Interleukin-10 inhibits the in vitro proliferation of human activated leukemic CD5+ B-cells

Understanding the immunodeficiency in chronic lymphocytic leukemia: potential clinical implications

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. Although significant advances have been made in the treatment of CLL in the last decade, it remains incurable. Treatments may be too toxic for some elderly patients, who constitute most of the individuals with this disease, and there remain subgroups of patients for which this therapy has minimal activity. This article summarizes the current understanding of the immune defects in CLL. It also examines the potential clinical implications of these findings.

Serum tumor necrosis factor-α and interleukin-10 levels as markers to predict outcome of patients with chronic lymphocytic leukemia in different risk groups defined by the IGHV mutation status

Tumor necrosis factor (TNF)-α and interleukin (IL)-10 are cytokines involved in the balance between cell-mediated and humoral immunity. We investigated whether serum TNF-α and IL-10 levels have any impact on clinical outcome of patients with chronic lymphocytic leukemia (CLL). TNF-α and IL-10 levels were determined in the serum of 160 CLL patients at the time of diagnosis. The cytokine low-risk group consisted of patients with either TNF-α and IL-10 levels below their medians or those with only one elevated parameter. Both TNF-α and IL-10 levels greater than or equal to their medians defined the cytokine high-risk group. The high-risk patients presented a shorter 3-year treatment-free survival (TFS) than low-risk subjects (15 vs. 69.6 %; p < 0.0001). The high-risk group (p = 0.0002) along with high leukocyte count (p < 0.0001) and unmutated immunoglobulin heavy-chain variable region genes (p < 0.0001) independently predict the risk of progression in patients with Rai stage 0-II. Furthermore, the high-risk group had an independent prognostic impact on shorter TFS both in patients with mutated (24.3 vs. 78.2 %; p < 0.0001) and unmutated (8.2 vs. 49 %; p = 0.004) immunoglobulin heavy-chain variable region genes (IGHV) as compared to the low-risk group. The estimated 5-year overall survival (OS) of high-risk patients was shorter than those in the low-risk group (83.3 vs. 97.1 %; p = 0.003). Multivariate analysis demonstrated the cytokine high-risk group (p = 0.02) followed by Rai stage III-IV (p = 0.048) to be independent factors predicting shorter OS. At diagnosis, TNF-α and IL-10 may predict the outcome of patients with CLL.

Macrophages, rather than T and B cells are principal immunostimulatory target cells of Lycium barbarum L. polysaccharide LBPF4-OL

AIM OF THE STUDY

Lycium barbarum L. is a renowned Yin strengthening agent in traditional Chinese medicine. Lycium barbarum L. polysaccharide-protein complex is well-known for its immunoregulatory and antitumor effects. LBPF4-OL is the glycan part of Lycium barbarum L. polysaccharide-protein complex fraction 4 (LBPF4). LBPF4-OL's active contribution in LBPF4 is still blank. In the study, we enrich the polysaccharide part of Lycium barbarum L. polysaccharide-protein complex, and investigate its immunostimulatory effects on mouse spleen cells, T cells, B cells and macrophages.

MATERIALS AND METHODS

Balb/C mice were used in vitro and in vivo studies. In in vitro study, lymphocyte proliferations were analyzed with (3)H-TdR incorporation method. Miltenyi MicroBeads were used in the purification of lymphocytes. Activation of T and B cells was analyzed by flow cytometry. In order to obtain the peritoneal macrophages, mice were injected i.p. with 1mL of sodium thioglycollate 3 days prior to killing. Spleen cells were stimulated with LBPF4-OL and cytokine concentrations in the supernatants were determined by multiplex bead analysis. In in vivo study, mice were injected i.p. with 1 mL of normal saline or 100 μg/mL LBPF4-OL daily for 6 days. Peritoneal macrophage functions were analyzed by enzyme-linked immunosorbent assay and flow cytometry assay.

RESULTS

Spleen cells and lymphocyte proliferation assay indicated that LBPF4-OL markedly induced the spleen cell proliferation, but could not induce proliferation of purified T and B lymphocytes. Further research revealed that B cell proliferation took place in the presence of activated macrophages or LPS. Multiplex bead analysis showed that LBPF4-OL can obviously induce IL-6, IL-8, IL-10 and TNF-α production of the spleen cells in a concentration-dependent manner. Flow cytometric analysis showed that LBPF4-OL (i.p.) prompts CD86 and MHC-II molecules expression on macrophages. ELISA assay showed that LBPF4-OL can greatly strengthen macrophage releasing of TNF-α and IL-1β.

