Fumaric acid esters suppress peripheral CD4- and CD8-positive lymphocytes in psoriasis

BACKGROUND

For severe forms of psoriasis vulgaris, the antipsoriatic fumaric acid esters (FAE) therapy has recently gained increasing acceptance and importance. Until today, there is little knowledge about the mode of action of FAE. However, some evidence exists indicating immunosuppressive effects.

OBJECTIVE

The aim of this study was to examine the systemic, particularly the immunological changes in patients suffering from psoriasis treated with FAE over a long period of time, since we expect to see pharmacological effects of FAE at this point.

METHODS

This study is based on continuously recorded clinical data and laboratory parameters of 10 patients, who were treated over a period of 12 months with FAE. A quantitative analysis of lymphocytes and their subtypes was carried out by means of flowcytometric methods.

RESULTS

3 months after starting treatment with FAE, a clinical effect with a remission index > 95% was achieved in all 10 patients examined. This remained constant until the end of this study. Focusing on leukopenia, and particularly on lymphopenia as important parameters, these effects were found in all patients. The lymphocyte subpopulations data demonstrated extensive proportionate reductions. Within the T cell fraction a stronger suppression of CD8+ lymphocytes was observed.

CONCLUSION

Our investigations of systemic effects of fumaric acid esters demonstrate the suppressive character of this medication. Effects of cell count reduction in leukocyte and lymphocyte numbers over the entire period of 12 months could be observed. The lymphocytic cell count number is obviously linked to the clinical effect.

Effect of melatonin treatment on 24-h variations in responses to mitogens and lymphocyte subset populations in rat submaxillary lymph nodes

Wistar male rats were injected s.c. with melatonin (30 microg) or vehicle, 1 h before lights off, for 11 days. Ten days after beginning melatonin treatment, rats received Freund's complete adjuvant or its vehicle s.c., and after 2 days, they were sacrificed at six different time intervals throughout a 24-h cycle. The mitogenic effect of lipopolysaccharide (LPS) and concanavalin A (Con A), the activity of ornithine decarboxylase (ODC) and the relative size of lymphocyte subset populations were measured in submaxillary lymph nodes. In control rats, the mitogenic effects of LPS and Con A and ODC activity peaked during the afternoon. Injection of Freund's adjuvant induced a 10-h shift in the diurnal rhythm of the mitogenic effect of LPS to attain maximal values at night. Melatonin pretreatment blunted the daily variations in the mitogenic activity of Con A or LPS and, when given to Freund's adjuvant-injected rats, augmented mesor and amplitude of diurnal rhythm in ODC activity. Maxima in B cell number occurred at night whereas those of T and B-T cell number occurred during the afternoon. During the early phase of immunization tested, the number of B cells augmented and the amplitude of its diurnal rhythmicity increased both after immunization and following melatonin pretreatment. Maxima of 24-h rhythms in CD4+ and CD4+/CD8+ cell populations occurred during the afternoon while those of CD8+ cells occurred at late night. Melatonin significantly augmented CD4+ cell number and decreased CD8+ cell number; it therefore augmented the CD4+:CD8+ ratio. The results suggest that pretreatment with a pharmacological dose of melatonin exerts immunomodulating effects at an early, preclinical, phase of Freund's adjuvant-induced arthritis in rats.

Immune reconstitution following high-dose chemotherapy with stem cell rescue in patients with advanced breast cancer

The present study examines the nature of humoral and cellular immune reconstitution in 28 patients with advanced breast cancer following high-dose chemotherapy with stem cell rescue. Patients underwent testing of T, B, NK and dendritic cell function at serial time points until 1 year post transplant or until the time of disease progression. Abnormalities in T cell phenotype and function were observed following high-dose chemotherapy that persisted for at least 6-12 months. The vast majority of patients experienced an inversion of the CD4/CD8 ratio and demonstrated an anergic response to candida antigen. Mean T cell proliferation in response to PHA and to co-culture with allogeneic monocytes was significantly compromised. In contrast, mean IgG and IgA levels were normal 6 months post transplant and NK cell yields and function were transiently elevated following high-dose chemotherapy. Dendritic cells generated from peripheral blood progenitors displayed a characteristic phenotype and were potent inducers of allogeneic T cell proliferation in the post-transplant period. The study demonstrates that patients undergoing autologous transplantation for breast cancer experience a prolonged period of T cell dysfunction. In contrast, B, NK, and DC recover more rapidly. These findings carry significant implications for the design of post-transplant immunotherapy.

Residual low-level viral replication could explain discrepancies between viral load and CD4+ cell response in human immunodeficiency virus-infected patients receiving antiretroviral therapy

We report the evolution of chronic infection with human immunodeficiency virus type 1 (HIV-1) in a patient treated with stavudine plus didanosine, whose CD4+ lymphocyte count progressively decreased, despite a sustained plasma viral load <20 copies/mL. After 12 months of therapy, treatment was switched to zidovudine plus lamivudine plus nelfinavir. CD4+ T cell count decreased from 559 x 10(6)/L at month 0 to 259 x 10(6)/L at month 12. Plasma viral load decreased from 21,665 HIV-1 RNA copies/mL at baseline (month 0) to <20 copies/mL after 1 month of therapy with stavudine plus didanosine, and remained below 20 copies/mL until month 12, but always >5 copies/mL. Viral load in tonsilar tissue at month 12 was 125,000 copies/mg of tissue. After the change to triple-drug therapy, the plasma viral load decreased to 5 copies/mL, the CD4+ T cell count increased to 705 x 10(6)/L, and the viral load in tonsilar tissue decreased to <40 copies/mg of tissue at month 24. A low level of HIV-1 replication could explain the lack of immunologic response in patients with apparent virological response.

Exogenous glucocorticoids alter parameters of early feline immunodeficiency virus infection

Feline immunodeficiency virus (FIV), a lentivirus, causes progressive immunosuppression and neurologic dysfunction in cats. Glucocorticoids are common therapeutic agents that are also immunosuppressive, and their use might enhance the pathogenic effects of lentivirus infections. Methylprednisolone acetate, a long-acting glucocorticoid, was administered to cats before FIV inoculation, and the course of early infection was monitored. The humoral immune response to FIV was not affected by corticosteroid treatment, but CD8+ cell-mediated antiviral activity was poor in cultures from FIV-infected cats treated with methylprednisolone. Steroid-treated cats had higher plasma viral RNA levels than untreated cats during acute viremia. In contrast, FIV-associated changes in brain stem auditory-evoked potentials were slow to develop in the methylprednisolone-treated cats. Methylprednisolone treatment of cats with established FIV infections appeared to reverse these neurophysiologic changes. These results emphasize the complexity of host-lentivirus interactions and suggest potential advantages and drawbacks of using glucocorticoids in lentivirus infections.

Four drug-HAART in primary HIV-1 infection: clinical benefits and virologic parameters

BACKGROUND

From a theoretical standpoint, primary HIV infection (PHI) represents a great chance to modify the natural history of the disease. In this study we purposed a four drugs regimen with zidovudine, lamivudine, ritonavir and saquinavir to treat aggressively the infection and achieve a complete immune reconstitution.

METHODS

This is an Italian multicentric open label study. Adult patients with PHI were eligible for the study if they met at least one clinical criterion and one laboratory criterion of the following. Clinical criteria: Signs and symptoms of acute retroviral syndrome within the past 70 days, exposure to HIV-1 within the last 3 months, a preceding negative antibody test within the past 6 months. Laboratory criteria: Detectable p24 antigen with neutralization in serum; detectable HIV-RNA in plasma; indeterminate Western blot test with negative or low positive value HIV antibody in ELISA test.

