Use of the FAB criteria for the diagnosis of acute erythroleukaemia (AEL).

The criteria proposed by the French-American-British (FAB) Group for the diagnosis of acute erythroleukaemia (AEL), including the requirement for greater than or equal 30% marrow myeloblasts, were used in a review of patients with erythroleukaemia. Ten patients with AEL were identified, and a further twelve patients with marrows suggestive of AEL but having less than 30% myeloblasts were classified as having refractory anaemia with excess of blasts (RAEB). The AEL patients had a poor prognosis, poor response to chemotherapy, and none showed evolution to myeloblastic or monoblastic leukaemia. In contrast, the patients with RAEB appeared to survive longer, respond better to chemotherapy, and several evolved into typical myelogenous leukaemia. The FAB criteria subdivides patients with erythroleukaemia into groups with apparent clinicopathological and prognostic differences. Further studies using these or equally strict criteria are required.