Effect of adult T-cell leukemia cells on pokeweed mitogen-induced normal B-cell differentiation

Tumor viruses, oncogenes, and human cancer

We review the biology of transforming retroviruses and their relationship to cellular transforming genes (tumor oncogenes). Evidence is discussed for the involvement of a retrovirus in a newly described syndrome, "adult T cell leukemia/lymphoma," which has a high incidence of skin involvement. This virus is related to the animal retroviruses which induce tumors in susceptible hosts after a long latent period. Cellular transforming genes encode proteins which directly change the oncogenic potential of a cell. These genes, which are altered forms of normal cellular genes, have been isolated from a wide variety of human tumors. Viral and cellular transforming genes produce their changes by at least two different mechanisms: abnormally high production of the normal protein encoded by these genes, or normal levels of an altered form of the protein.

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.

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.

Antibody probes in diagnosis and classification of lymphomas

The use of immunohistochemistry is discussed with respect to its role in assisting with the classification and diagnosis of lymphomas. Attention is drawn to methods of achieving optimal tissue fixation and preparation, which are necessary prerequisites for the precise cytochemical demonstration of the various lymphocyte and related cell type markers.

An OKT4+ T-cell population with suppressor activity in Sézary syndrome

This report describes a case of Sézary syndrome with the surface marker phenotype of a mature distinct T-cell subset OKT3+, OKT4+, OKT8-, OKT17+, OKIal-(+). Functional studies indicated that the patient's peripheral blood cells showed a very low proliferative response to non-specific mitogens (phytohaemagglutinin, concanavalin A, pokeweed mitogen) and failed to differentiate into plasma cells in a pokeweed mitogen--immunoglobulin-synthesis-driven system. In coculture with normal cells the leukaemic cells were able to suppress lectin-induced T-cell proliferation and B-cell differentiation in a dose-dependent manner. Suppressor function was not radiosensitive and did not require the presence of the OKT8+ subset for expression. These Sézary cells thus represent a suppressive T-cell subset within the OKT4+ population. This subset may well correspond to the recently described OKT4+, OKT17+ normal suppressor cells. These findings would therefore illustrate a pathological and possibly clonal expansion of a normal OKT4+ suppressor T-cell subset.

Adult T-cell leukemia cells expressing OKT 17 antigen in the activated state

The surface phenotype and the functional activities of leukemic cells from seven patients with adult T-cell leukemia (ATL) were studied using monoclonal antibodies OKT 3, 4 and 8, anti-Tac, and OKT 17. The latter defines the heterogeneity of the activated T4+ T cell subset. In all cases, ATL cells with the typical OKT3-T4+ T8- phenotype expressed OKT 17 antigen. In addition, in five out of the seven cases the fresh ATL cells possessed Tac antigen which is expressed on activated T cells in varying degree. After cultivation with PWM, most populations of ATL cells acquired Tac even in the cases expressing little antigen in uncultured preparations. However the PWM activated ATL cells did not lose OKT 17 antigen. Functional assays showed the suppressor activity of ATL cells on normal B cell differentiation in three out of six cases examined. These results suggest that ATL cells most probably arise from a particular subset characterized by OKT 17 antigen within the activated OKT4+ T cell subset.

Expression of a receptor for sheep erythrocytes by B lymphocytes from a chronic lymphocytic leukemia patient

