S. aureus superantigen protein A expands CD4(+)/CD8(+)/CD19(+)/CD34(+) cells in mice: a potential immunorestorer

Protein A (PA) of Staphylococcus aureus is known for its immunostimulatory, anti-cancer, and anti-toxic properties. The present study revealed that PA stimulates specific immunocytes to act as a potential immunorestorer. It has also been shown that the percentage of various cell types bearing different clusters of differentiation markers, e.g., CD4(+), CD8(+), CD19(+), increases considerably after inoculation with PA. It has also been observed that CD34(+) progenitor cells of bone marrow also increased significantly (P < 0.05) upon PA treatment. PA significantly elevated Th-1 cytokines, e.g., IFN-gamma, TNF-alpha, and IL-1alpha. The increased percentages of CD4(+), CD8(+), CD19(+), CD34(+) cells and elevated cytokine levels in PA treated animals may contribute to the reported anti-tumor, anti-fungal, anti-parasitic, and anti-toxic properties of PA. Since in various diseased conditions and during toxic drug therapy lymphocytes bearing such differentiation markers get suppressed, this type of approach could help in immunorestoration of the host. These findings might help in designing therapeutic approaches toward various diseases which cause immunosuppression.

Lymphocyte subsets in renal transplant recipients during growth hormone therapy

OBJECTIVE

To evaluate the effect of growth hormone treatment on growth, levels of insulin-like growth factor I (IGF-I) and lymphocyte subsets in immunosuppressed renal allograft recipients.

METHODS

18 children (aged 8.0-16.6 years) received growth hormone 1 IU/Kg/week daily for two years. Height, IGF-I levels and in 11/18 patients, lymphocyte subsets were evaluated serially.

RESULTS

Standardized growth velocity increased from -1.0+1.5 to +1.2+2.2 and standardized IGF-I levels from +0.8+1.5 to +3.1+1.1 (1 year) and to +1.4+1.7 (2 years). The total lymphocyte count and the number of T lymphocytes (CD3+) decreased. The decrease was more marked in CD8+ (from 1.5+0.3 x10(9)/L to 0.9+0.3 x10(9)/L, 1 year and to 0.8+0.1 x10(9)/L, 2 years) compared to CD4+ (from 1.5+0.3 x10(9)/L to 1.0+0.2 x10(9)/L, 1 year and to 1.3+0.2 x10(9)/L, 2 years), resulting in an increment of the CD4+/CD8+ index.

CONCLUSIONS

The differential effect of growth hormone treatment on CD4+ and CD8+ lymphocytes might be explained by different expression of the IGF-I receptor in these distinct subsets.

Quantitative changes in peripheral blood lymphocytes in erosive rheumatoid arthritis patients treated with methotrexate. Correlation with disease activity

In order to better understand the immunological mechanisms involved in the pathogenesis of rheumatoid arthritis (RA), the level of various lymphocyte subsets in the peripheral blood of 29 patients with erosive RA was determined. All the patients were treated with methotrexate for 2 years. The total number and the proportion of CD3 cells, CD3+CD4+ and CD3+CD8+ cells did not change during the study. The initially increased level of CD19+ B-cells and CD19+CD5+ cells decreased during the treatment. The percentage of CD3-CD16+ natural killer cells was not affected by the treatment. At the inception of the study, we observed a deficiency of CD4+ CD45RA+ cells and the level of CD3+CD29+ cells was slightly increased. During the treatment we noticed significant elevation of CD45RA cells. Consequently, the CD29/CD45RA ratio significantly decreased. We showed significant correlation between changes in disease activity and changes in the level of CD19+ cells and CD4+CD29+ cells. Our results suggest that low-dose methotrexate may affect immunocompetent cells. The lowering in the CD29+ subset population associated with depletion of CD19 B-cells after methotrexate therapy may limit abnormal CD4+ cell activation and reduce the migration of lymphocytes into inflamed synovium.