RESULTS

Since April 1997 to April 1999 40 patients with PHI have been enrolled; 80% of this cohort referred symptoms related to acute antiretroviral syndrome. Treatment has been withdrawn in 17 patients (12 for intolerance, 3 for toxicity and 2 for failure). At baseline the mean CD4+ T cells count and CD4/CD8 ratio were 537 (range 55-1287) and 0.58 (range 0.1-1.03) and the mean plasma HIV-RNA level was 5.9 log copies/ml (range 3-7.15). Plasmatic HIV-1 RNA levels of all patients dropped below 200 copies/ml in 68% of patients at week 12, 81% at week 24, 93% after 12 months and 100% after 18 months. Immunological parameters have been improved and have achieved normal range since 6th month.

CONCLUSIONS

A rapid virologic suppression and immunological reconstitution are associated with PHI therapy. However early treatment should be weighted against the potential disadvantages such as immediate adverse events (intolerance and drug toxicity) and long term manifestation (metabolic disorders).

GRANULOCYTE CHEMILUMINESCENCE ACTIVITY, ANTIBODY PRODUCTION AND PERCENTAGE OF CD4(+)AND CD8(+)LYMPHOCYTES IN PERIPHERAL BLOOD OF OFFSPRING OF SALBUTAMOL-TREATED PREGNANT C3H MICE

Preterm delivery is one of the most important problems in obstetric care. One of commonly used treatment of such high risk cases is salbutamol-beta(2)adrenoceptor agonist. The aim of present study was to determine if such treatment causes any changes in neonatal immune system and therefore should be considered in newborn care. The experiments were performed in 4-5- and 6-7-week-old female and male offspring of salbutamol treated C3H inbred mice. In the present study chemiluminescent activity of peripheral blood granulocytes, percentage of CD4(+)and CD8(+)lymphocytes and antibody production were evaluated. A lower number of peripheral blood granulocytes in 6-7-week-old offspring of salbutamol treated mothers was observed, while in the case of younger mice's lymphocytes count in both groups, the differences were not signtificant as compared to control group. In 4-5-week-old mice a lower percentage of CD4(+), CD3(+)and CD8(+)was evaluated, while in older offspring the percentage of CD4(+)and CD3(+)was higher in the case of the progeny of salbutamol treated mothers. As far as chemiluminescent activity was concerned no differences were found in any of experimental groups. We showed higher IgM production both in male and female offspring of the experimental group and no changes in IgG levels in mice sera. Alterations observed in progeny of salbutamol treated mice might have influence on their further immune system development and function. 2000 Academic Press@p$hr Copyright 2000 Academic Press.

Role of immune modulation in primary HIV infection

Hydroxyurea inhibits HIV without attacking the virus directly. By inhibiting a cellular enzyme (ribonucleotide reductase) the drug decreases the intracellular concentration of deoxynucleotide triphosphates, thus favoring the incorporation of other drugs, such as the reverse transcriptase inhibitors, into the nascent viral DNA. A large body of data has shown that hydroxyurea can be successfully used during chronic infection. In this manuscript we review the use of hydroxyurea during primary HIV infection. In several independent studies hydroxyurea has been shown to: 1) inhibit HIV in combination with a reverse transcriptase inhibitor and a protease inhibitor as efficiently as with standard highly active antiretroviral therapies; 2) stimulate the immune system by increasing the percentage of naïve cells and the percentage of cells capable of responding to antigens; 3) "cool down" the immune system hyper-activation. The role of hydroxyurea in inducing control of HIV during structured treatment interruptions remains to be clarified.

Toxicity, biological activity, and pharmacokinetics of TXU (anti-CD7)-pokeweed antiviral protein in chimpanzees and adult patients infected with human immunodeficiency virus

The purpose of the present study was to evaluate the toxicity and pharmacokinetics of TXU (anti-CD7)-pokeweed antiviral protein (PAP) in human immunodeficiency virus (HIV)-infected chimpanzees and adult patients. At a total dose of 100 microg/kg, TXU-PAP did not cause severe (grade >/= 3) toxicity in any of the four HIV type 1 (HIV-1)-infected or two healthy chimpanzees. The only side effects were a transient elevation of the liver enzyme alanine aminotransferase between days 2 and 14 without a concomitant rise in total bilirubin levels and a decrease in the serum albumin levels between days 1 and 5 without any concomitant weight gain or peripheral edema. TXU-PAP showed favorable pharmacokinetics in chimpanzees with a plasma elimination half-life of 5.1 to 12.0 h and a systemic clearance of 5.8 to 15.1 ml/h/kg. At 2 months after initiation of the TXU-PAP infusions, the HIV-1 burden was reduced to below-detection levels in three of the four chimpanzees, and in the remaining chimpanzee, the HIV burden was <500 RNA copies/ml at 2 weeks but returned to the pretreatment levels by 2 months. TXU-PAP was well tolerated by HIV-1-infected adult patients who received a single 5 microg/kg i.v. infusion of TXU-PAP. TXU-PAP showed very favorable pharmacokinetics in these patients with a relatively long plasma elimination half-life of 12.4 +/- 1.4 h, a mean residence time of 17.9 +/- 2.0 h, and a slow systemic clearance of 2.7 +/- 0.7 ml/h/kg. Concentrations of TXU-PAP required for effective inhibition of HIV-1 replication in preclinical models were achieved in HIV-1-infected patients at the 5 microg/kg dose level without any adverse reactions, and the mean value for AUC was 3059 +/- 721 ng. h/ml. The 1-h postinfusion plasma samples from TXU-PAP-treated patients showed potent anti-HIV activity in vitro and inhibited the replication of HIV in normal peripheral blood mononuclear cells (PBMCs) even at a 1:100 dilution. Although treatment with TXU-PAP at the 5 microg/kg dose level does not provide sustained therapeutic levels, it was capable of reducing the viral burden in six of six patients evaluated. To our knowledge, this is the first report of a clinical pharmacokinetics study of a PAP immunoconjugate in HIV-infected patients. The favorable long plasma elimination half-life of TXU-PAP in combination with its low toxicity provides the basis for further investigation of TXU-PAP as a potential anti-HIV agent.

Treatment of two patients with diffuse cutaneous leishmaniasis caused by Leishmania mexicana modifies the immunohistological profile but not the disease outcome

Two patients with diffuse cutaneous leishmaniasis caused by Leishmania mexicana were treated with two leishmanicidal drugs (pentamidine and allopurinol) combined with recombinant interferon-gamma restoring Th-1 favouring conditions in the patients. Parasites decreased dramatically in the lesions and macrophages diminished concomitantly, while IL-12-producing Langerhans cells and interferon-gamma- producing NK and CD8 + lymphocytes increased in a reciprocal manner. The CD4+/CD8 + ratio in the peripheral blood normalized. During exogenous administration of interferon-gamma the parasites' capacity to inhibit the oxidative burst of the patients' monocytes was abolished. Even though Th-1-favouring conditions were restored, both patients relapsed two months after therapy was discontinued. We conclude that the tendency to develop a disease-promoting Th-2 response in DCL patients is unaffected by, and independent of, parasite numbers. Even though intensive treatment in DCL patients induced Th-1 disease restricting conditions, the disease-promoting immunomodulation of few persistent Leishmania sufficed to revert the immune response.

