Heterogeneity of T-CLL defined by monoclonal antibodies in nine patients

T cell malignancy in Richter's syndrome presenting as hyper IgM. Induction and characterization of a novel CD3+, CD4-, CD8+ T cell subset from phytohemagglutinin-stimulated patient's CD3+, CD4+, CD8+ leukemic T cells

A patient is described, having Richter's syndrome and immunodeficiency with hyper IgM, who developed suppressor T cell lymphoma (CD3+, CD4-, CD8+) following untreated helper-suppressor T cell chronic lymphocytic leukemia (CD3+, CD4+, CD8+). The neoplastic T cells in both malignancies expressed interleukin (IL) 2 receptors but were deficient in typical CD2+ and CD5+ pan T antigens. Additionally, a large percentage of malignant lymph node T cells expressed HLA-DR+ activation antigens. In vitro immunoglobulin-production experiments demonstrated that the patient's leukemic blood T cells had an excess helper function for IgM synthesis but a suppressor function for IgG and IgA synthesis by normal B and T cells. The leukemic blood T cells demonstrated a poor response to phytohemagglutinin (PHA). A defect in IL 2 receptor expression was evident in PHA-stimulated leukemic blood T cells. Of interest was the observation that PHA stimulated the induction of a novel CD3+, CD4-, CD8+ T cell subset from patient's CD3+, CD4+, CD8+ leukemic blood T cells. These PHA-induced CD3+, CD4-, CD8+ T cell subsets produced an elevated proliferative response to PHA and concanavalin A, had a helper cell function for IgM synthesis and produced highly elevated amounts of IL 2.

Biology of natural killer cells

Studies of cytotoxicity by human lymphocytes revealed not only that both allogeneic and syngeneic tumor cells were lysed in a non-MHC-restricted fashion, but also that lymphocytes from normal donors were often cytotoxic. Lymphocytes from any healthy donor, as well as peripheral blood and spleen lymphocytes from several experimental animals, in the absence of known or deliberate sensitization, were found to be spontaneously cytotoxic in vitro for some normal fresh cells, most cultured cell lines, immature hematopoietic cells, and tumor cells. This type of nonadaptive, non-MHC-restricted cellmediated cytotoxicity was defined as “natural” cytotoxicity, and the effector cells mediating natural cytotoxicity were functionally defined as natural killer (NK) cells. The existence of NK cells has prompted a reinterpretation of both the studies of specific cytotoxicity against spontaneous human tumors and the theory of immune surveillance, at least in its most restrictive interpretation. Unlike cytotoxic T cells, NK cells cannot be demonstrated to have clonally distributed specificity, restriction for MHC products at the target cell surface, or immunological memory. NK cells cannot yet be formally assigned to a single lineage based on the definitive identification of a stem cell, a distinct anatomical location of maturation, or unique genotypic rearrangements.

Natural killer cell-mediated inhibition of bone marrow colony formation (CFU-GM) in refractory anaemia (preleukaemia): evidence for patient-specific cell populations

The role of peripheral blood mononuclear cells (PB-MNC) on the growth of bone marrow (BM) CFU-GM was investigated in refractory anaemia (RA) patients. Whereas normal donor PB-MNC were found to inhibit autologous day 7 CFU-GM, PB-MNC from RA patients exhibited little modulatory effect on autologous or allogeneic day 7 CFU-GM. In contrast, patient PB-MNC inhibited autologous CFU-GM at day 10 at a time where no significant inhibition was seen in the PB-MNC/RA CFU-GM combination. The identity of the inhibitory cells was investigated using anti-T8+ and anti-N901+ subsets purified by immune-rosette depletion with a panel of monoclonal antibodies. The activity of these subsets was tested on immature myeloid cells enriched for MY7+ cells, and it was found that cells highly enriched for NK cells were responsible for the inhibition. Further support for NK cells as the inhibitory cells was obtained in experiments where a positive correlation between the level of PB NK cytotoxicity against K562 cells and the degree of CFU-GM inhibition was demonstrated. Thus, these data suggest the presence of a specialized subset of NK cells with a capacity to inhibit autologous CFU-GM. Since RA is a potentially premalignant disease, in which a significant number of cases transform into AML, these findings also suggest a physiological role for NK cells in suppression of newly arisen clonogenic cells at least in early stages of the disease.

