Effect of alpha-interferon on the immune system of patients with hairy cell leukemia.

The role of in vivo administration of lymphoblastoid alpha-interferon (IFN-alpha) on the immune status of 12 patients with hairy cell leukemia (HCL) was studied. In most cases an increase in T3(CD3), T4(CD4), and T8(CD8) lymphocyte subsets was documented at the same time as hairy cells disappeared from the circulation. This led in most cases to an improved T4/T8 ratio. The effect of treatment with IFN-alpha was particularly evident on the natural killer cell compartment, which is often functionally depressed in HCL at diagnosis. After therapy, a progressive increase in the cytotoxic activity was observed in most patients. This was more evident 6-9 months after commencing treatment. These findings suggest that, in addition to the known clinicohematological effects, IFN-alpha can improve both the T and natural killer compartments in patients with HCL.

In vitro and in vivo susceptibility of human leukemic cells to lymphokine activated killer activity.

The susceptibility of human myeloid and lymphoid leukemic blasts to the lytic action of recombinant interleukin-2 (rIL-2)-generated lymphokine activated killer (LAK) cells was analyzed. With the exception of the K562 cell line, all 9 leukemic cell lines tested were resistant to the natural killer activity of freshly isolated peripheral blood lymphocytes (PBL) from healthy donors but were susceptible to the lytic action of PBL cultured for 3 days in the presence of rIL-2. Of the 32 primary myeloid and lymphoid acute leukemia samples investigated, the great majority were natural killer cell-resistant but were variably sensitive to LAK effectors. Variations in LAK activity were observed according to the donor of PBL, while little or no difference was documented in the capacity to elicit LAK activity of PBL cultured with 100 or 1,000 U of rIL-2/ml. Pretreatment of the leukemic target cells with neuraminidase did not increase substantially their sensitivity to LAK activity. LAK cells generated from the PBL of patients at the onset of the disease or in complete clinicohematological remission lysed Raji cells as efficiently as normal LAK effectors. Finally, LAK cells were capable of abrogating the tumor growth in nude mice of a human leukemic T cell line. These findings demonstrate the susceptibility in vitro and in vivo of human leukemic blasts to the lytic effect of LAK cells and point to a possible clinical exploitment of this new form of adoptive immunotherapy in the management of acute leukemia.

Lymphokine activated killer (LAK) activity in lymphoproliferative disorders.

Lymphokine activated killer (LAK) cells are being considered as a new and promising form of immunotherapy in the management of patients with solid tumours. Few informations are instead available on these cytotoxic effectors in haematological neoplasias. Here we shall discuss the possible role of LAK cells in human leukaemias. Evidence will be provided for a rationale in the clinical exploitment of Interleukin 2 (IL2)/LAK cells in the treatment of acute leukaemia patients, whilst the implication of these cytotoxic populations appears more uncertain in chronic lymphoproliferative disorders.

Lymphokine Activated Killer (LAK) Cells Inhibit the in vitro Growth of Myeloid and Erythroid Progenitor Cells Via the Release of Tumor Necrosis Factor-Alphadagger.

Adoptive immunotherapy with lymphokine-activated killer (LAK) cells induced by Interleukin 2 (IL2) has provided a new and promising strategy for the treatment of cancer patients. The clinical observation of variable degrees of cytopenia(s) in patients with solid tumors treated with LAK cells suggests that IL2-activated effector cells may play a role on the normal progenitor cell compartment. We therefore carried out in vitro studies designed to assess the influence of LAK cells on normal hemopoiesis. LAK cells from different individuals were cultured with enriched normal peripheral blood and bone marrow colony-forming cells at effector: target ratios ranging between 1:1 and 10:1. Both LAK effectors generated from peripheral blood mononuclear non-adherent cells (PBL-LAK) and from sheep erythrocyte rosette-forming cells (RFC-LAK) suppressed in a reproducible manner the growth of CFU-GM and CFU-E from both peripheral blood and bone marrow. This inhibitory effect is dose-dependent, appears to be smaller with LAK cells generated from RFC rather than from unfractionated PBL and is less evident on the early erythroid compartment. In general, the effect is more pronounced when LAK cells are pre-incubated for 18 hours with the target cell populations prior to seeding. Both autologous and allogeneic PBL-LAK inhibit colony formation. The mechanism of killing implicates a release of soluble factor(s) after close cell-to-cell interaction, as only cell-free supernatants produced after pre-incubation of PBL-LAK cells with hemopoietic progenitors give rise to inhibitory effects. The evidence that during this incubation time high levels of Tumor Necrosis Factor-alpha (TNF) are released and that the use of an anti-TNF antibody completely abolishes the inhibitory effect suggests that TNF plays a part in the LAK cell-induced inhibitory activity.

[Pleural effusion in a case of non-Hodgkin's lymphoma: diagnostic use of molecular analysis]. / Versamento pleurico in un linfoma non-Hodgkin: utilizzazione diagnostica delle analisi molecolari.

We describe a case of advanced non-Hodgkin lymphoma which lacked palpable superficial lymph nodes and in which conventional method did not allow a conclusive diagnosis. Recognition of lymphoproliferative disease was made by analysis at the DNA level of the configuration of the immunoglobulin and T-cell receptor gene regions.

Autocrine or paracrine models of cytokine production and utilization in B-cell chronic lymphocytic leukaemia.

The possibility that autocrine or paracrine mechanisms of cytokine production and utilization may take place in patients with B-cell chronic lymphocytic leukaemia (B-CLL) is discussed. In particular, evidence is provided for a likely role of interleukin 2 (IL2) on the neoplastic B-cell compartment. Furthermore, the possibility that tumor necrosis factor (TNF) may also be involved is suggested.

