B-cell leukemia in an adult sheep.

B-cell leukemia is a rare form of hematologic neoplasia in sheep, especially in adult animals. We present a case report of a 5-year-old WhiteFace Sheep wether with suspected acute lymphoblastic leukemia. The patient, a second-generation relative of ewes experimentally inoculated with atypical scrapie, exhibited acute lethargy and loss of appetite. Laboratory investigation revealed marked leukocytosis, lymphocytosis, and abnormal serum chemistry panel results. Microscopic examination of blood and bone marrow smears exhibited a high percentage of large neoplastic cells with lymphoid characteristics. Histopathologic analysis of the spleen, liver, lungs, and other organs confirmed the presence of widespread tissue infiltration by neoplastic cells. Immunohistochemical labeling demonstrated strong intracytoplasmic labeling for CD20, consistent with B-cell neoplasia. Flow cytometric analysis confirmed the B-cell lineage of the neoplastic cells. Screening for bovine leukemia virus, which can experimentally cause leukemia in sheep, yielded a negative result. In this case, the diagnosis of B-cell leukemia was supported by a comprehensive panel of diagnostic evaluations, including cytology, histopathology, immunohistochemistry, and immunophenotyping. This case report highlights the significance of accurate diagnosis and classification of hematologic neoplasia in sheep, emphasizing the need for immunophenotyping to aid in the diagnosis of B-cell leukemia. It also emphasizes the importance of considering spontaneous leukemia as a differential diagnosis in sheep with lymphoid neoplasia, especially in the absence of circulating infectious diseases.

Concurrent chronic lymphocytic leukemia and primary hyperparathyroidism in a mule.

A 26-year-old mule gelding was evaluated for chronic weight loss and decreased appetite. The mule had been losing weight and intermittently hypophagic for approximately 7 months. Laboratory analysis of whole blood and plasma identified severe total hypercalcemia, marked hypophosphatemia, markedly increased parathyroid hormone concentration, and marked lymphocytosis. A sestimibi scan intended to identify parathyroid gland tissue was nondiagnostic. Results of flow cytometry and PCR for antigen receptor rearrangement (PARR) were consistent with a B cell lymphoproliferative disorder, likely chronic lymphocytic leukemia (CLL). Although not previously described concurrently, these conditions may sometimes arise together, complicating definition of the underlying mechanism for weight loss and hypercalcemia in aged equids.

Extreme lymphocytosis in a dog with T-zone lymphoma.

Background: Canine T-zone lymphoma (TZL) is recognized as an indolent CD45-T cell lymphoma, with low aggressiveness and high overall survival. The diagnosis is obtained by histopathology and immunohistochemistry, but also by cytological examination of the lymph node associated with immunophenotyping. Lymphocytosis is commonly identified as around 10,000 cells/µl and may reach 30,760 cells/µl. Case Description: The present report describes a case of a female Golden Retriever, nine years old, with generalized lymphadenopathy. In the cytological examination of the superficial cervical lymph node, a monomorphic population of small, "clear cells" and "hand mirror" lymphocyte shape was suggestive of TZL. The leukogram showed intense leukocytosis (160,050 cells/µl) due to small clear cell lymphocytosis (152,048 cells/µl). The myelogram showed a myeloid:erythroid ratio of 2:3; with a pyramidal distribution of cell types and the presence of 22.8% of lymphocytes in the differential count. Bone marrow, peripheral blood, and lymph node immunophenotyping resulted in lymphocyte gates with 97.3% to 99.5% CD5+, predominantly CD4-, CD8-, and CD45- confirming the diagnosis of TZL with associated leukemia. Treatment with chlorambucil and prednisolone was started. During the first month, the lymphocytosis remained above 200,000 cells/uL. After four months of treatment, there was a decrease in lymphocytes, which progressively reached a count of 10,800 cells/ul in the eleventh month. Conclusion: In the literature, lymphocytosis above 30,760 cells/µl has not been observed in TZLs. Thus, it is believed that this is the first report of extreme lymphocytosis with a slow response to chemotherapy.

Relationship of persistent lymphocytosis, antibody titers, and proviral load with expression of interleukin-12, interferon-γ, interleukin-2, interleukin-4, interleukin-10, and transforming growth factor-ß in cows infected with bovine leukemia virus from a high-prevalence dairy complex.

