Abstract
Human Ig was demonstrated in paraffin sections of 12 trephine bone marrow biopsies by the unlabeled antibody peroxidase-antiperoxidase (PAP) method. The Ig-containing cells, which were counted with the Reichert-Jung (Kontron) MOP-AMO3 user-controlled image-analyzer, constitute approximately 42% of all the nucleated cells in the marrow.