Lymphocyte subsets as prognostic markers for cancer patients receiving immunomodulative therapy

Immunogenic features of some malignancies have aroused interest in immunotherapy of cancer. Immunotherapy seems most effective in patients with a small tumour burden, and the focus of immunotherapy trials has, thus, lately been on adjuvant treatment. To enable further development of immunotherapy we need to know more about the mechanisms involved in host defence, especially when the system is influenced by extrinsic factors, that is, immunomodulative agents. T lymphocytes play an important role in the host defence against tumour cells trying to escape from immune surveillance. The mechanisms that regulate the host defence systems are complex, and the influence of extrinsic factors such as immunotherapeutic agents is poorly understood. Most data on lymphocyte subsets in malignant disease originate from melanoma or renal cell carcinoma (RCC) studies, although there are scattered data on lymphocyte subsets also in other malignancies. There are several studies implying that the relative amount of CD4+, CD8+, and natural killer (NK) cells may be important and that, by reducing the tumour burden or by using different therapeutic agents, we can stimulate the host defence. However, only some of these studies imply that these changes can have an impact on clinical outcome and prognosis. The findings of the studies reviewed in this paper are mostly encouraging, but whether the lymphocyte subsets have any value as prognostic markers in patients with malignancies receiving immunotherapy is still unclear. Large randomized immunotherapy trials including an observation arm give an ideal opportunity to recognize those immunological changes that are due to therapy, related to the natural host defence, or whether they have any prognostic value.

The preoperative administration of lentinan ameliorated the impairment of natural killer activity after cardiopulmonary bypass

The aim of this study was to determine whether the preoperative administration of lentinan, which is used clinically to activate T cell function in cancer patients, prevents the impairment of lymphocyte function after cardiopulmonary bypass (CPB). A total of 25 adults undergoing coronary artery bypass grafting were enrolled in this study. Lentinan (2 mg) was given to 10 randomly selected patients 7 d before surgery, while the other 15 patients were considered as a control. The white blood cell count, percentage of lymphocytes, subsets of lymphocytes, and natural killer cell activity were measured preoperatively, immediately after CPB and 1, 3, and 6 d after surgery. The white blood cell counts and the percentage of lymphocytes were not significantly different between the two groups; however, the percentage of CD4-positive cells in the lentinan group recovered to normal more rapidly than in the control group. Although natural killer cell activity was impaired in the control group after CPB, it maintained a nearly normal level in the lentinan group. The preoperative administration of lentinan for patients undergoing CPB ameliorated the impairment of natural killer activity and promoted the rapid recovery of CD4-positive cells.

T-cell subsets in schizophrenia: a comparison between drug-naive first episode patients and chronic schizophrenic patients

T-cell subsets (CD3+, CD4+, CD8+, NK-cells) and the CD4+/CD8+ ratio were measured in 56 schizophrenic patients admitted to hospital with an acute psychosis. Thirty-five patients with chronic schizophrenia and 21 drug-naive first episode schizophrenic patients were compared with 16 healthy controls. T-cell subsets were quantified in the acute state of the illness (day 0), after 7 days of treatment and at the time of discharge. In the acute state, schizophrenic patients showed higher CD3+ and CD4+ cells (p = 0.05) and a higher CD4/CD8 ratio (p = 0.02) than healthy controls, while NK-cells were lower (p = 0.05). In first episode patients, all T-cell alterations normalized during treatment. In the chronic group the ratio remained high, whereas the initially low number of NK-cells normalized over time. These findings, supporting immune system dysregulation in schizophrenia, are discussed in relation to psychopathology, the stage of illness and effects of medication.

Successful treatment of alopecia areata-like hair loss with the contact sensitizer squaric acid dibutylester (SADBE) in C3H/HeJ mice

A type of hair loss closely resembling human alopecia areata has been described in C3H/HeJ mice. In order to test the assumed analogy with human alopecia areata, we investigated the efficacy of treatment with the contact allergen squaric acid dibutylester. In 12 C3H/HeJ mice with alopecia areata an allergic contact dermatitis was induced and elicited weekly on one side of the back by topical applications of squaric acid dibutylester. Overt hair regrowth was observed only on the treated side of the back in nine of 12 mice. Histopathologic examination revealed a change in the distribution of the inflammatory infiltrate from a dense perifollicular lymphocytic infiltrate around the mid and lower regions of hair follicles in untreated skin to a uniform presence in the upper dermis in treated skin. Immunohistomorphometric studies revealed that treatment with squaric acid dibutylester increased the CD4+/CD8+ ratio from approximately 1:2 in untreated alopecia areata to 1:1 in treated alopecia areata. Additional immunohistochemical investigations showed an aberrant expression of major histocompatibility complex class I, major histocompatibility complex class II and intercellular adhesion molecule 1 on keratinocytes of the mid and lower parts of hair follicles in untreated alopecia areata. In successfully treated skin ectopic major histocompatibility complex class I and II expression was clearly reduced, whereas intercellular adhesion molecule 1 expression showed only minor changes. In conclusion, alopecia areata-like hair loss in C3H/HeJ mice responded to treatment with the contact sensitizer squaric acid dibutylester analogous to human alopecia areata. Moreover, successful treatment changes the aberrant expression of major histocompatibility complex class I and II in a way similar to that observed in human alopecia areata. These observations support the concept that alopecia areata-like hair loss in C3H/HeJ mice can be utilized as an appropriate model for the study of human alopecia areata.

Acute toxicity of an anti-Fas antibody in mice

By histopathologic examination of various organs in 3 normal strains, C3H/HeN, ICR, and DBA/1J, of mice treated intravenously once with anti-Fas antibody (Jo2), we failed to determine any target organ, except the liver, responsible for the acute lethality induced by the Fas/anti-Fas antibody interaction. However, we could show the presence of Fas-mediated apoptosis in other organs aside from the liver and normal mouse strain differences in susceptibility to anti-Fas antibody. Among these strains, C3H/HeN was the most susceptible to the antibody, followed by ICR and DBA/1J. We observed Fas-mediated apoptosis in the liver, spleen, thymus, lymph nodes, Peyer's patch, intestine, skin, coagulation glands, ovary, uterus, and vagina in all 3 strains and additionally in the epididymides and seminal vesicles in the DBA/1J strain. We also demonstrated that Fas-mediated apoptosis of small lymphocytes in the mantle zone of splenic lymphatic follicles preceded that of the hepatocytes or thymic cells. Since cellular damage was most severe in the liver among all the apoptotic organs in the 3 mouse strains, liver injury induced by anti-Fas antibody is speculated to play a significant role in the death.

Effect of dexamethasone on lymphocyte subpopulations in premature infants with bronchopulmonary dysplasia

OBJECTIVE

This study was designed to determine the effect of dexamethasone treatment on peripheral blood lymphocyte counts and subpopulations in premature infants with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Peripheral blood lymphocyte subpopulations in 12 premature infants with BPD were analyzed before treatment with a 6-week course of dexamethasone (day 0), on days 3 and 10 of treatment, and 2 weeks after discontinuing dexamethasone therapy (day 56). Lymphocyte immunophenotypes were determined using direct two-color immunofluorescent staining followed by flow cytometry.

RESULTS

The percentage of lymphocytes was significantly lower on days 3 (17.55 +/- 2.55) and 10 (20 +/- 11.8) of dexamethasone therapy compared with before (30.36 +/- 6.41) or after treatment. The percentage of T cells was significantly lower on days 3 and 10 of dexamethasone therapy (mean +/- SEM; 58.09 +/- 1.93 and 60.09 +/- 2.47, respectively) compared with before (67.09 +/- 4.24) or after treatment. The absolute number of T cells was significantly lower on day 10 of therapy. The percentage of CD4+ cells was significantly lower on days 3 (38.91 +/- 2.49) and 10 (40.45 +/- 2.24) of therapy, and this decrease persisted after dexamethasone was stopped (36.73 +/- 3.41). The absolute number of CD4 cells was significantly lower on day 10 (1328 +/- 216) of therapy and reached a nadir on day 56 (1143 +/- 106). Similarly, the CD4/CD8 ratio was also significantly lower on days 3 and 10 of treatment (1.56 +/- 0.18 and 1.64 +/- 0.14, respectively) and reached a nadir on day 56 (1.04 +/- 0.13).