Bovine leukemia virus (BLV) subclinical infection promotes persistent lymphocytosis (PL), which is related to susceptibility and progression to lymphoma. Moreover, lymphocyte counts directly correlate with BLV antibody titers and proviral load, and cell immune responses are considered atypical due to immune suppression. In order to determine the relationship of PL, antibody titers, and proviral load with interleukin (IL)-12, interferon (IFN)-γ, IL-2, IL-4, IL-10, and transforming growth factor (TGF)-ß expression in a 3-month interval, 58 cows were selected (30 BLV+ and 28 BLV-) from a high-prevalence dairy herd to complete 3 monthly blood samplings for the assessment of PL, BLV antibody titers, BLV proviral load, and IL-12, IFN-γ, IL-2, IL-4, IL-10, and TGF-ß expression. At sampling conclusion, the BLV-infected cows were grouped according to PL, BLV proviral load, and BLV antibody titers as follows: BLV+PL+ (n = 16) and BLV+PL- (n = 14); high proviral load (HPL) (n = 18) and low proviral load (LPL) (n = 13); high antibody titers (HAT) (n = 17) and low antibody titers (LAT) (n = 14). The BLV+PL+ cows showed significantly higher proviral load and antibody titers than the BLV+PL- group; however, the former suggested spread presumably unrelated to lymphoma outcome, because HPL was observed in PL- cows in the last sampling. Consistent with the data, a higher antibody response strongly indicated BLV susceptibility since it was linked to PL+ occurrence and a cytokine profile compatible with immune suppression. Furthermore, a reversion to lower antibody titers was observed in cows with HPL far ahead of time, most likely due to long-term immune suppression. In addition, high expression of IL-10 and TGF-ß was associated with reduced IL-12, IFN-γ, IL-2, and IL-4 expression alongside PL, HAT, and HPL in BLV-infected cows, suggesting an IL-10- and TGF-ß-induced immune suppression. The IL-10 expression was increasing throughout, implying disease progression, as described. In conclusion, the proliferative expansion of lymphocytes known as PL might enhance a regulatory-rich cell population (Bregs and/or Tregs) that secretes IL-10 and TGF-ß, leading to immune suppression. Further studies must be conducted regarding the types of regulatory cells involved in BLV-induced immune suppression.

L'infection subclinique par le virus de la leucémie bovine (BLV) favorise une lymphocytose persistante (PL), qui est liée à la susceptibilité et à la progression vers le lymphome. De plus, le nombre de lymphocytes est directement corrélé aux titres d'anticorps BLV et à la charge provirale, et les réponses immunitaires cellulaires sont considérées comme atypiques en raison de la suppression immunitaire. Afin de déterminer la relation entre PL, les titres d'anticorps et la charge provirale avec l'interleukine (IL)-12, l'interféron (IFN)-γ, l'IL-2, l'IL-4, l'IL-10 et l'expression du facteur de croissance transformant (TGF)-ß dans un intervalle de 3 mois, 58 vaches ont été sélectionnées (30 BLV+ et 28 BLV−) à partir d'un troupeau laitier à forte prévalence pour compléter trois prélèvements sanguins mensuels pour l'évaluation de PL, des titres d'anticorps BLV, de la charge provirale BLV et l'expression d'IL-12, IFN-γ, d'IL-2, d'IL-4, d'IL-10 et TGF-ß. À la fin de l'échantillonnage, les vaches infectées par le BLV ont été regroupées en fonction du PL, de la charge provirale du BLV et des titres d'anticorps du BLV comme suit : BLV+PL+ (n = 16) et BLV+PL− (n = 14); charge provirale élevée (HPL) (n = 18) et charge provirale faible (LPL) (n = 13); titres d'anticorps élevés (HAT) (n = 17) et titres d'anticorps faibles (LAT) (n = 14). Les vaches BLV+PL+ ont montré une charge provirale et des titres d'anticorps significativement plus élevés que le groupe BLV+PL−; cependant, le premier suggère une propagation vraisemblablement sans rapport avec l'issue du lymphome, car HPL a été observé chez les vaches PL− lors du dernier échantillonnage. Conformément aux données, une réponse anticorps plus élevée indiquait fortement une sensibilité au BLV puisqu'elle était liée à l'apparition de PL+ et à un profil de cytokines compatible avec la suppression immunitaire. De plus, un retour à des titres d'anticorps plus faibles a été observé chez les vaches atteintes de HPL bien avant le temps, probablement en raison d'une immunosuppression à long terme. De plus, une expression élevée d'IL-10 et de TGF-ß était associée à une expression réduite d'IL-12, d'IFN-γ, d'IL-2 et d'IL-4 aux côtés de PL, HAT et HPL chez les vaches infectées par le BLV, suggérant une immunosuppression induite par IL-10 et le TGF-ß. L'expression d'IL-10 augmentait tout au long, impliquant une progression de la maladie, comme décrit. En conclusion, l'expansion proliférative des lymphocytes connus sous le nom de PL pourrait renforcer une population de cellules riches en régulation (Bregs et/ou Tregs) qui sécrète d'IL-10 et du TGF-ß, conduisant à une suppression immunitaire. D'autres études doivent être menées sur les types de cellules régulatrices impliquées dans la suppression immunitaire induite par le BLV.(Traduit par Docteur Serge Messier).

