Viruses and Langerhans cell histiocytosis: is there a link?

As a rare, sporadic disease Langerhans cell histiocytosis (LCH) presents a difficult problem in defining a likely etiology. Epidemiological data would not a priori lead one to choose a viral etiology. However, there are rare tumours which occur as sequelae of common infections from Epstein-Barr virus or human papilloma viruses. Likewise some viruses can cause cells to elaborate cytokines which could ultimately stimulate Langerhans cell growth. There is only a small amount of experimental data testing the hypothesis that viruses might be associated with LCH. The theoretical constructs surrounding this question and new data refuting the association are summarised.