BONE-MARROW ASPIRATE IMMUNOFLUORESCENT AND BONE-MARROW BIOPSY IMMUNOPEROXIDASE STAINING OF PLASMA-CELLS IN HISTOLOGICALLY OCCULT PLASMA-CELL PROLIFERATIVE MARROW DISORDERS

Immunofluorescent staining (immunofluorescence bone marrow aspirate) a nd immunoperoxidase staining (immunoperoxidase bone marrow biopsy) wer e compared in 26 patients with plasma cell dyscrasia and less than 10% marrow plasma cells. Their clinical diagnoses included monoclonal gam mopathy of undetermined significance (13 patients), treated multiple m yeloma (four patients), multiple myeloma with less than 10% marrow pla sma cells (two patients), primary systemic amyloidosis (two patients), monoclonal gammopathy of undetermined significance with neuropathy (t wo patients), angiofollicular lymph node hyperplasia (two patients, al l with the POEMS [polyneuropathy, organomegaly, endocrinopathy, monocl onal protein, and skin changes] syndrome), and primary (amyloidosis) a myloid neuropathy (one patient). The percentage of plasma cells was gr eater than 5% in 23% of patients and less than or equal to 5% in 77% o f patients. With immunofluorescence bone marrow aspirate and immunoper oxidase bone marrow biopsy, light-chain restriction was demonstrated i n 84% of all cases and accurately determined in 96% of all cases as sh own by serum and urine paraprotein analysis or tissue amyloid typing. Monoclonal populations of plasma cells can be readily identified with immunofluorescence bone marrow aspirate and immunoperoxidase bone marr ow biopsy in most patients with paraproteins and marrow plasmacytoses not diagnostic of multiple myeloma.