Identification of novel integration sites for bovine leukemia virus proviral DNA in cancer driver genes in cattle with persistent lymphocytosis.

Enzootic bovine leukosis is one of the unsolved problems of cattle breeding in many countries. The etiological agent of the disease is the bovine leukemia virus (BLV) - an oncogenic retrovirus, that infects B-lymphocytes in cattle. The number and genetic content of BLV provirus integration sites in the bovine genome were reported to can be used as an early diagnostic sign of leukemogenesis in the infected cattle, but patterns of BLV provirus integration into the bovine genome and associations between genomic features of the integration sites and development of lymphocytosis and B-cell lymphomas remain poorly elucidated. Here we present data on five novel BLV provirus integration sites in the genome of cattle with persistent lymphocytosis. Two of these sites were located in introns of scfd2 and pgpep1 genes, which have been recognized as cancer driver genes. Three of the rest integration sites were found in the intergenic spaces between ctps1 and cited4, nampt and ccdc71, skp2 and lmbrd2 genes, from which cited4 and skp2 also possess oncogenic properties. These data support previous findings of the association between localization of BLV proviral DNA near cancer driver genes and leukemogenesis in the BLV-infected cattle.

Immunophenotyping of intraepithelial lymphocytes in canine chronic enteropathy and intestinal T-cell lymphoma using endoscopic samples.

Human enteropathy-associated T-cell lymphoma (EATL) is considered to be derived from intraepithelial lymphocytes (IELs); however, the origin of canine intestinal T-cell lymphoma (ITCL) remains unclear. Histological, immunohistochemical, and clonality examinations were performed using endoscopically collected canine duodenum samples of mucosal lesions of chronic enteropathy (CE; 73 cases) and ITCL without transmural neoplastic mass lesions (64 cases). Histopathological examinations revealed the intraepithelial accumulation of lymphocytes (called "intraepithelial lymphocytosis") in 54/73 CE cases (74%) and the epitheliotropism of neoplastic lymphocytes in 63/64 ITCL cases (98%). Immunohistochemically, IELs in CE with intraepithelial lymphocytosis (IEL+CE) were diffusely immunopositive for CD3, with scattered immunopositivity for CD5, CD8, CD20, and granzyme B (GRB). The percentage of CD8+ in CD3+ IELs was significantly lower in IEL+CE than in CE without intraepithelial lymphocytosis (IEL-CE). Double-labeling immunohistochemistry revealed a high percentage of GRB expression in CD8- IEL among IEL+CE. Among 64 ITCL cases, CD3 was immunopositive in 64 (100%), CD5 in 22 (34%), CD8 in 8 (13%), CD20 in 12 (19%), CD30 in 13 (20%), and GRB in 49 (77%). In CD3+ cells, Ki67 immunopositivity was highest in ITCL, intermediate in IEL+CE, and lower in IEL-CE. A clonal TCR gene rearrangement was detected in 1/19 IEL-CE cases (5%), 15/54 IEL+CE (28%), and 38/58 ITCL (66%). These results indicate that the immunophenotype of canine ITCL (CD8-GRB+) is similar to that of the increased IELs in CE. The high proliferative activity and clonality of T cells in IEL+CE suggest that canine ITCL originates from these IELs, similar to human EATL.

Abnormal clonalities of B-lymphocytes in bovine leukemia virus-infected cattle with persistent lymphocytosis.

Peripheral B-lymphocyte clonality of 274 bovine leukemia virus-infected cattle with lymphocytosis was analyzed using clonality PCR based on sequences of the variable region of the bovine immunoglobulin H chain. None of the cattle showed monoclonal proliferation, while 10, 31, and 233 showed minor-clonal, oligoclonal, and polyclonal proliferation, respectively. A total of 163 cattle were analyzable the following year, and lymphocytosis was maintained in 157, indicating persistent lymphocytosis (PL). B-lymphocyte clonality of the 157 PL cattle was minor-clonal in 6 (3.8%), oligoclonal in 8 (5.1%), and polyclonal in 143 (91.1%). A higher rate of enzootic bovine leukosis (EBL) onset within a year was observed in PL cattle with minor-clonal (50.0% (3/6)) and oligoclonal (25.0% (2/8)) proliferation compared to those with polyclonal (5.6% (8/143)) proliferation. Minor-clonal and oligoclonal proliferation in PL cattle may be a prognosis factor for developing EBL.

Clinical outcome and prognostic factors in dogs with B-cell chronic lymphocytic leukemia: A retrospective study.

