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PubMedDate not supplied

The possible prognostic significance of immunophenotype in feline alimentary lymphoma: a pilot study.

Twenty-three retrospective biopsy specimens from feline intra-abdominal lymphomas including tumours affecting the gastrointestinal tract, mesenteric lymph nodes, liver and spleen were immunohistochemically labelled with monoclonal antibodies to CD79a (B-cell phenotype) and CD3 (T-cell phenotype). Positive labelling occurred in 15 (65%) and 6 (26%) of the tumours, respectively. No statistically significant relationship was found between tumour cell immunophenotype and age, breed, or gender. There was no significant difference in survival time between the two immunophenotypes, based on the 16 cats for which this information was available.

Animals↗

PubMed2004

Bone marrow mast cell immunophenotyping in adults with mast cell disease: a prospective study of 33 patients.

The aberrant co-expression of CD2 and CD25 antigens is the immunophenotypic hallmark of neoplastic mast cells, and has been consistently identified on bone marrow mast cells from patients with indolent mast cell disease (MCD). We prospectively analyzed the bone marrow mast cell immunophenotype by multiparametric flow cytometry (FC) for 33 MCD cases, to examine the role of CD2 and CD25 expression in establishing diagnosis, detecting histologically occult bone marrow mast cell infiltration, and assessing treatment response. While CD25 was almost uniformly expressed, only 6 of 13 patients with indolent MCD, 1 of 8 with aggressive MCD, 2 of 7 with MCD and an associated hematological disorder, and none of the 2 patients with either mast cell leukemia or smoldering systemic mastocytosis, expressed CD2. One of three patients with cutaneous mastocytosis had an aberrant CD2+/CD25+ mast cell population suggesting histologically occult bone marrow involvement. CD25 expression was lost in one patient who achieved complete histologic remission with therapy, but not in two patients who achieved a partial remission. In conclusion, CD25, but not CD2, is a reliable marker for neoplastic mast cells, and CD25 expression indicates histologically occult bone marrow infiltration and residual disease after therapy.

Adult↗

PubMed2026

Integrated morphologic, immunophenotypic, and molecular profiling of advanced upper tract urothelial carcinoma across tumor compartments supports biopsy-based testing.

Upper tract urothelial carcinoma (UTUC) is an aggressive malignancy with limited molecular characterization in advanced disease. FGFR3 alterations are well established in low-grade urothelial carcinoma, but their prevalence, stability, and biological significance in locally advanced and metastatic UTUC remain only partially defined. We performed an integrated morphologic, immunohistochemical, and molecular analysis of 24 locally advanced and/or metastatic UTUC from 20 patients. FGFR3 status was assessed by RT-PCR across multiple tumor compartments, including biopsies, primary tumors, lymph-node metastases, and distant metastatic sites. Immunohistochemistry included CK20, CK5, GATA3, p53, and mismatch repair proteins. Targeted next-generation sequencing (NGS) was used to characterize co-occurring genomic alterations and to assess concordance with p53 immunophenotype. FGFR3 alterations were identified in 50% of patients and in 54.2% of analyzed tumors. FGFR3 status showed high intra-patient stability, with concordance between primary tumors and distant metastases in 90% of cases, whereas concordance with lymph node metastases was lower (50%), suggesting site-specific clonal divergence. Despite advanced stage, 92.3% of FGFR3-altered tumors displayed papillary urothelial carcinoma morphology, and most showed a luminal immunophenotype (61.5% by CK20/CK5 and 69.2% by GATA3/CK5). Targeted NGS revealed additional pathogenic alterations in 75% of patients, most frequently involving RTK/RAS/MAPK signaling (70%), cell-cycle regulation (25%), and PI3K/AKT pathway components (10%). TP53 mutations co-occurred with FGFR3 alterations in 60% of FGFR3-mutated patients and showed 90.4% concordance with p53 immunohistochemistry. Finally, a few cases exhibited complex, multi-site FGFR3 mutational patterns, consistent with intratumoral clonal evolutions. In conclusion, FGFR3 alterations are frequent and remarkably stable in advanced UTUC, even in high-grade and metastatic disease. These findings support the reliability of FGFR3 testing on limited diagnostic material and reinforce its relevance for therapeutic stratification. UTUC emerges as a molecularly dynamic disease in which early oncogenic drivers such as FGFR3 continue to shape tumor biology and therapeutic vulnerability at advanced stages.

