Phytohemagglutinin-conditioned medium modulates adherence properties and morphology of hairy cells.

The effect of a PHA-conditioned medium was tested on a population highly enriched in hairy cells obtained from spleens of patients with hairy cell leukemia. Under PHA-CM treatment hairy cells adhered to both plastic and glass and spread assuming a typical stellate shape, without changing their enzymatic and antigenic properties. Provided PHA-CM was present, stellate adherent hairy cells remained viable in culture for several months. Mononuclear splenic cells from patients with various hematological disorders never showed similar phenotypic modifications after PHA-CM treatment.