A patient with a B-cell chronic lymphocytic leukemia, whose lymphocytes also formed rosettes with sheep red cells, is described. The B-cell nature of the malignant lymphocytes was determined by surface marker analysis, and cytochemical and ultrastructural studies. The lymphocyte membrane immunoglobulin (IgG1K) did not have anti-sheep red cell activity and was not responsible for the binding of sheep erythrocytes to the leukemic cells as shown by (i) the failure to inhibit rosette formation with anti-immunoglobulin reagents and (ii) the different sensitivity to proteolysis of the membrane immunoglobulin and the sheep erythrocyte receptor. The malignant lymphocytes expressed a receptor for sheep erythrocytes similar to that of normal T cells since they stained with monoclonal antibodies directed against the sheep red cell receptors. Furthermore these antibodies blocked rosette formation. Endogenous labeling experiments demonstrated that the patient's cells produced IgG both of the membrane and of the secretory type. The latter molecular form was also actively secreted. Ultrastructural studies demonstrated that the malignant clone comprised cells at different maturational stages and with different secretory properties. These findings were confirmed by the analysis of intracytoplasmic acid hydrolases, which are normally expressed at late maturational stages. These data are consistent with the hypothesis that a process of maturation was occurring within the malignant clone.

Epstein-Barr virus-specific antibodies in patients with adult T-cell leukemia (ATL) and healthy ATL virus-carriers

Antibodies to Epstein-Barr virus (EBV)-capsid antigen (VCA), early antigen (EA) and EBV-associated nuclear antigen (EBNA) in the sera of 103 patients with adult T-cell leukemia (ATL) and the sera of 243 age- and sex-matched healthy adults, namely 99 anti-ATLA-positive (antibodies to ATL virus-associated antigen) and 144 anti-ATLA-negative individuals, were determined by indirect immunofluorescence. The anti-VCA titers in the sera from ATL patients were within the range observed in healthy controls. Anti-EA was found in 27% of the sera from ATL patients, but in only 8% of the sera from anti-ATLA-negative healthy controls. Antibodies to EBNA, which were present in almost all healthy adults, were not found in 30% of the sera from ATL patients. Of the sera of anti-ATLA-positive healthy adult donors 11% were negative for EBNA antibody. These results suggest that functional impairment of the T-cell system in most ATL patients, and also to a lesser extent in anti-ATLA-positive adults who might be healthy ATLV-carriers, may cause an unusual immune response of antibodies to EBV-associated antigens.

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.

B-cell function in patients with chronic lymphocytic leukemia

Using a reverse hemolytic protein A plaque assay, spontaneous and pokeweed mitogen (PWM)-induced immunoglobulin (Ig) secretion was determined in peripheral blood from 22 patients with B1-chronic lymphocytic leukemia (CLL), one patient with B2-CLL, and one patient with suppressor T-CLL. Diagnoses were established by cytological and histological criteria as well as several marker analyses. Lymphocytes from B1- and B2-CLL patients were unable to secrete Ig either spontaneously or after PWM stimulation. In T-CLL lymphocytes, spontaneous Ig secretion was suppressed very probably by the OKT-8-positive leukemic population, since, after cultivation with PWM, a normal Ig secretion could be demonstrated which was paralleled by a decrease in the OKT-8-positive cells. Cocultivation experiments with freshly isolated, unseparated lymphocytes from normal subjects and lymphocytes from patients were of no informational value, since isolated normal B-cells alone already showed a high rate of Ig secretion. However, coculture experiments with separated subpopulations after PWM stimulation revealed an intrinsic B-cell defect in lymphocytes from B1-CLL patients, whereas their T-lymphocytes were found to be normal helper cells.

Immunoregulatory properties of childhood leukemias

Investigation of in vitro humoral immune responses and immunoregulatory properties of leukemic cell was carried out in 17 children with acute leukemia prior to therapy. Leukemias were of the non-T, non-B-cell type in 13 patients and of T-cell origin in four. Bone marrow and peripheral blood cells consisted of 24-96% lymphoblasts and were generally deficient in surface Ig-positive cells. Induction of Ig secreting cells in response to pokeweed mitogen was markedly decreased in marrow and peripheral mononuclear cell cultures of leukemic patients. Co-culture of leukemic cells with normal lymphocytes led to marked deviations from the expected Ig secreting-cell response of the cell mixtures. The predominant effect was enhancement, as was the case with eight non-T, non-B-cell and one T-cell leukemia samples. Suppression of the Ig secreting-cell response was observed in only three instances, two with non-T, non-B-cell and one with T-cell leukemia samples. These findings implicate non-T, non-B as well as more differentiated leukemic cells in having the potential for modifying Ig production by B cells.