Humans↗

PubMed2006

Canine microglial cells: stereotypy in immunophenotype and specificity in function?

Microglial cells represent the endogenous immune system of the central nervous system (CNS). Upon pathological insults they reveal their immunological potential aimed at regaining homeostasis. These reactions have long been believed to follow a uniform and unspecific pattern which is irrespective to the underlying disease entity. Evidence is growing that this view seriously underrates microglial competence as the defenders of the CNS. In the present study, microglial cells of 47 dogs were examined ex vivo by means of flow cytometry. Ex vivo examination included immunophenotypic characterization using eight different surface markers and functional studies such as phagocytosis assay and the reactive oxygen species (ROS) generation test. The dogs were classified according to their histopathological diagnoses in disease categories (controls, canine distemper virus (CDV) induced demyelination, other diseases of the CNS) and results of microglial reaction profiles were compared. Immunophenotypic characterization generally revealed relative high conformity in the microglial disease response among the different groups, however the functional response was shown to be more specific. Dogs with intracranial inflammation and dogs with demyelination showed an enhanced phagocytosis, whereas a significant up-regulation of ROS generation was found in dogs with demyelination due to CDV infection. This strongly suggests a specific response of microglia to infection with CDV in the settings of our study and underlines the pivotal role of microglial ROS generation in the pathogenesis of demyelinating diseases, such as canine distemper.

Animals↗

PubMed2006

The immunophenotype of pre-TALL/LBL revisited.

Flow cytometric analysis of cluster of differentiation (CD) markers in abnormal lymphocyte populations is crucial in the diagnosis of precursor T cell acute lymphoblastic leukemia (T-ALL)/lymphoblastic lymphoma (LBL). The World Health Organization (WHO) suggested immunophenotype for pre-T ALL/LBL typically includes the expression of TdT, cCD3, and CD7, while CD2, CD3, CD4, CD5, CD8, and CD10 are variably expressed. The myeloid antigens CD13 and CD33 are usually positive, whereas CD117 and cCD79a are infrequently expressed. Furthermore, there is frequent dual expression of CD4 and CD8. In the present investigation, 19 cases of pre-TALL/LBL were analyzed for selected CD marker expression. Fifteen of 19 cases studied were evaluated for TdT, cCD3, and cCD79a expression. Eleven (73.3%) positively expressed TdT, 15 (100%) positively expressed cCD3, and 9 (60%) positively expressed cCD79a. Of the 17 cases analyzed for CD7, CD5, and CD10 expression, CD7 and CD5 were positive in all 17 (100%) cases, whereas CD10 was positive in 8 (47.1%) cases. Of the 18 cases evaluated for CD2, CD3, CD4, CD8, and dual expression of CD4 and CD8, CD2 was expressed in 14 (77.8%), while CD3 was expressed in 7 (38.9%) cases. CD4 was positive in 11 (61.1%), and CD8 was expressed in 9 (50%). Dual expression of CD4 and CD8 occurred in only 4 (22.2%) of the cases. Of the 16 analyzed for CD13, CD33, and CD117, only 1 case (6.3%) expressed CD13, while 2 (12.5%) cases expressed CD33 and CD117. Thus, these data point to the need for a more extensive study to reevaluate the current WHO defined immunophenotype used in the diagnosis of pre-TALL/LBL.

Antigens, CD↗

PubMed2001

Immunophenotypic analysis of the TCR-Vbeta repertoire in 98 persistent expansions of CD3(+)/TCR-alphabeta(+) large granular lymphocytes: utility in assessing clonality and insights into the pathogenesis of the disease.

