First-line diagnosis based on immunological phenotyping in suspected acute leukemia: a prospective study

In a prospective analysis of the diagnostic value of immunophenotyping in acute leukemias (ALs), all patients admitted to a pediatric and a haematological department suspected of AL were examined consecutively with a selected panel of monoclonal antibodies (Mabs) against leucocyte differentiation antigens during an 8-month period. A total of 189 samples obtained from blood, bone marrow, spinal fluid and lymph nodes in 120 cases were all analysed blindly. The results were correlated with a routine morphological/cytochemical evaluation. Differing results were obtained in seven out of 38 cases in which the immunologically defined diagnosis was acute myeloid leukemia (AML), and in one out of 21 cases with the primary diagnosis acute lymphoid leukemia (ALL). Immunological phenotyping disclosed two cases of hybrid leukemia, one case of biphenotypic and one case of bilineal leukemia. No evidence of malignancy was found in 36 cases, 30 cases of blood and bone marrow and six cases of spinal fluids, in every case in accordance with the pathological examination. These results demonstrate that a first-line immunological evaluation of bone marrow, blood and spinal fluid from patients suspected of AL is highly capable of discriminating between different malignant and nonmalignant haematological diseases and also between various types of leukemias. The immunological methods do, however, require a sufficient amount of material which was a limiting factor in 14 out of 120 examinations, mainly from patients treated with several cycles of cytostatics. It is concluded that immunophenotyping can be used as a first-line diagnostic tool in malignant haematological diseases.