Mitogenic activity of purified capsular polysaccharide A from Bacteroides fragilis: differential stimulatory effect on mouse and rat lymphocytes in vitro

Bacteroides fragilis, a Gram-negative colonic bacterium, induces the formation of abscesses associated with intra-abdominal sepsis in humans. The singular ability of this organism to modulate abscess formation in experimental rodent models resides in the structurally distinct and ionically charged capsular polysaccharides A (PS A) and B (PS B). The regulation of abscess formation in animals is dependent on T lymphocytes. However, the manner in which PS A interacts with T cells remains unknown. We therefore tested the T cell stimulatory capacity of purified PS A on mouse and rat lymphocytes in cellular proliferation assays and found that the PS A molecule possesses mitogenic characteristics distinguishable from those of the polyclonal B cell activator LPS, the T cell mitogen Con A, and staphylococcal enterotoxin A superantigen. Further, PS A stimulated proliferation of normal mouse and rat lymphocytes differentially. Mouse B cells responded to PS A in a fashion that did not require exogenous APC function, while rat T lymphocyte responses to PS A required APC function derived from autologous or xenogenic feeder cells. Cellular depletion experiments showed that the CD4+ subset of rat spleen cells was the primary responder cell type to PS A in vitro. The differential stimulatory effects of PS A on mouse and rat lymphocytes may reflect its ability to stimulate different lymphocyte subsets in vivo through the activities of receptor/counter-receptor pairs present on responder lymphocytes and cognate APC.

Immunosuppressive effects of dihydroetorphine, a potent narcotic analgesic, in dihydroetorphine-dependent mice

The immunomodulatory effects of dihydroetorphine were systematically investigated in subchronically treated mice. In a dose-dependent fashion, dihydroetorphine (total doses at 444.5, 889 and 1778 microg/kg) lowered the increase of body weight, decreased the weight of the spleen and thymus, weakened the delayed-type hypersensitivity, reduced the generation of antibody-forming cells, inhibited splenic lymphocyte proliferation induced by concanavalin A and lipopolysaccharide, suppressed the production of interleukin-2 in the supernatant of splenocytes induced by concanavalin A, and depleted the ratio of CD4+ and CD8+ subpopulations. Moreover, the physical dependence on dihydroetorphine was also evaluated to confirm that the immunosuppression was concomitant with the addiction to the drug. These results demonstrate that subchronic treatment with dihydroetorphine dose dependently suppresses both humoral and cell-mediated immune function, and that the immunosuppressive effects of dihydroetorphine are much more potent than those of morphine.

Lymphocyte activation and cytokine production by Pisum sativum agglutinin (PSA) in vivo and in vitro

Mice spleen cells were incubated in vitro for 24 h with Pisum sativum agglutinin (PSA). The addition of these supernatants (SN) to macrophage cultures induced the production of nitric oxide (NO) by these cells in a dose-dependent manner. NO release was blocked in the presence of IFN gamma antibodies and partially inhibited by TNF alpha antibodies. The ability of PSA in inducing the production of IFN gamma and TNF alpha by spleen lymphocytes was confirmed assaying these cytokine levels in the SN. Spleen cells stimulated in vitro with PSA were highly activated showing an increased expression of the earlier activation marker, CD69, and a great proliferative response. On the other hand, spleen cells obtained from mice treated with PSA 24 h earlier, did not produce significant levels of IFN gamma or TNF alpha when incubated in vitro and showed a significantly lower proliferation rate when pulsed in vitro with PSA or Concanavalin A (ConA). The lower responsiveness to mitogens was also evident after 48 and 72 h after the treatment in vivo with the lectin. Nevertheless, the flow cytometric analysis of spleen lymphocytes obtained from PSA-treated animals showed a high degree of activation in cells CD3+. There was a decrease in the expression of L-selectin and VLA-4, when compared to controls, in parallel with a significant increase in the expression of CD69 and CD122 (IL-2R) in lymphocytes recovered from PSA-injected animals. The data point to evidence that PSA induces immunomodulatory effects, activating spleen lymphocytes in vivo, which become unresponsive to a second stimulation in vitro.

The effect of intranasal and inhaled corticosteroids in healthy volunteers on the number of circulating lymphocytes and lymphocyte subsets

BACKGROUND

There has been an increasing interest in the potential systemic effects of inhaled corticosteroids.

METHODS

The effect of locally inhaled corticosteroids in the nose and lung on blood lymphocytes was measured in two studies. In the first study, budesonide (BUD) (200 and 800 microg), fluticasone propionate (FP) (200 and 800 microg), and placebo were administered in the nose, and BUD (1600 microg) and FP (1500 microg) were inhaled into the lungs in a blinded, randomized fashion by 12 healthy volunteers. Blood samples were taken before and 4 h after the administration of the drug, and total lymphocyte count and different subpopulations were determined. In the second study, 15 healthy volunteers were randomized to BUD (1600 microg), FP (1600 microg), or placebo inhaled into the lungs. Blood samples were taken before and 4, 8, 24, 48, and 148 h (=7 days) after inhalation of the medication.