At present, a major challenge in the initial diagnosis of leukemia of large granular lymphocytes (LGLs) is to establish the clonal nature of the expanded population. In the present study we have analyzed by flow cytometry immunophenotyping the TCR-Vbeta repertoire of 98 consecutive cases of persistent expansions of CD4(+) or CD8(+bright) CD3(+)/TCR-alphabeta(+) LGLs and compared the results with those obtained in molecular studies of TCR-beta gene rearrangements. Fifty-eight cases were considered to be monoclonal in molecular studies whereas in the remaining 40 cases there was no evidence for monoclonality (11 cases were considered oligoclonal and 29 polyclonal). The TCR-Vbeta repertoire was biased to the preferential use of one or more TCR-Vbeta families in 96% of cases, a total of 124 TCR-Vbeta expansions being diagnosed: one TCR-Vbeta expansion in 71 cases and two or more TCR-Vbeta expansions in 23 cases. The highest TCR-Vbeta expansion observed in each case was higher among monoclonal (74 +/- 19%) as compared to nonmonoclonal cases (24 +/- 14%) (P = 0.001), as did the fraction of LGLs that exhibited a TCR-Vbeta-restricted pattern (86 +/- 16% and 42 +/- 23%, respectively; P = 0.0001); by contrast, the proportion of cases displaying more than one TCR-Vbeta expansion was higher in the latter group: 7% versus 48%, respectively (P = 0.001). Results obtained in oligoclonal cases were intermediate between those obtained in polyclonal and monoclonal cases and similar results were observed for CD4(+) as for CD8(+bright) T-cell expansions. TCR-Vbeta families expressed in CD8(+bright) T-cell-LGL proliferations showed a pattern of distribution that mimics the frequency at which the individual TCR-Vbeta families are represented in normal peripheral blood T cells. Assuming that a given proliferation of LGLs is monoclonal whenever there is an expansion of a given TCR-Vbeta family of at least 40% of the total CD4(+) or CD8(+bright) T-cell compartment, we were able to predict clonality with a sensitivity of 93% and a specificity of 80%. By increasing the cut-off value to 60%, sensitivity and specificity were of 81% and 100%. In summary, our results suggest that flow cytometry immunophenotypic analysis of the TCR-Vbeta repertoire is a powerful screening tool for the assessment of T-cell clonality in persistent expansions of TCR-alphabeta(+) LGLs.

Adolescent↗

PubMed2004

Clinicobiological, immunophenotypic, and molecular characteristics of monoclonal CD56-/+dim chronic natural killer cell large granular lymphocytosis.

Indolent natural killer (NK) cell lymphoproliferative disorders include a heterogeneous group of patients in whom persistent expansions of mature, typically CD56(+), NK cells in the absence of any clonal marker are present in the peripheral blood. In the present study we report on the clinical, hematological, immunophenotypic, serological, and molecular features of a series of 26 patients with chronic large granular NK cell lymphocytosis, whose NK cells were either CD56(-) or expressed very low levels of CD56 (CD56(-/+dim) NK cells), in the context of an aberrant activation-related mature phenotype and proved to be monoclonal using the human androgen receptor gene polymerase chain reaction-based assay. As normal CD56(+) NK cells, CD56(-/+dim) NK cells were granzyme B(+), CD3(-), TCRalphabeta/gammadelta(-), CD5(-), CD28(-), CD11a(+bright), CD45RA(+bright), CD122(+), and CD25(-) and they showed variable and heterogeneous expression of both CD8 and CD57. Nevertheless, they displayed several unusual immunophenotypic features. Accordingly, besides being CD56(-/+dim), they were CD11b(-/+dim) (heterogeneous), CD7(-/+dim) (heterogeneous), CD2(+) (homogeneous), CD11c(+bright) (homogeneous), and CD38(-/+dim) (heterogeneous). Moreover, CD56(-/+dim) NK cells heterogeneously expressed HLA-DR. In that concerning the expression of killer receptors, CD56(-/+dim) NK cells showed bright and homogeneous CD94 expression, and dim and heterogeneous reactivity for CD161, whereas CD158a and NKB1 expression was variable. From the functional point of view, CD56(-/+dim) showed a typical Th1 pattern of cytokine production (interferon-gamma(+), tumor necrosis factor-alpha(+)). From the clinical point of view, these patients usually had an indolent clinical course, progression into a massive lymphocytosis with lung infiltration leading to death being observed in only one case. Despite this, they frequently had associated cytopenias as well as neoplastic diseases and/or viral infections. In summary, we describe a unique and homogeneous group of monoclonal chronic large granular NK cell lymphocytosis with an aberrant activation-related CD56(-/+dim)/CD11b(-/+dim) phenotype and an indolent clinical course, whose main clinical features are related to concomitant diseases.

