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9.1 Describe the use of antibody panels in immunocytochemistry to identify tumours.
No single antibody offers a magic bullet to diagnosis and antibodies should be used in panels to help identify epitopes /cells in conjunction with the information provided by the H&E to identify pathological conditions.
9.2 Explain the value of CD nomenclature in antibody classification.
Cluster of differentiation (CD) is a system employed to provide guidance on the cell surface labelling profile or characteristics of any given antibody, mainly but not exclusively on white blood cells. It was first introduced following the first Human Leucocyte Differentiation Antigen (HLDA) working group in Paris in 1982. The CD system allows cell marker profiles to be established in immunophenotyping. These markers are then used to associate certain immune functions or to define tumour profiles. Selected tumours or tumour groups will have defined CD profiles.
9.3 Explain the main tumour groups in which immunocytochemistry is used to assist in determining diagnosis.
Carcinomas are identified using cytokeratin markers to distinguish the various subtypes i.e. lung, breast, colonic carcinoma. Lymphomas are subtyped by the use of CD markers. Sarcomas are subtyped by the use of connective tissue markers.
9.4 Explain why the demonstration of basal cells andmyoepithelial cells is significant in prostate and breast disease, respectively.
Basal and myoepithelial cells are significant as their presence determines whether a tumour is invasive or not. Myoepithelial and basal cells are the cells which lie in between the epithelial cells from which prostate and breast carcinomas arise.
9.5 Describe the use of immunofluorescence in the study of autoimmune disease.
Immunofluorescence methods offer a more photogenic approach to the identification of low levels of epitope seen in samples investigated. Immunofluorescence markers for IgG, IgA, IgM and C3c are used in combination to investigate deposits of antibody and complement products at vessels, glomeruli, intraepithelial cell junctions and at the dermoepidermal junction where immune reactions occur in some conditions, namely in the skin diseases pemphigoid and pemphigus.