Canine Nervous System Lymphoma Subtypes Display Characteristic Neuroanatomical Patterns.

Primary and secondary nervous system involvement occurs in 4% and 5%-12%, respectively, of all canine non-Hodgkin lymphomas. The recent new classification of canine malignant lymphomas, based on the human World Health Organization classification, has been endorsed with international acceptance. This histological and immunocytochemical classification provides a unique opportunity to study the histologic anatomic distribution patterns in the central and peripheral nervous system of these defined lymphoma subtypes. In this study, we studied a cohort of 37 dogs with lymphoma, which at necropsy had either primary (n = 1, 2.7%) or secondary (n = 36; 97.3%) neural involvement. These T- (n = 16; 43.2%) or B-cell (n = 21; 56.8%) lymphomas were further classified into 12 lymphoma subtypes, with predominant subtypes including peripheral T-cell lymphoma (PTCL) or diffuse large B-cell lymphoma (DLBCL), respectively. This systematic study identified 6 different anatomically based histologically defined patterns of lymphoma infiltration in the nervous system of dogs. Different and distinct combinations of anatomical patterns correlated with specific lymphoma subtypes. Lymphoma infiltration within the meningeal, perivascular, and periventricular compartments were characteristic of DLBCL, whereas peripheral nerve involvement was a frequent feature of PTCL. Similarly cell counts above 64 cells/µL in cerebrospinal samples correlated best with marked meningeal and periventricular lymphoma infiltration histologically. Prospective studies are needed in order to confirm the hypothesis that these combinations of histological neuroanatomic patterns reflect targeting of receptors specific for the lymphoma subtypes at these various sites.

Clonality Testing in Veterinary Medicine: A Review With Diagnostic Guidelines.

The accurate distinction of reactive and neoplastic lymphoid proliferations can present challenges. Given the different prognoses and treatment strategies, a correct diagnosis is crucial. Molecular clonality assays assess rearranged lymphocyte antigen receptor gene diversity and can help differentiate reactive from neoplastic lymphoid proliferations. Molecular clonality assays are commonly used to assess atypical, mixed, or mature lymphoid proliferations; small tissue fragments that lack architecture; and fluid samples. In addition, clonality testing can be utilized to track neoplastic clones over time or across anatomic sites. Molecular clonality assays are not stand-alone tests but useful adjuncts that follow clinical, morphologic, and immunophenotypic assessment. Even though clonality testing provides valuable information in a variety of situations, the complexities and pitfalls of this method, as well as its dependency on the experience of the interpreter, are often understated. In addition, a lack of standardized terminology, laboratory practices, and interpretational guidelines hinders the reproducibility of clonality testing across laboratories in veterinary medicine. The objectives of this review are twofold. First, the review is intended to familiarize the diagnostic pathologist or interested clinician with the concepts, potential pitfalls, and limitations of clonality testing. Second, the review strives to provide a basis for future harmonization of clonality testing in veterinary medicine by providing diagnostic guidelines.

Cutaneous Lymphoma at Injection Sites: Pathological, Immunophenotypical, and Molecular Characterization in 17 Cats.

Feline primary cutaneous lymphomas (FPCLs) account for 0.2% to 3% of all lymphomas in cats and are more frequently dermal nonepitheliotropic small T-cell tumors. Emergence of FPCL seems unrelated to feline leukemia virus (FeLV) serological positivity or to skin inflammation. A total of 17 cutaneous lymphomas with a history of vaccine injection at the site of tumor development were selected from 47 FPCLs. Clinical presentation, histology, immunophenotype, FeLV p27 and gp70 expression, and clonality were assessed. A majority of male (12/17), domestic short-haired (13/17) cats with a mean age of 11.3 years was reported. Postinjection time of development ranged from 15 days to approximately 9 years in 5 cats. At diagnosis, 11 of 17 cats had no evidence of internal disease. Lymphomas developed in interscapular (8/17), thoracic (8/17), and flank (1/17) cutaneous regions; lacked epitheliotropism; and were characterized by necrosis (16/17), angiocentricity (13/17), angioinvasion (9/17), angiodestruction (8/17), and peripheral inflammation composed of lymphoid aggregates (14/17). FeLV gp70 and/or p27 proteins were expressed in 10 of 17 tumors. By means of World Health Organization classification, immunophenotype, and clonality, the lesions were categorized as large B-cell lymphoma (11/17), anaplastic large T-cell lymphoma (3/17), natural killer cell-like (1/17) lymphoma, or peripheral T-cell lymphoma (1/17). Lineage remained uncertain in 1 case. Cutaneous lymphomas at injection sites (CLIS) shared some clinical and pathological features with feline injection site sarcomas and with lymphomas developing in the setting of subacute to chronic inflammation reported in human beings. Persistent inflammation induced by the injection and by reactivation of FeLV expression may have contributed to emergence of CLIS.

