Practical approach to the immunodiagnosis of lymphomas emphasizing differential diagnosis.

Immunological studies on tissue sections are often useful for supporting a diagnosis of lymphoma in cases with unusual histological or clinical findings and for identifying clinically important subgroups of lymphoma. Recent advances in both reagents and immunohistochemical methods allow the construction of monoclonal antibody panels for use both on routinely-fixed and processed tissues and on fresh frozen tissues. Commercially available monoclonal antibodies that are reactive with fixation-resistant antigenic determinants on lymphoid and related differentiation antigens often allow the distinction of lymphoma from non-lymphoid neoplasms. Better reagents and/or methods are needed for the identification of subset and lineage-specific markers on B cells and T cells and on the atypical cells of Hodgkin's disease. The use of fresh frozen tissue allows the application of a wide range of monoclonal antibodies to B-cell, T-cell and accessory cell differentiation antigens, many of which react only in fresh tissue. Appropriate monoclonal antibody panels distinguish B-cell lymphoma and Ig- B lineage lymphoma from hyperplasia. A broad panel of antibodies to T-cell differentiation antigens is needed to identify the abnormal T-cell phenotypes which are observed in T-cell lymphoma.