Docetaxel-induced lymphopenia in patients with solid tumors: a prospective phenotypic analysis.

BACKGROUND: The quantitative abnormalities of the different peripheral blood lymphocyte subsets during docetaxel administration were prospectively studied. METHODS: Forty-six chemotherapy-naive patients with solid tumors were treated with docetaxel either in a 3 weekly (n = 33) or weekly (n = 13) schedule. Twenty patients with central nervous system (CNS) metastatic disease as the first clinical presentation of cancer and 35 patients with metastatic colorectal carcinoma treated with chemotherapy were enrolled as controls. The phenotype of peripheral blood lymphocytes was determined by indirect immunofluorescence using appropriate monoclonal antibodies and fluorescent-activated cell sorter analysis. RESULTS: After the administration of the first docetaxel cycle, the absolute number of peripheral blood lymphocytes (P < 0.005), CD3(+) (P < 0.01), CD4(+) (P < 0.01), CD8(+) (P < 0.01), and CD56(+) (P < 0. 01) but not CD20(+) (P < 0.3) cells was significantly decreased compared with the pretreatment values. Further treatment resulted in a further decrease of these lymphocyte subsets including CD20(+) cells (P < 0.01). Similarly, after the administration of the first weekly dose of docetaxel, the absolute number of total lymphocytes, CD3(+), CD4(+), and CD8(+) cells was decreased. The administration of the second weekly docetaxel dose resulted in a further decrease of CD56(+) (P = 0.012) and CD20(+) (P = 0.007) cells. The administration of either high dose corticosteroids in patients with CNS metastases or an irrelevant chemotherapy (CPT-11/5-FU) did not result in similar abnormalities. The discontinuation of docetaxel was associated with a recovery of CD3(+) and CD4(+) lymphocytes within a 3-month period. Eight (17%) patients developed nonneutropenic infections during docetaxel treatment. CONCLUSIONS: Docetaxel has an important but reversible nonspecific lymphopenic effect that seems to be associated with an increased risk for nonneutropenic infections.

NK cell activity in the presence of IL-12 is a prognostic assay to neoadjuvant chemotherapy in cervical cancer.

OBJECTIVE: Little is known about the impact of neoadjuvant chemotherapy on cell-mediated immunity in patients with advanced cervical cancers. PATIENTS AND METHODS: We have studied 24 patients with advanced cervical cancer submitted to neoadjuvant chemotherapy (CT) using cis-platinum (100 mg/m(2)/cycle) and bleomycin (30 mg/cycle). The cell-mediated immunity parameters available before and after CT were NK cells, CD4(+)/CD28 and CD8(+)/CD28 T-lymphocyte numbers, PBMC cytotoxicity, and modification of this parameter with "in vitro" addition of IL-12. RESULTS: The number of NK cells was higher before CT (P < 0.008) in 13 patients who presented a good clinical response to treatment, compared to 11 patients with a poor clinical response. In addition, PBMC cytotoxicity (P < 0.001), CD4(+) and CD8(+) T-lymphocyte values (P < 0.0047), and CD8(+)/CD28(+) cells were also higher in the group with a good response compared with the group with a poor response. Addition of IL-12 to the medium increased the lytic capacity of PBMC after CT only in the group with a good clinical response (P < 0.05). CONCLUSIONS: NK cell numbers, CD8(+) T-cell levels, and CD8(+)/CD28(+) cell levels can be used as prognostic factors before CT. Our results suggest that patients with a poor response have lower lytic activity per NK cell and are refractory to IL-12 stimulation, probably as a result of the reduced expression of IL-12 receptors or of an intracellular defect in the mechanism of transduction. These observations also provide support for human clinical trials of IL-12 and neoadjuvant CT in patients with cervical cancer.

The significance of timing of FTY720 administration on the immunosuppressive effect to prolong rat skin allograft survival.