BACKGROUND: B-cell chronic lymphocytic leukemia (BCLL) in dogs generally is considered an indolent disease, but previous studies indicate a wide range in survival times. OBJECTIVES: We hypothesized that BCLL has a heterogeneous clinical course, similar to chronic lymphocytic leukemia in humans. We aimed to assess presentation and outcome in dogs with BCLL and evaluate the prognostic relevance of clinical and flow cytometric factors. ANIMALS: One hundred and twenty-one dogs with BCLL diagnosed by flow cytometry. Three breed groups were represented: small breed dogs (n = 55) because of increased risk of BCLL; Boxers (n = 33) because of preferential use of unmutated immunoglobulin genes; and other breeds (n = 33). METHODS: Retrospective study reviewing signalment, clinicopathologic data, physical examination findings, treatment, and survival of dogs with BCLL. Cellular proliferation, determined by the percentage of Ki67-expressing CD21+ B-cells by flow cytometry, was measured in 39 of 121 cases. Clinical and laboratory variables were evaluated for association with survival. RESULTS: The median survival time (MST) for all cases was 300 days (range, 1-1644 days). Boxers had significantly shorter survival (MST, 178 days) than non-Boxers (MST, 423 days; P < .0001), and no significant survival difference was found between small breeds and other non-Boxer breeds. Cases with high Ki67 (>40% Ki67-expressing B-cells) had significantly shorter survival (MST, 173 days) than did cases with <40% Ki67 (MST undetermined; P = .03), regardless of breed. Cases with a high lymphocyte count (>60 000 lymphocytes/µL) or clinical signs at presentation had significantly shorter survival. CONCLUSIONS AND CLINICAL IMPORTANCE: B-cell chronic lymphocytic leukemia had a variable clinical course and Boxer dogs and cases with high Ki67 had more aggressive disease.

Lymphocyte proliferative responses in dairy cows supplemented with an immunomodulatory feed additive and administered polyvalent vaccination / [Proliferação de linfócitos em vacas leiteiras suplementadas com um aditivo alimentar imunomodulador e vacinadas com vacina polivalente]

O presente estudo avaliou o efeito da suplementação com OmniGen-AF® na proliferação de linfócitos e títulos de anticorpos após vacinação em bovinos leiteiros. Amostras de sangue periférico foram coletadas de 32 vacas leiteiras para quantificação dos títulos de anticorpos anti-Leptospira, e amostras de sangue periférico de 16 vacas leiteiras foram também coletadas para avaliação da proliferação de linfócitos. Observou-se que a suplementação com OmniGen-AF® aumentou a proliferação basal de linfócitos (sem estímulos) 21 dias após a vacinação (P=0,03), apesar de reduzir a proliferação de linfócitos B quando estimulada com Leptospira borgpetersenii serovar Hardjo inativada pelo calor (P=0,03). Ademais, nenhum efeito da suplementação sobre a proliferação de linfócitos no momento imediatamente anterior à vacinação e nos títulos de anticorpos anti-Leptospira foi encontrado. Além disso, a proliferação de linfócitos estimulada com lipopolissacarídeos foi maior em vacas multíparas que em primíparas 21 dias após a vacinação (P=0,03). Desse modo, o presente estudo demonstra que a suplementação com OmniGen-AF® não afetou de forma robusta a proliferação de linfócitos e os títulos de anticorpos anti-Leptospira após vacinação em vacas leiteiras sadias.(AU)

IFN-γ mRNA expression is lower in Holstein cows infected with bovine leukemia virus with high proviral load and persistent lymphocytosis.

Bovine leukemia virus (BLV) is a retrovirus that affects primarily milky cows. Animals serologically positive to BLV show a Th1 cytokine profile with a predominance of interferon gamma (IFN-γ). IFN-γ has antiviral activity through mechanisms such as resistance to infection, inhibition of viral replication and apoptosis. The objective of this work was to determine the transcription levels of IFN-γ and its relationship with proviral load and persistent lymphocytosis in a population of Holstein cows of the province of Antioquia, Colombia. IFN-γ transcription levels were evaluated by qPCR in 140 Holstein cows. A one-way analysis of variance and a Student's t test were used to evaluate the differences between the means. The amount of IFN-γ mRNA found in BLV-positive cows was lower than in BLV-negative cows. Moreover, in the group of infected cows a lower level of IFN-γ mRNA expression was found in BLV and persistent lymphocytosis cows (BLV+PL) compared with BLV and aleukemia cows (BLV+AL). The level of IFN-γ mRNA expression was lower in cows with high proviral load (HPL) compared to cows with low proviral load (LPL). BLV infection is related to abnormal expression of IFN-γ mRNA, although IFN-γ has antiviral activity, its expression is affected by high proviral load. Keywords: cytokine; immune system; leukemia; bovine leukemia virus.

Polyclonal B-cell lymphocytosis in English bulldogs.

