Aplastic anaemia. Histological investigation of methacrylate embedded bone marrow biopsy specimens; correlation with survival after conventional treatment in 15 adult patients.

Aplastic anaemia is a rare disease with a poor prognosis: 40% of the patients die within 6 months after diagnosis. The clinical condition and laboratory data show only a poor correlation with the chance of survival for longer than 6 months. Conventional bone marrow biopsy investigations did not have any predictive value, but methyl-methacrylate embedded biopsy material from 15 patients given only supportive care showed histological features considered important for the assessment of the prognosis. In 3 micron methacrylate sections non-myeloid cells, like lymphocytes, could be readily distinguished from erythropoietic cells. Three types of inflammatory infiltrate were easily distinguished according to amount and distribution. Seven of the eight patients with marked infiltration (Grade III) died within 6 months after biopsy, but none of the patients with a sparse infiltrate (Grade I), including five patients in remission. In six of 10 patients, who were not in remission, histological data permitted correction of the clinically estimated prognosis.