Unique immunological behaviour of CD8+ (suppressor T cell) leukaemia cells

A patient with chronic lymphocytic leukaemia and elevated serum IgM antibody is described. A multiparameter surface marker analysis of his peripheral blood lymphocytes demonstrated a unique phenotype of OKT3-, OKT11+, E-rosetting+, OKT4-, OKT8+, OKIa1+, OKCLL+, OKDR+, Tac+, characterizing the disease as suppressor (CD8+) T cell chronic lymphocytic leukaemia. Because of the uncommon phenotype and the abnormal serum immunoglobulin pattern, in vitro functional assays were performed that showed decreased mitogenic response to the phytohaemagglutinin, but increased response to concanavalin A. However, these leukaemic T cells demonstrated phytohaemagglutinin-specific suppressor cell activity on normal blood lymphocytes. In vitro functional studies indicated that a defect in the patient's T cells may cause IgM hypergammaglobulinaemia. The regulatory function of the patient's T cells on immunoglobulin synthesis by normal B cells was found to be mediated by a soluble factor secreted from neoplastic T cells.

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.

A unique malignant T-cell lymphoproliferative disorder with neutropenia simulating hairy cell leukemia

The association of neutropenia with an indolent chronic T-suppressor cell lymphoproliferative disorder (LPD) has been well documented. The morphologic features and course suggest that this is a benign disorder. The authors studied a 58-year-old man with a chronic T-cell LPD, splenomegaly, and neutropenia. Chromosomal analysis revealed multiple abnormalities which progressively increased in number as the marrow lymphocytosis became more prominent. Subsequently he developed small bowel infiltration. A splenectomy resulted in only brief improvement in the neutropenia. Immunopathologic examination of the spleen was consistent with a well-differentiated lymphocytic lymphoma of a mature peripheral T-cell type without subset specific markers. Granulocyte-monocyte colony (CFU-GM) formation from the patient's marrow was normal and not augmented by T-cell depletion. Neither the patient's splenic T-cells nor serum suppressed granulopoiesis. In contrast to previous T-LPD with neutropenia whose malignant nature has been questioned, the clinical, cytogenetic, and pathologic features and course in this case indicate a malignant lymphoid process which was effectively treated with chemotherapy. Although the histologic pattern of red pulp involvement simulated hairy cell leukemia, that diagnosis was excluded by this patient's clinical, morphologic, and cytochemical features.

'Supernatural' killer cells

The observation that lymphocytes from healthy individuals, without any known sensitization, could spontaneously lyse tumour target cells in vitro(1,2) was first thought to be an in-vitro artefact. Now the effector cells, known as natural killer (NK) cells, are accepted as a clearly distinct albeit heterogeneous subpopulation of lymphocytes. Yet their lineage remains controversial and despite much interest in the role of NK cells in protection against infection and cancer, their biological significance is far fiom clear(3-5). In this article Gordon Burns and his colleagues discuss recent research on NK cells which has illuminated the diverse effects of lymphokines, expanded knowledge on the mechanisms of cell recognition and killing by cytotoxic effector cells, and illustrated how a variety of leukocytes mediate more than one function - results of general interest to cell biologists.

A case of T-cell chronic lymphocytic leukemia with an unusual phenotype and central nervous system involvement

A case of T-cell chronic lymphocytic leukemia is reported. The leukemic cells had the morphologic features of medium-sized, mature-looking lymphocytes, and had an affinity for the central nervous system. Cytochemically, they were positive for alpha-naphthyl acetate esterase and acid phosphatase. They formed E-rosettes (E+) and reacted with OKT11 but not with OKT3/Leu-4, OKT4/Leu-3, OKT8/Leu-2, or OKM1, and did not possess IgG-Fc receptors (Fc gamma R). Functionally, they did not respond to phytohemagglutinin or concanavalin A, were not natural killer cells or antibody-dependent as well as alloantigen-reactive killer cells. Furthermore, they did not possess a helper or suppressor T-cell function for immunoglobulin synthesis. Results of immunologic studies suggest that the leukemic cells were derived from a normal counterpart of a lymphocyte subset present as a minor component of the peripheral blood, namely an E+, OKT3-, OKM1-, Fc gamma R- subset, the function of which is not yet identified.