FTY720, a potent immunosuppressant, dramatically decreases the number of peripheral blood lymphocytes within a few hours after administration. The current study assessed the significance of timing of FTY720 administration on the immunosuppressive effect to prolong rat skin allograft survival (WKAH donor to F344 recipient). The median survival time of allografts was 7 days in the control recipients. FTY720 (1 mg/kg/day) significantly prolonged allograft survival when administered from days 0 and 3, but failed to exert an immunosuppressive effect when administered from day 4. Intragraft T cells, especially CD8(+) T cells, were markedly increased in number from day 4 to 6, peaking on day 5 in control recipients. FTY720 markedly decreased the number of intragraft CD8(+) T cells on day 5 when administered from days 0 and 3. In recipients administered with FTY720 from day 4, the number of intragraft CD8(+) T cells were only partially decreased on day 5. Intragraft CD8(+) T-cell number in those recipients on day 5 was almost the same as that in control recipients on day 4. In addition, FTY720 did not affect the increase in frequency of CD25(+) cells in the CD8(+) T-cell subset in allografts. It is likely that recipients treated with FTY720 from day 4 reject allografts by intragraft immune responses involved in CD8(+) T cells which had infiltrated before day 4, similar to control recipients. These findings suggest that FTY720 should be administered before increase in T cell infiltration into grafts to inhibit acute allograft rejection.

Disorders in the immune responses of T- and B-cells in mice administered intravenous verotoxin 2.

To obtain a better insight into the pathogenesis of verotoxin-producing Escherichia coli (VTEC)-associated diseases, we explored the effect of verotoxin 2 (VT2) on the immune response in mice. The distribution of lymphocyte phenotypes and the lymphocyte immune response were examined after intravenous administration of VT2 to mice. Among the peripheral lymphocytes and splenocytes of 4-week-old C57BL/6 mice, there was first of all a decrease in T-cells, which began 24 h after intravenous administration of VT2 (50 ng/kg, lethal dose). The CD4+ cell subpopulations of the peripheral blood and spleen were significantly decreased at 24 h, while the B220+ splenocyte subpopulation was markedly decreased at 45 h after VT2 administration. In the thymus, a decrease in CD4+CD8+ cells was predominantly observed near death. Interestingly, in E. coli lipopolysaccharide (LPS)-responder mouse strains (C57BL/6 and C3H/HeN) cotreated with LPS, the susceptibility to VT2 was enhanced, and the increase in B220+ cells induced by LPS alone was suppressed. Furthermore, splenocytes from C57BL/6 mice treated with VT2 (50 ng/kg) 6-24 h earlier reduced LPS-induced proliferative responses to 50-52% of that in control cells, indicating that the effect of VT2 on the immunoresponse seen in vivo may be negatively exerted on the proliferation of the cells. In addition, the number of splenocytes that produced anti-sheep red blood cell antibody was decreased in mice treated with VT2. These results suggest that VTEC infection may eliminate CD4+ and CD8+ T-cells and B-cells by affecting their survival and proliferative responses, leading to reduced antibody production.

Antiviral therapy reduces viral burden but does not prevent thymic involution in young cats infected with feline immunodeficiency virus.

The thymus is a major target organ in human immunodeficiency virus type 1 (HIV-1)-infected children and feline immunodeficiency virus (FIV)-infected young cats (G. A. Dean and N. C. Pedersen, J. Virol. 72:9436-9440, 1998; J. L. Heeney, Immunol. Today 16:515-520, 1995; S. M. Schnittman et al., Proc. Natl. Acad. Sci. USA 87:7727-7731, 1990; T. A. Seemayer et al., Hum. Pathol. 15:469-474, 1984; H.-J. Shuurn et al., Am. J. Pathol. 134:1329-1338, 1989; J. C. Woo et al., J. Virol. 71:8632-8641, 1997; J. C. Woo et al., AIDS Res. Hum. Retrovir. 15:1377-1388, 1999). It is likely that the accelerated disease process in children and cats is due to infection of the thymus during the time when generation of naive T lymphocytes is needed for development of the mature immune system. Zidovudine (ZDV) monotherapy, which is used to prevent and treat perinatal HIV-1 infection (R. Sperling, Infect. Dis. Obstet. Gynecol. 6:197-203, 1998), previously had been shown to reduce viral burden in FIV-infected young cats (K. A. Hayes et al., J. Acquir. Immune Defic. Syndr. 6:127-134, 1993). The purpose of this study was to evaluate the effect of drug-induced reduction of viral burden in the thymus on virus-mediated thymic involution and peripheral blood CD4 decline using FIV-infected cats as a model for pediatric HIV-1 infection. Eight-week-old cats were randomly assigned to uninfected, saline-treated; uninfected, ZDV-treated; FIV-infected, saline-treated; and FIV-infected, ZDV-treated groups. Parameters measured included blood lymphocyte numbers, viral load in blood and thymic tissue, and thymic histopathology. While the viral burden was significantly reduced by ZDV monotherapy in peripheral blood lymphocytes, plasma, and thymus, thymic lesions were similar for the treated and untreated FIV-infected cats. Further, markedly lowering the viral burden did not increase blood CD4 lymphocyte numbers or prevent their decline. The data suggest that an inflammatory process continued in spite of reduced virus replication. These observations imply that reducing virus load and limiting thymic inflammation are separate factors that must be addressed when considering therapeutic strategies aimed at preserving thymic function.

