Modulation of early immune responses and suppression of Trypanosoma brucei brucei infections by surgical denervation of the spleen.

OBJECTIVE: To examine critical interactions between the nervous system and the immune system during experimental African trypanosomiasis. METHODS AND RESULTS: Inoculation of Trypanosoma brucei brucei resulted in early interferon (IFN)-gamma production, elevated corticosterone and prostaglandin E(2) (PGE(2)) levels and increased splenocyte proliferation, as measured by enzyme-linked immunospot assay, radioimmunoassay and thymidine incorporation assay, respectively. Splenic denervation suppressed IFN-gamma, corticosterone and PGE(2) production, enhanced splenocyte proliferation, and significantly reduced parasitemia and prolonged rat survival. CONCLUSIONS: Our data show substantial effects of the nervous system on early immune responses that may influence the outcome of this disease. These effects were not dependent on cytokine inhibitory mediators such as prostaglandins or stress hormones. More investigations are required to understand the evident neural control over the immune system during infectious challenges, which may assist in novel therapeutic approaches.

Interferon-gamma and interleukin-12 genes are preferentially expressed during early experimental African trypanosomiasis and suppressed by denervation of the spleen.

The cross talk between the central nervous system (CNS) and the immune system includes among others, the modulation of immune responses by the autonomic nervous system. Here, we investigated the effects of a splenic denervation on cytokine induction in early experimental African trypanosomiasis. Profiles of the cytokine mRNA expression for interleukin (IL)-4, interleukin (IL)-6, interleukin (IL)-10, interleukin (IL)-12, tumour necrosis factor (TNF)-alpha, tumour necrosis factor (TNF)-beta, transforming growth factor (TGF)-beta and interferon (IFN)-gamma were examined at 4 h, 8 h and 12 h postinfection (p.i.), and in noninfected controls. Only IFN-gamma and IL-12 were significantly expressed over noninfected controls. Already at 4 h p.i. both cytokines were expressed and showed more increased levels at 12 h. Sympathetic denervation of the spleen markedly reduced the mRNA expression for both IFN-gamma and IL-12. Con A was used as a positive control and showed an enhanced mRNA expression, which was also suppressed by a splenic denervation. To demonstrate that the mRNA expression had resulted in a cytokine production, we looked for the protein level of IFN-gamma at 4 h p.i. by immunohistochemistry and found increased levels of IFN-gamma, which was also inhibited by the denervation. Sham-operated animals exhibited similar responses as the nondenervated controls. Our data present for the first time very early kinetics for a cytokine gene expression during an experimental African trypanosomiasis. Furthermore, the data suggest a regulatory role for the autonomic nervous system on cytokine responses at both the mRNA and the protein levels.

Quantitative assessment of protein content in irradiated human skin.

PURPOSE: Radiation-induced fibrosis is a common late reaction of radiation therapy. Due to a lack of feasible noninvasive techniques to assess this reaction, the long-term development of radiation fibrosis is not well described. In order to develop quantitative means for the purpose, subcutaneous fibrosis of breast cancer patients after postmastectomy radiotherapy was evaluated by clinical scoring and a new technique based on dielectric properties of the skin. METHODS AND MATERIALS: Dielectric properties of biological tissues at radiofrequencies are principally determined by tissue water content. The major skin components are proteins, proteoglycans, and water either free or bound to the surface of proteins and proteoglycans. Since the MR studies have shown that bound water is tightly attached onto the surface of collagen, a dielectric measurement sensitive to bound water could be related to the protein content. Therefore, the dielectric constant of human skin was measured in vivo with an open-ended coaxial probe at electromagnetic (EM) frequencies in the range of delta-dispersion. Since the in vitro experiments with protein-water solutions have indicated that the slope of the dielectric constant vs. the EM frequency is a measure of the protein concentration, a respective slope was determined with irradiated skin of 14 breast cancer patients 2 years after postmastectomy radiotherapy at 63, 100, 300, and 500 MHz. Irradiated skin sites were clinically scored for subcutaneous fibrosis using a scale: none, slight, moderate, or severe fibrosis. RESULTS: A statistically significant correlation was found between the slope and the clinical score of subcutaneous fibrosis at 63, 100, and 300 MHz but not at 500 MHz. The correlation was best at 100 and 300 MHz. CONCLUSIONS: Considerable changes in the dielectric constant of the irradiated skin were found. The correlation between the dielectric constant and clinical score suggests that this novel technique is a potential tool for the follow-up and quantitative assessment of radiation-induced subcutaneous fibrosis.

A phase II study of metastatic melanoma treated with a combination of interferon alfa 2b, dacarbazine and nimustine.