Immunoregulatory T-cell defects in B-cell chronic lymphocytic leukemia: cause or consequence of the disease? The contributory role of decreased availability of interleukin 2 (IL-2).

Several phenotypic and functional defects have been described within the residual T-lymphocyte population of patients with B-cell chronic lymphocytic leukemia (B-CLL), particularly in those in the more advanced stages of the disease. In this study, we review these abnormalities and discuss their possible effects on the course of the illness. Particular emphasis is devoted to the role of interleukin 2 (IL-2) in B-CLL. Evidence is provided that the IL-2 released by B-CLL T-lymphocytes may be utilized by the neoplastic B-cell clone that expresses the IL-2 receptor and that decreased availability of IL-2 may play a contributory role in some of the T-cell defects encountered in B-CLL.

Defective lymphokine-activated killer cell generation and activity in acute leukemia patients with active disease.

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.

Interleukin 2 does not promote the in vitro and in vivo proliferation and growth of human acute leukaemia cells of myeloid and lymphoid origin.

The effect of recombinant interleukin 2 (IL2) on the in vitro and in vivo proliferation and growth of human acute leukaemia cells of both myeloid and lymphoid origin was investigated. In none of the 25 primary samples tested could a continuously in vitro growing cell line be obtained by adding IL2 to the culture medium. Although IL2 induced a proliferative signal in three of the 31 acute leukaemias analysed, the overall 3H-thymidine uptake of the neoplastic cells was significantly reduced (P less than 0.05) in the presence of IL2. The unlikelihood of an important proliferative signal triggered by IL2 was confirmed in a semisolid clonogenic assay, which failed to document an increased colony growth in the 26 samples studied. Furthermore, using a colorimetric assay as a test for cell proliferation and survival, in seven of the 11 fresh acute leukaemia samples tested a 22-40% reduction in viability was observed in the presence of IL2, while in the remaining four, IL2 was ineffective. In order to investigate the effect of IL2 in an in vivo setting, an experimental model in heavily immunosuppressed nu/nu mice was established. In no case did IL2 promote the in vivo proliferation and growth of human myeloid and lymphoid acute leukaemia cells injected in the mice. On the contrary, with seven of the eight leukaemic cell lines which gave rise spontaneously to leukaemic masses, this could be prevented when the mice received locally 300 U of IL2 three times daily for 90 d. IL2 also blocked the growth in vivo of three fresh acute leukaemia samples (two myeloid and one lymphoid). Co-culture experiments using leukaemic cell lines and increasing numbers of normal lymphocytes suggest that the inhibitory effect of IL2 is probably exerted via an indirect mechanism. These findings, coupled to the well-documented ability of IL2 to generate lymphokine activated killer cells cytolytic against leukaemic blasts, further point to the potential role of immunotherapy with IL2 in the management of patients with haematological malignancies.

Lymphokine-activated killer (LAK) cell activity in B and T chronic lymphoid leukemia: defective LAK generation and reduced susceptibility of the leukemic cells to allogeneic and autologous LAK effectors.

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.

Treatment of hairy-cell leukaemia with alpha-interferon (alpha-IFN).

Twenty-three patients with hairy-cell leukaemia (HCL), six of whom were previously splenectomized, were treated with alpha-interferon (alpha-IFN) 3 MU per day for 3-6 months and then with 3 MU three times per week for at least 3 further months. Seven patients (two splenectomized) showed a complete response (CR), 11 patients achieved a partial response (PR) and the remaining five experienced only a minor response (MR). All seven patients who achieved a CR are still in CR after 10-21 months from the onset of the disease. Among the 11 PRs, five showed an increase in the number of circulating hairy cells during the follow-up; they were re-started on alpha-IFN and an improvement of the haematological values was again obtained. One patient who achieved only a MR died after 1 month therapy because of severe infection. Following treatment with alpha-IFN, the improvement or normalization of the peripheral blood counts was paralleled by an improvement of the immunologic surface markers, as determined by monoclonal antibodies, and by an improvement of the response to PHA and of the natural killer activity. These findings, coupled to the mild drug-related toxicity observed, confirm that treatment with alpha-IFN represents a safe and effective therapeutic approach for both splenectomized and non-splenectomized HCL patients.

Lymphokine-activated killer (LAK) cells inhibit the clonogenic growth of human leukemic stem cells.

The effect of lymphokine-activated killer (LAK) cells on the in vitro clonogenic capacity of acute myeloid leukemia (AML) blasts was investigated in a semisolid medium assay. The leukemic clonogenic capacity of 11 AML cases, selected on the basis of their ability to grow in vitro, was highly reduced following overnight preincubation with LAK effectors. The degree of colony inhibition, which ranged between 66% and 98% (mean 83.8% +/- 11.4 SD), was quantitatively greater than by 51Cr release, which gave rise to lytic values between 5% and 65% (mean 43.2% +/- 19.2 SD). The demonstration that the clonogenic inhibition was still induced following a shorter pre-incubation period (4 hours) suggests that the effect is unlikely to be due only to the generation of cytotoxic activity during the incubation time. The possibility that LAK cells may be employed in the management of residual disease is strengthened by the evidence that the clonogenic potential of samples containing as few as 20% and 14.3% leukemic cells could be almost completely abolished by LAK effectors. These findings further point the possible role of adoptive immunotherapy with interleukin 2/LAK cells in the treatment of patients with acute leukemia.