Dynamics of HIV-specific CD8+ T lymphocytes with changes in viral load.The RESTIM and COMET Study Groups.

The influence of HIV burden variations on the frequencies of Ag-specific CD8+ T cell responses was evaluated before and during highly active antiretroviral therapy by analyzing the number, diversity, and function of these cells. The frequencies of HLA-A2-restricted CD8+ PBL binding HLA-A2/HIV-epitope tetramers or producing IFN-gamma were below 1%. A panel of 16 CTL epitopes covering 15 HLA class I molecules in 14 patients allowed us to test 3.8 epitopes/patient and to detect 2.2 +/- 1.8 HIV epitope-specific CD8+ subsets per patient with a median frequency of 0.24% (0.11-4. 79%). During the first month of treatment, viral load rapidly decreased and frequencies of HIV-specific CD8 PBL tripled, eight new HIV specificities appeared of 11 undetectable at entry, while CMV-specific CD8+ PBL also appeared. With efficient HIV load control, all HIV specificities decayed involving a reduction of the CD8+CD27+CD11ahigh HIV-specific effector subset. Virus rebounds triggered by scheduled drug interruptions or transient therapeutic failures induced four patterns of epitope-specific CD8+ lymphocyte dynamics, i.e., peaks or disappearance of preexisting specificities, emergence of new specificities, or lack of changes. The HIV load rebounds mobilized both effector/memory HIV- and CMV-specific CD8+ lymphocytes. Therefore, frequencies of virus-specific CD8 T cells appear to be positively correlated to HIV production in most cases during highly active antiretroviral therapy, but an inverse correlation can also be observed with rapid virus changes that might involve redistribution, sequestration, or expansion of these Ag-specific CD8 T cells. Future strategies of therapeutic interruptions should take into account these various HIV-specific cell dynamics during HIV rebounds.

Soluble granzymes are released during human endotoxemia and in patients with severe infection due to gram-negative bacteria.

Extracellular release of granzymes is considered to reflect the involvement of cytotoxic T lymphocytes and NK cells in various disease states. To obtain insight into granzyme release during bacterial infection, granzyme levels were measured during experimental human endotoxemia and in patients with melioidosis, a severe infection due to gram-negative bacteria. Plasma concentrations of granzyme A (GrA) and GrB increased transiently after endotoxin administration, peaking after 2-6 h. In patients with bacteremic melioidosis, GrA and GrB levels were elevated on admission and remained high during the 72-h study period. In whole blood stimulated with heat-killed Burkholderia pseudomallei, neutralization of tumor necrosis factor, interleukin-12, or interleukin-18 inhibited granzyme secretion, which was independent of interferon-gamma. Stimulation with endotoxin and other gram-negative and gram-positive bacteria also strongly induced the secretion of granzymes, suggesting that granzyme release is a general immune response during bacterial infection. The interaction between the cytokine network and granzymes may play an important immunoregulatory role during bacterial infections.

Acute and subchronic toxicity of sucralose.

