Phenotypic heterogeneity of human T-cell malignancies: demonstration by monoclonal antibodies and cytochemical markers

Deoxyadenosine toxicity in an adenosine deaminase-inhibited human CCRF-CEM T-lymphoblastoid cell line causes cell swelling

The human T-lymphoblastoid cell line CCRF-CEM, pre-treated with 2'-deoxycoformycin, was used as a model for adenosine deaminase deficiency to investigate how 2'-deoxyadenosine exerts its cytotoxic effects. Incubation of these cells with 1 microM or 5 microM deoxyadenosine for 24 and 48 h caused an increase of up to 50% in their modal cell volume as measured by a Coulter Size Distribution Analyzer and this increase in cell volume was accompanied by an increase in their fragility and deformability. The swelling of cells was concomitant with the phosphorylation of deoxyadenosine and its intracellular accumulation as dATP. There was no evidence of osmotic imbalance or of inhibition of the Na+/K(+)-dependent ATPase activity as the intracellular concentrations (and the intracellular:extracellular ratios) of Na+, K+ and Ca2+ were essentially unchanged. Cytochalasin B (20 microM) also caused lymphoblasts to swell over a 6-h period and its effect on cell size was similar to that of either 1 microM or 5 microM deoxyadenosine over 24 or 48 h. Longer time-courses of incubation with cytochalasin B caused severe toxicity leading to the death and lysis of a significant proportion of the cells. Other drugs, such as colchicine, vincristine and vinblastine that are known to affect various components of the cytoskeleton also caused swelling of cells in a concentration- and time-dependent manner but there was no evidence that these effects were additive or synergistic with those of deoxyadenosine. Inhibition of DNA synthesis, either directly by aphidicolin or indirectly by hydroxyurea, was less cytotoxic than the effect caused by deoxyadenosine. We conclude that one of the toxic effects resulting from the excessive phosphorylation of deoxyadenosine and its accumulation as dATP in human T-lymphoblasts is not dependent on inhibition of DNA synthesis but may be caused by the disruption of the cytoskeleton in these cells.

Correlation between histology and immunophenotype in a series of 322 cases of non-Hodgkin's lymphoma

The non-Hodgkin's lymphomas (NHL) are a heterogeneous group of lymphoid neoplasms displaying a wide variation in cell morphology, histological patterns, immunological phenotype and prognosis. In this paper we compare the results of phenotypic investigation of 322 tissue biopsies with the histology based on the Kiel classification. Immunological analysis revealed that 81 per cent of these tumours were of B cell origin, 12 per cent of T cell origin and the remaining 7 per cent could not be characterized as representing either cell lineage. This last group included a number of cases which had received a histological diagnosis of true histiocytic lymphoma. The original morphological diagnosis, based on routine haematoxylin and eosion sections correlated with the immunologically determined phenotype in 86 and 93 per cent of the T- and B-cell cases respectively. The B cell tumours were phenotypically heterogenous with respect to immunoglobulin (Ig) heavy chain and B lymphocyte subset marker expression. IgG was most often found associated with NHL of cb/cc histology and a small subgroup of lymphocytic NHL. IgA expression was uncommon and occurred in combination with IgD and G in three cases and alone in two cases of NHL. The most common immunoglobulin isotype expressed was IgM this isotype occurred with IgD most often in lymphocytic and centrocytic NHL and less often in tumours of cb/cc histology. Whilst greater than 90 per cent of the lymphocytic NHLs expressed the CD5 antigen, between 20 and 75 per cent of B-cell tumours of other histologies also expressed this epitope. The CD10 antigen and the epitope recognized by the monoclonal reagent FMC7 were widely distributed on tumour cells from all histologies. TdT expression commonly regarded as a marker for immature cells was found in one case of follicle centre cell lymphoma. All cases of T cell NHL displayed marked heterogeneity for both pan T and T subset antigens which is significant in terms of the routine diagnosis of T NHL and with regard to the rational classification of node based T NHL. Unlike resting peripheral blood T cells, MHC class II, OKT 10 and CD25 epitopes were expressed reflecting activation of tumour populations.(ABSTRACT TRUNCATED AT 400 WORDS)