BACKGROUND: English bulldogs disproportionally develop an expansion of small B-cells, which has been interpreted as B-cell chronic lymphocytic leukemia (BCLL). However, clonality testing in these cases has often not been supportive of neoplasia. HYPOTHESIS: English bulldogs have a syndrome of nonneoplastic B-cell expansion. ANIMALS: Eighty-four English bulldogs with small-sized CD21+ B-cell lymphocytosis in the blood as determined by flow cytometry. METHODS: This is a retrospective study. We characterized this syndrome by assessing B-cell clonality, clinical presentation, flow cytometric features, and immunoglobulin gammopathy patterns. We identified 84 cases with CD21+ lymphocytosis among 195 English bulldogs with blood samples submitted to the Colorado State University-Clinical Immunology laboratory for immunophenotyping between 2010 and 2019. Flow cytometry features were compared to normal B-cells and BCLL cases. PCR for antigen receptor rearrangements (PARR) by multiple immunoglobulin primers was performed to assess B-cell clonality. A subset of cases with gammopathy were examined by protein electrophoresis, immunofixation, and immunoglobulin subclass ELISA quantification. RESULTS: Seventy percent (58/83) of cases had polyclonal or restricted polyclonal immunoglobulin gene rearrangements, suggesting nonmalignant B-cell expansion. The median age of all dogs in the study was 6.8 years and 74% were male. The median (range) lymphocyte count was 22 400/µL (2000-384 400/µL) and B-cells had low expression of class II MHC and CD25. Splenomegaly or splenic masses were detected in 57% (26/46) of cases and lymphadenopathy in 11% (7/61). Seventy-one percent (52/73) of cases had hyperglobulinemia and 77% (23/30) with globulin characterization had IgA ± IgM polyclonal or restricted polyclonal gammopathy patterns. CONCLUSIONS AND CLINICAL IMPORTANCE: Polyclonal B-cell lymphocytosis in English bulldogs is characterized by low B-cell class II MHC and CD25 expression, splenomegaly and hyperglobulinemia consisting of increased IgA ± IgM. We hypothesize that this syndrome has a genetic basis.

CD4 and CD8 double-negative immunophenotype of thymoma-associated lymphocytes in a dog.

Persistent small-cell lymphocytosis in dogs with a concurrent mediastinal mass has been associated with both thymoma and small-cell lymphoma. In thymomas, neoplastic thymic epithelial cells induce overproduction and release of polyclonal lymphocytes, whereas thymic lymphoma results in thymic effacement by a clonal expansion of neoplastic lymphocytes and subsequent leukemic phase of lymphoma. Flow cytometry has been used to differentiate these 2 entities by immunophenotyping mediastinal mass aspirates. It has been reported that cases with mediastinal masses in which ≥ 10% of the associated small-cell lymphocytes were double positive for CD4 and CD8 were thymomas, whereas masses associated with < 10% were suggestive of lymphoma. We report a unique case of thymoma-associated lymphocytosis lacking the classic CD4+CD8+ immunophenotype. Our findings suggest that there may be more diversity in the thymoma-associated lymphocyte immunophenotype than has been identified previously; immunophenotyping alone might not be sufficient to differentiate thymic small-cell lymphoma from thymoma-associated lymphocytosis. In dogs with mediastinal masses and peripheral lymphocytosis, employing a variety of testing modalities to avoid misdiagnosis is prudent. These modalities include cytologic and/or histologic evaluation, immunophenotyping, and clonality assessment.

Características epizootiológicas da infecção natural pelo vírus da cinomose canina em Belo Horizonte / Natural canine distemper virus infection epizootiology characteristics in Belo Horizonte

O perfil epizootiológico da cinomose canina em Belo Horizonte é desatualizado e não alberga algumas características relevantes. Uma análise recente da distribuição do vírus em relação às características do hospedeiro e do meio ambiente associada aos principais sinais clínicos e achados laboratoriais são importantes para se adotarem medidas estratégicas para o controle da enfermidade. Objetivou-se, assim, determinar as características epizootiológicas da infecção pelo vírus da cinomose canina associada à variedade de sinais clínico-neurológicos e laboratoriais em Belo Horizonte, auxiliando no diagnóstico precoce da infecção e na diminuição das taxas de morbidade e mortalidade da doença. A avaliação do perfil epizootiológico de 90 cães revelou que a doença é mais frequente em animais adultos (um a seis anos de idade) e que não receberam vacinas conforme recomendado pelos protocolos. Os sinais clínicos extraneurais e neurais foram variados, com predomínio para manifestações gastrentérica e respiratória, mioclonia e déficit motor, respectivamente. O exame do fluido cérebro-espinhal demonstrou predomínio de proteinorraquia associada à pleocitose linfocítica. O teste de imunocromatografia para pesquisa de antígeno com amostras do fluido cerebroespinhal foi eficaz para identificar a doença em pacientes com sinais neurológicos, diferentemente das amostras do swab conjuntival, que não devem ser utilizadas.(AU)