CONCLUSION

These results suggested that glycan LBPF4-OL plays an important role in the immunopharmacological activity of Lycium barbarum L. polysaccharide-protein complex, and primary mouse macrophages, rather than T and B cells, are the principal target cells of it.

Interleukin-10 mediated autoregulation of murine B-1 B-cells and its role in Borrelia hermsii infection

B cells are typically characterized as positive regulators of the immune response, primarily by producing antibodies. However, recent studies indicate that various subsets of B cells can perform regulatory functions mainly through IL-10 secretion. Here we discovered that peritoneal B-1 (B-1P) cells produce high levels of IL-10 upon stimulation with several Toll-like receptor (TLR) ligands. High levels of IL-10 suppressed B-1P cell proliferation and differentiation response to all TLR ligands studied in an autocrine manner in vitro and in vivo. IL-10 that accumulated in cultures inhibited B-1P cells at second and subsequent cell divisions mainly at the G1/S interphase. IL-10 inhibits TLR induced B-1P cell activation by blocking the classical NF-κB pathway. Co-stimulation with CD40 or BAFF abrogated the IL-10 inhibitory effect on B-1P cells during TLR stimulation. Finally, B-1P cells adoptively transferred from the peritoneal cavity of IL-10^−/− mice showed better clearance of Borrelia hermsii than wild-type B-1P cells. This study described a novel autoregulatory property of B-1P cells mediated by B-1P cell derived IL-10, which may affect the function of B-1P cells in infection and autoimmunity.

Secretion of Cytokines in Breast Cancer Cells: The Molecular Mechanism of Procathepsin D Proliferative Effects

Procathepsin D (pCD) is a major secreted protein in estrogen receptor-positive (ER+) breast cancer cell lines. Several independent studies have documented pronounced mitogenic effect of secreted pCD on cancer tissue-derived cell lines, including those from breast, lung, and prostate cancer. It has also been shown that the proliferative effect of pCD involves both autocrine and paracrine modes of action. Recent studies have suggested that pCD could act as a key paracrine communicator between cancer and stromal cells. We have shown earlier that the proliferative activity of pCD depends on the activation peptide sequence of pCD. The present study casts light on the mechanism by which pCD influences the proliferation of cancer cells expressing the ER. Results described in the current paper clearly show that pCD initiates secretion of cytokines interleukin-4 (IL-4), IL-8, IL-10, IL-13, macrophage inflammatory protein-1beta and (MIP-1beta) from such tumor cells. Secreted cytokines take part in the proliferation of the cancer cells, as proven by selective inhibition using antibodies. In addition, expression of cytokine receptors on tested cell lines corresponded to the effects of individual cytokines. An analogous pattern was also observed for fibroblasts, which, under physiologic conditions, are the cells in closest contact with the tumor tissue and play a role in tumor growth and invasion. Our observations were further supported by coculture experiments that are in agreement. Although very similar in response to addition of pCD, the invasive ER- cells do not secrete cytokines. Together with previous in vivo results, these data point to pCD as one of key molecules for therapeutic attack in breast cancer.

Bone biopsy derived marrow stromal elements rescue chronic lymphocytic leukemia B-cells from spontaneous and drug induced cell death and facilitates an "angiogenic switch"

A novel bone biopsy technique was used to generate a robust stromal cell system to study how stroma modulates CLL B-cell apoptosis and how the leukemic cell-stromal interaction influences secretion of vascular factors. Marrow stromal elements (MSE) rescued CLL B-cells from both spontaneous and drug induced apoptosis, partly due to soluble factors. When CLL B-cells were added to the MSE cultures, a dramatic increase in the secretion of basic fibroblast growth factor and decrease in the secretion of thrombospondin was observed. These results indicate the interaction between CLL B-cells and marrow stromal elements regulates angiogenic switching and may be linked to disease progression.