The toxicity of sucralose has been evaluated in acute and subchronic toxicity studies. Acute oral toxicity studies in male and female mice and male rats documented no deaths or treatment-related signs at doses of 16g/kg for mice and 10g/kg for rats. Sucralose was administered to male and female rats for 4 and 8 weeks at dietary concentrations of 1.0, 2.5 or 5.0%. Achieved dose ranges (mg/kg/day) for the respective dietary levels were 737-1287, 1865-3218 and 2794-6406. There were no toxicologically significant effects observed at the 1.0% or 2.5% dietary levels. However, decreases in food consumption, body weight gain and selected organ weights and ratios as well as splenic and thymic histopathologic changes occurred in rats administered 5.0% for 4 or 8 weeks. A gavage study wherein doses of 0, 750, 1500 or 3000mg/kg/day were administered to male and female rats for 26 weeks investigated further the observations from the dietary study as well as general subchronic toxicity. The gavage study documented no sucralose-related toxicity. These results implicate the reduced palatability and digestibility of diets containing high concentrations of sucralose seen in the diet study as the cause for the decreased food consumption and other accompanying alterations. Dose selection for chronic toxicity studies in rats took into consideration the effect of high concentrations of sucralose on digestion and food consumption and the limitations that would be imposed on subsequent studies. In male and female dogs, no sucralose-related adverse effects were observed following the dietary administration of 0.3, 1.0 or 3.0% for 12 months achieving doses of approximately 90, 300 and 900mg/kg/day respectively. These studies establish that sucralose is non-toxic in rodents following acute oral administration. The rat no-observed-adverse-effect level ranged between 2.5 and 5.0% following subchronic dietary administration. A 3.0% dietary concentration equivalent to a dose of 900mg/kg/day produced no adverse effects in beagle dogs when fed for 12 months.

Characterization of T cell lines derived from glatiramer-acetate-treated multiple sclerosis patients.

We analyzed the effects of glatiramer acetate (GA) therapy on in vitro proliferative responses and cytokine production by lymphocytes derived from multiple sclerosis patients receiving this therapy. We confirmed that lymphocytes derived from GA naïve patients show a high frequency of response when initially exposed to GA in vitro; this frequency decreased following GA therapy. The frequency of lymphocytes responding to whole MBP stimulation did not change with GA therapy. GA- and MBP-specific T cell lines generated from these patients by repeated cycles of in vitro stimulation did not cross react. Some (23%) whole MBP-reactive T cell lines did cross react with MBP peptide 83-99. The mean levels of interferon (IFN) gamma secretion and the mean ratio of IFN-gamma/IL-5 were lower for GA-reactive cell lines, derived from patients both prior to and during GA therapy, compared to MBP-reactive T cell lines. The proportion of IFN-gamma(+) cells in unfractionated lymphocyte preparations derived from the GA-treated patients did not differ from that found for healthy controls. Our findings indicate that GA-reactive T cell lines derived from GA-treated MS patients continue to show a relative Th2 cytokine bias consistent with a bystander suppressor function. GA treatment is not associated with a cytokine phenotype shift in the total T cell or MBP-reactive T cell populations.

Treatment of chemotherapy-induced leukopenia in a rat model with aqueous extract from Uncaria tomentosa.

The Uncaria tomentosa water extracts (C-Med-100) depleted of indole alkaloids (< 0.05%, w/w) have been shown to induce apoptosis and inhibit proliferation in tumor cells in vitro and to enhance DNA repair, mitogenic response and white blood cells in vivo. In this study, the effect of C-Med-100 in the treatment of chemically induced leukopenia was evaluated in a rat model. W/Fu rats were treated first with doxorubicin (DXR) 2 mg/kg x 3 (i.p. injection at 24 hour-intervals) to induce leukopenia. Twenty-four hours after the last DXR treatment, the rats were daily gavaged with C-Med-100 for 16 consecutive days. As a positive control, Neupogen, a granulocyte colony stimulator was also administered by subcutaneous injection at a dose of 5 and 10 microg/ml for 10 consecutive days. The results showed that both C-Med-100 and Neupogen treatment groups recovered significantly sooner (p < 0.05 by Duncan test) than DXR group. However, the recovery by C-Med-100 treatment was a more natural process than Neupogen because all fractions of white blood cells were proportionally increased while Neupogen mainly elevated the neutrophil cells. These results were also confirmed by microscopic examination of the blood smears. The mechanism of the C-Med-100 effect on WBC is not known but other data showing enhanced effects on DNA repair and immune cell proliferative response support a general immune enhancement.

Clinical and immunologic parameters during thalidomide treatment of lupus erythematosus.