Adult↗

PubMed1999

Composite low grade B-cell lymphomas with two immunophenotypically distinct cell populations are true biclonal lymphomas. A molecular analysis using laser capture microdissection.

Low grade B-cell lymphomas comprise several well defined, clinically and immunophenotypically distinct disease entities. Composite lymphomas showing phenotypic characteristics of more than one of these tumor subtypes in the same site are rare, and both common and separate clonal origins of the two tumor parts have been reported for cases studied by molecular methods. We describe the detailed immunohistochemical and molecular findings in three cases with features of composite low grade B-cell non-Hodgkin's lymphoma (B-NHL). All three neoplasms contained morphologically distinct but interwoven compartments of different cell types, which exhibited discordant expression of several markers, including CD5, CD10, CD43, and cyclin D1. According to their morphology and phenotypes, they were classified as mantle cell lymphoma and follicular lymphoma (Case 1), follicular lymphoma and small lymphocytic lymphoma (Case 2), and mantle cell lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma (Case 3). PCR analysis of DNA obtained from whole tissue sections failed to reveal evidence for biclonality in any of the cases. We therefore isolated cell populations with different antigen expression patterns by laser capture microdissection and analyzed them by polymerase chain reaction amplification and sequencing of clonal immunoglobulin heavy chain gene rearrangements and oncogene rearrangements. Sequence analysis revealed unrelated clonal rearrangements in each of the two tumor parts in all three cases, suggesting distinct clonal origins. In addition, Case 1 showed a bcl-2 rearrangement present only in the follicular lymphoma part. Our findings suggest that low grade B-NHL with two distinct morphological and immunophenotypic patterns in the same anatomical site are frequently biclonal. This is in keeping with current classification schemes, which recognize subtypes of low grade B-NHL as separate disease entities. Furthermore, our analysis demonstrates the power of laser capture microdissection in revealing molecular microheterogeneity in complex neoplasms.

Aged↗

PubMed2000

A java-based application for differential diagnosis of hematopoietic neoplasms using immunophenotyping by flow cytometry.

We describe the implementation of a Java-based application for differential diagnosis of hematopoietic neoplasms using immunophenotyping by flow cytometry. The current version of this Java applet includes the knowledge-base for 33 hematopoietic neoplasms and 43 diagnostic immunophenotyping markers. Java, a new object-oriented computing language, helps facilitate development of this applet, a platform-independent module that can be implemented on the World Wide Web. As the Web rapidly becomes more accessible to users around the world, Web-based software may eventually form the core of decision-support systems in clinical settings. Java-based applications, such as the one described in this paper, are expected to contribute significantly in this area.

Antigens, CD↗

PubMed2001

Reference values for peripheral blood B-lymphocyte subpopulations: a basis for multiparametric immunophenotyping of abnormal lymphocytes.