A lymphoproliferative disorder of T gamma cells with the phenotype of cytotoxic/suppressor T-cell

A 25-yr-old Japanese male showed unique T gamma cell proliferation different from cases reported previously. His clinical and hematological features were characterized by persistent high fever and the appearance of large lymphocytes with abundant cytoplasm and azurophilic granules in the peripheral blood (11% of the leukocyte differential count) and the ascitic fluid. These lymphocytes showed the ability to bind the Fc portion of IgG and they beared the antigen of cytotoxic/suppressor T-cell defined by monoclonal antibodies. T-cells from this patient suppressed the immunoglobulin production of normal B-cells by pokeweed mitogen, although a polyclonal hypergammaglobulinemia was observed in the serum. Chromosomal abnormality indicated the malignant nature of the proliferating T gamma cells in this patient. The clinical, hematological, and immunological findings characterized the disease of this patient as a distinct entity among the lymphoproliferative disorders of T-cell origin.

Inhibition of bone marrow colony formation by human natural killer cells and by natural killer cell-derived colony-inhibiting activity

Incubation of human peripheral blood lymphocytes with bone marrow cells resulted in significant inhibition of colony formation by committed myeloid and erythroid cells. Using positively selected homogeneous natural killer (NK) cell preparations and lymphocyte subpopulations depleted of or enriched for NK cells, we definitively characterize as NK cells the cells in normal peripheral blood that are responsible for inhibition of bone marrow colony growth. The inhibitory effect of NK cells on hematopoiesis can be mediated by a soluble factor that is produced only by NK cells upon culture with HLA-DR+ hematopoietic cells and with NK-sensitive cell lines. Both NK cells and the NK-produced, colony-inhibiting activity (NK-CIA) are suppressive for allogeneic and autologous bone marrow CFU-GEMM (colony-forming units, granulocyte, erythroid, monocyte, megakaryocyte), CFU-E (CFU, erythroid), and early CFU-GM (CFU, granulocyte, monocyte), but not for either BFU-E (burst-forming units, erythroid) or late CFU-GM. [3H]Thymidine incorporation was inhibited by NK-CIA-containing supernatants in HLA-DR+ but not HLA-DR- bone marrow cell populations stimulated to proliferative by colony-stimulating factor (CSF). These data suggest that the NK cell-mediated inhibitory effect on proliferation and differentiation of hematopoietic precursor cells is mediated in part or completely by the secreted NK-CIA. The concentration of NK-CIA reached in the supernatant of the mixture of NK cell-containing lymphocyte populations with bone marrow cells is sufficient to account for the inhibitory effect mediated by NK cells. Our data support the hypothesis that human NK cells play a major role in the control of hematopoiesis, down-regulating it under conditions in which the NK cells are functionally activated.

Cultured T cells from patients with T cell chronic lymphocytic leukemia demonstrate a normal phenotype

Peripheral blood mononuclear cells from eight patients with the rare T-cell form of chronic lymphocytic leukemia were isolated and cultured with Interleukin-2 (IL-2). In all but one case, cultured T-cells (CTC) were established. Various culture conditions were tested for their effectiveness; feeder layers proved valuable for expanding the cultures to large volumes. The CTC remained IL-2 dependent. Analysis of surface determinants on these CTC showed a polyclonal proliferation of T-cells. The distribution of subset markers in the patients' CTC population had completely changed in comparison to the "fresh" peripheral blood cell population but was similar to CTC initiated from healthy donors. Our data suggest that the patients' few contaminating normal T-lymphocytes expanded in culture, while the malignant cells were unresponsive to IL-2. This conclusion is supported by growth characteristics and morphology of the CTC.

Large granular lymphocyte (LGL) lymphoproliferative diseases: naturally cytotoxic tumors in man and experimental animals

It has recently become clear that in the spleen and blood of both rodents and man that a unique subpopulation of lymphocyte is the mediator of virtually all of the inherent natural killer (NK) and antibody-dependent cell-mediated cytotoxic (ADCC) activity. Because of their large size, eccentric kidney-shaped nucleus and prominent cytoplasmic granules, these cytotoxic cells, termed large granular lymphocytes (LGL), can be readily identified in Geimsa stained cytocentrafuge preparations. Unfortunately, the relatively low numbers of these cells in normal lymphoid tissues has made the detailed analysis of LGL quite difficult. Recently however, a number of investigators have reported both rodent and human leukemias or leukocytosis in which there was an abnormally high number of circulating lymphocytes with either the appearance and/or function of LGL. The present manuscript reviews this literature with an emphasis on the biological and clinical characteristics of this lymphoproliferative disease. Emphasis is also placed on the usefulness of these cells for the detailed analysis of LGL morphology and function.

