co-infection: case reportAnnette Fox, Peter Horby, Nguyen Hong Ha, Le Nguyen Minh Hoa, Nguyen Tien Lam, Cameron Simmons, Jeremy Farrar, Nguyen Van Kinh, Heiman Wertheim
BMC Infectious Diseases 2010, 10:167 (14 June 2010)
[Abstract] [Provisional PDF]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/ul 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.
While the `The course of H5N1 infection was not notably different from other cases’, there were a few surprises along the way.
First, the patient showed some clinical improvement after two days of treatment (including oseltamivir). Despite his HIV status, he was apparently able to begin clearing the virus by day 6, much as might be expected in a non-immunocompromised patient.
But the patient’s condition deteriorated around day 10 with relapse of fever, a raised CRP (C-Reactive Protein) level, and neutrophilia (elevated neutrophil white count) – all suggestive of a secondary infection.
Throughout his hospitalization, however, the patient’s lab cultures were negative for bacterial infection, but positive for Candida albicans (and eventually, on 14) Aspergillus fumigatus.
Despite aggressive antibiotic and antifungal treatment, the patient died on day 16 of respiratory and renal failure. A fate, and course of illness, not unlike that which we’ve seen with a great many other H5N1 cases.
It is possible, according to the authors, that the administration of corticosteroids early in this patient’s treatment may have contributed to the development of invasive pulmonary aspergillosis.
The authors conclude with the following (but read the whole report):
In conclusion the course of H5N1 infection in this case was not notably different in the presence of HIV co-infection but it is possible 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.
