Sheep erythrocyte rosette formation and phytohemagglutinin-stimulated cells. Two cases of mycosis fungoides with skin tumors and lymph nodes.

Infiltrating cells were harvested by mechanical means from skin tumors and lymph nodes of myocis fungoides. Sheep erythrocyte rosette formation was observed on more than 90% of small lymphocyte-like cells with irregular nuclei but seemed to be hardly detectable on larger cells. The small and large cells that formed erythrocyte rosettes showed similar basic ultrastructures, which suggested that these two types of cells are of the same origin. When cultured with phytohemagglutinin (PHA), 90% of the small cells underwent transformation, and they were found to be lymphoblast-like cells with irregular nuclei by electron microscopy. Only 40% of the large cells were transformed with PHA.