Proliferation of T gamma-lymphocytes in two patients: clinical features and functional properties of the proliferating cells

Two patients suffering form proliferation of T gamma cells exhibited uncommon clinical features, such as activation of intravascular coagulation after low dose irradiation of the enlarged spleen in one patient and isolated neutropenia in the other patients. While the malignant nature of the disease was doubtless in one patient, cell proliferation in the other patient was more likely reactive. In addition to T cell determinants the proliferating cells expressed a monocytic antigen. They did not suppress B-lymphocyte differentiation into plasma cells. In contrast the proliferating cell, especially in one patient, acted as potent effectors in NK and ADCC using melanoma and MOLT 4 target cells. Erythrophagocytosis by T gamma cells was seen in one patient. The data suggest that subsets of T gamma cells are related to the monocytic lineage and that these cells cen mediate both NKA and ADCC and partly can develop phagocytic activity.

Atypical T lymphoproliferative disorder demonstrating in vitro suppressor and helper characteristics

A patient initially diagnosed on surface marker status as having T cell chronic lymphatic leukaemia (T-CLL) was found to have arthropathy and recurrent pulmonary infarction associated with a high anti-DNA antibody titre. The T cell from this patient, on assessment in an in vitro pokeweed mitogen driven B cell system, demonstrated suppressor and helper characteristics but lacked antibody dependent cellular cytotoxicity (ADCC) activity and natural killer (NK) activity. Using peripheral blood mononuclear cells (PBM) from patients with Hashimoto's thyroiditis and normals, it was shown that the patient's T cells suppressed both IgG and thyroid autoantibody production. Irradiation of the patient's PBM inhibited the suppressor effect and a residual helper effect remained. The patient was treated with systemic steroids for exacerbations of arthropathy which caused a fall in lymphocyte count. After 36 months the DNA binding activity spontaneously improved and the lymphocytosis disappeared. It is indicated that T-cell proliferations demonstrating functional activity must be assessed within the context of any underlying non-haematological clinical and laboratory findings.

Immunoregulation by blasts from null cell and T-cell leukemias: help and suppression of T-cell proliferative responses to mitogens

The immunoregulatory activity of bone marrow leukemic blasts from five patients with null-cell acute lymphoblastic leukemia (ALL) and two children with T-cell ALL was evaluated. Blasts were studied in co-culture for their effects on the proliferative responses of normal allogeneic peripheral blood lymphocytes to phytohemagglutinin. Mitomycin C-treated null cell ALL blasts from two of five children suppressed the proliferative responses of normal responder cells by 80% and 58% whereas those from two other children enhanced the responses by 118% and 31%. T-cell leukemic blasts from one patient with T-cell ALL exhibited helper cell activity (26%) and T-leukemic blasts from the other demonstrated suppressor cell activity (53%). The helper cell activity of leukemic blasts was associated with stimulating capacity of null blasts in one-way mixed lymphocyte reactions. In six of seven cases, incubation of blast cells with concanavalin A (20 microgram/ml) for 48 hours prior to co-culture with responder cells did not result in the generation of significant suppressor cell activity. Our study suggests that leukemic blasts from certain patients with 'null' and T-cell ALL may possess spontaneous helper or suppressor cell immunoregulatory activity. This functional heterogeneity of leukemic blasts may help in subclassifying the ALL.