BACKGROUND: Thalidomide is used as an experimental drug for the treatment of chronic inflammatory diseases with an autoimmune or infectious background. The pharmacologic action involves the downregulation of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and inhibition of basic fibroblast growth factor (bFGF)-induced angiogenesis; however, not much is known about thalidomide's effect on immunologic parameters in lupus erythematosus (LE). Method This is an open study of a group of five consecutive systemic lupus erythematosus (SLE) patients treated with thalidomide (100 mg/day) and five consecutive cutaneous LE patients not responsive to conventional therapy. The clinical and immunologic parameters (C-reactive protein, immunoglobulin, and complement serum levels, lymphocyte counts) were investigated during thalidomide treatment for up to 2 years in both patient groups. RESULTS: An increase in the absolute peripheral lymphocyte count was observed beginning after 2 weeks of systemic thalidomide treatment in nine out of 10 LE patients, and remained stable throughout thalidomide treatment. Elevated serum levels of C-reactive protein and titers of autoantibodies to double-stranded (ds) DNA decreased in SLE patients. No significant changes were detected in the serum levels of the complement components C3 and C4 and immunoglobulins in all LE patients. Regression of inflammatory skin lesions and regrowth of hair were recorded. As a side-effect, polyneuropathy was observed in four out of 10 patients, with the earliest onset at 3 weeks of thalidomide treatment. CONCLUSIONS: Thalidomide is a potent anti-inflammatory drug in patients with SLE and cutaneous LE, possibly interacting with the recruitment of lymphocytes. It leads to the regrowth of hair in LE-related alopecia and effluvium. Early symptoms of polyneuropathy should be registered and the drug should be withdrawn. Thalidomide should be restricted to patients who show no response to standard therapeutic regimens and should only be used under strict precautions with regard to its known teratogenic risk.

Growth hormone and markers of immune function in children with renal transplants.

Lymphocyte subsets and T cell activation markers were measured in ten children with renal transplants for up to 1 year before and during their 1st year of recombinant human growth hormone (rhGH) treatment. The number of lymphocytes, helper or cytotoxic T cells or natural killer cells, and the T cell expression of CD25, CD26 and HLA-DR antigens were not altered by rhGH. B cell numbers declined both before and during treatment. There was no difference in lymphocyte subset numbers between children with and without rejection episodes.

Effect of mycophenolate mofetil in heart transplantation.

OBJECTIVE: To study the effect of mycophenolate mofetil (MMF), a new immunosuppressive drug that acts by inhibiting de novo pathways of purine synthesis, and rabbit antithymocyte globulin (RATG) on the lymphocyte subpopulation after heart transplantation. DESIGN: A review of clinical and laboratory records. SETTING: The Montreal Heart Institute. PATIENTS: Thirty-one patients who underwent heart transplantation. In 9 patients, neoral cyclosporine, prednisone and azathioprine were administered (group 1). In 14 patients RATG was added during the first 3 postoperative days (group 2) and in 8 patients RATG and combination immunosuppression was given, but MMF was used instead of azathioprine (group 3). The demographic characteristics of donors and recipients were similar among the 3 groups. MAIN OUTCOME MEASURES: The proportion of CD2, CD4 and CD8 receptor-positive lymphocytes, expressed as a mean (and standard deviation) percentage of the total lymphocyte population, measured at 7, 15 and 30 days and 6 months after transplantation. RESULTS: At 7 days after transplantation, CD2 lymphocytes averaged 55% (18%), 16% (15%) and 14% (11%) in groups 1, 2 and 3 respectively (p < 0.05), CD4 averaged 36% (11%), 9% (12%) and 7% (8%) in groups 1, 2 and 3 (p < 0.05), and CD8 averaged 14% (6%), 4% (3%) and 4% (3%) in groups 1, 2 and 3 (p < 0.05). At 15 days after transplantation CD2 averaged 69% (10%), 42% (16%) and 47% (20%) in groups 1, 2 and 3 respectively (p < 0.05), and CD8 averaged 16% (7%), 16% (6%) and 19% (7%) (p = NS). At 30 days after transplantation the percentages of CD2, CD4 and CD8 lymphocytes were similar among the groups. The freedom rate from acute rejection averaged 22% (14%), 9% (8%) and 50% (18%) (p < 0.05) in groups 1, 2 and 3 at 6 months after transplantation, and the freedom rate from infection averaged 56% (17%), 36% (13%) and 38% (17%) for the 3 groups at this time period (p = NS). CONCLUSIONS: A short course of RATG causes severe, transitory depletion of CD2, CD4 and CD8 lymphocyte subpopulations. MMF decreases the incidence of early acute rejection after heart transplantation without affecting the lymphocyte subpopulation when compared with azathioprine.