Expression of soluble CD27 and interleukins-8 and -10 in B-cell chronic lymphocytic leukemia: correlation with disease stage and prognosis

Investigators in this study explored levels of soluble CD27 (sCD27), interleukin (IL)-8, and IL-10 in B-cell chronic lymphocytic leukemia (B-CLL), and the correlation of these levels with disease stage and prognosis. Plasma IL-8, IL-10, and sCD27 levels were assessed with enzyme-linked immunosorbent assay tests in 22 healthy donors and 70 patients with B-CLL (49 men and 21 women). Mean patient age was 61.57 y (range, 44-75 y). Mean healthy donor age was 62.09 y (range, 40-72 y). In the study group, mean values were as follows: plasma IL-8, 284.758 pg/mL (0-1000 pg/mL) plasma IL-10, 26.152 pg/mL (0-100 pg/mL) sCD27, 731.357 U/mL (139.9-1000 U/mL) white blood cell count, 59.9 x 10(9)/L (0.8-250.0 x 10(9)/L) hemoglobin count, 11.2 g/dL (5.0-16.2 g/dL) platelet count, 162.5 x 10(9)/L (29.8-317 x 10(9)/L) B(2) microglobulin (B(2)M) 3350.2 mg/L (274.7-7499.9 mg/L) CD38, 19.5% and lactate dehydrogenase (count, 497.5 U/L (263.0-1507 U/L). Patients represented all Rai stages, with 22.9% at stage 0, 11.4% at stage I, 11.4% at stage II, 41.4% at stage III, and 12.9% at stage IV. Plasma levels of IL-8, IL-10, and sCD27 were correlated between study and control groups; significantly higher IL-8 (P=.001) and sCD27 (P=.000) levels were found, but the IL-10 level was not significant (P=.139). Plasma IL-10 (P=.01) and sCD27 (P=.008) were positively correlated with Rai stage, but IL-8 was not (P=.146). Levels of sCD27 were significantly correlated with values for B2M (P=.000), hemoglobin (P=.028), lactate dehydrogenase (P=.001), CD19 (P=.03), and IL-10 (P=.000). IL-8 was significantly correlated with white blood cell (P=.000) count, and CD38 (P=.001) and CD5 (P=.006) levels. IL-10 was significantly correlated with B(2)M (P=.017), CD19 (P=.000), platelet (P=.002), and CD27 (P=.000). In survival distributions for CD27, IL-8 and IL-10 were found to have more significant relationships for all parameters (P=.0000). In conclusion, the authors suggest that sCD27, IL-8, and IL-10 are more significant prognostic factors for B-CLL when compared with others, and these values should correlate with new prognostic factors (eg, zeta-associated protein-70, mutated/unmutated immunoglobulin variable heavy chain).

Use of interleukin-15 for preparation of adherent NK cells from human peripheral blood: comparison with interleukin-2

To search the possibility of utilizing interleukin-15 (IL-15) in preparation of adherent human natural killer (A-NK) cells, recombinant human IL-15 (rhIL-15) or rhIL-2 (500 u/ml of each cytokine) were added to purified human NK cell culture in 24-well plastic plate. The cytokine-induced adherent ratio was calculated by percentage of A-NK cell in whole NK cells. The cytotoxicity of NK cells (NA- or A-NK cells) was examined by 4-h 51Chromium release assay, the surface markers of NK cells were checked by flow cytometry, and the cytokines were analyzed by reverse transcript (RT)-PCR and ELISA method. RhIL-15-induced adherence of human NK cells into plastic was higher than IL-2 when harvesting the A-NK cells at each hour point from hr 1 to hr 12. IL-15- and IL-2-induced adherent ratio peaked to 36.67% and 27.73% at hr 1, and the IL-15-induced adherent ratio was around two folds higher than IL-2-induced group at hrs 2, 3, 4, 5, 6, 7, and 8. The IL-15 group expanded more rapidly than IL-2 during 2 weeks' culture. IL-15- and IL-2-A-NK cells exerted similar levels of higher cytotoxic potentials. A-NK cells were characterized with phenotypes of CD3(-)CD16(+)CD56(+) (more than 93%) in the presence of IL-2 or IL-15 stimulation. CD54, an intracellular adhesion molecule (ICAM), was also continuously expressed in A-NK cells (more than 85%) induced by each cytokine. Interestingly, IL-15 stimulated relatively low level of expression of CD18, a beta2 integrin molecule related to lymphocyte apoptosis in A-NK cells (11.45%), whereas IL-2 exerted a strong effect on CD18 expression (87.54%). IL-11b was only expressed at A-NK cell induced by IL-2 (49.56%), IL-15 did not exert any stimulating effect on CD11b expression. All A-NK cells expressed high levels of interferon gamma (IFNgamma) after stimulation with IL-2 or IL-15. In contrast to IL-2, IL-15 did not stimulate gene expressions of type 2 cytokines (e.g. IL-4, IL-6, IL-10 and IL-13) in A-NK cells. The results indicate that rhIL15 is possibly a stronger stimulator for A-NK cell preparation by improving adherence and proliferation through inhibiting apoptosis by down-regulating the expression of CD18 and type 2 cytokines.