52 patients with metastatic melanoma have been treated with a combination of recombinant interferon-alfa-2b, dacarbazine and nimustine. The objective response rate was 23% with 9 complete responses (CR) and 3 partial responses (PR). The mean duration of the response was 18+ months for CR (6-31+ months) and 7 months for PR patients (4-10 months). The mean survivals were 24+ months (8-38 months) and 7 months (4-12 months), respectively. The mean duration of the response for patients with stable disease was 10+ months (2-48+ months) and the mean survival 17+ months (3-48+ months), while the patients with progressive disease died within 12 months (mean 4 months). The best responding sites were the lymph node, the lung and the subcutaneous metastases. Myelosuppression was the main adverse effect of the therapy. WHO grade 3-4 toxicity was seen in 27 patients leading to delay and reduced dosage of therapy; in 4 patients treatment was discontinued, 8 patients had no side effects. Combination therapy with interferon and dacarbazine and nimustine for metastatic melanoma offers no advantage over interferon and dacarbazine.

Levamisole in the treatment of advanced breast cancer. A ten-year follow-up of a randomized study.

A total of 101 patients with advanced breast cancer were treated during the years 1976 to 1978 with doxorubicin, vincristine and cyclophosphamide, and randomized to receive either levamisole or placebo in a double-blind fashion. The chemotherapy cycles were repeated every four weeks, and levamisole, 2.5 mg/kg, was given on two consecutive days every week except on the days chemotherapy was given. The patients treated with levamisole exhibited higher response rates (63%) than patients given placebo (47%). The survival rate was also significantly higher in the levamisole group. The results correlated with potentiation of intracutaneous PPD test. In the lymphocyte blast transformation tests, the suppression of T-cell response to mitogens two weeks after the start of chemotherapy was markedly diminished by levamisole. In contrast to some negative reports, the results of the present study are encouraging for further evaluation of levamisole and other biological response modifiers in breast cancer.

Lymphocyte activation with release of soluble mediators induced by Thermoactinomyces vulgaris in vitro.

Murine spleen lymphocytes stimulated in vitro with a hypersensitivity pneumonitis-associated bacterium, Thermoactinomyces vulgaris, were found to secrete interleukin-2 up to 7 days after mitomycin C blockade. They exerted helper effect in secondary mitogen or antigen-induced lymphocyte proliferation. Cyclosporin A, an inhibitor of interleukin-2 synthesis, caused a complete abrogation of the helper effect, suggesting that the effect was mainly due to interleukin-2. Indomethacin, an inhibitor of prostaglandin synthesis, enhanced the helper effect in some inbred strains of mice, indicating prostaglandin-dependent downregulation. The strain variation in the prostaglandin-induced downregulation was not H-2 linked.

Interactions of Thermoactinomyces vulgaris and mouse alveolar macrophages. Loss of mitogenic activity and release of suppressive prostaglandins and interleukin 1.

Interactions of mouse alveolar macrophages from three different inbred strains of mice and Thermoactinomyces vulgaris, a microbe associated with Farmer's lung disease, were studied. Alveolar macrophages were found to abolish the mitogenic activity of T. vulgaris. A prostaglandin synthesis inhibitor indomethacin, could not restore the activity. Alveolar macrophage supernatants generated by T. vulgaris treatment exerted strong suppression in secondary concanavalin A-induced lymphocyte transformation. Indomethacin partly relieved the suppression but a histamine 2 receptor blocker, cimetidine, had no effect. Interleukin 1 activity was practically undetectable by the thymocyte co-stimulation assay unless indomethacin was used. When indomethacin was used, interleukin 1 activity could be detected in all strains of mice tested. Major differences in the abolition of the mitogenic effect, in the suppressive effect, or in the release of interleukin 1 were not detected between inbred strains of mice tested. The results indicate that alveolar macrophages exert suppressive actions in vitro after T. vulgaris treatment but in vivo activities remain to be elucidated.

Postoperative radiation therapy and adjuvant chemoimmunotherapy in breast cancer. Aspects of timing and immune competence.

The effects of radiation therapy and adjuvant chemoimmunotherapy on the immune competence of patients with breast cancer were investigated. The tests performed included intradermal tuberculin tests, T- and B-lymphocyte counts, and lymphocyte blast transformation tests; phytohemagglutinin (PHA), concanavalin A (ConA) and pokeweed mitogen (PWM) were used as mitogens. Enhancement in lymphocyte proliferative response to mitogenic stimulation by PHA and PWM was seen in patients after 3 courses of chemotherapy + levamisole, whereas irradiation given after chemotherapy caused long-lasting depression in response to PHA (p = 0.039) and PWM (not significant). T-lymphocyte counts were also lower after irradiation than after chemoimmunotherapy (p = 0.007). Clinically, the 16 patients treated with radiation therapy after chemotherapy exhibited a higher recurrence rate than the 24 patients treated first by irradiation. Enhanced reactivity to tuberculin tests occurred generally in patients receiving a planned treatment including irradiation, chemotherapy (5-fluorouracil, doxorubicin, cyclophosphamide) and levamisole. Enhancement of reactivity was seen more often in patients who had not relapsed.