Which of the following immunohistochemical stains is used for the diagnosis of lymphomas -

Ans. is 'c' i.e., Leukocyte common antigen CD45 (leucocyte common antigen) is a _family of single chain transmembrane glycoproteins. o CD45 (leucocyte common antigen) is exclusively expressed in hematolymphoid cells. o Almost all hematolymphoid cells including precursor cells and mature B and T lymphocytes granulocytes, monocytes/ histocytes and interdigitating reticulum cells and follicular dendritic cells express CD45. o While CD45 is strongly expressed on the lymphocytes membranes, histiocytes only exhibit a weak membrane staining. o CD45 is lost in maturing erythrocytes, megakaryocytes and plasma cells. o CD45 is detected in large majority of hematolymphoid neoplasmic e.g. leukemias and malignant lymphomas.