BACKGROUND AND OBJECTIVES: Immunophenotyping has become a useful tool for the differential diagnosis of chronic B-cell lymphoproliferative disorders. The aim of this work was to determine reference values of normal B-cell subpopulations. MATERIAL AND METHODS: Blood samples from 38 healthy volunteers were analyzed by multidimensional flow cytometry, using a panel of directly conjugated antibodies. Results were expressed as percent of positive B cells and as median fluorescence intensity, an indirect assessment of the expression level. RESULTS: CD20, CD22, CD24, CD40, CD79a, CD79b, FMC7, CD11a, CD18, CD44 were positive in the whole B cell population, whereas CD10, CD86, CD103, CD154 and FasL were almost absent from the B-lymphocyte population. 75% were IgD positive. The kappa/lambda ratio was 1.5. CD5, CD23, CD25, CD38, CD43, CD54, CD62L, CD80 and CD95 were positive in different B-cell subpopulations. The utility of all these markers in the differential diagnosis of chronic B-cell lymphoproliferative disorders is discussed. CONCLUSION: In order to interpret a pathological immunophenotype, it is necessary to refer to quantitative and qualitative values of normal B-cell subpopulations.

Adult↗

PubMed1992

Immunophenotyping of lymphocyte subsets in bronchoalveolar lavage fluid. Comparison of flow cytometric and immunocytochemical techniques.

In order to compare flow cytometry with the conventional peroxidase anti-peroxidase method for the immunophenotyping of bronchoalveolar lavage fluid (BALF) lymphocytes, we studied BALF samples from 27 patients with various interstitial lung diseases. The results achieved with both methods were consistent concerning CD3+ pan T cells, CD4+ T helper/inducer, CD8+ T suppressor/cytotoxic and CD57+ natural killer cells. In contrast, a statistically significant lower anti-HLA-DR positive subset was obtained with flow cytometry than with the immunoperoxidase method (p less than 0.005). Since regression analyses and reliability counts showed further agreement between the methods, we conclude that flow cytometric immunophenotyping of BALF lymphocytes leads to similar, if not better, subset analyses than the immunoperoxidase method.

Bronchoalveolar Lavage Fluid↗

PubMed2003

Analysis of the immunophenotypes of de novo acute lymphoblastic leukaemia (ALL) in the Sultanate of Oman.

Acute lymphoblastic leukaemia (ALL) immmunophenotypes were analysed by flow cytometry in 65 Omani patients (46 children, 19 adults). Common ("CALLA-positive") ALL was the most frequently encountered (70%) B-cell lineage immunophenotype. Among T-cell lineage ALL patients, mature T-cell ALL was the least frequent (7%). Expression of certain surface markers including CD20 and CD6 appears to have an effect on some clinical and haematological features but FAB morphology was not useful in predicting cell lineage immunophenotypes. Other interesting findings, currently of uncertain significance, include the sizeable proportions of pre-B-ALL (group V) and cortical thymocytic ALL (stage III). Results of this study should help strengthen the emerging leukaemia database of the recently established Oman National Cancer Register and thereby contribute to a successful global attack against the haematological malignancies.

Adolescent↗

PubMed2003

Burkitt's leukemia with precursor B-cell immunophenotype and atypical morphology (atypical Burkitt's leukemia/lymphoma): case report and review of literature.

A 45-year-old male presented with fever, night sweats, splenomegaly, high LDH, high uric acid, and high blast count with atypical L3 morphology. Flow cytometry showed neoplastic clone consistent with pre B-cell immunophenotype, on the basis of lack of cytoplasmic immunoglobulins, surface immunoglobulins, and light chain immunoglobulins. Cytogenetic analysis revealed t(8;14)(q24; q32), the characteristic translocation of Burkitt's leukemia. A few similar case reports of Burkitt's leukemia with precursor B-cell immunophenotype have been described primarily in pediatric literature and usually with typical L3 morphology. This case recognizes this subset in adult ALL and emphasizes the need for comprehensive diagnostic analysis.

Adolescent↗

PubMed1997

Immunophenotypic analysis of T-cell acute lymphoblastic leukaemia in Madras, India.

