Lymphomatoid papulosis: a premalignant T cell disorder.

In an attempt to better define the process of lymphomatoid papulosis, two cases were studied by means of light and electron microscopy, immunohistochemistry studies, including the use of monoclonal antibodies, and cytogenetic technics. About 90% of the dermal lymphoid infiltrate, including the atypical cells, reacted with antibodies that define helper-inducer T cells. Only a few cells, about 5%, reacted with antibodies that define cytotoxic-suppressor T cells. Langerhans cells were increased mostly within the epidermis, and in the dermis they were in close proximity to lymphoid cells. Cytogenetic studies disclosed an abnormal hypertetraploid karyotype in dividing cells from the skin lesion, whereas skin fibroblast and phytohemagglutinin-stimulated cells from peripheral blood cultures had a diploid karyotype. The results support the concept that lymphomatoid papulosis is a disorder characterized by a predominance of helper-inducer T cells, including the atypical cells bearing an abnormal karyotype.