A review of histiocytic diseases of dogs and cats.

Histiocytic proliferative disorders are commonly observed in dogs and less often cats. Histiocytic disorders occur in most of the dendritic cell (DC) lineages. Canine cutaneous histiocytoma originates from Langerhans cells (LCs) indicated by expression of CD1a, CD11c/CD18, and E-cadherin. When histiocytomas occur as multiple lesions in skin with optional metastasis to lymph nodes and internal organs, the disease resembles cutaneous Langerhans cell histiocytosis of humans. Langerhans cell disorders do not occur in feline skin. Feline pulmonary LCH has been recognized as a cause of respiratory failure due to diffuse pulmonary infiltration by histiocytes, which express CD18 and E-cadherin and contain Birbeck's granules. In dogs and cats, histiocytic sarcomas (HS) arise from interstitial DCs that occur in most tissues of the body. Histiocytic sarcomas begin as localized lesions, which rapidly disseminate to many organs. Primary sites include spleen, lung, skin, brain (meninges), lymph node, bone marrow, and synovial tissues of limbs. An indolent form of localized HS, progressive histiocytosis, originates in the skin of cats. Hemophagocytic HS originates in splenic red pulp and bone marrow macrophages in dogs and cats. In dogs, histiocytes in hemophagocytic HS express CD11d/CD18, which is a leuko-integrin highly expressed by macrophages in splenic red pulp and bone marrow. Canine reactive histiocytic diseases, systemic histiocytosis (SH) and cutaneous histiocytosis, are complex inflammatory diseases with underlying immune dysregulation. The lesions are dominated by activated interstitial DCs and lymphocytes, which invade vessel walls and extend as vasocentric infiltrates in skin, lymph nodes, and internal organs (SH).

Hepatosplenic and hepatocytotropic T-cell lymphoma: two distinct types of T-cell lymphoma in dogs.

The clinical, clinicopathologic, and pathological findings of 9 dogs with T-cell lymphoma that involved the liver in the absence of peripheral lymphadenopathy were assessed. Seven dogs had hepatosplenic T-cell lymphoma (HS-TCL). Dogs with HS-TCL presented with hepato- and/or splenomegaly, regenerative anemia, thrombocytopenia, and hypoproteinemia. The clinical course was rapidly progressive with all dogs but 1 dead within 24 days of initial presentation. Neoplastic lymphocytes were centered on hepatic and splenic sinusoids and had a CD3+ (5/7), TCRαß- (5/5), TCRγδ+ (3/5), CD11d+ (6/7), granzyme B+ (5/7) immunophenotype. Bone marrow and lungs were consistently but variably involved. These findings closely resemble the human disease and support the classification of HS-TCL as a distinct World Health Organization entity in dogs. The remaining 2 dogs markedly differed in the pattern of hepatic involvement by neoplastic lymphocytes, which were not confined to hepatic sinusoids but invaded hepatic cords. In addition, neoplastic cells had a CD11d- immunophenotype, and clinicopathologic data indicated marked cholestasis and mild to absent anemia. Based on the distinct tropism of neoplastic lymphocytes for hepatocytes, the name hepatocytotropic T-cell lymphoma (HC-TCL) is proposed. Given the histomorphologic, clinicopathologic, and immunophenotypic differences, HC-TCL likely represents a separate biological entity rather than a histomorphologic variant of HS-TCL.

Feline gastrointestinal lymphoma: mucosal architecture, immunophenotype, and molecular clonality.