CONCLUSION

Dexamethasone significantly reduced the percentage and absolute number of lymphocytes, T cells, and CD4 cells, as well as the CD4/CD8 ratio. A reduction in CD4 cells and in the CD4/CD8 ratio persisted 2 weeks after dexamethasone therapy was stopped. In contrast, the absolute number of B cells increased transiently, and CD8 cells were unaffected by dexamethasone. This alteration in lymphocyte subpopulations may help account for the clinically beneficial anti-inflammatory effect of dexamethasone in the treatment of BPD complicated by respiratory failure. The dexamethasone-induced decrease in CD4 cells may also increase the susceptibility of these infants to infection.

The absence of correlation between immunoregulatory T cells and induced lymphoproliferative response in treated B-chronic lymphocytic leukemia patients

BACKGROUND

Many data suggest T cell functional impairment in B-cell chronic lymphocytic leukemia (B-CLL). The mechanism responsible for this phenomenon is still unresolved.

METHODS

In 88 B-CLL patients (RAI II-IV) the relationship between immunoregulatory T cells and PHA induced lymphoproliferative response (LPR) was analysed before and after the therapy. The number of peripheral blood CD3+, CD4+ and CD8+ T lymphocytes was determined by indirect immunofluorescence assay using monoclonal antibodies. LPR was estimated in whole blood culture method.

RESULTS

The absolute number of CD3+, CD4+ and CD8+ cells in untreated CLL patients was much higher than in healthy controls (n = 26), but the percentages of these subpopulations, CD4/CD8 ratio and LPR to PHA were significantly (p < 0.00001) decreased. The chemotherapy induced a significant rise of CD3+ and CD4+ percentages (p < 0.006 < p < 0.022 respectively) in comparison to baseline levels, but their levels remained significantly (p < 0.00001) lower than the controls. The CD4/CD8 ratio was also elevated after the therapy (p < 0.048) but remained below the normal value as well. The absolute number of CD3+ and CD4+ T cells were normalized after treatment, while the CD8+ cells were still higher (p < 0.044) than controls. The increase of LPR has been registered after treatment, but it failed to reach the control values. We could not find any correlation between the number of immunoregulatory T cells and induced LPR (r = 0.07, for CD4+; r = 0.09 for CD8+ cells).

CONCLUSIONS

These data indicate some profound lymphoid cell defect in CLL patients affecting CD8+ proliferation as well as LPR.

Role of macrophage protection in the development of murine AIDS

Macrophages play a key role in AIDS pathogenesis and thus controlling infectivity and viral replication in these cells is a key issue in any antiretroviral therapy. In the present study, using a murine model of AIDS, we evaluated new therapeutic approaches specifically designed for the protection of macrophages. Based on previous observations, we took advantage of the unique ability of autologous erythrocytes to deliver drugs selectively to macrophages. The antiviral drugs selected were a new homodimer of AZT (AZTp2AZT) and reduced glutathione (GSH). The addition of an oral drug for the protection of lymphocytes (i.e., AZT) was also investigated. C57BL/6 mice infected with the retroviral complex LP-BM5 were treated with GSH-loaded erythrocytes, GSH-loaded erythrocytes plus oral AZT, or GSH/AZTp2AZT-loaded erythrocytes plus oral AZT. The treatments including AZT and erythrocytes loaded with GSH alone or with GSH plus AZTp2AZT provided similar results and were most effective in inhibiting the progression of MAIDS; they reduced splenomegaly, lymphadenopathy, and hypergammaglobulinemia by about 70%, 90% and 83%, respectively, when compared with infected animals at 10 weeks postinfection. Evaluation of BM5d proviral DNA content in infected organs revealed that both treatments were able to almost completely protect most infected animals. They were also able to normalize the blood lymphocyte phenotype and to restore the responses of T and B cells to mitogens significantly. Treatment with GSH-loaded erythrocytes alone did not provide significant results for most parameters investigated, but a marked reduction in proviral DNA content was obtained in infected organs, including the brain. The results reported in this paper confirm the important role of macrophages in retroviral infection and moreover prove that erythrocytes, by selectively protecting these cells, strongly affect MAIDS progression. Furthermore, the combination of GSH- or GSH/AZTp2AZT-loaded erythrocytes with an oral nucleoside analogue (AZT) for the protection of lymphocytes provides additive responses in all the parameters investigated.

Evaluation of immunomodulatory effects of nisin-containing diets on mice

The effect of nisin on the immune response of mice was studied. Nisin (in the form of the commercial preparation Nisaplin) was incorporated in the diet of experimental mice which were fed for 30, 75 or 100 days. Short-term administration of diets containing Nisaplin induced an increase of both CD4 and CD8 T-lymphocyte cell counts and also a decrease of B-lymphocyte counts. After prolonged diet administration, T-cell counts returned to control levels. Normal levels of B-lymphocytes were also reached after prolonged administration of the lower (but not the higher) Nisaplin concentration. The macrophage/monocyte fraction isolated from peripheral blood became significantly increased after long-term administration (100 days) of Nisaplin-containing diets in a concentration-dependent way. Although the number of peritoneal cells was not affected by the diets, the phagocytic activity of peritoneal cells decreased after prolonged administration of low (but not high) Nisaplin doses.

Vanadium stimulates immunological responses of chicks

In a continuation of studies on the interaction of dietary phosphorus (P) and vanadium (V) levels, studies have directed toward an examination of this interaction on the immune system of chicks. Antibody titers to sheep red blood cells (SRBC) were increased at 7 days post-inoculation (PI) by as little as 10 mg V/kg diet in the P-deficient group, while 50 mg V/kg was required in the P-supplemented group. At 14 days PI, only the 50 mg V/kg was significantly higher in both P-deficient and P-supplemented groups. At 21 days PI, vanadium had no significant effect. P-deficiency resulted in a decrease in the percentage of phagocytic macrophages obtained from the abdominal cavity and a decrease in the number of intracytoplasmic SRBC per phagocytic macrophage. These two criteria were increased by vanadium in both the P-deficient and P-supplemented animals. In P-supplemented animals, the CD4/CD8 ratios of lymphocytes obtained from the blood and spleen were increased by the inclusion of 50 mg V/kg diet. The IL-1-like activity of macrophage supernatants was not significantly affected by dietary V, but IL-6 activity was increased. Densitometric analysis of lysates of macrophages isolated from control and V-fed chicks for anti-protein-tyrosinephosphate (PTP) bands indicate that dietary V increased PTP. While the evidence is not clear that there is a P x V interaction in the immune system studies, it is clear that dietary V at the levels used results in a positive immune response of chicks, possibly mediated through increased PTP.

