CANINE LYMPHOMA - IMMUNOCYTOCHEMICAL ANALYSIS OF FINE-NEEDLE ASPIRATION BIOPSY

Cytospin preparations of fine-needle aspirates from 21 dogs with perip heral lymphadenopathy (18 with lymphoma and three with lymph node hype rplasia) were studied by combining morphologic and immunocytochemical analysis. Fine-needle aspirates were taken from at least two enlarged lymph nodes, and the diagnosis was based on air-dried smears stained w ith May-Grunwald Giemsa. Fine-needle aspiration biopsy always provided an adequate quality and quantity of cells to perform morphologic and immunologic studies. Immunophenotyping was performed on cytospin prepa rations with a panel of eight monoclonal antibodies specific for canin e cell surface antigens and one rabbit polyclonal antibody (A452) agai nst human CD3, which cross-reacts with dog antigen. The immunocytochem ical study resulted in the diagnosis of 14 B-cell lymphomas (CD21+, CD 3-) and three T-cell lymphomas (all CD3+, two CD8+). One lymphoma lack ed surface antigens specific for the B- or T-cell lineage and was clas sified as non-B-non-T lymphoma (CD21-, CD3-, CD4-, CD8-). The monoclon al antibodies CA12.10C12, CA4.1D3, and CA1D6 and the polyclonal antibo dy A452, used as a group, appeared to be the most useful reagents to s uggest lymphoid origin and to discriminate between T- and B-cell pheno type. Cytospin preparations in combination with immunocytochemistry pr ovided a practical, economical, and accurate method for the diagnosis and phenotyping of canine lymphoma.