RESULTS

Neither the nasal applications nor the inhalation of FP (1500 microg/1600 microg) showed significant differences in total lymphocyte count or different subpopulations between baseline and 4 h after the administration. In both studies, a significant reduction was found in the total lymphocyte count, B cells, T cells, and the CD4+ and the CD8+ fractions 4 h after application of BUD 1600 microg.

CONCLUSIONS

Nasal application of BUD or FP in doses up to 800 microg do not induce lymphopenia. BUD 1600 microg inhalation in the lung reduces lymphocytes and their subfractions. Further studies have to be done to determine whether the results obtained in this study in healthy volunteers will also be found in patients with diseased mucosa and whether there is any correlation with adverse effects such as growth inhibition or osteoporosis.

Effects of single intravenous doses of recombinant human interleukin-10 on subsets of circulating leukocytes in humans

Recombinant human interleukin-10 (rhIL-10) is a potent and specific immunomodulatory agent which inhibits endotoxin-stimulated pro-inflammatory cytokine production by monocytes, blocks T-lymphocyte activation by antigen presenting cells, and modulates T(H)1/T(H)2 balance in immune responses. In previous clinical trials, rhIL-10 administered to healthy volunteers induced rapid and transient elevations of neutrophil and monocyte counts and reductions of lymphocyte counts in addition to suppression of endotoxin-stimulated whole blood cytokine synthesis. We sought to better characterize the effects of rhIL-10 on immunophenotypically defined subsets of circulating leukocytes that could be relevant to its immunomodulatory effects. Healthy volunteers were given single doses of 10 microg/kg rhIL-10 (n = 8) or equivalent placebo (n = 4) by intravenous injection. Significant changes of circulating leukocytes included transiently increased neutrophils and monocytes with parallel increases of CD33+ and CD14+ cells. Total lymphocytes as well as total CD3+, CD3+/CD4+ and CD3+/CD8+ cells transiently decreased. Mean fluorescence intensity of CD11a (integrin alpha-chain subunit of lymphocyte function antigen-1, LFA-1) on lymphocytes transiently but significantly decreased, suggesting a mechanism for transient alteration of lymphocyte trafficking. In addition, mean fluorescence intensity of HLA-DR (major histocompatibility class II) on CD14+ cells (predominantly monocytes) transiently but significantly decreased, implying a possible alteration of antigen presenting function. Further study will be required to elucidate the immunomodulatory roles and potential clinical significance of these hematologic changes in therapeutic trials of rhIL-10 in patients with chronic inflammatory and autoimmune diseases.

Inhibition of natural killer cell activity in mice treated with tobacco specific carcinogen NNK

Among the different chemicals present in tobacco and tobacco smoke, 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK) is the most potent carcinogen. In the present study the immunosuppressive effect of NNK was investigated in laboratory animals by analyzing the antitumor immune responses. Mice of B6C3F1 strain were treated with different doses of NNK by IP and assayed for natural killer cell activity by the lysis of 51Cr-labeled YAC-1 lymphoma cells. The control mice received physiological saline. The results showed a significant inhibition of natural killer cell activity in the spleen cells of mice treated with 100 or 250 mg/kg NNK. In contrast to the high-dose NNK group, treatment of mice with lower doses of NNK like 10 or 50 mg/kg had no significant effect on the natural killer cell activity. In addition to spleen, the natural killer cell activity was also suppressed in the hilar lymph nodes and lung cells of NNK-treated mice. The clearance of 125I labeled YAC-1 tumor cells was also reduced from the lungs of mice injected with NNK. Further, the metastatic potential of B16F10 melanoma cells was significantly higher, as evidenced by the increased lung tumor nodules in the high-dose NNK-treated mice. The decreased antitumor immune response in the carcinogen-treated mice was not due to a decrease of NK cells, because flow cytometric analysis indicated no change in the frequency of NK 1.1+ cells between control and treated animals. However, there was an increased plasma cortisone levels in the carcinogen-treated mice compared to control animals. Injection of mice with poly I:C or interleukin-12 was able to restore natural killer cell activity in the tobacco carcinogen-treated mice.