Orally administered dextran sulfate is absorbed in HIV-positive individuals

Preliminary in vivo studies suggested that oral dextran sulfate was poorly absorbed, but investigations were limited by inadequate methods for measuring the drug in the body. To determine absorption in HIV-positive subjects, hydrogenated dextran sulfate, average molecular weight 8000 (Usherdex 8), was orally administered in a short-term (single dose, 4 g/day for 5 days, 7 subjects) and in a long-term study (1 g, 4 times per day for 29 to 335 days, 8 subjects), which was a continuation of the short-term study with the inclusion of an additional subject. When an agarose gel electrophoresis technique with toluidine blue staining was used, the drug was recovered from plasma (67%, peak 2.2 microg/mL) and circulating peripheral blood lymphocyte (PBL) samples (50%, peak 333 microg/L blood) obtained at 5 and 15 minutes and 1, 3, 6, and 24 hours after the first day's dose and from plasma (56%) and PBL samples (38%) obtained 5 minutes after administration on 4 subsequent days in the short-term study. In the long-term study, the drug was found in plasma (67%, peak 2.4 microg/mL) and PBL samples (25%, peak 126 microg/L blood) obtained at monthly visits within 4 hours of the last dose. The drug was found in all urine samples from all subjects in both studies (short-term study, 24-hour samples up to 4 days after the final dose; long-term study, monthly samples within 4 hours of the last dose). In the long-term study, bone marrow preparations from 3 subjects showed metachromatic inclusions present in reticular cells when the cells were stained with toluidine blue, indicating the presence of sulfated polyanions. A significant rise in activated partial thromboplastin time and a drop in platelet count (P < .025) were demonstrated, with thrombocytopenia developing in 3 patients. Mild-to-moderate gastrointestinal disturbances were experienced by 6 subjects in the short-term study and by all subjects in the long-term study. One subject experienced mild central nervous system symptoms in the short-term study. These results indicate that dextran sulfate is absorbed after oral administration; therefore, further studies on its efficacy, particularly in the early stages of the disease, along with additional observations on its toxicity, are warranted.

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.

[Immunity of middle age and aged patients with tuberculosis and its changes during multimodality treatment by using T-activin]

Fifty six patients with pulmonary tuberculosis were examined. Of them 30 had T-activin in multimodality treatment. To supplement the agent in elderly and old patients was found to elevate the counts of T lymphocytes and T helper cells, to normalize Tx/Tc ratios, to enhance T lymphocytic activity and IL-2 synthesis. At the same time there was an increase in nonspecific responsiveness: enhancement of NKC activity and IL-1 synthesis by macrophages. With this, stimulation of specific antituberculous immunity took place. Normalization of immunological responsiveness and stimulation of specific antituberculous immunity were associated with enhanced therapeutical efficiency.

Effect of d-fenfluramine on the lymphocyte response of HIV+ humans

The objective of this study was to analyse the effect of d-dexfenfluramine (d-FEN) on the human lymphocyte response, in vitro. Experiments were designed to determine whether d-FEN augments specific human immune parameters associated with protection from opportunistic microbial pathogens and particularly focuses on d-FEN as a means by which to augment the function of CD8+ and CD4+ lymphocytes. Lymphocytes were examined for three reasons: (1) for their ability to inhibit the growth of Candida albicans; (2) for their ability to proliferate in response to a mitogen; and, (3) their cytokine profile (vis., production of IL-2, IFN-gamma and TNF-alpha). Peripheral blood mononuclear cells (PBMC) were obtained from 20 HIV+ patients. The patients were diagnosed as HIV+ within the past 0.5-9 years. d-FEN was found to augment the capacity of CD8+ lymphocytes to inhibit the growth of the opportunistic microbial pathogen, C. albicans. d-FEN enhanced the capacity of CD4+ lymphocytes to proliferate in response to the mitogen, Concanavalin A, and to increase the amount of IL-2 produced by CD4+ and CD8+ lymphocytes from AIDS patients. d-FEN increased the number of CD4+ and CD8+ lymphocytes that produced IFN-gamma from either non-AIDS or AIDS patients and increased the number of AIDS patient's CD8+ lymphocytes that produce TNF-alpha. These in vitro data suggest that d-FEN may be effective in enhancing immune function in immunocompromised individuals.

Host response to mycobacterial infection in the alcoholic rat: male and female dimorphism

Increased susceptibility to tuberculosis occurs in the alcoholic. One explanation for the altered susceptibility is a change in T-lymphocyte modulation. To evaluate this, 24 male and 24 female Sprague-Dawley rats were treated with either a Lieber-type liquid ethanol diet (LED) or an isocaloric control (LCD). After 2 weeks, half the subjects were infected with BCG (10(8) colony-forming units) and sacrificed after 42 days. Splenic helper (CD4) and suppressor/cytoxic (CD8) cells were quantitated by flow cytometry. By three-way analysis of variance, splenic cellularity was significantly increased by infection (p < 0.0001) but suppressed by LED (p = 0.0002). There was a marginal sexual difference (p = 0.065) with females exhibiting a 35% lower response while on alcohol. Examining lymphocyte subsets, the most significant changes were observed after infection (BCG) and alcohol treatment (LED). CD4 levels were diminished by LED (p = 0.0002) but markedly increased by infection (p < 0.0001), producing a highly significant interaction that affected both absolute number (p < 0.0001) and relative percent present (p = 0.0078). CD8 was influenced only by infection (p < 0.0001). This resulted in a infection-related increase in the CD4/CD8 ratio which was lower with LED (p = 0.0032). Splenic T-lymphocytes, predominately CD4, are involved in the host response to BCG hepatitis and are adversely influenced by LED, which may contribute to increased susceptibility.

Changes in immunological parameters after combination adjuvant therapy with intravenous DTIC, ACNU, and VCR, and local injection of IFN-beta (DAV + IFN-beta therapy) into malignant melanoma

Combination adjuvant therapy with intravenous dimethyl triazeno imidazole carboxamide (DTIC), 1-[4-amino-2-methyl-5-pyrimidinyl]-methyl-3-[2-chloroethyl]-3-nitrosoure a hydrochloride (ACNU) and vincristine (VCR) and local injection of interferon-beta (IFN-beta) (DAV + IFN-beta therapy) has been widely applied to treat malignant melanoma, and its therapeutic effect is accepted in Japan. Natural killer (NK) activity, CD4+ and CD8+ T cell counts, CD4/CD8 ratio, and white blood cell counts were analyzed before and after DAV + IFN-beta therapy in order to validate its efficacy. After DAV + IFN-beta therapy, the CD4/CD8 ratio was elevated; however, numbers of both CD4+ and CD8+ T cells and NK activity were consecutively depressed. Peripheral lymphocytes were also decreased, possibly by myelosuppression due to the DAV therapy. The posttreatment suppression of NK activity appeared in spite of the administration of IFN-beta. It is suggested that a more effective adjuvant immunomodulator should be introduced to improve the therapeutic effect of the combination adjuvant chemotherapy in malignant melanoma.

Immunoaugmenting effect of FK 506 on experimental allergic encephalomyelitis in Lewis rats

The effect of the immunosuppressive drug FK 506 on encephalomyelitis (EAE) in Lewis rats was studied. Treatment that began during EAE induction delayed EAE onset, but when the disease started it was chronic/progressive and of unusual severity and duration, leading to death in many animals. Treatment started after onset of EAE shortened the disease. Forty seven days after immunization, extensive demyelination and inflammation were observed in the spinal cords of rats treated with FK 506 from the day of EAE induction. Rats treated after EAE onset had only minimal pathological abnormalities.

Effect of nickel chloride on mouse T-lymphocyte subsets

The study was carried out to observe the effect of nickel chloride (NiCl2) on T-lymphocyte subsets, CD4, CD8 and CD4/CD8 ratios in vivo. BALB/C mice were injected i.p. with NiCl2 every other day for 2 w. The NiCl2 doses were 1, 3, 6, 9 or 12 mg/kg. Lymphocytes were obtained from mouse spleen and cultured in the presence of monoclonal antibody FITC conjugated, anti-CD4 or anti-CD8. Samples were determined with a flow cytometer. A suppressive effect on CD4-positive cells was found in the 6 mg/kg group, but this subset was restored to the control level in the 9 and 12 mg/kg groups, suggesting that there was an "immune tolerance" effect. No significant changes were found in CD8-positive cells and CD4/CD8 ratios. The results suggested the NiCl2 had a deleterious effect on mouse T-lymphocytes in short-term in vivo exposure, but the effects may depend on the dose and cell subset.