Gastrointestinal lymphomas were identified in 120 cats between 1995 and 2006. Lymphomas were classified according to the World Health Organization (WHO) scheme. Cats with mucosal T-cell lymphoma (n = 84) predominated and had a median survival of 29 months. Mucosal T-cell lymphoma matched WHO enteropathy-associated T-cell lymphoma (EATCL) type II. Epitheliotropic T-cell infiltrates were present in 62% of cats and occurred as clusters or diffuse infiltrates of small to intermediate-sized T cells in villous and/or crypt epithelium. Similar lymphocytes infiltrated the lamina propria in distinctive patterns. Cats with transmural T-cell lymphoma (n = 19) had a median survival of 1.5 months. Transmural T-cell lymphoma matched WHO EATCL type I. Epitheliotropic T-cell infiltrates were present in 58% of cats. Large lymphocytes (n = 11), mostly with cytoplasmic granules (LGL-granzyme B+) (n = 9) predominated. Transmural extension across the muscularis propria characterized the lesion. Both mucosal and transmural T-cell lymphomas were largely confined to the small intestine, and molecular clonality analysis revealed clonal or oligoclonal rearrangements of T-cell receptor-γ in 90% of cats. Cats with B-cell lymphoma (n = 19) had a median survival of 3.5 months. B-cell lymphomas occurred as transmural lesions in stomach, jejunum, and ileo-cecal-colic junction. The majority were diffuse, large B-cell lymphomas of centroblastic type. In conclusion, T-cell lymphomas characterized by distinctive mucosal architecture, CD3 expression, and clonal expansion predominated in the feline gastrointestinal tract.

Characterization of the gastric immune response in cheetahs (Acinonyx jubatus) with Helicobacter-associated gastritis.

Captive cheetahs have an unusually severe progressive gastritis that is not present in wild cheetahs infected with the same strains of Helicobacter. This gastritis, when severe, has florid lymphocyte and plasma cell infiltrates in the epithelium and lamina propria with gland destruction, parietal cell loss, and, in some cases, lymphoid follicles. The local gastric immune response was characterized by immunohistochemistry in 21 cheetahs with varying degrees of gastritis. The character of the response was similar among types of gastritis except that cheetahs with severe gastritis had increased numbers (up to 70%) of lamina proprial CD79a+CD21- B cells. CD3+CD4+ T cells were present in the lamina propria, and CD3+CD8α+ T cells were within the glandular epithelium. Lymphoid aggregates had follicular differentiation with a central core of CD79a+/CD45R+ B cells and with an outer zone of CD3+ T cells that expressed both CD4 and CD8 antigens. MHC II antigens were diffusely expressed throughout the glandular and superficial epithelium. No cheetah had evidence of autoantibodies against the gastric mucosa when gastric samples from 30 cheetahs with different degrees of gastritis were incubated with autologous and heterologous serum. These findings indicate that T-cell distribution in cheetahs is qualitatively similar to that in other species infected with Helicobacter but that large numbers of lamina propria activated B cells and plasma cells did distinguish cheetahs with severe gastritis. Further research is needed to determine whether alterations in the Th1:Th2 balance are the cause of this more plasmacytic response in some cheetahs.

Recommended guidelines for the conduct and evaluation of prognostic studies in veterinary oncology.

There is an increasing need for more accurate prognostic and predictive markers in veterinary oncology because of an increasing number of treatment options, the increased financial costs associated with treatment, and the emotional stress experienced by owners in association with the disease and its treatment. Numerous studies have evaluated potential prognostic and predictive markers for veterinary neoplastic diseases, but there are no established guidelines or standards for the conduct and reporting of prognostic studies in veterinary medicine. This lack of standardization has made the evaluation and comparison of studies difficult. Most important, translating these results to clinical applications is problematic. To address this issue, the American College of Veterinary Pathologists' Oncology Committee organized an initiative to establish guidelines for the conduct and reporting of prognostic studies in veterinary oncology. The goal of this initiative is to increase the quality and standardization of veterinary prognostic studies to facilitate independent evaluation, validation, comparison, and implementation of study results. This article represents a consensus statement on the conduct and reporting of prognostic studies in veterinary oncology from veterinary pathologists and oncologists from around the world. These guidelines should be considered a recommendation based on the current state of knowledge in the field, and they will need to be continually reevaluated and revised as the field of veterinary oncology continues to progress. As mentioned, these guidelines were developed through an initiative of the American College of Veterinary Pathologists' Oncology Committee, and they have been reviewed and endorsed by the World Small Animal Veterinary Association.