In vitro production of anti-RBC antibodies and cytokines in chronic lymphocytic leukemia

B-chronic lymphocytic leukemia (B-CLL) patients have a high prevalence of autoimmune phenomena, mainly autoimmune hemolytic anemia (AIHA). Immunoregulatory cytokines play a role in the regulation of both autoimmunity and leukemic B-cell growth. Mitogen-stimulated direct antiglobulin test (MS-DAT) is a recently described test able to disclose latent anti-RBC autoimmunity in AIHA. We investigated the prevalence of anti-RBC autoimmunity by MS-DAT and the pattern of cytokine production by PHA-stimulated whole blood cultures from 69 B-CLL patients and 53 controls. Results showed that anti-RBC IgG values in unstimulated, PHA-, PMA-, and PWM-stimulated cultures were significantly higher in B-CLL patients compared with controls. In B-CLL, the prevalence of anti-RBC autoimmunity was 28.9% by MS-DAT, compared with 4.3% by the standard DAT. Production of IFN-gamma, IL-2, IL-13, TNF-alpha, sCD23, and sCD30 was significantly increased in all B-CLL patients compared with controls, whereas there was no difference in IL-4, IL-6, IL-10, and TGF-beta production. Multivariate analysis showed that IL-4 was significantly increased in MS-DAT-positive compared with -negative patients. Patients with autoantibody positivity displayed greater IFN-gamma production than negative patients. These data are in line with the hypothesis that autoimmune phenomena in B-CLL are associated with an imbalance towards a Th-2-like profile. The elevated prevalence of anti-RBC autoimmunity found by MS-DAT suggests that an underestimated latent autoimmunity exists in B-CLL.

Factor(s) released from irradiated B-CLL cells induce apoptosis in leukemic lymphocytes

Photon irradiation of peripheral blood lymphocytes from 25 patients with untreated B-chronic lymphocytic leukemia (B-CLL) induced an increase in apoptotic response by 270%. No significant increase in apoptosis was observed after irradiation of peripheral blood mononuclear cells from 15 healthy volunteers. Supernatants (sups) derived from irradiated leukemic cells incubated with non-irradiated autologous cells induced a 75% enhancement in number of apoptotic cells, as compared with sups from non-irradiated CLL cells. The level of tumor necrosis factor alpha, a cytokine known to prevent apoptosis, was reduced in the sups of irradiated CLL cells in comparison to that of non-irradiated lymphocytes. The interleukin (IL)-10 level, an IL reported to induce apoptosis, was similar in the sups of irradiated and non-irradiated lymphocytes from B-CLL patients. No change in IL-2 levels was observed. The significance of these findings and the role of factor(s) in the sups of irradiated leukemic lymphocytes as inducers of apoptosis are discussed.

Surface antigen expression in chronic lymphocytic leukemia: clustering analysis, interrelationships and effects of chromosomal abnormalities