The epizootiology profile of canine distemper in Belo Horizonte is outdated and does not harbor some important characteristics. A recent analysis of the virus distribution in relation to host and environmental characteristics associated with the main clinical signs and laboratory findings are important for adopting strategic measures to control the disease. The aim of this study was to determine the epizootiology characteristics of canine distemper virus infection associated with a variety of clinical and neurologic signs and laboratory findings in Belo Horizonte, helping to detect early infection and reduce morbidity and mortality rates. The evaluation of the epizootiology profile of 90 dogs revealed that the disease is more frequent in adult animals (1-6 years of age) and did not receive vaccines as recommended by the protocols. Extra neural and neural clinical signs were varied, with predominance for gastrointestinal and respiratory manifestations and myoclonus and motor deficit, respectively. Examination of the cerebrospinal fluid of 16 dogs showed a predominance of increase protein associated with lymphocytic pleocytosis. The immunochromatography test for antigen screening with samples of cerebrospinal fluid in 76 animals with neurological signs was effective in identifying the disease, unlike conjunctival swab samples, which should not be used.(AU)

Lymphocytosis and lymphadenopathy in a dog arising from two distinct lymphoid neoplasms.

A 10-year-old intact male Golden Retriever was presented to The Ohio State University Veterinary Medical Center for acute, non-painful facial swelling of the right mandibular region. On physical examination, the right mandibular swelling was found to represent marked lymphadenopathy of the submandibular lymph node. At this time, marked lymphadenopathy of the prescapular and popliteal lymph nodes was also appreciated. The CBC showed a moderate leukocytosis (38.4 × 109 cells/L, reference interval [RI] 4.8-13.9 × 109 cells/L) characterized by a moderate lymphocytosis (28.4 × 109 cells/L, RI 1.0-4.6 × 109 cells/L). Evaluation of peripheral blood and enlarged prescapular and popliteal lymph nodes revealed two morphologically different populations of homogeneous lymphocytes, with the lymphocyte population in the lymph nodes being distinct from that in the blood smear. Flow cytometry of peripheral blood revealed CD45-, CD5+, CD4-, CD8-, variably CD21+ neoplastic lymphocytes compatible with T-zone lymphocytes due to the absence of CD45 expression. Flow cytometry of the lymph node aspirate indicated a distinct population of CD21+ lymphocytes consistent with a B-cell phenotype along with a smaller proportion of the T-zone lymphocytes observed in the blood confirming the presence of two distinct populations of neoplastic lymphocytes, one involving T cells, and the other involving B cells.

Immunophenotypic characterization and clinical outcome in cats with lymphocytosis.

BACKGROUND: Lymphocytosis is relatively common in cats, but few studies describe lymphocyte populations or the clinical course associated with different immunophenotypic expansions. HYPOTHESIS/OBJECTIVES: We hypothesized that cats frequently develop non-neoplastic lymphocytosis and that different neoplastic immunophenotypes have variable prognoses. We aimed to characterize the lymphocyte expansions in a large population of cats with lymphocytosis and to assess clinical presentation and outcome in a subset. ANIMALS: Three cohorts of cats older than 1 year with lymphocytosis (>6000/µL) were examined to define immunophenotypic categories (n = 146), evaluate outcome (n = 94), and determine prevalence of immunophenotypes (n = 350). METHODS: Retrospective study of cats with blood submitted for flow cytometry. Medical records (n = 94) were reviewed for clinical data, treatment, and survival information. RESULTS: Five major immunophenotypic categories were identified: B cell, heterogeneous (≥2 lineages expanded), CD4+ T cell, CD4-CD8- (double negative [DN]) T cell, and CD5-low-expressing T cell. B-cell and heterogeneous phenotypes were more consistent with a non-neoplastic process, having polyclonal antigen receptor gene rearrangements, younger age at presentation, lower lymphocyte counts, and prolonged survival. The neoplastic phenotypes, CD4+ T cell, DN T cell, and CD5 low T cell, had different median survival times (752 days [n = 37], 271 days [n = 7], 27.5 days [n = 12], respectively). Among CD4+ T-cell cases, cats with abdominal lymphadenopathy, intestinal involvement, or both and females had shorter survival. Among 350 cats with lymphocytosis, CD4+ T-cell lymphocytosis was most common, followed by heterogeneous and B-cell phenotypes. CONCLUSIONS AND CLINICAL IMPORTANCE: Neoplastic CD4+ T-cell lymphocytosis is common in cats and has a prolonged clinical course compared to aberrant T-cell phenotypes. Cats with heterogeneous and B-cell lymphocyte expansions commonly have non-neoplastic disease.

B-cell chronic lymphocytic leukemia in a miniature American Eskimo dog.

