Use of image analysis and immunostaining of bone marrow trephine biopsy specimens to quantify residual disease in patients with B-cell chronic lymphocytic leukemia.

Marrow residual disease (RD) in patients with B-cell chronic lymphocytic leukemia (B-CLL) who are in complete remission (CR) after treatment with purine analogues is reported to have a prognostic value, but sample dilution, factors interfering with marrow aspiration, or undetectable immunoglobulin rearrangement can affect the assessment of RD by molecular or immunologic methods. As demonstrated for hairy cell leukemia and follicular lymphoma, bone marrow trephine biopsy specimen immunostaining (BMT/IS) can successfully detect residual malignant cells. The aim of this study was to use BMT/IS and computerized image analysis (CIMA) of bcl-2-positive cells to quantify RD in B-CLL patients in CR, after achievement of CR and more than 1 year later. This methodology was compared with other conventional techniques, i.e., cytologic, flow cytometric, cytogenetic, and molecular analysis. BMT/IS readily detected RD in every trephine biopsy specimen examined, either after CR or at distant follow-up. CIMA allowed an objective quantification of residual B-CLL cells, as evidenced by the correlation with semiquantitative polymerase chain reaction results. Both analyses indicated a progression of RD. This finding was also supported (but inconsistently) by the other techniques. CIMA with an interstitial labeling index, therefore, seems to be a reproducible and sensitive method to detect persistence and progression of RD in patients with B-CLL. This method could apply to other hematologic malignancies infiltrating the bone marrow.