An analysis of morphological, cytochemical, immunological and clinical features of adult T cell acute lymphoblastic leukemia

Morphological, cytochemical, immunological and clinical features of 19 adult patients with T cell acute lymphoblastic leukemia (T-ALL) were investigated at the time of diagnosis and were compared with those of 34 adult patients affected by B cell acute lymphoblastic leukemia (B-ALL). Immunophenotypic studies employing a wide panel of monoclonal antibodies (mAbs) revealed a heterogeneous pattern of antigen expression in the five T-ALL groups that were identified on the basis of blast T cell differentiation levels. PAS (periodic acid Schiff) negativity and focal AP (acid phosphatase) positivity, as well as white blood cell count and serum lactic dehydrogenase levels, were significantly related to T-ALL when compared with B-ALL. On the contrary, no statistically significant difference was demonstrated in the clinical outcome.

Ploidy, proliferative activity, cluster differentiation antigen expression and clinical remission in high-grade non-Hodgkin's lymphoma

Using a large range of monoclonal antibodies to specific cluster differentiation antigens the phenotypes of a series of high-grade non-Hodgkin's lymphomas of B- and T-cell type were investigated. Cell ploidy and proliferative fraction were assessed by fluorescent staining of DNA and flow cytometry and data on the incidence of complete clinical remission were obtained. With the exception of some lymphoblastic lymphomas, high-grade B-cell lymphomas normally expressed the pan B-cell antigens CD19 and CD22 but only immunoblastic lymphomas consistently expressed the pan B marker CD20. Variable, generally weak expression of CD21 was observed whilst CD23 expression was most prevalent in rapidly proliferative cases and in Burkitt's and centroblastic lymphomas. A rapidly proliferative, multilobated B-cell lymphoma displayed phenotypic properties intermediate between centroblastic and immunoblastic lymphomas. The T-cell lymphomas generally showed low proliferative activity and expression of CD4 prevailed over CD8. Most cases also showed CD2 and CD5 positivity with some also showing CD3 and CD7 expression. Patients with rapidly proliferative diploid or DNA aneuploid tumours obtained complete remission more readily than patients with lowly proliferative diploid tumours. An excess of early deaths occurred among T-cell cases.

The arrangement of immunoglobulin and T cell receptor genes in human lymphoproliferative disorders

Immunoglobulin and T cell antigen receptor genes in their germ-line form are organized as discontinuous DNA elements that are joined by recombinations during lymphocyte development. The analysis of immunoglobulin gene structure and arrangement has been of great value in the study of human lymphoid neoplasms. The analysis of rearranged immunoglobulin and T cell receptor genes has been of value in defining the lineage (T or B cell) of neoplasms that were of controversial origin previously, determining the clonality of abnormal lymphocyte proliferations, diagnosing and monitoring the therapy of lymphoid malignancies, determining the state of maturation and the causes for failure of maturation of cells of the B cell series, and providing major insights into the cause of malignant transformation of B and T lymphoid cells. Thus, the application of this molecular genetic approach has great potential for complementing conventional marker analysis, cytogenetics, and histopathology, thus broadening the scientific basis for the classification, diagnosis, and monitoring of the therapy of lymphoid neoplasia.