Dual-color flow cytometric analysis of phenotype, activation marker expression, and proliferation of mitogen-stimulated bovine lymphocyte subsets

Bovine peripheral blood mononuclear cells were cultured in vitro for 3 days with the mitogens concanavalin A (Con A), pokeweed mitogen (PWM), phytohemagglutinin (PHA), and anti-CD3 monoclonal antibody. Activation of T-lymphocyte subsets (CD4+, CD8+, and gammadelta T-cell receptor+) and of B-cells was measured by two-color flow cytometric analysis of subset expression of IL-2 receptor alpha (CD25) and MHC class II. Proliferation of lymphocyte subsets was directly measured by two-color flow cytometric analysis of fluorescence intensity of PKH2, a fluorescent dye that stably incorporates into cell membranes. CD4+ and CD8+ T-cell subsets were stimulated by all the mitogens to increase expression of IL2r and MHC II and to proliferate. Deltagamma+ T-cells responded to all four mitogens with increased IL2r and MHC II expression. Con A and PHA caused measurable proliferation of deltagamma+ T-cells, but PWM and anti-CD3 did not. B-cells generally responded to the mitogens with increased IL2r and MHC II expression. B-cells proliferated when incubated with Con A, but did not measurably proliferate in response to PWM, PHA, or anti-CD3.

The effects of prednisone and azathioprine on circulating immunoglobulin levels and lymphocyte subpopulations in normal dogs

This study investigates serum immunoglobulin (SIg) levels and lymphocyte subpopulations in normal dogs in response to putative immunosuppressive doses of prednisone and/or azathioprine. The objectives were to quantify SIg levels and lymphocyte subpopulations, including Thy-1+, CD4+, CD8+ and B cells, in normal dogs both before and after the administration of prednisone and/or azathioprine at 2 mg/kg, PO, each. Eighteen beagles were divided into 3 groups of 6 dogs each. Blood samples for radial immunodiffusion assay of IgG, IgM and IgA, complete blood count (CBC)and flow cytometry were collected prior to the administration of any drugs and again after 14 d of azathioprine, prednisone or azathioprine and prednisone. Peripheral blood mononuclear cells were isolated using density centrifugation and were incubated with monoclonal antibodies reacting with CD4+, CD8+, Thy-1+ and membrane immunoglobulin. Lymphocyte subsets were quantified using flow cytometry. Azathioprine-treated dogs had no significant changes in SIg levels or lymphocyte subpopulations. Prednisone-treated dogs had significant (P < 0.05) decreases in all SIg levels, all lymphocyte subpopulations and erythrocyte numbers, and had an increase in neutrophil counts. Prednisone and azathioprine-treated dogs had significant (P < 0.05) decreases in serum IgG levels and Thy-1+ and CD8+ lymphocyte subpopulations, with an increase in the CD4:CD8. These dogs also had a significant decrease in erythrocyte number and a significant increase in the monocyte count. These findings suggest that azathioprine and prednisone in combination or prednisone alone may be useful for the treatment of T cell-mediated diseases since decreased circulating T cell levels were demonstrated following treatment. The combination of drugs or azathioprine alone may not be appropriate for treatment of acute or autoantibody-mediated immune disease, because SIg levels were minimally affected by treatment.

Immunological effects of interleukin 12 administered by bolus intravenous injection to patients with cancer

The immunological effects of recombinant human interleukin 12 (rhIL-12) administration were examined during the conduct of a Phase I clinical trial. Forty patients with advanced cancer received bolus i.v. injections of rhIL-12 in doses ranging between 3 and 1000 ng/kg. Dose-dependent increases in serum IFN-gamma levels were seen during rhIL-12 therapy. Significant lymphopenia was observed 24 h after single i.v. injections of rhIL-12 at each dose level. The degree of lymphopenia was dose dependent, and a plateau effect was seen with rhIL-12 doses of 100 ng/kg and higher. Lymphocyte counts reached nadir levels at approximately 10 h after rhIL-12 injection and returned to baseline within 14 days postinjection. Rebound lymphocytosis, as seen after interleukin 2 therapy, was not observed after recovery from rhIL-12-induced lymphopenia. rhIL-12-induced lymphopenia involved all major lymphocyte subsets, although natural killer (NK) cell numbers were the most profoundly affected, and CD4 T-cell numbers were the least affected. CD2, LFA-1, and CD56 were transiently up-regulated on the surface of NK cells exposed to rhIL-12 in vivo. Peripheral blood mononuclear cells obtained from cancer patients before rhIL-12 therapy exhibited defective NK cell cytotoxicity and T-cell-proliferative responses. Peripheral blood mononuclear cells obtained after lymphocyte recovery following the administration of a single 500 ng/kg dose of rhIL-12 displayed augmented NK cell cytolytic activity in four of four patients tested and enhanced T-cell proliferation in three of four patients tested. These studies confirm that doses of rhIL-12 resulting in significant immunological activity can be administered with acceptable toxicity to cancer patients. Furthermore, rhIL-12 therapy can reverse defects in NK cell and T-cell function that are associated with advanced cancer in humans.

