Multiparametric analysis of normal and postchemotherapy bone marrow: Implication for the detection of leukemia-associated immunophenotypes.

BACKGROUND: The knowledge of normal marrow is mandatory to assess the malignant counterpart of normal cells and define leukemia-associated immunophenotypes (LAIPs). In this study, the expression of a variety of antigens expressed in normal and postchemotherapy bone marrow (BM) was analyzed to provide a frame of reference for the identification of myeloid LAIPs. METHODS: Multiparameter four- and six-color flow cytometry was used to define antigen combinations totally absent or present at very minimal levels in marrow cells of normal individuals (n = 20) and patients receiving chemotherapy for acute lymphoblastic leukemia (n = 20). Immature (blast) cells were gated according to CD45/SSC properties. Fifty-three acute myeloid leukemia (AML) samples were studied in six-color combinations. RESULTS: In six-color flow cytometry, 47 phenotypes were totally absent from blast gate in all normal samples. Forty-one other phenotypes were identified in less than 0.05% of blast cells. There was no difference between normal and postchemotherapy BMs. The four-color panel allowed to identify only 30 phenotypes present at a frequency <0.05%. Using the six-color panel, 58% of the absent or infrequent phenotypes in normal BM were found in at least one of 53 AML samples. All AML cases exhibited at least one LAIP. CONCLUSION: Our results show that the ability to distinguish leukemic from healthy cells is considerably increased by a six-color approach. Furthermore, these absent or infrequent phenotypes in normal BM are identified in AML and can be utilized for minimal residual disease study.

[Unexpected occurence of hemoglobin Athens-Georgia]. / Révélation inattendue de l'hémoglobine Athens-Georgia.

The following report concerned a 47 year old Caucasian diabetic patient. Routine HPLC of HbA1c (Variant II Biorad Laboratories - hemoglobin A1c program) resulted only in the evidence of HbF (1%) and increase in HbA1c (10%). Considering the presence of HbF a standard agarose gel electrophoresis of patient's hemoglobin was performed and revealed the presence of Hb Athens-Georgia. Consequently the occurrence of HbF during determination of HbA1c by HPLC should lead to perform a standard hemoglobin electrophoresis in order to explore an hidden, unsuspected and clinically silent occurrence of rare Hb variant or additional unsuspected increase in HbA2.