Phenotypic heterogeneity displayed by T-non Hodgkin's lymphoma (T-NHL) cells dispersed from diagnostic lymph node biopsies

In this communication we present the results of the study of the surface antigen expression of cells dispersed from 19 fresh lymph node biopsies. All cases subsequently received a histological diagnosis of T-cell lymphoma (T-NHL). The monoclonal antibody (Mab) panel employed for surface staining of viable cells contained reagents reactive with the sheep red blood cell receptor (OKT11) and T3-receptor associated determinants (UCHT1, OKT3) and a range of surface antigens found on subsets of T-cells. These antibodies are characterized according to their CD group as allocated by the First and Second Monoclonal Antibody Workshops. Cells were also stained with Mabs reactive with MHC class II subregion products. All 19 cases displayed marked heterogeneity for both pan-T-cell and T-subset antigens. An observation which is significant in terms of the routine diagnosis of T-NHL and with regard to the rational classification of node-based tumours of T-cell origin. Unlike resting peripheral blood T-cells, MHC class II subregion products were expressed on most of the cases examined though Tu22, directed towards a monomorphic determinant of HLA-DQ, stained fewer cells than other antibodies. Aberrant expression of MHC class II on lymphoma cells may reflect the activation of the tumour population.

The human T-cell leukemias: clinical, cytomorphologic, immunophenotypic, and genotypic characteristics

The distribution of the conventional lymphoid cell markers on T lymphocytes and the principal panels of monoclonal antibodies used to recognize distinctive T-lymphocyte-associated differentiation antigens are discussed. These reagents have been used to probe the early and late stages of T-cell differentiation, and a hypothetical schema of T-cell differentiation has been constructed. Application of these reagents to the investigation of neoplastic T cells has resulted in the determination of the subset of origin and the stage of differentiation of the neoplastic cells in T-cell-derived lymphoproliferative malignancies. Recent advances in molecular biology have made possible the Southern blot hybridization analysis of DNA extracted from neoplastic T cells for patterns of T-cell-receptor gene rearrangements. Examination of these patterns in benign and malignant T and non-T cell has provided the basis for the use of T-cell-receptor gene rearrangements as specific genetic markers of T-cell lineage, clonality, and differentiation. These and other advances have resulted in the delineation of a new category of T-cell neoplasia, the adult T-cell leukemia/lymphoma syndrome. They have also demonstrated that the majority of clinically indolent neoplasms composed of large granular lymphocytes in so-called T gamma-lymphoproliferative disease are monoclonal proliferations. Further phenotypic, functional, and genotypic analyses of the T-cell malignancies should provide better understanding of T-lymphocyte differentiation and heterogeneity. Such studies should also lead to better clinicopathologic correlations and greater understanding of the basis for the clinical diversity of the T-cell-derived lymphoproliferative malignancies.

Lymphocyte markers in health and disease

In the 7 years since the last review of lymphocyte markers, written by Tomasi and Stobo, appeared in this journal, there has been a revolution in the diversity and sophistication of immunologic tests directly applicable to investigations of clinical disorders. The promise of such procedures and their allied genetic and monoclonal antibody probes in aiding the classification, early recognition, and therapy of hematologic malignancies, autoimmune disorders, and infectious diseases now is approaching fruition. A synopsis of those assays in vitro and in vivo, together with the primary immune cell subsets they define, is given in Table 12. A grasp of the basic mechanisms underlying them should permit their judicious use, as they are requested either through the clinical laboratory (the initial screen) or as they are complemented by more complex studies obtained through university-affiliated immunology centers (further workup). In this manner, clinically relevant information for the diagnosis and treatment of disorders of immune function will be realized.

Adult T-cell lymphoma leukemia in Western countries

A new T-cell disorder has recently emerged: the so-called adult T-cell lymphoma leukemia (ATLL) initially described in Japan. Subsequently, ATLL cases were recognized in patients from the Caribbean. We summarize the clinical and hematological features of 19 published cases from Western countries, in addition to a new case we encountered. The leukemic cells display characteristic morphological features and a T3+T4+T8-T6- surface antigenic phenotype. Overall survival is of short duration, but remission could be obtained in our case despite a subsequent relapse in skin and CNS. Geographic clusters of ATLL cases have led to the discovery of the possible role of a new retrovirus, HTLV, in the genesis of this rare malignancy.

