The mortality rate for avian influenza A virus subtype H5N1 infection is around 50% and there is an urgent need for novel treatments. In their Hypothesis Jan-Inge Henter (Karolinska Hospital, Stockholm, Sweden) and colleagues in Hong Kong state that patients with H5N1 infection have similar symptoms and post-mortem features to people with an immune disorder called haemophagocytic lymphohistiocytosis (HLH). Patients with HLH have too many infection-fighting white blood cells, which can accumulate in healthy tissue and cause damage to a variety of organs. One of the key treatments for HLH is the chemotherapy drug etoposide, which helps kill the excess immune cells.

The authors suggest that although chemotherapy for avian influenza is a substantial jump in thinking, such therapy could still be reasonable, particularly since it has been shown to be very effective in decreasing mortality in HLH disease associated with severe infection by another virus, the Epstein-Barr virus. The scientists emphasise that their suggestion at present is only a hypothesis, and that the treatment has not yet been tested in patients infected by avian influenza.

Professor Henter states: "We would welcome WHO [World Health Organization] to consider a platform for the undertaking of clinical trials based on a modified HLH protocol (including etoposide and corticosteroids) in addition to supportive and antiviral therapy [for patients infected by H5N1]."

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Contact: Joe Santangelo
j.santangelo@elsevier.com
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Lancet
1-Mar-2006