Immunophenotypic analysis of 285 newly diagnosed previously untreated, unselected, acute lymphoblastic leukaemia cases carried out at the Cancer Institute (W.I.A) in Madras reveals that 126 (44.2%) cases showed T-immunophenotype. The study was conducted using flow-cytometric immunofluorescent or immunoperoxidase methods using an extensive panel of monoclonal antibodies comprising CD1, 2, 3, 4, 5, 7, 8, 57, 19, 20 kappa, lambda, IgG, M, D, CIg, CD10, HLA-DR, CD13, 14, 33, 34 and CD61. The study group comprised 73 (57.9%) paediatric cases (<15 years) and 53 (42.1%) adult cases (>15 years). Based on their reactivity with various anti-T-cell monoclonal antibodies, all T-ALL cases were assigned to one of the intrathymic differentiation compartments. 56.2% of paediatric T-ALLs arise from intrathymic compartment II, 34.2% from compartment III and 9.6% from compartment I. Among adults, 45.3% arise from compartment I. 33.9% from compartment III and 20.8% from compartment II. The most frequently observed CD antigens in our study group are CD7, 5, 2 and 3. A correlative study of socioeconomic status reveals that 67.5% of T-ALL cases occurred among lower socioeconomic strata.

Adolescent↗

PubMed1999

Heterogeneity of T-acute lymphoblastic leukemia (T-ALL) cell lines: suggestion for classification by immunophenotype and T-cell receptor studies.

Hematopoietic cell lines are often used as representatives for a certain cell differentiation lineage and stage, particularly in immunological and hematological studies. Acute lymphoblastic leukemia (ALL) of T-cell type is a rather heterogeneous group of ALL at least by immunophenotyping. Our aim was to present a comprehensive characterization of frequently used T-cell leukemia cell lines and to suggest a correlation with the normal differentiation pattern. A total of 16 T-ALL cell lines were analyzed for their immunophenotype and for T-cell receptor (TCR) rearrangement and expression. The panel of 20 cell surface markers included two new monoclonal antibodies (MoAb), TC-12 and TH-111, which were raised in our laboratory and detect subpopulations of T-cell ALL. TC-12 was typed 'unique', TH-111 was assigned to the CD96 cluster at the Vth Conference on human leucocyte differentiation antigens (HLDA). We categorized the 16 cell lines into the four groups pro-T, pre-T, cortical T and mature T differentiation stage according to the recent proposal of the European Group for the Immunological Characterization of Leukemias (EGIL). Interestingly, none of the T-cell lines were found to be alike. In conclusion, it appears necessary to consider the particular differentiation stage of each individual cell line when using T-cell leukemia lines as models for malignant or normal T cells.

Adolescent↗

PubMed1996

Immunophenotypic characterization of tumor infiltrating lymphocytes and peripheral blood lymphocytes isolated from melanomatous and non-melanomatous Sinclair miniature swine.

Selectively-bred Sinclair miniature swine exhibit a high incidence of congenital malignant melanoma which either proves fatal (10-15% of tumor-bearing piglets) or spontaneously regresses with a biphasic immunological phenomenon (85-90%) and no recurrence of malignancy. Mononuclear leukocytes were isolated from cutaneous melanomas and peripheral blood specimens collected from melanomatous (tumor-bearing) Sinclair swine during second-phase regression, and from peripheral blood specimens collected from non-melanomatous (tumor-free) Sinclair swine and control Hanford swine. Leukocyte identities were determined with single- and dual-parameter indirect immunofluorescence assays via flow cytometry. Assays for the specific surface antigens CD45, CD2, CD4, CD8, CD1, MHC class II, and N1 were employed to develop immunophenotypic profiles within the gated lymphocyte clusters from each TIL and PBL suspension. Significantly more CD8+ T-lymphocytes were identified in TIL suspensions than in peripheral blood leukocyte (PBL) suspensions (P < and = 0.05), regardless of breed or tumor status. Conversely, PBL suspensions contained significantly higher percentages of CD4+ T-lymphocytes than the levels found in TIL suspensions (P < and = 0.05). Virtually all TIL were MHC class II+, whereas the percentages of PBL expressing this antigen were markedly lower (P < and = 0.05). The percentages of T-lymphocytes co-expressing CD4 and CD8, a normal subset unique to swine, were generally consistent in all TIL and PBL suspensions examined. The results of this study have firmly established the immunophenotypic identities of cells associated with the second-phase regression phenomenon of this melanoma and have identified specific variations in the leukocyte profiles of the respective TIL and PBL suspensions.

