Role of Immunohistochemistry in Diagnosis and Subtyping of Acute Leukemia using Selected IHC Markers in a Resource Limited Setting

ABSTRACT

Introduction: In resource limited settings where geneticstudies and flow cytometry were not routinely done oravailable, morphology is primarily used for diagnosis andsubtyping of acute leukemias with use of ancillary tests likecytochemistry and immunohistochemistry in selected casesfor a more accurate and definitive diagnosis. This study wasdone to assess the role of immunohistochemistry in diagnosisand subtyping of acute leukemias in resource poor settingusing selected IHC markers and to find diagnostic accuracy ofmorphologic diagnosis.Material and methods: The study was done on 45 selectedcases of acute leukemia. Immunohistochemistry was doneon all cases for typing and confirmation of diagnosis aftermorphological examination of peripheral blood smears andall three bone marrow preparations.A limited panel of IHCmarkers were used including Anti MPO, Anti CD3, AntiCD20, Anti CD22, Anti TdT, Anti CD117, Anti CD15 andAnti CD68(KP1) for immunohistochemistry.Results: The accuracy of morphological diagnosis in casesof AML and ALL in the study was 84.09% and 82.22%respectively. By intercalating immunohistochemical studieswith morphological examination almost all cases of acuteleukemia can be diagnosed and subclassified, and diagnosticaccuracy is increased as compared to morphologicalexamination alone.Conclusion: Though morphology remains thegold standard for paraffin embedded bone marrowtrephines,immunohistochemical staining has became anintegral part of diagnostic workup in cases of hematologicmalignancies in limited resource settings.