Phase-II randomized study of pre-operative IL-2 administration in operable NSCLC

Lymphocytopenia is a prognostic factor for shorter survival in advanced lung cancer and it is likely related to an interleukin-2 (IL-2) deficiency occurring during cancer progression. Major surgery itself for cancer is known to induce lymphocytopenia in the postoperative period. Postoperative lymphocyte decrease in colorectal cancer can be prevented by preoperative administration of recombinant human (rhIL-2), indicating that it is possible to drive appropriately important host defence agents during critical events, such as major surgery. The aim of this study is to verify if recombinant human interleukin-2 (rhIL-2) administered preoperatively is able to prevent the lymphocyte decrease occurring after radical surgery in operable lung cancer. This phase II study included 40 patients with operable NSCLC screened as stage II or IIIA, randomized to receive rhIL-2, 9000000 IU subcutaneously twice daily for 3 days before surgery (treated group, 20 patients) or not (control group, 20 patients). At baseline, there were no significant differences in total lymphocyte number and lymphocyte subsets (T-cell, T-helper, CD8+, natural killer, CD4/CD8 ratio) between groups. Postoperatively the control group showed a decrease in total lymphocyte count, T-lymphocyte count, T-helper cell number and CD4/CD8 ratio, significant at the 14th postoperative day relative to baseline values. In contrast, in the rhIL-2 treated group, at the 3rd and at the 14th postoperative days, a significant increase was observed over both baseline and control group values of total lymphocyte count, T-cells and T-helper cells. NK cell number increased significantly only over the control group. CD4/CD8 ratio was increased at the 14th postoperative day significantly over both baseline and control values. At pathological staging after surgery, four patients in the rhIL-2 group and four in the control group resulted in stage pIIIB; one patient in the rhIL-2 group resulted in stage IV (contralateral metastasis). Indeed, 15/20 rhIL-2 treated patients and 16/20 control patients were radically operated. After a 24-month follow-up, 12/20 rhIL-2 treated patients were alive and 8/15 radically operated were disease-free; 8/20 control patients were alive and 4/16 radically operated were disease-free. Toxicity was mild to moderate and easy manageable; treatment was suspended in one patient due to skin rash with hypotension grade II. The preoperative administration of rhIL-2 is feasible and prevents lymphocyte decrease occurring postoperatively after surgery for lung cancer. Further studies are required to assess the impact on survival.

Induction of apoptosis with fusarenon-X in mouse thymocytes

The effects of fusarenon-X (12,13-epoxytrichothecene; FX) on mouse thymus and T-cell subpopulations were studied. In mice that received three intraperitoneal injections of FX, the thymus showed severe atrophy, the thymic cortex almost completely disappeared, and the total number of thymocytes decreased to 2.2% of that of normal mice. CD4+ CD8+ thymocytes were almost completely depleted by this treatment while CD4+ CD8-, CD4- CD8+ and CD4- CD8- thymocytes were not reduced to such an extent, suggesting that selective damage in CD4+ CD8+ thymocytes was induced by FX. In spleen, CD4+ or CD8+ lymphocytes and CD4- CD8- non-T cells remained unchanged. Next, the mode of damage in thymocytes was investigated by a single injection with FX. The lymphocyte nuclei were fragmented and positive for TUNEL (TdT-mediated dUTP nick-end labeling) staining in the thymic cortex 20 h after FX injection. By electron microscopy, apoptotic lymphocytes with condensed nuclei and stroma cells ingesting many nuclear fragments were frequently observed in the thymic cortex. Internucleosomal DNA fragmentation was apparent in the thymocytes treated with FX both in vivo and in vitro. Thus, we demonstrated that the trichothecene mycotoxin FX is a new cause of apoptosis in CD4+ CD8+ thymocytes of mice besides the other factors that cause similar effects.

2,3,7,8-Tetrachlorodibenzo-p-dioxin and diethylstilbestrol affect thymocytes at different stages of development in fetal thymus organ culture

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and estrogen induce thymic atrophy and alter thymocyte development. In the present study we investigate whether TCDD and the synthetic estrogen diethylstilbestrol (DES) alter intrathymic development by the same or different mechanisms. We compared the effects of TCDD and DES on thymocyte development in fetal thymus organ culture (FTOC) and found that both compounds caused a reduction in cell yield. TCDD- and DES-treated FTOCs yielded fewer CD4 + CD8+ double-positive cells. However TCDD treatment also led to a greater percentage of cells in the CD8+ single-positive compartment. At lower dioxin concentrations, our results demonstrated an actual increase in CD8+ cells, whereas DES-treated fetal thymocytes were mainly enriched in CD4-CD8- double-negative cells. More alpha beta-TCR+ positive cells were seen in TCDD- but not in DES-exposed cultures. Furthermore, in this study we found that TCDD and DES also alter intrathymic development at different stages in the CD4-CD8- double-negative compartment. TCDD induced a relative increase in c-kit + CD44 + CD25-HSA-thymocytes, while DES induced an relative increase in c-kit-CD44-CD25 + HSA+ cells. RT-PCR revealed that TCDD reduced RAG-1, RAG-2, and TdT gene expression in the CD4-CD8- double-negative thymocytes. Co-treatment by TCDD and DES in FTOC yielded a mixture of effects induced by each agent. Taken together, our results demonstrate that TCDD and DES affect thymocytes at different stages of development, suggesting distinct mechanisms for induction of thymic atrophy.

Effects of dietary vitamin E on the immune system in broilers: altered proportions of CD4 T cells in the thymus and spleen

To gain insight into the immunomodulatory effects of vitamin E (VE), immune cell population analyses were conducted using thymus and spleen from male broilers fed diets with various levels of VE supplementation (0, 17, 46, and 87 mg dl-alpha-tocopherol acetate/kg of feed). At 2 and 7 wk of age, the percentages of B cells, macrophages, and T cell subsets, delineated by the expression of CD4, CD8, and T cell receptor (TCR) isotype, in thymus and spleen were determined by flow cytometry. The percentages of thymic and splenic B cells and macrophages from 2- and 7-wk-old chickens, as well as the percentage of thymic T cells in 2-wk-old chickens, were unaffected by VE treatment. However, 7-wk-old broilers maintained on 87 mg VE/kg feed had a higher percentage of CD4+CD8- thymocytes, a higher CD4+CD8- to CD4-CD8+ thymocyte ratio, and a lower percentage of CD4+CD8+ thymocytes than chickens receiving no dietary VE supplementation. The VE-induced increase in the percentage of CD4+CD8- thymocytes was due to an increase in the TCR2+CD4+CD8- thymocyte subset, whereas the decrease in the percentage of CD4+CD8+ thymocytes involved all TCR defined T cell subsets. In the spleen, the percentage of CD4+CD8- T cells was lower in 2-wk-old chickens and higher in 7-wk-old chickens maintained on 87 mg/kg feed than in chickens receiving no dietary VE supplementation. The decrease in CD4+CD8- splenocytes at 2 wk of age was due to a decline in the percentage of TCR2+CD4+CD8- splenocytes, whereas the increase in CD4+CD8- splenocytes in 7-wk-old chicks was due to an increase in the percentages of all TCR defined CD4+CD8- T cell subsets. These data support an immunomodulatory effect of VE on CD4+CD8- T cells.

