Alterations of effector cell molecule expression on neutrophils in granulocyte colony-stimulating factor-producing tumour.

A 68-year-old man was diagnosed as having a granulocyte colony-stimulating factor (G-CSF)-producing mediastinal tumour. Mediastinotomy was performed, and thereafter the elevated leucocyte count and serum G-CSF concentration returned to the normal range. The surface expression of effector cell molecules on neutrophils was serially examined. Before operation, the expression of FcRI and CR1 was increased but the expression of FcRIII and L-selectin was reduced in the patient. The altered expression of these molecules returned to the normal levels after operation. These findings suggest that G-CSF produced by the tumour modulated neutrophil effector cell molecule expression in the patient.