ALBERT

Description: Tumor necrosis factor-alpha (TNF) is a cytokine that displays a pleomorphic array of effects on different cell populations. Evidence is presented that TNF may be constitutively produced by B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia (HCL) cells and that it may play a relevant role in these diseases. These conclusions are based on the presence of circulating levels of TNF in the serum of 20 of the 24 patients tested (83.3%), while undetectable values were found in normal sera. The suggestion that the increased serum levels were due to the leukemic cell population is strengthened by the evidence that purified B-CLL and HCL cells may constitutively release variable degrees of TNF. These levels markedly increase after incubation with interferon gamma or phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). The cellular release of TNF by primary B-CLL cells was significantly (P less than .001) higher in B-CLL stage O-I patients compared with stage II-III patients. The demonstration that, in B-cell chronic lymphoproliferative disorders, the pathologic cells may release TNF was further confirmed by the presence of the mRNA for this cytokine in primary and/or in pre-activated cells. Recombinant TNF was capable of inducing a proliferative signal only in a minority of cases (4/24); in most cases it was ineffective, and, in a few, it reduced the degree of proliferation. Furthermore, in costimulatory experiments with interleukin-2 and PHA plus PMA, TNF was ineffective. On the other hand, when primary B-CLL cells were incubated in the presence of an anti-TNF antibody, in 8 of 12 independent experiments a 2- to 15-fold increase in thymidine uptake was documented. Taken together, these results suggest that TNF may play a regulatory role in the progression of the neoplastic clone in B-cell chronic lymphoproliferative disorders and may be implicated in some of the side effects associated with these diseases.

Description: The capacity of T lymphocytes from patients with B cell chronic lymphocytic leukemia (B-CLL) to release interleukin 2 (IL 2) and interferon (IFN)-gamma was assessed following various stimuli. The spontaneous release of IL 2 and IFN-gamma was practically absent both with B-CLL and normal T lymphocytes. By contrast, after stimulation with phytohemagglutinin (PHA) or with PHA plus 12-O- tetradecanoylphorbol-13-acetate, the production of IL 2 and IFN-gamma by B-CLL T lymphocytes was similar to that of normal T lymphocytes, irrespective of the reversed T lymphocyte subset distribution (OKT4/OKT8 ratio) observed in B-CLL. However, the titer of IL 2 was greatly reduced when autologous leukemic B cells were added to the culture system. Unlike IL 2, the presence of leukemic B cells did not affect the titer of IFN-gamma in the culture supernatants. The indication that IL 2 may be adsorbed in vivo by the neoplastic B cells was further confirmed by the demonstration of the IL 2 receptor (revealed by anti-Tac monoclonal antibody) on the leukemic B cells, particularly following mitogenic stimulation, and by the evidence that exogenous IL 2 can be directly absorbed by untreated B-CLL T lymphocytes to release IFN-gamma and IL 2 is preserved, but that IL 2 may be rapidly removed by the neoplastic B-CLL cells, thus contributing to the well-documented T lymphocyte abnormalities present in this disease.

Description: The capacity to generate lymphokine-activated killer (LAK) cells and the susceptibility of the neoplastic cells to both allogeneic and autologous LAK effectors were studied in B and T chronic lymphoproliferative disorders. While in B-cell chronic lymphocytic leukemia (B-CLL) the depressed natural killer function could be restored after a 7-day incubation with recombinant interleukin (IL-2), B-CLL mononuclear cells showed a reduced LAK activity compared with normal LAK cells. Furthermore, in all but 1 of the 20 B-CLL samples tested the leukemic cells were totally resistant to autologous LAK effectors. In most cases the leukemic cells were also resistant to normal allogeneic LAK cells. Competition experiments demonstrated that the patients' LAK cells, as well as normal LAK effectors, were capable of recognizing B-CLL cells, pointing, therefore, to a postbinding cytolytic defect. In hairy cell leukemia (HCL) an overall reduced LAK activity against allogeneic targets was documented, but, at variance from B-CLL, hairy cells were often susceptible to the lytic effect of normal LAK cells, and in half of the cases tested the neoplastic population was also sensitive in an autologous system. Similarly to B- CLL, in the great majority of T chronic lymphoproliferative disorders studied, the pathologic cells were resistant to normal and autologous LAK effectors and a defective LAK generation was found. These results demonstrate that in most B and T chronic leukemias the LAK function is defective and, when inducible, does not appear directed against the leukemic population. The possibility of exploiting an immunotherapeutic approach with IL-2/LAK cells in the management of chronic lymphoproliferative disorders does not gain support by these findings.