Comparison of the effects of various clinically applied mistletoe preparations on peripheral blood leukocytes

The aim of the present study was to compare the biological effects of 12 different clinically applied mistletoe preparations (I, II, III and IV) from the host trees "pinus" (P), "malus" (M), "abies" (A) and "quercus" (Q) on human leukocytes. When the preparations I-P, II-P, III-P and IV-A were added to the whole blood cell cultures of 37 cancer patients (breast cancer, n = 22, colorectal cancer, n = 15) and 34 healthy controls, a significant induction of the cytokines IL-1-beta, IL-2, IL-6, IL-10 and TNF-alpha was found with preparation I-P. A significant induction of IL-1-beta and TNF-alpha was obtained with the preparations II-P and III-P as compared to the nonstimulated control cultures. Induction of IFN-gamma was not found with any preparation. Cytokine induction was comparable in the blood cell cultures of the tumor patients and the healthy controls. When the clinical preparations I-P, I-M, I-Q, II-P, II-M, II-A, III-P, III-M, III-A and IV-P, IV-M, IV-A were tested in cultures of peripheral blood mononuclear cells from 5 healthy donors, differences in the induction of cytokine production and apoptosis were seen after addition of the mistletoe preparations from different host trees. Increased levels of IL-1-beta were found after addition of the preparations I-P and I-M, increased levels of TNF-alpha were measured after addition of preparations I-P and III-A. Induction of apoptosis was most evident with the preparations I-M, I-Q, III-M and IV-A. Neither cytokine induction nor apoptosis could be correlated to the amount of lectins found in the preparations. Stimulation of separated CD4(+)-, CD8(+)- and CD14(+)-cells from 5 healthy donors with the above noted preparations revealed an induction of IL-1-beta and TNF-alpha production by the preparations I-P, I-M and I-Q mainly in monocytes and to a minimal extent in lymphocytes. Also apoptosis was seen mainly in CD14(+)-monocytes. From these results it is concluded that both, apoptosis and cytokine production are induced differentially in leukocyte cultures by clinically applied mistletoe preparations. However, there is no correlation between the biological effects and the lectin content of the various preparations and none of them were comparable with respect to the extent of these effects. Therefore, it may be expected that clinical studies with different preparations are not comparable either.

Long-term treatment with GM-CSF in patients with chronic lymphocytic leukemia and recurrent neutropenic infections

In this prospective study we evaluated the multiple effects of long-term GM-CSF therapy on blood counts, granulocyte functions and disease progression in patients with chronic lymphocytic leukemia (CLL) with chronic neutropenia and recurrent bacterial infections. The treatment duration varied from 2 to 12 weeks. The neutrophil count was raised in all patients, by the median of 6.6-fold. The neutrophil level of 1.0 x 10(9)/l was usually reached after two weeks. The initial dose of GM-CSF was 5 microg/kg/day, and 1-7 microg/kg/day was required to maintain the neutrophil level above 1.0 x 10(9)/l. Granulocyte functions, i.e. chemiluminescence (CL), random migration, and fMLP-stimulated chemotaxis were initially depressed in all patients when compared to healthy controls. GM-CSF enhanced significantly CL even when given at small doses (less than 1 microg/kg/day), even lower than the dose required to promote granulopoiesis. We conclude that GM-CSF is effective in improving CLL associated chronic neutropenia and also enhances impaired granulocyte chemiluminescence. Thus, GM-CSF could be helpful for giving chemotherapy without neutropenic delays and for prophylaxis of infectious complications in CLL patients.

Analysis of peripheral blood leukocytes in patients with cyclosporine A-induced gingival hyperplasia

BACKGROUND

Gingival overgrowth is one of the major adverse effects of the immunosuppressive drug cyclosporine A (CsA). Although several studies have attempted to determine the immunological mechanisms of gingival hyperplasia (GO) due to CsA therapy, the pathogenesis remains unclear. In this study, the distribution of the peripheral blood leukocytes in a group of renal transplant patients undergoing CsA therapy was analyzed and possible correlations of periodontal and pharmacological variables to lymphocyte subpopulations, natural killer cells, and monocytes investigated.

