Dual antibody immunohistochemistry: an efficient and sensitive tool for the detection of residual disease in chronic lymphocytic leukemia

AbstractHighly effective treatments for chronic lymphocytic leukemia (CLL) have the potential to reduce significant tumor burden to single cells and therefore require sensitive tools to assess for minimal residual disease (MRD) in bone marrow (BM) biopsies. Flow cytometry (FC) is the current gold standard for detection of MRD, but requires a specialized facility, specific antibody panels, collecting hundreds of thousands-to-millions of cells, and personnel with expertise in the analysis and interpretation of FC MRD data, which may not be feasible in many small laboratories. Dual-antibody immunohistochemistry (DA-IHC) can identify abnormal populations better than morphology alone, but its correlation with FC assessment is not known. Our aims are to characterize the efficacy of DA-IHC in assessing BM samples post-treatment and to compare results with FC to evaluate for residual disease in CLL. We collected 2-year post-therapy data from 33 CLL patients on two treatment protocols, chemoimmunotherapy (CIT) and single agent ibrutinib (IB), as well as BMs from 10 healthy volunteers as morphologic controls. BM biopsy specimens were examined for the presence or absence of CLL based on morphologic evidence of lymphoid infiltration and aberrant co-expression of CD5 and PAX5 DA-IHC. FC using a standard CLL antibody panel was performed in parallel. All IB patients had residual disease detected by DA-IHC and FC, although five patients (22%) were morphologically negative by routine hematoxy...
Source: Journal of Hematopathology - Category: Pathology Source Type: research