Description: The capacity of T lymphocytes from patients with B cell chronic lymphocytic leukemia (B-CLL) to release interleukin 2 (IL 2) and interferon (IFN)-gamma was assessed following various stimuli. The spontaneous release of IL 2 and IFN-gamma was practically absent both with B-CLL and normal T lymphocytes. By contrast, after stimulation with phytohemagglutinin (PHA) or with PHA plus 12-O- tetradecanoylphorbol-13-acetate, the production of IL 2 and IFN-gamma by B-CLL T lymphocytes was similar to that of normal T lymphocytes, irrespective of the reversed T lymphocyte subset distribution (OKT4/OKT8 ratio) observed in B-CLL. However, the titer of IL 2 was greatly reduced when autologous leukemic B cells were added to the culture system. Unlike IL 2, the presence of leukemic B cells did not affect the titer of IFN-gamma in the culture supernatants. The indication that IL 2 may be adsorbed in vivo by the neoplastic B cells was further confirmed by the demonstration of the IL 2 receptor (revealed by anti-Tac monoclonal antibody) on the leukemic B cells, particularly following mitogenic stimulation, and by the evidence that exogenous IL 2 can be directly absorbed by untreated B-CLL T lymphocytes to release IFN-gamma and IL 2 is preserved, but that IL 2 may be rapidly removed by the neoplastic B-CLL cells, thus contributing to the well-documented T lymphocyte abnormalities present in this disease.

Description: The capacity to generate lymphokine-activated killer (LAK) cells and the susceptibility of the neoplastic cells to both allogeneic and autologous LAK effectors were studied in B and T chronic lymphoproliferative disorders. While in B-cell chronic lymphocytic leukemia (B-CLL) the depressed natural killer function could be restored after a 7-day incubation with recombinant interleukin (IL-2), B-CLL mononuclear cells showed a reduced LAK activity compared with normal LAK cells. Furthermore, in all but 1 of the 20 B-CLL samples tested the leukemic cells were totally resistant to autologous LAK effectors. In most cases the leukemic cells were also resistant to normal allogeneic LAK cells. Competition experiments demonstrated that the patients' LAK cells, as well as normal LAK effectors, were capable of recognizing B-CLL cells, pointing, therefore, to a postbinding cytolytic defect. In hairy cell leukemia (HCL) an overall reduced LAK activity against allogeneic targets was documented, but, at variance from B-CLL, hairy cells were often susceptible to the lytic effect of normal LAK cells, and in half of the cases tested the neoplastic population was also sensitive in an autologous system. Similarly to B- CLL, in the great majority of T chronic lymphoproliferative disorders studied, the pathologic cells were resistant to normal and autologous LAK effectors and a defective LAK generation was found. These results demonstrate that in most B and T chronic leukemias the LAK function is defective and, when inducible, does not appear directed against the leukemic population. The possibility of exploiting an immunotherapeutic approach with IL-2/LAK cells in the management of chronic lymphoproliferative disorders does not gain support by these findings.

Description: In 26 myeloid and lymphoid acute leukemia patients at presentation the capacity to generate interleukin-2 (IL-2)-induced lymphokine-activated killer (LAK) cells effective against the natural killer (NK)-resistant Raji cell line, as well as the susceptibility of the blasts to normal peripheral blood (PB) LAK cells and to autologous LAK effectors was analyzed. The overall PB LAK activity against Raji cells was significantly lower in acute leukemia patients compared with normal controls (mean, 1,473 +/- 971 SD LU/10(8) LAK effectors v 3,340 +/- 1,862; P less than .001). The sensitivity of the blasts to autologous LAK cells was also significantly lower than to normal LAK effectors (517 +/- 593 LU/10(8) LAK effectors v 1,304 +/- 1,066; P less than .01). When the data were analyzed independently, four patterns of behavior could be recognized. The relatively largest group (9 of 26) included patients in whom effective LAK cells could be generated against the Raji line, but in whom the blasts were resistant to autologous PB-LAK effectors while being susceptible to normal LAK cells (defective specific LAK activity). In 5 of 26 cases, an incapacity to generate LAK activity against both allogeneic and autologous target cells was observed (defective LAK generation). In six further cases, the blasts were resistant to both allogeneic and autologous LAK populations, though the latter were effective against the Raji line (resistant blasts). The same defects could also be shown with bone marrow-derived LAK cells. Only in six cases did the leukemic blasts appear susceptible to autologous and allogeneic LAK cells. In four patients the analysis could be repeated at remission, and in three a restoration of the LAK function against the primary blasts was recorded. In the 10 cases studied at relapse, the blasts were resistant to autologous LAK effectors in nine and to normal LAK in seven. These data demonstrate that in most acute leukemia patients with active disease, a defect of the LAK machinery, either a deficient generation of LAK cells or the resistance of the blasts to LAK effectors, may be documented, pointing therefore to a possible contributory role of the LAK system in the control of leukemic cell growth. In view of the frequent normalization of the autologous LAK activity at the time of remission, immunotherapy with IL-2/LAK cells should be primarily aimed to patients with minimal residual disease.