METHODS

Thirty-six patients were classified into 2 groups of 18 each according to the degree of gingival overgrowth. The periodontal evaluation included plaque index (PI), gingival index (GI), gingival overgrowth (GO), calculus index (CI), and probing depth (PD). The pharmacological variables of current doses of the therapeutic serum levels of CsA were investigated. The peripheral blood leukocytes were studied by 2-color flow cytometric analysis using anti-human CD2, CD3, CD4, CD8, CD11b, CD11c, CD16, CD19, HLA-DR, and CD3+HLA-DR+ monoclonal antibodies.

RESULTS

Statistical evaluation revealed that none of the pharmacological variables varied between the 2 groups. Responders (GO >30%) had significantly higher GI, PD, and GO scores compared to nonresponders (GO < or =30%). Of the immunological parameters studied, only CD2 was higher in the responder group. None of the clinical parameters correlated to the immunological values.

CONCLUSIONS

The results of this study may be useful in explaining the underlying mechanisms of drug-induced gingival overgrowth. Several previously unsuspected cells and accessory activation mechanisms for T lymphocytes could play a role in the pathogenesis.

Phase I study of the pharmacokinetics of a radioimmunoconjugate, 90Y-T101, in patients with CD5-expressing leukemia and lymphoma

Ten patients with advanced or refractory CD5-expressing hematologic neoplasms [two with chronic lymphocytic leukemia and eight with cutaneous T-cell lymphoma (CTCL)] were treated in a Phase I study with the radioimmunoconjugate 90Y-T101, which targets CD5+ lymphocytes. Prior imaging studies using 111In-T101 demonstrated uptake in involved lymph nodes and skin in patients with CTCL, and Phase I studies with unmodified T101 demonstrated transient responses. In this study, patients were treated with 5 or 10 mCi of 90Y chelated to T101 via isothiocyanatobenzyl diethylenetriamine pentaacetic acid, along with tracer doses of 111In-T101 for imaging. The biodistribution of the radioimmunoconjugate was determined by measuring 90Y and 111In blood clearance, urine excretion, and accumulation in bone marrow and in involved skin lesions. The intravascular pharmacokinetics of 90Y were predicted by 111In-labeled T101. The greatest differences in biodistribution between 111In and 90Y were in the higher bone accumulation of 90Y and its lower urinary excretion. Imaging studies demonstrated targeting of skin lesions and involved lymph nodes in CTCL patients. The predominant toxicity was bone marrow suppression. Rapid antigenic modulation of CD5 on circulating T and B cells was observed. Recovery of T-cell populations occurred within 2-3 weeks; however, suppression of B-cell populations persisted after 5+ weeks. All CTCL patients developed human antimouse antibody after one cycle and thus were not retreated; one patient with chronic lymphocytic leukemia received a second cycle of therapy. Partial responses occurred in five patients, two with chronic lymphocytic leukemia and three with CTCL. The median response duration was 23 weeks. One CTCL patient who subsequently received electron beam irradiation to a residual lesion is disease-free after 6 years.

Effect of high-dose methylprednisolone and G-CSF treatments on lymphocyte subtypes in neutropenic children with acute lymphoblastic leukemia: a pilot study

Treatment of neutropenia with corticosteroids and hemopoietic growth factors may cause alterations in the immune system. This study investigated and compared the effects of various regimens (HDMP, G-CSF, and G-CSF + HDMP) on total lymphocyte counts and subtypes in neutropenic patients with acute lymphoblastic leukemia. Lymphocyte subtypes were studied just prior to treatment and 1 week later. In the HDMP group, total lymphocyte counts and the numbers of CD3+, CD4+, CD8+, and CD19+ lymphocytes and monocytes increased, while the helper/suppressor lymphocyte ratio decreased. No significant changes were seen in lymphocyte subtypes in the G-CSF and G-CSF + HDMP groups, apart from an increase in total lymphocyte numbers. In the control group there was an increase in the number of CD3+ and CD8+ lymphocytes and a decrease in the helper/suppressor lymphocyte ratio. These results suggest that HDMP has an inducing, rather than a suppressive effect on all lymphocyte subtypes studied.

