CLINICOPATHOLOGICAL AND IMMUNOLOGICAL CHARACTERISTICS OF 6 CATS WITH GRANULAR LYMPHOCYTE TUMORS

Clinical and immunological characteristics were investigated in six ca ses of feline granular lymphocyte (GL) tumor. The ages of the affected cats were relatively old, ranging from 4 to 13 years of age. Gastroin testinal signs were commonly observed in these cases. Only one of the six GL tumor cases was positive for feline leukemia virus (FeLV) antig en. Phenotypic analysis revealed that the CL tumor cells from all of t he six cases lacked the T-or B-cell markers. These GL tumor cells were examined by Southern blot analysis using feline immunoglobulin (Ig) a nd T-cell receptor (TCR) gene probes. GL tumor cells obtained from two cases were identified as cells of T-cell lineage by the presence of a rearranged TCR beta gene, whereas those from the other four cases wer e considered to be derived from non-T-non-B-cell lineage because of th e absence of rearrangement of these genes. These findings indicated th at feline GL tumors can be considered as a specific disease entity in feline lymphomas because the cases examined in this study showed onset at an older age, a low incidence of FeLV infection and frequent invol vement of gastrointestinal lesions, which are not found in typical FeL V-associated lymphomas. Although no specific phenotypes was observed b y phenotypic analysis, the feline GL tumor cells were divided into two consistent genotypes of T-cell or non-T-non-B-cell lineages. (C) 1998 Elsevier Science Ltd. Ali rights reserved.