Description: In 26 myeloid and lymphoid acute leukemia patients at presentation the capacity to generate interleukin-2 (IL-2)-induced lymphokine-activated killer (LAK) cells effective against the natural killer (NK)-resistant Raji cell line, as well as the susceptibility of the blasts to normal peripheral blood (PB) LAK cells and to autologous LAK effectors was analyzed. The overall PB LAK activity against Raji cells was significantly lower in acute leukemia patients compared with normal controls (mean, 1,473 +/- 971 SD LU/10(8) LAK effectors v 3,340 +/- 1,862; P less than .001). The sensitivity of the blasts to autologous LAK cells was also significantly lower than to normal LAK effectors (517 +/- 593 LU/10(8) LAK effectors v 1,304 +/- 1,066; P less than .01). When the data were analyzed independently, four patterns of behavior could be recognized. The relatively largest group (9 of 26) included patients in whom effective LAK cells could be generated against the Raji line, but in whom the blasts were resistant to autologous PB-LAK effectors while being susceptible to normal LAK cells (defective specific LAK activity). In 5 of 26 cases, an incapacity to generate LAK activity against both allogeneic and autologous target cells was observed (defective LAK generation). In six further cases, the blasts were resistant to both allogeneic and autologous LAK populations, though the latter were effective against the Raji line (resistant blasts). The same defects could also be shown with bone marrow-derived LAK cells. Only in six cases did the leukemic blasts appear susceptible to autologous and allogeneic LAK cells. In four patients the analysis could be repeated at remission, and in three a restoration of the LAK function against the primary blasts was recorded. In the 10 cases studied at relapse, the blasts were resistant to autologous LAK effectors in nine and to normal LAK in seven. These data demonstrate that in most acute leukemia patients with active disease, a defect of the LAK machinery, either a deficient generation of LAK cells or the resistance of the blasts to LAK effectors, may be documented, pointing therefore to a possible contributory role of the LAK system in the control of leukemic cell growth. In view of the frequent normalization of the autologous LAK activity at the time of remission, immunotherapy with IL-2/LAK cells should be primarily aimed to patients with minimal residual disease.

Description: Tumor necrosis factor-alpha (TNF) is a cytokine that displays a pleomorphic array of effects on different cell populations. Evidence is presented that TNF may be constitutively produced by B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia (HCL) cells and that it may play a relevant role in these diseases. These conclusions are based on the presence of circulating levels of TNF in the serum of 20 of the 24 patients tested (83.3%), while undetectable values were found in normal sera. The suggestion that the increased serum levels were due to the leukemic cell population is strengthened by the evidence that purified B-CLL and HCL cells may constitutively release variable degrees of TNF. These levels markedly increase after incubation with interferon gamma or phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). The cellular release of TNF by primary B-CLL cells was significantly (P less than .001) higher in B-CLL stage O-I patients compared with stage II-III patients. The demonstration that, in B-cell chronic lymphoproliferative disorders, the pathologic cells may release TNF was further confirmed by the presence of the mRNA for this cytokine in primary and/or in pre-activated cells. Recombinant TNF was capable of inducing a proliferative signal only in a minority of cases (4/24); in most cases it was ineffective, and, in a few, it reduced the degree of proliferation. Furthermore, in costimulatory experiments with interleukin-2 and PHA plus PMA, TNF was ineffective. On the other hand, when primary B-CLL cells were incubated in the presence of an anti-TNF antibody, in 8 of 12 independent experiments a 2- to 15-fold increase in thymidine uptake was documented. Taken together, these results suggest that TNF may play a regulatory role in the progression of the neoplastic clone in B-cell chronic lymphoproliferative disorders and may be implicated in some of the side effects associated with these diseases.