An 11-year-old neutered male miniature American Eskimo dog was presented for routine dental cleaning with moderately enlarged submandibular, prescapular, and popliteal lymph nodes. On pre-anesthetic blood analysis a moderate, poorly regenerative anemia and marked lymphocytosis were observed. Although cytologic evaluation of a lymph node aspirate was interpreted as lymphoma, a complete blood cell count, flow cytometric immunotyping of blood leukocytes, and serum electrophoresis identified B-cell chronic lymphocytic leukemia. Chemotherapy with chlorambucil was recommended.

Leucémie lymphocytaire chronique à cellules B chez un chien Eskimo américain miniature. Un chien mâle castré âgé de 11 ans de race Eskimo miniature fut présenté pour nettoyage dentaire de routine avec une hypertrophie modérée des ganglions sous-mandibulaires, pré-scapulaires et poplités. Lors des analyses sanguines pré-anesthésie, une anémie pauvrement régénératrice et une lymphocytose marquée furent observées. Bien que l'évaluation cytologique d'une aspiration d'un des ganglions fut interprétée comme un lymphome, un comptage cellulaire sanguin complet, l'immunotypage des leucocytes sanguins par cytométrie en flux, et une électrophorèse du sérum identifièrent une leucémie lymphocytaire chronique à cellules B. Une chimiothérapie avec du chlorambucil et de la prednisone fut recommandée.(Traduit par Dr Serge Messier).

Linfocitose extrema associada à leucemia linfoblástica aguda (LLA) de células T em um cão jovem: relato de caso / Extreme lymphocytosis associated with acute T-cell lymphoblastic leukemia (ALL) in a young dog: case report

A leucemia linfoblástica aguda (LLA) é uma enfermidade de origem linfóide e consiste na proliferação de células neoplásicas na medula óssea. O objetivo desse trabalho é relatar o caso de um cão macho, sem raça definida, de apenas um ano de idade, atendido no Hospital Universitário de Medicina Veterinária Prof. Firmino Mársico Filho (HUVET) da Universidade Federal Fluminense (UFF) com queixa principal de inapetência e diarreia há três dias e que foi diagnosticado com essa neoplasia por meio da sintomatologia clínica, resultados do hemograma e do mielograma. O paciente apresentava valores exacerbados de linfócitos (553.094 células/µL), além de anemia, trombocitopenia, hipoalbuminemia e elevação da atividade das enzimas fosfatase alcalina e ALT. Foram observadas manchas de Gümprecht, linfócitos atípicos apresentando anisocitose, anisocariose, intensa basofilia citoplasmática e monócitos ativados. O mielograma apresentou também um aumento de linfócitos e contagem de linfoblastos superior a 30% na medula, confirmando o diagnóstico de leucemia linfoblástica aguda. Ademais, posteriormente, foi realizado exame de Reação em Cadeia de Polimerase (PCR) para rearranjos de receptores de antígenos e foi detectado clonalidade para linfócitos T. O animal foi submetido à quimioterapia (protocolo com ciclofosfamida, vincristina e prednisona) mas não resistiu à gravidade do quadro, vindo a óbito após a primeira sessão, pouco tempo após o diagnóstico.

Acute lymphoblastic leukemia (LLA) is a disease with a lymphoid origin and consists of the proliferation of neoplastic cells in the bone marrow. The aim of this study was to report the case of only one year old mixed breed male dog, attended at the University Hospital of Veterinary Medicine Prof. Firmino Mársico Filho (HUVET) from Universidade Federal Fluminense (UFF), with major complaint of inappetence and diarrhea three days ago and which was diagnosed with this neoplasm through clinical symptoms, complete blood count and myelogram results. The patient had increased values of lymphocytes (553,094 cells/µL), in addition to anemia, thrombocytopenia, hypoalbuminemia and elevated alkaline phosphatase and ALT activities. Gümprecht shadows, atypical lymphocytes presenting anisocytosis, anisocariosis, and severe cytoplasmic basophilia and activated monocytes were observed. Myelogram also showed an increase in lymphocytes and a lymphoblastic count greater than 30% in the marrow, confirming the diagnosis of LLA. In addition, polymerase chain reaction (PCR) for antigen receptor rearrangements was performed and clonality for T lymphocytes was detected. The animal underwent chemotherapy (protocol with cyclophosphamide, vincristine and prednisone), but did not withstand the severity of the disease, coming to death after the first session, shorly after diagnosis.

