IMMUNODIAGNOSIS OF CHILDHOOD ALL - PROBLEMS ASSOCIATED WITH THE USE OF PERIPHERAL-BLOOD ALONE

The immunologic classification of acute lymphoblastic leukemia (ALL) based solely on peripheral blood (PB) cell phenotypes may lead to conflicting results. This was demonstrated by the simultaneous assay of five immunologic markers on PB and bone marrow (BM) cells from 13 children with untreated ALL. We assayed erythrocyte (E) rosettes at 4°C and 37°C, presence of membrane Ig(mIg), and binding of antisera raised against thymus (T), and E− ALL blasts, respectively. At diagnosis, the PB of these children contained > 90% lymphoid cells with 0–48% E rosettes and 1‐84% cells with T antigen(s). Of 7 children with WBC < 10,000/cu mm there were 4 who had 20% or more E rosettes and T‐antigen‐positive cells. Of 6 children with WBC > 10,000/cu mm there were only 2 who had more than 20% E rosettes and T‐antigen‐positive cells. Based on examination of PB alone, six children may have been classified as having T‐like ALL. However, these results were due to the presence of circulating normal T lymphocytes, and assay of BM cells established that only one of the 13 children had T‐like ALL and none had B‐cell ALL. Bone marrow blasts from 12 patients did not form rosettes at 37°C, did not have mIg, and did not react with anti‐T serum. A high proportion of BM blasts from these 12 patients (39‐96%) did react with antiserum against E− ALL blasts. Of these 12 patients 11 had a higher proportion of E− ALL antiserum‐positive blasts in the BM than PB. Thus, immunologic classification of ALL should be based on the study of BM blasts, or both PB and BM cells. Copyright © 1979 Wiley‐Liss, Inc., A Wiley Company