Ultrasonographic evaluation of the muscularis propria in cats with diffuse small intestinal lymphoma or inflammatory bowel disease.

BACKGROUND: An ultrasonographic pattern of thickened muscularis propria in the small intestine and lymphadenopathy have been associated with gastrointestinal lymphoma and inflammatory bowel disease (IBD) in cats. OBJECTIVES: To investigate the association of these imaging biomarkers with IBD and lymphoma in cats. ANIMALS: One hundred and forty-two cats with a histologic diagnosis of normal small intestine (SI) (n = 56), lymphoma (n = 62), or IBD (n = 24). METHODS: Retrospective case review. Pathology records from 1998-2006 were searched for cats with a diagnosis of normal, IBD, or lymphoma, an ultrasonographic examination < 28 days before surgery, and without ultrasonographic evidence of a mass. Multinomial regression analysis was used to determine the association of imaging biomarkers with disease status. RESULTS: Cats with thickening of the muscularis propria detected by ultrasonographic examination were more likely to have lymphoma compared with normal SI cats (odds ratio [OR] = 4.0, 95% confidence interval [95% CI] 1.2-13.1, P = .021) and those with IBD (OR = 18.8, 95% CI 2.2-162.7, P = .008). Histologic samples of cats with muscularis propria thickening were more likely to have disease infiltrates in both the mucosal and submucosal layers (OR = 8.1, 95% CI 1.7-38.4, P = .008) than cats with normal SI. Cats with ultrasonographic evidence of lymphadenopathy were more likely to have a diagnosis of lymphoma (OR = 44.9, 95% CI 5.1-393.0, P = .001) or IBD (OR = 10.8, 95% CI 1.1-106.3, P = .041) than normal SI. Fifty-six of 62 cats had confirmed or presumptive diagnosis of diffuse T-cell lymphoma. CONCLUSIONS AND CLINICAL RELEVANCE: Older cats with muscularis layer thickening are more likely to have T-cell lymphoma than IBD. The ultrasonographic pattern is associated with histologic infiltrates in the mucosal and submucosal layers of small intestine. Lymphadenopathy is associated with lymphoma or IBD.

Disproportionally strong increase of B cells in inflammatory cerebrospinal fluid of dogs with Steroid-responsive Meningitis-Arteritis.

Steroid-responsive Meningitis-Arteritis (SRMA) is a systemic inflammatory disease of juvenile to young adult dogs with a relapsing course and most prominent manifestation in the cervical meninges. Immunophenotyping and flow cytometric measurement of lymphocytes in peripheral blood (PB) and CSF was performed in the acute phase of SRMA (n=12) and during glucocorticosteroid treatment (n=10). Values were compared to those from dogs with other neurologic diseases (n=63) and healthy individuals (n=7). Dogs with SRMA had high CD4:CD8alpha ratios in PB and low T:B cell ratios in PB and CSF suggesting that a T(H)2-mediated immune response occurs. The T:B cell ratio in CSF was markedly lower than that in PB indicating that either a selective recruitment of B cells or, alternatively, their strong intrathecal proliferation takes place. SRMA appears to be a valuable animal model for the investigation of compartmentalization of immune responses and for studies on differences in local central nervous system and systemic immune responses.

Clinical characteristics and outcome in dogs with small cell T-cell intestinal lymphoma.