T-cell function in chronic lymphocytic leukaemia

Fifteen patients with chronic lymphocytic leukaemia (CLL) were studied. The diagnosis was made by a combination of clinical findings, peripheral blood morphology and cell surface markers. The Rai clinical staging (Rai et al, 1975) was used to classify all patients. Serum immunoglobins, B and T cell lymphocytes, TG and TM cell populations were evaluated in all patients before commencing treatment. No correlation was found between clinical staging and the presence or absence of hypogammaglobulinaemia. The ratios of TG to TM cells were abnormal in all patients and this abnormality paralleled the stage of the disease. While there was significant difference in the proliferative responses of highly purified T cells from patients and controls at 1 micrograms and 2 micrograms/ml of Concanavalin A (Con A) (P values = P less than 0.005 and P less than 0.01 respectively). There was no significant difference at dose 5 micrograms/ml. The ability of T cells to suppress allogeneic PBMC responses to Con A was dependent on T cell purification procedures. The significance of the results and the possible role of T cells in the pathogenesis of CLL is discussed.

Suppressor mononuclear cells in giant lymph node hyperplasia and thymoma

The existence of suppressor mononuclear cells were demonstrated in two lymphoproliferative disorders: giant lymph node hyperplasia and thymona. The three patients tested also showed cell-mediated immunodeficiency as expressed in the low number of T cells, negative graft versus host reactions and negative skin tests; the one patient tested with phytohemagglutinin (PHA) and concavalin A (Con A) showed a low response. Suppressor activity was tested with a new experimental model, the local xenogeneic graft versus host reaction. It is proposed that this model be used for testing suppressor activities in other human disorders as well.

Activation of leukemic pro-suppressor cells to become suppressor-effector cells. Influence of cooperating normal T cells

We studied the suppressor activity and surface-membrane antigens of immunoregulatory neoplastic T cells from a child with acute lymphoblastic leukemia and hypogammaglobulinemia. The neoplastic T cells were potent inhibitors of immunoglobulin production by pokeweed-mitogen-stimulated normal B cells when radiosensitive cooperative normal T cells were present. Preculturing the leukemic cells with normal T cells or soluble factors allowed them to mediate suppression without the need for cooperating T cells. While acquiring new functional capabilities, approximately 95 per cent of the leukemic cells displayed an antigen (OKT-3) that is found on mature normal T cells; 77 per cent displayed an antigen (Tac) that is found on normal activated immunoregulatory effector cells but not on thymocytes or circulating T cells that are precursors of these effector cells. The results suggest that a population of leukemic prosuppressor cells can be induced to undergo both functional and antigenic differentiation by the influence of normal T cells.

Neoplasms of immunoregulatory T cells in clinical investigation

Normal T cells play a critical role in the regulation of humoral immune responses by acting as potentiators (helper cells) or inhibitors (suppressor cells) of the process by which B cells differentiate into immunoglobulin-secreting plasma cells. Certain diseases in which malignant T cells appear to retain an immunoregulatory function are characterized by a propensity of a lymphomatous T-cell population to infiltrate skin. Some cutaneous T-cell lymphomas, as well as some T-cell neoplasms without dermatologic involvement, provide a homogeneous supply of T lymphocytes which act as immunoregulators. The availability of neoplastic T cells with immunoregulatory properties could accelerate the serologic and biochemical analysis of the cellular control of normal immunity in man.

Proliferation of T gamma cells with killer-cell activity in two patients with neutropenia and recurrent infections

Two patients with severe granulocytopenia and recurrent infections of the skin and oropharynx had excess T lymphocytes with receptors for the Fc portion of IgG (T gamma cells) in blood and bone marrow. The abnormal T gamma cells killed antibody-sensitized target cells in vitro (killer-cell activity) but did not suppress immunoglobulin production by B lymphocytes (suppressor-cell activity). T gamma lymphocytes from normal persons showed both killer-cell activity and suppressor-cell activity. In the serum of one patient, granulocyte antibodies, possibly of an autoimmune nature, were detected. The clinical picture in conjunction with the hematologic and immunologic findings characterized the disease of both patients as a distinct entity among the chronic lymphoproliferative diseases of T-cell origin.