Chronic lymphocytic leukemia (CLL) is a phenotypically distinguishable form of B-lymphoid leukemias. The regularity of surface membrane antigen expression patterns, their interrelationships as well as the effects of the three frequent chromosomal aberrations, ie 11q deletion, 13q deletion and trisomy 12, were investigated in 35 classic CLL cases by flow cytometry. The two-way cluster analysis of 31 individual antigens revealed three expression patterns: (1) most cells in most cases positive (CD5, CD19, CD20, CD23, CD27, CD40, CD45, CD45RA); (2) most cells in most cases negative (CD10, CD14, CD34, CD122, CD154, mIgG); and (3) a mixed pattern with a variable number of positive cases and a variable percentage of positive cells in individual cases (CD11c, CD21, CD22, CD25, CD38, CD45RO, CD79b, CD80, CD95, CD124, CD126, CD130, FMC7, mIgD, mIgkappa, mIglambda, mIgM). The expressions of several antigens were strongly interdependent, even when antigens belonged to entirely different gene families. Such antigen pairs were: CD11c/CD21; CD19/CD45; CD19/CD79b; CD22/CD45RA; CD23/Igkappa; CD25/mIgM; CD27/CD45; CD45/CD79b; CD45RA/Igkappa. In contrast, the expression of some antigens was mutually exclusive, the best examples being CD45RA/CD45RO, CD38/CD80 and CD45RA/CD80. Deletion of chromosome arm 11q attenuated expression of splicing variant CD45RA, but enhanced CD45RO expression. In contrast, cases of trisomy 12 were associated with enhanced CD45RA and attenuated CD45RO expression. Similarly, trisomy 12 was associated with enhanced CD27 and mIgkappa expression. The variable levels of signaling surface membrane antigens, their interactions and interference by genetic aberrations are likely to affect the clinical progression and drug response of CLL.

Cell cycle effects of IL-10 on malignant B-1 cells

IL-10 is overexpressed in human chronic lymphocytic leukemia (CLL), and is an autocrine growth factor involved in the development of malignant B1 clones in NZB mice, a murine model for CLL. Antisense IL-10 oligonucleotide treatment induces apoptosis and cell cycle disruption in these cells both in vitro and in vivo. In addition, NZB IL-10 knock-out mice fail to develop the B-1 clones. Dampening of IL-10 protein production via antisense IL-10 oligonucleotide treatment is correlated with decreased p27/Kip1 protein expression which results in increased cyclin D2, cyclin E and cyclin A associated kinase activity. The action of the antisense oligonucleotides is through alterations in cell cycle regulation, resulting in accelerated cell cycle progression, a G2/M block which culminates in apoptosis induction in the malignant cells. This implies that the role of IL-10 as an autocrine growth factor in malignant B-1 cells lies in its ability to inhibit apoptosis induction through the maintenance of sustainable cell cycle progression in malignant cells.

Interleukin-6 and interleukin-10 levels in chronic lymphocytic leukemia: correlation with phenotypic characteristics and outcome

The objective of this study was to examine the correlation between serum interleukin-6 (IL-6) and IL-10 levels and outcome in chronic lymphocytic leukemia (CLL). Serum IL-6 and IL-10 levels were measured by enzyme-linked immunoabsorbent assays from 159 and 151 CLL patients, respectively, and from healthy control subjects (n = 55 [IL-6]; n = 37 [IL-10]). Cytokine levels were correlated with clinical features and survival. Serum IL-6 levels were higher in CLL patients (median, 1.45 pg/mL; range, undetectable to 110 pg/mL) than in control subjects (median, undetectable; range, undetectable to 4. 30 pg/mL) (P <.0001). Serum IL-10 levels were higher in CLL patients (median, 5.04 pg/mL; range, undetectable to 74 pg/mL) than in normal volunteers (median, undetectable; range, undetectable to 13.68 pg/mL) (P <.00001). Assays measuring both Epstein-Barr virus-derived and human IL-10 yielded higher values than assays measuring primarily human IL-10 (P <.05). Patients with elevation of serum IL-6 or IL-10 levels, or both, had worse median and 3-year survival (log rank P <.001) and unfavorable characteristics (prior treatment, elevated beta(2)-microglobulin or lactate dehydrogenase, or Rai stage III or IV). Elevated IL-6 and IL-10 levels were independent prognostic factors for survival when analyzed individually or in combination (Cox regression analysis). However, if beta(2)-microglobulin was incorporated into the analysis, it was selected as an independent prognostic feature, and IL-6/IL-10 were no longer selected. In patients with CLL, serum IL-6 and IL-10 (viral and human) levels are elevated and correlate with adverse disease features and short survival. In multivariate analysis, however, beta(2)-microglobulin is the most important prognostic factor.