Linfocitose extrema associada à leucemia linfoblástica aguda (LLA) de células T em um cão jovem: relato de caso / Extreme lymphocytosis associated with acute T-cell lymphoblastic leukemia(ALL) in a young dog: case report

A leucemia linfoblástica aguda (LLA) é uma enfermidade de origem linfóide e consiste na proliferação de células neoplásicas na medula óssea. O objetivo desse trabalho é relatar o caso de um cão macho, sem raça definida, de apenas um ano de idade, atendido no Hospital Universitário de Medicina Veterinária Prof. Firmino Mársico Filho (HUVET) da Universidade Federal Fluminense (UFF) com queixa principal de inapetência e diarreia há três dias e que foi diagnosticado com essa neoplasia por meio da sintomatologia clínica, resultados do hemograma e do mielograma. O paciente apresentava valores exacerbados de linfócitos (553.094 células/µL), além de anemia, trombocitopenia, hipoalbuminemia e elevação da atividade das enzimas fosfatase alcalina e ALT. Foram observadas manchas de Gümprecht, linfócitos atípicos apresentando anisocitose, anisocariose, intensa basofilia citoplasmática e monócitos ativados. O mielograma apresentou também um aumento de linfócitos e contagem de linfoblastos superior a 30% na medula, confirmando o diagnóstico de leucemia linfoblástica aguda. Ademais, posteriormente, foi realizado exame de Reação em Cadeia de Polimerase (PCR) para rearranjos de receptores de antígenos e foi detectado clonalidade para linfócitos T. O animal foi submetido à quimioterapia (protocolo com ciclofosfamida, vincristina e prednisona), mas não resistiu à gravidade do quadro, vindo a óbito após a primeira sessão, pouco tempo após o diagnóstico.

Acute lymphoblastic leukemia (LLA) is a disease with a lymphoid origin and consists of the proliferation of neoplastic cells in the bone marrow. The aim of this study was to report the case of only one year old mixed breed male dog, attended at the University Hospital of Veterinary Medicine Prof. Firmino Mársico Filho (HUVET) from Universidade Federal Fluminense (UFF), with major complaint of inappetence and diarrhea three days ago and which was diagnosed with this neoplasm through clinical symptoms, complete blood count and myelogram results. The patient had increased values of lymphocytes (553,094 cells/μL), in addition to anemia, thrombocytopenia, hypoalbuminemia and elevated alkaline phosphatase and ALT activities. Gümprecht shadows, atypical lymphocytes presenting anisocytosis, anisocariosis, and severe cytoplasmic basophilia and activated monocytes were observed. Myelogram also showed an increase in lymphocytes and a lymphoblastic count greater than 30% in the marrow, confirming the diagnosis of LLA. In addition, polymerase chain reaction (PCR) for antigen receptor rearrangements was performed and clonality for T lymphocytes was detected. The animal underwent chemotherapy (protocol with cyclophosphamide, vincristine and prednisone), but did not withstand the severity of the disease, coming to death after the first session, shortly after diagnosis.

Rapid clinical progression of B-cell chronic lymphocytic leukemia in a horse.

CASE DESCRIPTION: A 17-year-old Friesian gelding was examined at a referral hospital because of a 1-month history of mild exercise intolerance and marked lymphocytosis. CLINICAL FINDINGS: Physical examination revealed no peripheral lymphadenopathy or other abnormalities. Results of an abdominal palpation examination per rectum and thoracic and abdominal ultrasonographic examinations were unremarkable. B-cell chronic lymphocytic leukemia (CLL) was diagnosed on the basis of severe lymphocytosis and positive expression of the B-cell marker CD20 by lymphocytes in the bone marrow and peripheral blood. TREATMENT AND OUTCOME: Treatment with prednisolone (2 mg/kg [0.9 mg/lb], PO, every other day) and chlorambucil (20 mg/m2, PO, every 3 weeks for 2 doses, then every 2 weeks) was initially associated with improvement in clinical signs and a decrease in the lymphocyte count. However, 3 weeks after administration of the first dose of chlorambucil, the lymphocyte count began to increase. One week later, the horse developed episodes of recurrent fever and the lymphocyte count continued to increase. Despite continued administration of the prednisolone-chlorambucil protocol, the horse's clinical condition deteriorated rapidly, and it was euthanized 6 weeks after initial examination at the referral hospital because of a poor prognosis. A necropsy was not performed. CLINICAL RELEVANCE: B-cell CLL has been infrequently described in horses. This report was the first to describe the use of chemotherapy, albeit unsuccessful, for the treatment of B-cell CLL in a horse. This information should be useful for guiding expectations for prognosis and management of other horses affected with the disease.

Canine and Feline Cutaneous Epitheliotropic Lymphoma and Cutaneous Lymphocytosis.

Cutaneous lymphomas are divided into categories based on histologic evaluation of the skin and location of neoplastic lymphocytes. Epitheliotropic cutaneous lymphoma, also known as cutaneous T-cell lymphoma, is diagnosed when neoplastic lymphocytes show tropism for the epidermis and these cells infiltrate the epidermis and adnexae. In diagnosis of nonepitheliotropic cutaneous lymphoma, neoplastic lymphocytes are found mostly in the dermis and/or subcutis. Neoplastic cells are of either B-cell or T-cell origin. This article focuses on epitheliotropic cutaneous lymphomas and cutaneous lymphocytosis, which is considered a form of indolent lymphoma, in dogs and cats.