Reactivity of monoclonal antibodies Leu 1 and OKT1 with malignant human lymphoid cells. Correlation with conventional cell markers

This study delineated the distribution of reactivity of malignant human lymphoid cells with monoclonal antibodies Leu 1 and OKT1, and correlated this expression with that of conventional lymphoid cell markers. The presence of Leu 1 on benign lymph nodal T-cells and its absence from benign lymph nodal B-cells was confirmed. Twenty-two T-cell neoplasms, expressing a variety of intrathymic and mature peripheral phenotypes, expressed Leu 1, but this expression was heterogeneous with respect to percent-positive cells and antigenic density, and appeared to correlate with stages of T-cell differentiation. This study demonstrated the expression of Leu 1 by 33 of 36 cases of B-CLL, by 10 of 15 cases of the closely allied small lymphocytic cell lymphoma, and by 9 of 29 follicular center-cell lymphomas. This included B-cell malignancies of each surface immunoglobulin isotype, and some cases associated with a monoclonal protein spike. Leu 1 was not expressed by myeloma plasma cells, and was absent from non-B, non-T acute lymphoblastic leukemia cells in each of 15 cases studied. Finally, Leu 1 and OKT1 were expressed in parallel, with respect to percent-positive cells and staining intensity, on benign and malignant T-cells, and on malignant B-cells, wherever studied. Possible explanations for this shared antigen are the existence of a minor Leu 1+ B-cell subset, a transformation-associated event, or glycosylation.

Cytochemistry of normal lymphocyte subsets defined by monoclonal antibodies and immunocolloidal gold

The cytochemical reactivities of 3 acid hydrolases, alpha-naphthyl acetate esterase (ANAE), acid phosphatase and beta-glucuronidase were investigated in normal peripheral blood lymphocyte subsets defined by monoclonal antibodies OKT3, 4, 8 and FMC4 (anti-Ia). A combined monoclonal antibody-immunocolloidal gold/cytochemical staining procedure was used to determine enzyme activities and distributions of reaction product in each subset. Cytochemical profiles for each lymphocyte subset were defined. The majority (greater than 85%) of T cells (OKT3+) were positive for all 3 enzymes whereas a minority (less than 40%) of B cells (FMC4+) displayed reactivity. The cytochemical profiles of T helper/inducer (OKT4+) and T suppressor/cytotoxic (OKT8+) cells were not significantly different and corresponded to that observed for OKT3+ cells; thus none of these enzymes can be used to distinguish normal lymphocyte subsets cytochemically. ANAE reactions were further analysed, in the respective subsets, on the basis of dot-like or scattered/diffuse reactivity. The ratios of cells displaying dot-like: scattered/diffuse reactivity, in the respective subsets, were OKT3+, 5.4:1; OKT4+, 8.1:1; OKT8+, 2.4:1; FMC4+, 0.4:1. The cytochemical profiles and ANAE reactivities of T cell subsets identified by monoclonal antibodies differ from those displayed by T cell subsets defined by Fc receptors and confirms that there is little correlation between subsets defined by these two methods.

Routine flow cytometric diagnosis of lymphoproliferative disorders

The results of the analysis of suspected lymphoproliferative disorders using flow cytometry (FACS II) over the past 12 months have been evaluated and assessed with respect to "conventional" microscopical examination. The major advantages in using these methods is the speed, the number of parameters which are capable of measurement, the sensitivity, and the ability to quantitate large numbers of cells for a particular criterion. These qualities have proved extremely helpful in the diagnosis of chronic lymphocytic leukemia, acute lymphoblastic leukemia, lymphoma, and other abnormalities. The combination of flow cytometry and a panel of monoclonal antisera (many of which are available commercially) allows the investigator a system of fine resolution which can confidently identify or characterize an abnormal clone or population of cells. With the increase in advanced flow cytometers, it is suggested that time should be allocated for the routine analysis of possible lymphomas and leukemias to allow quick and accurate evaluations of the disease status.