The experimental (in vitro) and clinical (in vivo) immunosuppressive effects of a rat IgG2b anti-human CD2 mAb, LO-CD2a/BTI-322.

BACKGROUND: CD2 is a cell surface glycoprotein expressed on most human T cells and natural killer (NK) cells, working as a cell adhesion and costimulatory molecule. The aim of this paper is to analyze the mechanism of action of a rat IgG2b anti-human CD2 monoclonal antibody (mAb) (LO-CD2a/BTI-322 mAb), which is a potent immunosuppressive agent and inducer of cell death. In vivo, this mAb is able to prevent or treat kidney allograft rejection. METHODS: The mechanisms by which the LO-CD2a/BTI-322 mAb is able to induce inhibition of cell activation and cell death were analyzed by mixed lymphocyte reactions and by flow cytometry. After in vivo treatment, levels of circulating mAb were measured by ELISA as well as anti-rat immunization and cytokine release. RESULTS: We show that the inhibition of cell activation induced by LO-CD2a/BTI-322 mAb after allogeneic or OKT3 stimulation is due to an Fcgamma receptor-dependent CD2 down-modulation and to T-cell depletion through an antibody-dependent cell-mediated cytotoxicity mechanism mediated by NK cells or activated monocytes. Peripheral T- and NK-cell depletion was observed after in vivo treatment with LO-CD2a/BTI322. Cytokine release (TNFalpha) was correlated with some side effects, but only after the first injection, and the effects were never severe or life threatening. CONCLUSION: The correlation between the in vitro and in vivo data suggests that T-cell depletion, especially of activated cells, and inhibition of cell activation after CD2 down-modulation are the main mechanisms of action of the LO-CD2a/BTI-322 mAb.

Dietary lutein stimulates immune response in the canine.

The possible immuno-modulatory action of dietary lutein in dogs is not known. Female Beagle dogs (17-18-month old; 11.4+/-0.4kg body weight) were supplemented daily with 0, 5, 10 or 20mg lutein for 12 weeks. Delayed-type hypersensitivity (DTH) response to saline, phytohemagglutinin (PHA) and a polyvalent vaccine was assessed on Weeks 0, 6 and 12. Blood was sampled on Weeks 0, 2, 4, 8 and 12 to assess (1) lymphocyte proliferative response to PHA, concanavalin A (Con A), and pokeweed mitogen (PWM), (2) changes in peripheral blood mononuclear cell (PBMC) populations, (3) interleukin-2 (IL-2) production and (4) IgG and IgM production. After the completion of 12-week study, we continued to collect the blood weekly up to 17 weeks to evaluate the changes in immunoglobulin production upon first and second antigenic challenges on Weeks 13 and 15. Plasma lutein+zeaxanthin was undetectable in unsupplemented dogs but concentrations increased (P<0.05) rapidly on Week 2 in lutein-supplemented dogs. Thereafter, concentrations generally continued to increase in dose-dependent manner, albeit at a much slower rate. Dogs fed lutein had heightened DTH response to PHA and vaccine by Week 6. Dietary lutein increased (P<0.05) lymphocyte proliferative response to all three mitogens and increased the percentages of cells expressing CD5, CD4, CD8 and major histocompatibility complex class II (MHC II) molecules. The production of IgG increased (P<0.05) in lutein-fed dogs after the second antigenic challenge. Lutein did not influence the expression of CD21 lymphocyte marker, plasma IgM or IL-2 production. Therefore, dietary lutein stimulated both cell-mediated and humoral immune responses in the domestic canine.

Enhanced lymphocyte proliferation in patients with adrenoleukodystrophy treated with erucic acid (22:1)-rich triglycerides.