Chromosome studies in patients with T-CLL chronic lymphocytic leukemia and expansions of granular lymphocytes

Chromosome analyses were carried out in eight patients with lymphoproliferative disorders of mature T and NK cells. Three cases were characterized by an abnormal expansion of granular lymphocytes (GL), one by a lymphoma of GL with leukemic spread, and four by an OKT4-T-CLL. In four patients cytogenetic studies were performed on bone marrow cells; in seven patients peripheral blood lymphocytes were examined by either direct preparations or PHA-stimulated cultures. Six patients displayed a normal karyotype. Two cases belonging to the OKT4-T-CLL group had a chromosome number ranging from 44 to 47, with multiple numerical and structural clonal anomalies. Clonal anomalies could be a feature of patients with the more aggressive clinical course.

Classification of patients with T-cell chronic lymphocytic leukemia and expansions of granular lymphocytes: heterogeneity of Italian cases by a multiparameter analysis

The peripheral blood mononuclear cells (PBMC) from 750 Italian patients with chronic lymphocytic leukemia (CLL) were evaluated in order to detect cases with T-cell expansions. The PBMC of 18 patients (2.4%) were found to be capable of rosetting with sheep red blood cells. Further characterization of these cells with a panel of monoclonal antibodies and other immunological and cytochemical tests led us to tentatively subdivide these 18 patients into three groups. The first one included 6 patients whose cells expressed a T-helper phenotype: they exhibited frequent skin involvement and an aggressive clinical course, and some of the patients in this group demonstrated chromosome abnormalities. On the other hand, group 2 (10 cases with expansions of granular lymphocytes and/or T suppressor-bearing phenotype cells) usually presented with a mild clinical course. These cases did not generally require therapy and a diagnosis of leukemia could not be unequivocally confirmed. Cells from the two remaining patients displayed both B-cell markers and E-rosetting ability, thus belonging to the rare group of false T-cell CLL. In fact, the clinical course and management of the latter cases were similar to those of classical B-CLL disease. In the first and second groups, mechanisms reported to be involved in mature T-cell proliferations (response to interleukin-2, production of interleukin-2 or interferon) were investigated, but the cells under study displayed neither growth ability nor lymphokine production in the above assays. In addition, these cells were negative with the anti-Tac monoclonal antibody that appears to recognize the receptor for interleukin-2. More importantly, none of these patients had serum antibodies to the recently described human T-cell leukemia/lymphoma virus (HTLV), possibly responsible for Japanese and West Indian adult T-cell leukemia (ATL) and for sporadic cases of ATL observed in other countries. Taken together, our results outline some differences between European and ATL patients. Furthermore, the data presented point out the heterogeneity of the disease and emphasize that an immunological classification and, in particular, the detection of a helper phenotype have relevant prognostic and therapeutical importance.

Characterization of two patients with lymphomas of large granular lymphocytes

Two patients with non cutaneous well-differentiated lymphocytic lymphoma with leukemic spread are reported. The large majority of their peripheral blood mononuclear cells (PBMC) formed rosettes with sheep erythrocytes, had receptors for the Fc portion of IgG, and an enzymatic profile of relatively mature T-cells. These cells were morphologically characterized as large granular lymphocytes. Studies with monoclonal antibodies in one of the cases showed an OKT3+, OKT10-, OKT4-, OKT8-, HNK-1-, OKM1+ phenotype, whereas PBMC from the other case were OKT3+, OKT10-, OKT4-, OKT8+, HNK-1+, OKM1-. PBMC from the first patient were able to suppress in vitro B-cell differentiation and were capable of a strong antibody dependent cellular cytotoxicity (ADCC) activity. Natural killer (NK) activity was reduced. Cells from the other patient who was hypogammaglobulinemic, exerted suppressor activity in immunoregulatory assays, and showed ADCC and NK activity. These data support the existence of LGL lymphomas consisting of the proliferation of mature appearing cells capable of functional activity.