Decreased nitric oxide-mediated natural killer cell activation in chronic fatigue syndrome

BACKGROUND

L-Arginine (L-Arg), one of the essential amino acids, has been reported to have an immunomodulatory effect. The precise mechanism of the L-Arg-induced natural killer (NK) cell activation remains unresolved,and the effect of L-Arg on NK cells in chronic fatigue syndrome (CFS) patients has not been estimated.

METHODS

NK cell function was evaluated in 20 subjects with CFS and compared with that in 21 healthy individuals.

RESULTS

In healthy control subjects, NK activity was significantly increased after treatment with L-Arg, an NK function enhancer, for 24 h, whereas the same treatment failed to enhance NK activity in the CFS patients. We thus focused on L-Arg metabolism, which involves nitric oxide (NO) production through NO synthase (NOS). The expression of inducible NO synthase (iNOS) transcripts in peripheral blood mononuclear cells was not significantly different between healthy control subjects and CFS patients. The L-Arg-mediated NK cell activation was abolished by addition of NG-monomethyl-L-arginine, an inhibitor for iNOS. Furthermore, incubation with S-nitroso-N-acetyl-penicillamine, an NO donor, stimulated NK activity in healthy control subjects but not in CFS patients.

CONCLUSION

These results demonstrate that the L-Arg-induced activation of NK activity is mediated by NO and that a possible dysfunction exists in the NO-mediated NK cell activation in CFS patients.

Effect of zinc or zinc plus arginine supplementation on antibody titre and lymphocyte subsets after influenza vaccination in elderly subjects: a randomized controlled trial

OBJECTIVE

to evaluate whether oral supplementation with zinc or zinc/arginine increases the antibody response to influenza vaccine or modulates the lymphocyte phenotype in elderly subjects.

DESIGN

a randomized controlled trial with two supplemented groups and one control group.

SETTING

a community nursing home.

PARTICIPANTS

384 subjects aged 64-100 (mean age 82 years) examined in three separate studies.

INTERVENTION

oral supplementation with zinc (400 mg/day) or zinc plus arginine (4 g/day) for 60 days starting 15 days before influenza vaccination. The control groups received vaccine only.

MEASUREMENTS

haematological and nutritional indices, antibody titre against influenza viral antigens, lymphocyte phenotype.

RESULTS

supplementation with zinc or zinc plus arginine increased zinc plasma concentrations restoring the age-related impairment in zinc concentrations to values found in younger people. The antibody titre against influenza viral antigens was not increased in zinc or zinc/arginine supplemented groups in comparison with subjects receiving vaccine alone. The number of CD3, CD4 or CD8 lymphocytes was not affected by zinc or zinc/arginine supplementation.

CONCLUSION

prolonged supplementation with zinc or zinc/arginine restores zinc plasma concentrations but is ineffective in inducing or ameliorating the antibody response after influenza vaccination in elderly subjects.

Bone marrow-derived dendritic cells pulsed with a tumor-specific peptide elicit effective anti-tumor immunity against intracranial neoplasms

Although the central nervous system (CNS) is often regarded as an immunologically privileged site, it is well established that specific CNS immunoreactivity can be generated through peripheral vaccination with CNS antigens. Dendritic cells (DC) are potent antigen presenting cells of hematopoietic origin that have emerged as a promising tool for cancer immunotherapy capable of evoking significant anti-tumor immunity when pulsed with tumor-associated peptides. To explore a role for DC-based immunization strategies for the treatment of CNS tumors, we developed a brain tumor model using the C3 sarcoma cell line which expresses the tumor-specific, major histocompatibility complex (MHC) class I-restricted peptide epitope E7(49-57). Syngeneic C57Bl/6 mice receiving intravenous (i.v.) injections of bone marrow-derived DCs pulsed with E7 peptide were effectively protected against a subsequent intracerebral challenge with C3 tumor cells. More importantly, this systemic immunization strategy was effective in a therapy model as 67% of animals (10 of 15) with established (day 7) intracerebral C3 tumors treated with 3 weekly injections of E7 peptide-pulsed DCs achieved a long-term survival (>90 days) while no control animals survived beyond day 41. In vivo depletion of CD8+ cells, but not CD4+ or asialo-GM1+ cells, abrogated the efficacy of E7 peptide-pulsed DC therapy of established tumors, indicating a pivotal role of specific CD8+ T-cell responses in mediating the anti-tumor effect. Our findings support the hypothesis that effective CNS anti-tumor immunoreactivity can be generated with DC-based tumor vaccines.