Small cell intestinal lymphoma has not been well characterized in dogs. The objective of this study was to describe clinical characteristics and outcome in dogs with small cell intestinal lymphoma. We hypothesized that affected dogs would have prolonged survival compared with high-grade gastrointestinal (GI) lymphoma. Pathology records were searched for dogs with histologically confirmed small cell GI lymphoma. Seventeen dogs with confirmed small cell intestinal lymphoma were identified, and clinical and outcome data were retrospectively collected. Histopathology was reviewed by a board-certified pathologist, and tissue sections were subjected to immunophenotyping and molecular clonality assessment. All dogs had small cell, T-cell, lymphoma confirmed within various regions of small intestine, with 1 dog also having disease in abdominal lymph nodes. All dogs had clinical signs attributable to GI disease; diarrhoea (n = 13) was most common. Ultrasonographic abnormalities were present in 8 of 13 dogs with abnormal wall layering (n = 7) and hyperechoic mucosal striations (n = 7) representing the most common findings. In total, 14 dogs received some form of treatment. The median survival time (MST) for all dogs was 279 days and the MST for the 14 dogs that received any treatment was 628 days. Dogs with anaemia and weight loss at presentation had significantly shorter survival times and dogs that received a combination of steroids and an alkylating agent had significantly longer survival times. Small cell, T-cell, intestinal lymphoma is a distinct disease process in dogs, and those undergoing treatment may experience prolonged survival.

Feline Respiratory Extramedullary Plasmacytoma with Lymph Node Metastasis and Intrahistiocytic Amyloid.

A 14-year-old domestic longhaired cat presented with a 2-year history of nasal discharge and a recent onset of inappetence and submandibular lymphadenopathy. The cat was humanely destroyed after developing severe respiratory distress. Necropsy examination revealed thickened nasal turbinates and soft palate, and friable red-tan material within the frontal sinus, nasal cavity and nasopharynx. The lungs contained multifocal irregular friable tan nodules. Multiple lymph nodes were enlarged, friable and red-tan in colour. Histopathology revealed a mature type extramedullary plasmacytoma (EMP) within the frontal sinus, nasal cavity, soft palate, larynx, trachea, lungs and multiple lymph nodes. The lymph nodes and larynx also contained marked granulomatous inflammation with extensive intrahistiocytic (and lesser amounts of extracellular) lambda light chain amyloid, confirmed by electron microscopy and immunohistochemistry. Neoplastic cells expressed CD79a and MUM1. This is the first report of an infiltrative EMP of the feline respiratory tract with lymph node metastasis and predominantly intrahistiocytic amyloid.

Multicentric T-cell lymphosarcoma in an alpaca.

A two-year-old female alpaca with multicentric lymphosarcoma presented because of progressive weakness and recumbency. The diagnosis of lymphosarcoma was based on the detection of immature and atypical lymphocytes in a lumbosacral CSF sample. Post mortem examination confirmed multicentric lymphosarcoma involving multiple organs. Immunophenotyping using cross reactive T- and B-cell antibodies characterized the tumour as a T-cell lymphosarcoma.

Retrospective characterisation of solitary cutaneous histiocytoma with lymph node metastasis in eight dogs.

OBJECTIVES: To describe a small subset of canine solitary cutaneous histiocytoma in which lymph node metastasis has been documented. METHODS: Cases of dogs with solitary cutaneous histiocytoma lesions and regional lymph node metastasis diagnosed via histopathology were found through a retrospective search of the databases of IDEXX Laboratories and the University of California, Davis Veterinary Medical Teaching Hospital Clinical Diagnostic Laboratories. Information on signalment, history and clinical follow-up was obtained from the submittal form and/or via a questionnaire to the submitting veterinarian. Slides were available for review in seven cases and when possible immunohistochemistry was reviewed or performed by a single pathologist. RESULTS: Eight cases met the inclusion criteria. The neoplasms had the typical appearance of histiocytomas. All tested samples were immunoreactive for CD18 and lacked immunoreactivity for other lymphocyte markers and CD11d. Immunoreactivity for E-cadherin varied among the neoplasms tested. Outcome was known for five dogs and at the time of manuscript preparation three of those dogs were alive 1682 days, 570 days and 318 days post-diagnosis. Of the other two dogs with known outcome, one was euthanased shortly after diagnosis and another was hit by a car. Of the dogs that were eventually lost to follow-up, one was reported to be disease-free 1003 days after diagnosis. CLINICAL SIGNIFICANCE: Metastatic histiocytoma is rarely reported and distinction from aggressive disease processes such as histiocytic sarcoma may be difficult. Based upon a small number of cases with known outcomes, some dogs with solitary metastatic histiocytoma may experience favourable outcomes.

Differential expression of bovine MHC class II antigens identified by monoclonal antibodies.