Lymphocytopenia and depression of natural killer cells have been observed in patients with adrenoleukodystrophy (ALD) treated with glycerol trioleate and glycerol trierucate ('Lorenzo's oil'). To investigate possible alterations of cellular immunoreactivity, we measured lymphocyte proliferation in response to mitogens (PHA, Con A, PWM, OKT3) in 27 patients on treatment and in 14 patients without treatment. In patients on treatment, lymphocyte proliferation in response to the mitogens PHA and Con A was significantly higher than in patients without treatment. Lymphocyte proliferation in patients without treatment was comparable to that of normal control lymphocytes. Additionally, we found increased concentrations of erucic acid, C22:1, in lymphocytes from patients with treatment. The enhanced proliferation of lymphocytes in response to mitogens is an indication of increased reactivity of cellular immunity to unspecific immunological stimuli. Long-term side-effects on cellular immunoreactivity have to be considered in ALD patients treated with Lorenzo's oil.

Dose-dependent changes in influenza virus-infected dendritic cells result in increased allogeneic T-cell proliferation at low, but not high, doses of virus.

During the acute phase of infection with influenza A virus, the degree of lymphopenia correlates with severity of disease. Factors that contribute to T-cell activation during influenza virus infection may contribute to this observation. Since the immune response is initiated when dendritic cells (DC) interact with T cells, we have established an in vitro system to examine the effects of influenza virus infection on DC function. Our results show that allogeneic T-cell proliferation was dependent on the dose of A/PR/8/34 used to infect DC, with enhanced responses at low, but not high, multiplicities of infection. The lack of enhancement at high virus doses was not primarily due to the increased rate of DC apoptosis, but required viral replication and neuraminidase (NA) activity. Clusters that formed between DC or between DC and T cells were also dependent on the viral dose. This change in cellular interaction may oppose T-cell proliferation in response to DC infected with high doses of PR8, since the increased contact between DC resulted in the exclusion of T cells. The enhanced alloreactive T-cell response was restored by neutralization of transforming growth factor beta1 (TGF-beta1). It is likely that NA present on viral particles released from DC infected with high doses of PR8 activates TGF-beta1. Future studies will determine the mechanism by which TGF-beta1 modifies the in vitro T-cell response and address the contribution of this cytokine to the lymphopenia observed in severe disease.

Phase I trial of combined immunotherapy with subcutaneous granulocyte macrophage colony-stimulating factor, low-dose interleukin 2, and interferon alpha in progressive metastatic melanoma and renal cell carcinoma.

The purpose of our study was to determine the maximally tolerated dose (MTD) and DLT of combined administration of granulocyte macrophage colony-stimulating factor (GM-CSF), low-dose interleukin 2 (IL-2) and IFN-alpha in patients with progressive metastatic melanoma or renal cell carcinoma (RCC). In addition, the activation and expansion of effector cells were measured. Cohorts of three patients were treated with increasing doses of IL-2 (1, 4, and 8 MIU/m2) and GM-CSF (2.5 and 5 microg/kg) with a constant dose of IFNalpha (5 million units) s.c. for 12 days every 3 weeks. An additional six patients were treated at the MTD. Immune activation was monitored during the first cycle. Response was evaluated after two cycles. The MTD was found to be 2.5 microg/kg GM-CSF, 4 MIU/m2 IL-2, and 5 mega units of IFNalpha. DLT was grade 4 fever, chills with hypotension, grade 3 fatigue/malaise, and fluid retention. Dose reduction of IL-2 to 2 MIU/m2 was necessary in three of nine patients who initially received the MTD. Treatment was initiated in the hospital but could be continued at home after 3-4 days. Significant increases in lymphocytes, (activated) T cells (CD4+ and CD8+), NK cells, monocyte DR expression, neutrophils, and eosinophils were found. CD8+ T-cell activation (sCD8) and NK cell expansion was mainly present in patients receiving 2 or 4 MIU/m2 IL-2. Of eight patients with progressive metastatic RCC after nephrectomy, three achieved a complete remission, and 1 of 7 patients with metastatic melanoma achieved a partial remission. In our study, the MTD of combined immunotherapy with GM-CSF, IL-2, and IFNalpha was established; DLT was: (a) grade 4 fever with hypotension needing i.v. fluid support; and (b) grade 3 fluid retention and/or fatigue/malaise. The scheme resulted in considerable expansion and/or activation of various effector cells. The complete responses in RCC patients are promising but need to be confirmed in Phase II studies.