Peripheral T-cell lymphoma with unique immunologic features

Abnormal levels of proinflammatory cytokines in serum and monocyte cultures from patients with chronic myeloid leukemia in different stages, and their role in prognosis

Interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), primarily monocyte-derived cytokines, form a group of proinflammatory cytokines with related and overlapping spectra of activities. The role of these cytokines in chronic myeloid leukemia (CML) has been investigated. A distinctive pattern of cytokine secretion has been found in chronic myeloid leukemia in chronic phase (CML-CP), in blastic crisis (CML-BC) and in normal subjects. Serum IL-6 levels in CML-CP and CML-BC were significantly raised compared with normal controls (p = 0.0026 for CML-CP and p = 0.0011 for CML-BC). IL-6 was significantly elevated in blastic crisis of CML (103.5 +/- 20.77 pg ml-1) compared with CML-CP (37.35 +/- 10.88 pg ml-1; p = 0.014). IL-6 serum levels were found to correlate significantly with peripheral blood monocyte counts and bone marrow blast and basophil counts. We have analysed monocyte/macrophage function with respect to their ability to produce IL-1, IL-6 and TNF-alpha, spontaneously as well as in response to LPS, in comparison with normal controls. A direct correlation of IL-6 levels in unstimulated and stimulated cultures with bone marrow blast and basophil counts has been observed. From these results it is inferred that the monocyte function is impaired in CML patients, and the cytokine secretion is deficient. Our limited data suggest that serum IL-6 levels may play an important role as a prognostic marker for CML.

Regulation of interleukin-4 production and cytokine-induced growth potential in peripheral T-cell non-Hodgkin's lymphomas

The malignant cells in tumour tissues produce cytokines/growth factors that may influence tumour growth, tumour immunogenicity and host immune response. We demonstrate that lymph node cell (LNC) purified neoplastic T cells from CD4+ peripheral T-cell lymphoma (CD4+ PTCL) and CD8+ PTCL spontaneously, and after stimulation with anti-CD3, secreted high amounts of interleukin-4 (IL-4) as compared to LNC-purified CD4+ and CD8+ non-malignant T cells. Furthermore, IL-4 was observed to be the most potent cytokine that induced in vitro proliferation and growth of the malignant T cells. Moreover, malignant T-cell-derived IL-4 secretion was augmented by exogeneous recombinant human interferon-gamma (IFN-gamma) and was profoundly inhibited by IL-2. Because IL-4 was shown to be a locally active cytokine with a wide range of immunoregulatory properties, regulation of IL-4 production by IFN-gamma and IL-2 in malignant T cells may be one of the important parameters to be assessed in the design of anticancer-specific immunotherapy. In summary, we report that malignant T cells produce IL-4, a type 2 cytokine (Th2 cell response) that acts as a growth factor and which may play a critical role in PTCL disease mechanism.

Expression of cytokine genes in T cell leukemias

Normal T cells secrete cytokines which have important effects on a wide range of other cells. In the present study, the expression of IL-2, IL-4, IL-5, IL-10 and IFN-gamma was assessed in PBMC from 3 cases of T cell leukemia, using reverse transcription and polymerase chain reaction (RT-PCR). The major difference between the leukemia cases and control PBMC samples was that, without in vitro stimulation, IFN-gamma was much more readily detected in 2 of the leukemia cases. IL-2 and IL-5 mRNA were also detected in 2 of the patients but not in the other samples. IL-4 mRNA was not detected in any unstimulated sample, whereas IL-10 was always present. After polyclonal stimulation in vitro, mRNA for all these cytokines was detected in all samples. Thus cytokine expression, particularly of IFN-gamma, may be more prominent in PBMC from adult T cell leukemia cases than in controls.

Peripheral T-cell lymphomas. Immunoregulatory cytokine (interleukin-2, interleukin-4, and interferon-gamma) abnormalities and autologous mixed lymphocyte reaction

BACKGROUND

Cytokines are the most important secretions of the immune system and have a wide range of immunoregulatory functions in various immune disorders and T-cell malignancy. The authors have determined that characteristic enhanced autologous mixed lymphocyte reaction (AMLR) of the lymph node-derived malignant T-cells from peripheral T-cell lymphomas is a function of the T-cell derived cytokines interleukin (IL)-2, IL-4, and interferon-gamma (IFN-tau).

METHODS

Autologous mixed lymphocyte reaction assay was performed by the standard proliferative response (3H-thymidine incorporation), by culturing autologous lymph node-derived or blood-purified T-cells with autologous blood-purified mitomycin-c treated non-T-cells. The production of IL-2, IL-4, and IFN-tau in the AMLR cultures was determined by bioassay or enzyme immunoassays.

RESULTS

Enhanced IL-2 and IFN-tau but deficient IL-4 production is the most characteristic and unique feature of the augmented AMLR in peripheral T-cell lymphomas.

CONCLUSION

The immunoregulatory aberrations in lymph node-derived malignant T-cells that produce highly elevated IL-2 and IFN-tau but decreased IL-4 during augmented AMLR may play an important role in immune dysfunction in this neoplasm (peripheral T-cell lymphomas).

Circulating levels of cytokines and soluble cytokine receptors in various T-cell malignancies

BACKGROUND

Cytokines, interleukin (IL)-4, IL-6, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), soluble CD23 (sCD23), and soluble IL-2 receptors (sIL-2R) are mediators of inflammation and immune response. Alterations in immune status of patients with various cancers may result in release of cytokines in circulation. The authors measured the circulating levels of IL-4, IL-6, IFN-gamma, TNF-alpha, sCD23, and sIL-2R from patients with T-cell chronic lymphocytic leukemia (T-CLL), T-cell acute lymphoblastic leukemia (T-ALL) and peripheral T-cell lymphoma (PTCL) to determine their importance in these T-cell disorders.

METHODS

IL-4, IL-6, IFN-gamma, TNF-alpha, sCD23, and sIL-2R levels were measured from the serum samples by enzyme-linked immunosorbent assay or bioassay methods.

RESULTS

IL-4 levels were higher only in T-CLL, whereas, IFN-gamma and sIL-2R levels were higher in T-CLL and T-ALL. However, IL-6, TNF-alpha, and sCD23 levels were higher in PTCL.

CONCLUSIONS

T-cell-derived IL-4 and IFN-gamma in T-CLL may act as an autocrine growth factor for proliferation of neoplastic T-cells. The sIL-2R levels in T-CLL, T-ALL, and PTCL are an indication of the degree of T-cell or immune activation due to concomitant immunologic processes in these disorders. However, IL-6, TNF-alpha, and sCD23 levels may contribute to inflammatory response and provide evidence of monocyte/macrophage, T-cell, or B-cell aberrations in PTCL.