Four monoclonal antibodies (mAbs), UC-A4, UC-D3, UC-H9, and IL-A21, specific for bovine major histocompatibility complex class II proteins are described. Sequential immunoprecipitation experiments using biotin-labeled peripheral blood mononuclear cells suggested, but did not conclusively establish, that each of these antibodies recognized a different epitope. The epitope identified by IL-A21 appeared to be common to all of the class II proteins precipitated by the four mAbs, and UC-D3 and UC-H9 each appeared to react with distinct epitopes on separate subsets of these class II proteins. Monoclonal antibody UC-A4 appeared to identify an epitope on a subset of the class II molecules identified by UC-H9. Differences found in the expression by lymphoid cells of class II proteins identified by the four mAbs were indicative of each mAb recognizing a different epitope. UC-H9 and IL-A21 class II proteins were detected on all surface immunoglobulin (S'Ig) positive cells in peripheral blood, but UC-A4 and UC-D3 class II proteins were not. Expression of UC-A4 class II proteins, detected at low density on a strikingly reduced number of S'Ig+ cells from the blood of some bovine leukosis virus-infected cattle, could be increased by culturing these B cells with lipopolysaccharide. All peripheral blood monocytes expressed UC-H9 and IL-A21 class II proteins, but only a proportion of monocytes expressed detectable UC-A4 and UC-D3 class II proteins. Almost all mitogen-stimulated BoCD4+ and BoCD8+ T cells expressed UC-H9 and IL-A21 class II proteins, whereas fewer stimulated T cells of both subsets expressed UC-A4 and UC-D3 class II proteins. All gamma/delta receptor (gamma/delta R) T cells expressed UC-D3, UC-H9, and IL-A21 class II proteins, but no cells (of gamma/delta R+ or CD4+/CD2+ phenotype) from gamma/delta R+ T cell-enriched cultures expressed UC-A4 class II proteins.

Acute monocytic leukaemia in a cat.

A three-year-old cat with lymphadenopathy, non-regenerative anaemia and marked leucocytosis (171.3 x 10(9) white blood cells/l) was diagnosed with monocytic leukaemia and treated with a combination of anticancer drugs. A number of mature and immature monocyte-like cells were detected in the peripheral blood and bone marrow; they proved to be monocytic cells by cytochemical examination and an analysis of their cell surface phenotype, indicating that the cat suffered from acute myeloid leukaemia, subclassified as monocytic leukaemia (M5). Treatment with cytarabine, doxorubicin, vincristine and prednisolone greatly reduced the number of blast cells in the cat's peripheral blood and bone marrow. The cat was in partial remission for 67 days and survived for 95 days after it was first examined.

Histologic classification and immunophenotyping of canine non-Hodgkin's lymphomas: unexpected high frequency of T cell lymphomas with B cell morphology.

Using three different classification schemes (Rappaport, the Working Formulation, and the Kiel classification), 116 canine malignant lymphomas were classified histologically. The number of lymphomas with a completely follicular growth pattern was low (14.9%). The majority of the lymphomas (50.8%) had a diffuse type of architecture, while 34.3% were diffuse with some nodularity. In the Rappaport scheme, 69.3% of the canine lymphomas were classified as histiocytic lymphomas, but these consisted of a group of tumors with different morphologic and immunologic cell types. The Working Formulation and the Kiel classification could be applied to differentiate the canine lymphomas cytomorphologically. In both the Working Formulation and the Kiel classification, only a minority of lymphomas (16.4 and 12.0%, respectively) were low-grade malignant lymphomas. Large cell or centroblastic lymphomas were the most frequently encountered in the Working Formulation or the Kiel classification, respectively. Immunophenotyping of 95 lymphomas was performed with the aid of a panel of monoclonal and polyclonal antibodies. The majority of the lymphomas were of B cell origin (58.9%) while three were classified as non-B/non-T cell lymphomas. Contrary to the distribution pattern of human non-Hodgkin's lymphoma (NHL) in western countries, there was a high percentage of T cell lymphomas (37.9%) in the canine. However, the phenotype could not be predicted by the morphologic characteristics alone.