Animals↗

PubMed1997

Immunophenotype of the canine transmissible venereal tumour.

The canine transmissible venereal tumour is a naturally occurring contagious round-cell neoplasia which is primarily located in the mucous membrane of the external genitalia in dogs of either sex. In order to specify the controversial cytogenetic origin of this round-cell tumour, 14 cases of canine transmissible venereal tumour, formalin- or Bouin-fixed and paraffin-embedded, were subjected to extensive immunophenotypic analysis using reagents specific to a variety of cytoplasmic or surface antigens: lysozyme, ACM1 antigen, vimentin, neuron-specific enolase, glial fibrillary acidic protein, desmin, alpha smooth muscle actin, CD3, IgG, kappa and lambda light chains, and keratin. Lysozyme immunoreactivity was detected in all cases, ACM1 antigen in 11 of 14, neuron-specific enolase in 11 of 14, vimentin in 10 of 14, glial fibrillary acidic protein in 4 of 14 and desmin in 1 of 14. All the sections were negative to keratins, alpha smooth muscle actin and CD3, whereas in five cases, perivascular tumour cells contained Ig G, kappa and lambda light chains. The immunoreactivity to lysozyme and ACM1 antigen supports the hypothesis of a histiocytic immunophenotype for the canine transmissible venereal tumour.

Animals↗

PubMed1999

An immunophenotypic study of canine leukemias and preliminary assessment of clonality by polymerase chain reaction.

There is a relative lack of information in the veterinary literature regarding the immunophenotypes present in canine leukemias. Utilizing a panel of thirty monoclonal antibodies, canine leukemias were assessed by flow cytometry alone or by flow cytometry in combination with immunocytochemical staining of smears. Canine chronic lymphocytic leukemia (CLL) occurred in older dogs (mean age 9.75 years; range 1.5-15 years; n = 73 cases). Blood lymphocyte counts ranged from 15,000 to 1,600,000/microl. Surprisingly, 73% of CLL cases involved proliferation of T lymphocytes (CD3+), and 54% of CLL cases had large granular lymphocyte (LGL) morphology. LGL CLL's were almost exclusively proliferation's of T cells that expressed CD8 and the leukointegrin alphaDbeta2 and more frequently expressed T cell receptor (TCR) alphabeta (69%) than TCRgammadelta (31%). The non-LGL T cell CLL cases (19% of CLL) involved proliferation of TCRalphabeta T cells in which no consistent pattern of CD4 or CD8 expression was found. B cell CLL, based on expression of CD2 or CD79a, comprised 26% of canine CLL cases. These results are in marked contrast to people where greater than 95% of CLL cases involve proliferation of B lymphocytes. Thirty eight (38) acute leukemias were also immunophenotyped. The majority (55%) of these leukemias had a phenotype most consistent with a myeloid origin. Acute LGL leukemias were also observed (7/38), although less commonly than the CLL counterpart. CD34 expression was common in acute, non-LGL leukemias of dogs, both myeloid and lymphoid. In some circumstances, it can be difficult to differentiate a reactive (polyclonal) lymphoid proliferation from a neoplastic (monoclonal) one. Therefore, as an adjunct to phenotypic studies, we have developed a polymerase chain reaction (PCR) based test for assessment of clonality in T cell proliferations. The test amplifies the junction of the variable gamma (Vgamma) and joining gamma (Jgamma) gene segments region of the TCR gamma genes. Preliminary data indicates that our test is effective and is capable of differentiating a neoplastic from a reactive lymphoproliferative process.

Animals↗