CD101 expression by Langerhans cell histiocytosis cells

Aims: Our objective was to study the expression of a recently identified ce ll surface molecule, CD101 and in Langerhans cell histiocytosis (LCH) patie nts as CD101 has been shown to be present on dendritic cells. We wanted to determine if CD101 expression could be helpful for the diagnosis of LCH in conjunction with other markers (CD1a, S100 protein), and could be predictiv e of the evolution and dissemination of the disease. Methods and results: The expression of CD101 was studied by immunohistochem ical technique in 11 cases of Langerhans cell histiocytosis on frozen secti ons. The expression of CD101 was positive in nine cases, high in six cases and low in three cases. There was no expression in the other two cases. No correlation with the evolution, the localization or the dissemination of th e disease could be evidenced. Conclusions: CD101 is a new phenotypic marker that might be useful in combi nation with other markers for the diagnosis of LCH. However, as the anti-CD 101 antibody works only in frozen sections, its value is limited compared t o anti-CD1a antibody.