The acute effect of intravenously administered recombinant human erythropoietin on the immune response of uremic patients maintained on regular hemodialysis

The uremic patient on regular hemodialysis (RHD) is subjected to a wide range of immune modulators including the uremic state per se, multiple transfusions and exposure to bioincompatible materials and endotoxins. Erythropoietin (EPO) therapy may raise concern about its potential influence on this complex scenario. To envisage this issue, 15 adequately selected patients, stable on RHD, were randomly assigned in a 2:1 ratio into EPO and placebo groups. After initial assessment and determination of baseline values, they received, in a double-blind manner, either EPO or normal saline as an intravenous bolus immediately after termination of dialysis for 30 successive sessions. Thirty minutes later, following sessions 1, 10, 20, and 30, samples were obtained for determination of blood counts, red cell indices, peripheral lymphocyte counts (PLC), CD4/CD8 ratios, blood EPO levels, and serum concentrations of interleukins (IL) IL-2r, IL-3, and IL-6, tumor necrosis factor (TNFs and TNFalpha), and neopterin (NPT). Blood EPO levels displayed the predicted rise in the EPO group, which correlated with partial improvement of red cell parameters. The mean total leukocyte count and PLCs was significantly increased in the EPO group (p < 0.05) but not in the placebo group. CD4/CD8 ratios were not significantly changed in either group. The serum concentrations of IL-2r, IL-3, and NPT remained fairly stable while that of IL-6 was widely variable in both study groups. The mean serum concentrations of TNF and particularly TNFalpha showed a steady and statistically significant increment in the EPO group from 6 to 41 pg/ml (p < 0.05) and 93 to 128 pg/ml (p < 0.03), respectively. No significant change was noticed in the control group. It is concluded that intravenous administration of EPO under the conditions of this study may have an immune stimulating effect. This is shown by the release of TNFs, which in turn may be responsible, through different potential mechanisms, for the increase in the mean peripheral neutrophil count and the blunting of erythroid responsiveness to EPO therapy.

IFN-gamma-inducing factor/IL-18 administration mediates IFN-gamma- and IL-12-independent antitumor effects

We evaluated the mechanism of the antitumor effects of mouse rIFN-gamma-inducing factor/IL-18 protein on the growth of mouse tumor cell lines in vivo. Mice received IL-18 before or after challenge with CL8-1, a mouse melanoma cell line. Both regimens significantly suppressed tumor growth and reduced the number of mice with growth of tumor from 60% (3/5) to 20% (1/5). Furthermore, IL-18 administered before and after tumor inoculation completely abrogated the establishment of CL8-1 in all animals. IL-18 administration also significantly suppressed the growth of MCA205, a sarcoma cell line, even when treatment was delayed to 7 days following tumor inoculation. Although IL-18/IL-12 combination therapy had the most significant and immediate antitumor effects, many mice so treated succumbed with markedly elevated serum IFN-gamma levels. The antitumor effects of IL-18 were abrogated almost completely when NK cells were eliminated using anti-asialo GM1 Ab administration, but only marginally impaired in IFN-gamma or IL-12 gene-disrupted mice. Immunohistochemical staining revealed that the number of the CD8+ T cells, but not CD4+ T cells, found at the tumor site was reduced in animals treated with IL-18. These results indicate that IL-18 has potent antitumor effects mediated by CD4+ T cells and NK cells, but in IFN-gamma- and IL-12-independent pathways.

Effect of 2,4-dicholorophenoxyacetic acid, trifluralin and triallate herbicides on immune function

The commercial formulations of 3 commonly used herbicides (the amine salt of 2,4-dichlorophenoxyacetic acid, trifluralin and triallate) were evaluated for effects on immune function in male Fisher 344 rats. The herbicides were prepared in an olive oil vehicle and administered by oral gavage twice weekly for 28 d at the following doses: 10.0 mg 2,4-D/kg; 17.5 mg trifluralin/kg; 5.0 mg triallate/kg/treatment. Normal body weight and organ/body weight ratios indicated the rats tolerated the herbicide treatments without difficulty. Exposure to 2,4-D did not alter lymphocyte blastogenesis, 1 gm antibody production (anti-sheep red blood cell), lymphocyte cell surface marker expression or phagocytic function of peritoneal macrophages. Trifluralin acted as a weak mitogen, but impaired T-lymphocyte blastogenesis induced by phytohemagglutinin and concanavalin A. Other immunological measurements were unaffected by trifluralin exposure. Triallate exposure reduced peritoneal macrophage phagocytosis by 33%, showed weak mitogenic properties and impaired T-lymphocyte blastogenesis in the presence of phytohemagglutin. Triallate also increased the anti-sheep red blood cell response expressed/spleen by 43%, a phenomenon suggestive of a compensatory response to minimize the impact on overall immune function. The changes in lymphocyte or macrophage function due to the herbicide treatments were not associated with changes in lymphocyte cell surface antigen expression.

T-2 toxin induces thymic apoptosis in vivo in mice

A single intraperitoneal injection of T-2 toxin (0.35, 1.75, or 3.5 mg/kg body wt) induced time- and dose-dependent thymic atrophy in young female BALB/c mice. T-2 toxin (1.75 mg/kg) induced maximal atrophy by day 3 with complete recovery by day 7. Flow cytometric analysis showed that the CD4(+)CD8(+) double positive thymocyte population decreased markedly. Histopathological examination of the thymus indicated that the pattern of cell death in the thymocytes had a characteristic apoptotic morphology with cell shrinkage and nuclear condensation. The in vivo effects of T-2 toxin included the induction of DNA fragmentation of approximately 200 base pairs in ladder form and cell death in thymocytes. Furthermore, flow cytometric analysis of PI-stained thymocytes from animals dosed with T-2 toxin revealed the formation of apoptotic cells. Of nine kinds of trichothecene mycotoxins tested, T-2 toxin appeared to be the most potent agent to induce apoptosis in the thymus. We sought insight into the mechanism of T-2 toxin-induced apoptosis in vivo. Administration of the protein synthesis inhibitor, CHX (15 mg/kg ip), 5 min after T-2 toxin (1.75 mg/kg ip) inhibited the induction of apoptosis in thymocytes, suggesting that the de novo protein synthesis was necessary. By using adrenalectomized mice and anti-TNF-alpha antibody-injected mice, it was shown that neither endogenous glucocorticoid nor TNF-alpha appeared to be involved in the apoptotic process. Taken together, these findings suggest that T-2 toxin-induced thymic atrophy is associated with cell death through a mechanism of apoptosis.

[The influence of ricin on the course of experimental infections of mice with Trichinella spiralis]

Mice received 5 ng of ricin 24 hours after infection (experiment I) or 1 ng of ricin twice, 24 hours and 17 days of infection (experiment II). Animals were killed in 7, 14, 21, 28, 35, 42 and 60 days after infection. In the jejunum and masseter muscle sections, CD4+ and CD8+ lymphocytes, mast cells and eosinophils were studied. Heavy suppression of CD8+ lymphocytes, strong eosinophils and less pronounced mast cells stimulation was observed in the jejunum of mice received ricin (experiment I). Worm expulsion in intestine was faster than in the control (opposite results in experiment II). The composition of cells infiltration in the muscle was in both experiments similar to the control, however, fewer CD4+ lymphocytes were observed in larva capsule and there were fewer muscle larvae. Therefore CD8+ cells are believed to take part in restricting only the muscle stage of trichinellosis.

