The relationship between argyrophilic proteins and some immunophenotypic markers in acute leukemia cells

This study reports the immunophenotypic features of a series of 62 selected acute leukemia patients with increased incidence of argyrophilic proteins (AgNORs) at the time of initial diagnosis. Peripheral blood and bone marrow cells of patients with T-ALL, B-precursor ALL and AML were studied. The method of silver staining was used to determine the number of AgNORs per cell. Cell surface markers were detected by a standard immunofluorescence assay. To demonstrate the relationship between AgNOR quantity and cell proliferation, the expression of activation and proliferation antigens CD38 and CD71 was investigated. To characterize the immunophenotype and the discrete stages of differentiation, the wide panel of antibodies against lymphoid, myeloid and non-lineage specific antigens was used. The number of AgNORs at diagnosis ranged from 3.05 to 6.70. Immunophenotypic analysis showed a variation in CD38 and CD71 expression among different leukemia subtypes. CD71 antigen was more expressed in T-ALL than in B-precursor ALL or in AML. Notable was the relationship between increased AgNOR quantity and antigens that characterize the immaturity of leukemic cells. The association with CD7, CD2, CD5 (without CD3 membrane expression) and CD34 in T blasts was evident. High positivity of CD19, CD10, CD34 and HLA-DR in relation to the increased amount of AgNORs in B-lineage ALL was observed. The vast majority of AML patients with high numbers of AgNORs simultaneously expressed CD13, CD33, CD34 and HLA-DR. One third of AML cases coexpressed T cell marker CD7. In conclusion, the presence of increased numbers of AgNORs at diagnosis might reflect the dependence on an early stage of leukemia cell differentiation.