T-cell receptor gene rearrangement in canine mycosis fungoides: further support for a canine model of cutaneous T-cell lymphoma.

Canine cutaneous T-cell lymphoma (CTCL) is a morphologic and immunophenotypic simulant of human mycosis fungoides (MF) characterized by an infiltrate of atypical, hyperconvoluted, epidermotropic T cells. To further support our hypothesis that canine MF is a useful model for the study of human CTCL, we have used Southern blotting to search for clonal T-cell proliferations in canine MF. Cellular DNA was extracted from normal dog buffy coat cells (n = 8), lesional canine MF skin (n = 8), canine MF buffy coat cells (n = 7), normal dog skin (n = 3), and normal human buffy coat cells (n = 5), digested with a panel of restriction enzymes and Southern blotted onto nylon membranes. All cases of canine MF were also immunophenotyped with anti-canine monoclonal antibodies to CD4, CD8, CD18, CD45RA, canine class II, T-cell activation antigens, and pan-B-cell antigens. Normal dogs gave reproducible digestion patterns in blood and skin, which differed from the human germline patterns when probed with a human T-cell receptor (TCR), beta chain constant region (C beta) cDNA. Common germline bands between the species included the 3.5-kb Eco RI, 3.4-kb Bam HI, 5.4-kb Sac I. These results confirmed that the TCR-beta gene is evolutionarily conserved between dog and man. Immunostaining revealed that 3/7 cases were CD4+ canine CTCL and 4/7 were CD8+ canine CTCL. Rearranged bands, deletion of germline bands, as well as minor alterations in electrophoretic mobility were observed in lesional DNA from seven of eight cases of canine MF, with at least two restriction digests in each case. Dog rearrangements were best detected with Bgl II, Eco RI, Eco RV, and Sac I, whereas deletions were detected with Bgl II, Sac I, Eco RV, and Bam HI. These studies demonstrate the presence of clonal TCR rearrangement in canine MF, further supporting the similarity of this tumor to human MF and its role as an animal model of CTCL.

Acquired immune dysfunction in cats with experimentally induced feline immunodeficiency virus infection: comparison of short-term and long-term infections.

Specific pathogen-free domestic cats with experimentally induced feline immunodeficiency virus (FIV) infections of short duration (less than or equal to 10 months) exhibited depressed total leukocyte and neutrophil numbers and a marginally decreased lymphocyte proliferative response to pokeweed mitogen (PWM), while cats with infections of more lengthy duration (greater than or equal to 25 months) exhibited normal leukocyte and neutrophil numbers but a dramatic loss of responsiveness to both PWM and concanavalin A (Con A). Cats with short-term infections exhibited a decrease in the percentage of CD4+ lymphocytes in peripheral blood and a corresponding depression of the CD4+:CD8+ ratio. Cats with long-term infections exhibited a similar but more profound perturbation of the CD4+ lymphocyte subset that also included a decrease in the absolute number of CD4+ cells. The decreased responsiveness to Con A and PWM in cats infected long term paralleled the decline in CD4+ cell counts, and the duration of infection was directly correlated with the decrease in the percentage of CD4+ cells. These data provide evidence supporting the hypothesis that FIV is the cause of an immune dysfunction in cats, with distinct similarities to that produced by human immunodeficiency virus (HIV) in people.

Development of ethyl 3,4-dihydro-4-oxopyrimido[4,5-b]quinoline-2-carboxylate, a new prototype with oral antiallergy activity.

Structural modification of 3,4-dihydro-4-oxoquinazoline-2-carboxylic acid leading to ethyl 3,4-dihydro-4-oxopyrimido[4,5-b]quinoline-2-carboxylate, a new prototype with oral antiallergy activity of the disodium cromoglycate type, is described. This prototype is 10 times more potent than disodium cromoglycate in the rat passive cutaneous anaphylaxis test. Structure-activity studies indicate that a carboxylic acid moiety directly attached to the 2 position of the pyrimidine ring is most favorable for intravenous activity while esters of this acid are preferred for oral activity. The oral activity of ethyl 3,4-dihydro-4-oxopyrimido[4,5-b]quinoline-2-carboxylate (ED50 = 3 mg/kg) places this ester among the more potent orally active antiallergy agents reported to date.