Diethylaminoethanol action in the arthritis with Freund adjuvant, in rats

The authors have studied the action of diethylaminoethanol on Freund adjuvant arthritis, induced in female Lewis rats. They worked on 3 groups, each one including 14 rats, weighing 110-130 g: group I = control; group II = rats injected intracutaneous with 0.1 ml Freund adjuvant; group III = rats injected with Freund adjuvant and treated with diethylaminoethanol i.m. (10 mg/kg body weight), and gel application (2.5%) on paws and tail, daily. During the experiment clinical observations and measurements were made and when the animals were killed, blood was sampled for haematological and immunological assays (CD4, CD8, CD25 T cells and NK cells, antinuclear autoantibody and immune complexes). While in all the rats from group II (without treatment) inflammatory processes developed at the level of the peripheral joints, in group III (diethylaminoethanol treated), these ones were present in only 64% of the rats and by much more reduced forms, followed by a short period of involution. The paw volume, measured with an electronic plethysmometer, was more reduced in the treated rats (7.1-14.2%) than in the non treated ones (27.7-29.3%). The haematologic examination showed an increased number of neutrophiles in both groups with FA injecting. The immunological investigations revealed: a decrease of CD4 cells and an increase of CD8 T cells and NK cells in both groups, a much more decreased level (13.2%) of circulatory immune complexes in treated rats, as compared to the non-treated ones (71.7%). No differences were found regarding the CD25 cells and antinuclear antibodies. The histo-pathological examination showed that the intensity and the extension area of the joint lesions (granulation tissue with fibrous change, cartilage invasion and dilaceration, bone atrophy) were much more reduced in the treated rats. The authors put forward the hypothesis that these effects might be due to diethylaminoethanol antiinflammatory properties.

T lymphocytes in mercury-exposed workers

In this work we have investigated the changes in T-helper and T-suppressor cells and T-cell proliferative response to phytohemagglutinin (PHA) in mercury-exposed workers. The study group consisted of 33 workers from a mercury-producing plant with a mean age of 29 years and a mean exposure period of 19 months. At the time of testing, and for the three previous months, the exposed population had urinary mercury levels below the currently accepted limit of 50 micrograms/g creatinine. A reverse CD4+/CD8+ ratio was observed in the mercury-exposed individuals which was characterized by a reduction in the number of CD4+ lymphocytes. No changes were observed in the proliferative response of lymphocytes from exposed individuals to PHA. Similarly, no proliferative response was observed when lymphocytes from normal individuals were cultivated in the presence of serum from the exposed workers. We found no correlations between lymphocytes changes and urinary mercury concentrations, time of exposure or the age of the workers.

Single dose anti-CD4 monoclonal antibody for induction of tolerance to cardiac allograft in high- and low-responder rat strain combinations

Repeated administration of monoclonal antibodies (mAb) directed against the CD4 lymphocyte receptor may induce specific, long-lasting unresponsiveness to fully MHC-mismatched cardiac allografts in rats without additional immunosuppression. We assessed the effect of a single dose of murine anti-rat depleting anti-CD4 mAb (OX-38) on allograft survival in high- and low-responder rat strain combinations. Isogenic strains of DA (RT1av1), PVG (RT1c), AUG (RT1c), and WF (RT1u) rats were used. Recipients in antibody treated groups were given one dose of 5 mg/kg OX-38 mAb on the day of transplant, a dose which was shown to effectively deplete (or block) circulating CD4+ T cells. Other groups were treated for 10 days with cyclosporin A (CsA) and/or Linomide, a novel immunomodulator, which is the first compound able to fully eliminate the effect of CsA in the rat cardiac allograft model. The DA strain was identified as a low-responder to the allogeneic haplotype RT1c (PVG or AUG), but not to RT1u (WF), and developed true tolerance following RT1c grafting and OX-38 or low-dose CsA (5 mg/kg) induction, as verified by the response to retransplantation of a graft from the same donor strain or a third-party challenge. PVG recipients of DA grafts were characterized by high response and only modest (OX-38; median 9.5 days) or moderate (CsA; 23.5 days) prolongation of graft survival. Contrasting graft survival results were obtained in the low-responder combination, either very early rejection (at 10 days) or permanent graft survival (> 100 days). Linomide challenge affected CsA treatment in the high-responder combination but not tolerance induction in the low-responder combination, or the effect of OX-38. It was concluded that in rat heart transplantation a single-dose anti-CD4 mAb therapy may induce permanent donor-specific unresponsiveness in a low-responder strain combination, and that anti-CD4 mAb seems to be unique among immunosuppressive agents while being resistent to challenge by Linomide.

Lower serum zinc in major depression is a sensitive marker of treatment resistance and of the immune/inflammatory response in that illness

The aims of the present study were to examine i) serum zinc (Zn) and copper (Cu) in treatment resistant depression (TRD); ii) the effects of subchronic antidepressant therapy on these trace elements; and iii) the relationships between serum Zn and Cu and immune/inflammatory markers. Serum Zn was significantly lower in TRD than in normal controls. There was a significant inverse correlation between baseline serum Zn and staging of depression based on severity of prior treatment resistance. There were no significant effects of antidepressive treatment on serum Zn, whereas serum Cu was significantly reduced. There were highly significant correlations between serum Zn and the CD4+/CD8+ T-cell ratio (negative), and total serum protein, serum albumin, and transferrin (all positive). The results suggest that lower serum Zn is a marker of TRD and of the immune/inflammatory response in depression. It is suggested that treatment resistance may bear a relationship with the immune/inflammatory alterations in major depression.

Is alcohol a cofactor of HIV and AIDS? Evidence from immunological and behavioral studies

The authors aim to critically examine empirical research on the effects of alcohol on HIV and AIDS from the immunological and behavioral fields. In vitro immunological studies demonstrate that social drinking increases the susceptibility of human cells to HIV infection. Animal studies show that acute and chronic alcohol ingestion increases rate of progression from retrovirus to clinical illness. In humans with HIV, no experimental evidence shows that alcohol is a cofactor of AIDS. Findings from behavioral studies show that a link between social drinking and risk of HIV is weak. No experimental evidence demonstrates that chronic drinking influences rate and course of disease progression to AIDS in humans who are HIV+. It is premature to promote the role of alcohol as a cofactor in HIV and AIDS.

Glutamine requirement of proliferating T lymphocytes

Glutamine is required for lymphocyte proliferation but the site of glutamine action is not yet known. In this study, the effect of glutamine on key events that occur during lymphocyte activation [interleukin-2 (IL-2) production, IL-2 use, IL-2 receptor expression, transferrin receptor expression] was investigated. Rat or mouse spleen lymphocytes were cultured in the presence of the T-cell mitogen concanavalin A (Con A) and various concentrations of glutamine. There was a trend (not significant) for the ratio of CD4+:CD8+ spleen lymphocytes to increase (from 1.9 to 2.6) as the concentration of glutamine in culture medium increased from 0 to 2 mmol/L. As the concentration of glutamine increased, there was an increase in the proportion of cells expressing the IL-2 receptor (from 30 to 45%) and the transferrin receptor (from 34% to 55%). As the concentration of glutamine increased there was a 2.7-fold increase in the concentration of IL-2 in the culture medium. The IL-2 concentration was decreased when an IL-2 receptor-blocking antibody was included in the culture medium; the IL-2 concentrations measured were taken to indicate the initial Con A-stimulated production of IL-2. In these conditions, the IL-2 concentration in the medium increased 39-fold as the glutamine concentration increased. The use of IL-2 by an IL-2-dependent cell line was dependent on the glutamine concentration in the culture medium. Thus, all four components of lymphocyte activation investigated (IL-2 production, IL-2 use, IL-2 receptor expression, transferrin receptor expression) were dependent on the concentration of glutamine present in the culture medium. Thus, glutamine might provide an early signal in the lymphocyte activation process.