Phenotypic and functional characterization of HTLV positive neoplastic T cells cultured with interleukin-2--II. Inhibition of lymphoproliferative responses

T cells from the peripheral blood of a T-cell chronic lymphocytic leukemia (T-CLL) patients, were expanded by culture in the presence of interleukin-2 (IL-2). In contrast to the original leukemic T cells that showed a complete lack of suppressor activity, the proliferating T-CLL cells were extremely potent inhibitors of mitogen, antigen and alloantigen induced lymphoproliferative responses. Compared to the fresh T-CLL cells, the proliferating T-CLL cells showed an enhanced expression of the human T-cell leukemia/lymphoma virus (HTLV) p19 antigen and released type C virus particles into their culture supernatant. A direct involvement of the virus particles in the suppression was however unlikely, since the inhibition was found to be mediated by a soluble inhibitor in the culture supernatant of proliferating T-CLL cells. This inhibitor was very hydrophobic and was inactivated by treatment with trypsin, by heating to 56 degrees C for 2 h and by storage at -70 degrees C for more than 14 weeks. It could be excluded that the suppression of lymphoproliferation was due to competition for IL-2, to toxic effects, to nutrient depletion or to a shift in the kinetics of the target cell responses. Furthermore, it could not be attributed to suppressor inducer activity of the OKT4+ proliferating T-CLL cells, since normal T cells enriched for OKT4+ T cells and depleted for OKT8+ T cells were also inhibited in their proliferation. Since other hemopoietic cell lines, not of OKT4+ T lymphocyte origin, also were suppressed to proliferate, it is concluded that the proliferating T-CLL cells represent a neoplastic T-cell clone that had differentiated into suppressor effector T cells after prolonged culture in the presence of IL-2.

Expanded T gamma cell populations with the morphology of large granular lymphocytes -- I. Immunological, clinical and morphological characterization

Lymphocytes from two patients with T gamma cell proliferations displaying the morphology of large granular lymphocytes (LGL) were characterized in terms of cell marker phenotyping and immunologic functions. In both patients, the lymphocytes were positive for E-R, HuTLA, OKT5, OKT8, OKT11, OKM1, VEP13, Leu1, Leu2a, Lyt2 and Lyt3 and were negative for Tmu, Tar, SIg, BA1, BA2, EM-R, C3d-R, C3b-R, OKT6, OKT9, Leu3a, OKIa1 and TdT. In addition, investigations for T411, T811 and M522 in patient 1 yielded positive results. There were differences in the phenotype of the two patients with regard to the reactions with OKT3, OKT10 and VEP10. While, in patient 1, OKT3 was very pronounced and OKT10 and VEP10 were completely negative, OKT10 and VEP10 were very pronounced in patient 2, whereas OKT3 was positive only in a very small percentage of cells. Though the lymphocytes in both patients were potent effectors of NK and K functions (patient 2 more strongly than patient 1) and a noticeably reduced mitogen response was shown to PHA, Con A and zinc, patient 1 showed a distinct suppression of allogenic and autologous B cell response to transformation into ISC, coinciding with the clinical observation of a hypogammaglobulinemia; neither B cell suppression nor dysgammaglobulinemia was seen in patient 2. The results are discussed with regard to other comparable T gamma proliferations reported in the literature.

Chronic T-cell leukaemias. III. T-colonies, PHA response and correlation with membrane phenotype

The functional capacity of T lymphocytes from 28 cases of chronic T-cell leukaemia--T-CLL, T-PLL, T-LCL and Sézary syndrome--was evaluated in a T-colony forming system and in a PHA response assay. Reduced or absent T-colony growth was observed in 23 cases (82%) while in five the growth was normal. Although a good correlation was generally observed between colony formation and PHA transformation, in a few cases a low PHA response was accompanied by moderate colony growth and vice versa. Characterization of the leukaemic T lymphocytes using monoclonal antibodies (OKT series) indicates that cases with a helper/inducer phenotype (OKT4+) showed moderately reduced or near-normal T-colony numbers, whilst cases with a suppressor/cytotoxic phenotype (OKT8+)--confined to T-CLL in this study--had a very low or absent colony growth. The functional abnormalities reported here suggest that neoplastic T-cells with a helper/inducer phenotype show a low proliferative response in the assay systems used, although expressing mature T-cell characteristics. The low growth observed in T-CLL confirms that cells with a suppressor/cytotoxic phenotype form few T-cell colonies.