N-acetylcysteine does not affect the lymphocyte proliferation and natural killer cell activity responses to exercise

This study evaluated whether N-acetylcysteine (NAC) attenuates the reduced lymphocyte proliferation and natural killer (NK) cell activity responses to exercise in humans. Fourteen oarsmen were double-blind randomized to either NAC (6 g daily for 3 days) or placebo groups. During 6-min "all-out" ergometer rowing, the concentration of lymphocytes in the peripheral blood increased, with no significant difference between NAC and placebo as reflected in lymphocyte subsets: CD4(+), CD8(+), CD16(+), and CD19(+) cells. The phytohemagglutinin-stimulated lymphocyte proliferation decreased from 9,112 +/- 2,865 to 5,851 +/- 1,588 cpm (P < 0.05), but it was not affected by NAC. During exercise, the NK cell activity was elevated from 17 +/- 3 to 38 +/- 4% and it decreased to 7 +/- 1% below the resting value 2 h into recovery. Yet, when evaluated as lytic units per CD16(+) cell, the NK cell activity decreased during and after exercise without a significant effect of NAC. We conclude that NAC does not attenuate the reduction in lymphocyte proliferation and NK cell activity associated with intense exercise.

Effects of environmentally relevant concentrations of 2,3,7,8-TCDD on domestic chicken immune function and CYP450 activity: F1 generation and egg injection studies

Domestic chickens (Gallus gallus) were used as a surrogate species for wild turkey to assess risk from environmental 2,3,7,8-TCDD exposure. Lymphocyte proliferation and CYP450 induction were assessed in adults exposed via i.m. injection, in F1 14-day old hatchlings, in F1 adults (30-weeks old), and in 14-day old hatchlings exposed via yolk sac injections. Hatchlings from injected eggs exhibited a dose-response in lymphocyte proliferation, IgM titers, EROD, and PROD endpoints. Exposed adults showed a significant dose-dependent increase in CYP450 induction. F1 14-day old chicks exhibited a significant dose-dependent suppression of B-cell proliferation and induction of CYP450 enzymes. F1 adult proliferative responses exhibited B-cell suppression, that was not statistically significant. Significant sex-dependent EROD and MROD induction was also observed in F1 adults, indicating mixed-function oxidase imprinting from maternal exposure.

Postnatal exposure to chlorinated dioxins and related chemicals on lymphocyte subsets in Japanese breast-fed infants

Effects of postnatal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on lymphocyte subpopulations were investigated in the peripheral blood of 36 breast-fed Japanese babies. As a result, estimated total intakes of these chemicals in toxic equivalent quantity (TEQ) converted into 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) equivalents from the breast milk positively and negatively correlated with the respective percentages of CD4+ and CD8+ lymphocytes in the blood of breast-fed babies. Consequently, the ratios of CD4+ to CD8+ T cells showed significant increasing tendency with the estimated total TEQ intakes. Therefore, our study suggests that exposure to background levels of the highly toxic organochlorine compounds through the breast milk influences the human neonatal immune system.

Modulation of innate immune functions by intracerebroventricularly applied neuropeptide Y: dose and time dependent effects

Centrally applied neuropeptide Y (NPY) interacts with the autonomic nervous system and the hypothalamo-pituitary-adrenal (HPA) axis activity. Since these physiological systems have been shown to modulate innate immune functions, the effects of intracerebroventricular (i.c.v.) NPY administration on leukocyte subsets in the blood, spleen and intravascular pool of the lung, blood granulocyte chemiluminescence response, and splenic natural killer (NK) cell-mediated lysis were studied in Lewis rats. Concentration-dependent NPY effects were tested at 15 min and 24 h post i.c.v. injection at dosages of 10(-6) M, 10(-9) M, and 10(-12) M. Time dependent effects were investigated at 15 min, 1 h and 24 h after i.c.v. administration of 10(-9) M NPY. Compared to saline controls, an increased number of granulocytes and NK cells in the blood, associated with a decreased granulocyte function and NK cytotoxicity was observed 15 min following NPY infusion. This initial immunosuppression was followed by long lasting stimulatory effects of NPY on the functional capacity of both cell populations when tested at 1 h and 24 h. The dosage of i.c.v. 10(-6) M NPY produced no changes, whilst 10(-9) M produced maximal, and 10(-12) M still significant effects. Results provide evidence that centrally applied NPY influences innate immunity in a dose and time dependent fashion. Cell mobilization from the vascular marginal pool is likely to be an underlying mechanism for the initial immunosuppression.