Phase II trial of single-agent panobinostat consolidation improves responses after sub-optimal transplant outcomes in multiple myeloma.

Panobinostat is a pan-deacetylase inhibitor that modulates the expression of oncogenic and immune-mediating genes involved in tumour cell growth and survival. We evaluated panobinostat-induced post-transplant responses and identified correlative biomarkers in patients with multiple myeloma who had failed to achieve a complete response after autologous transplantation. Patients received panobinostat 45 mg administered three-times weekly (TIW) on alternate weeks of 28-day cycles commencing 8-12 weeks post-transplant. Twelve of 25 patients (48%) improved their depth of response after a median (range) of 4·3 (1·9-9·7) months of panobinostat. In responders, T-lymphocyte histone acetylation increased after both three cycles (P < 0·05) and six cycles (P < 0·01) of panobinostat when compared to baseline, with no differences in non-responders. The reduction in the proportion of CD127+ CD8+ T cells and CD4:CD8 ratio was significantly greater, after three and six cycles of panobinostat compared to pre-transplant, in non-responders when compared to responders. Whole marrow RNA-seq revealed widespread transcriptional changes only in responders with baseline differences in genes involved in ribosome biogenesis, oxidative phosphorylation and metabolic pathways. This study confirmed the efficacy of panobinostat as a single agent in multiple myeloma and established acetylation of lymphocyte histones, modulation of immune subsets and transcriptional changes as pharmacodynamic biomarkers of clinical benefit.

Association of synovial tissue polyfunctional T-cells with DAPSA in psoriatic arthritis.

OBJECTIVE: This study examines polyfunctional T-cells in psoriatic arthritis (PsA) synovial tissue and their associations with clinical disease and implications for therapy. METHODS: PsA synovial tissue was enzymatically/mechanically digested to generate synovial tissue single cell suspensions. Frequencies of polyfunctional CD4, CD8, T-helper 1 (Th1), Th17 and exTh17 cells, using CD161 as a marker of Th17 plasticity, were determined by flow cytometry in matched PsA synovial tissue and peripheral blood. Synovial T-cell polyfunctionality was assessed in relation to Disease Activity in PSoriatic Arthritis (DAPSA) and in synovial cell suspensions cultured with a current mode of treatment, phosphodiesterase 4 (PDE4) inhibitor. RESULTS: PsA synovial tissue infiltrating CD4+ T-cells expressed higher levels of interleukin (IL)-17A, interferon gamma (IFN-γ), GM-CSF and CD161, with parallel enrichment of Th1, Th17 and exTh17 T-helper subsets (all p<0.05). Interestingly, a significant proportion of synovial T-cell subsets were triple-positive for GM-CSF, tumour necrosis factor (-TNF), -IL-17 or IFN-γ compared with matched blood (all p<0.05). Importantly, frequencies of polyfunctional T-cells correlated with DAPSA: Th1-GM-CSF+/TNF+/IFN-γ+ (r=0.7, p<0.01), Th17-GM-CSF+/TNF+/IL-17+ (r=0.6, p<0.057) and exTh17-GM-CSF+/TNF+/IFN-γ+ (r=0.7, p=0.0096), with no associations observed for single cytokine-producing T-cells. Following ex vivo culture of PsA synovial tissue cell suspensions, polyfunctional GM-CSF+TNFα+IL-17A+ or/IFN-γ+-producing T-cells (p<0.05), but not single cytokine-producing T-cells, were inhibited with a PDE4 inhibitor. CONCLUSION: These data demonstrate enrichment of polyfunctional T-cells in PsA synovial tissue which were strongly associated with DAPSA and ex vivo therapeutic response.

Deltamethrin-Induced Immunotoxicity and its Protection by Quercetin: An Experimental Study.

BACKGROUND: Deltamethrin (DLM) is a type 2 pyrethroid insecticide used in agriculture and home to control pests. However, emerging reports have indicated the immunotoxicity of DLM. OBJECTIVE: Thus, in the current investigation, we have checked the immune-protective role of quercetin in DLM-induced immunotoxicity by using in silico and in vitro techniques. RESULTS: In silico results have shown good interaction of quercetin towards immune cell receptors (T & B cell receptors). The findings of in vitro studies indicated the decrease in oxidative stress which is elevated by DLM in concentration & time-dependent manner. The increased caspases-3 activity was decreased by treatment of quercetin. The apoptosis induced by DLM in thymus and spleen was suppressed only at higher concentration (50µg/ml) of quercetin. Finally, the phenotypic changes due to DLM were restored by quercetin. CONCLUSION: Quercetin has strong binding affinity towards CD4, CD8 and CD28, CD45 receptors and protects the thymocytes and splenocytes against DLM-induced apoptotic signaling pathways.

Involvement of central immunity in uncomplicated diverticular disease.

OBJECTIVE: The pathogenesis of symptoms of uncomplicated diverticular disease (UDD) is unclear, but changes in gut microflora and physiologic inflammation may be implicated. The objective of the study was to investigate the distribution of gut homing lymphocytes in peripheral blood and intestinal mucosa of UDD patients, and the effects of luminal antibiotic treatment. MATERIAL AND METHODS: Ten UDD patients and 10 age- and gender-matched healthy subjects underwent peripheral blood sampling, and colonoscopy with biopsies taken from the transverse and sigmoid colon. Treatment consisted of a 2-month course of rifaximin 1.2 g/day for 15 days/month. Blood sample and mucosal biopsies were repeated in UDD patients at the end of treatment. Flow cytometry was performed using monoclonal antibodies (CD3, CD4, CD8, CD25, CD19, CD45, CD62L, CD103). RESULTS: In peripheral blood, both CD4+ and CD8+/CD103+ were significantly higher in patients at baseline than in controls (0.95% versus 0.36%, and 0.5% versus 0.09%, respectively). After treatment, peripheral CD4+/CD103+ decreased (0.27%), while CD8+/CD103+ did not change (0.35%); on the contrary, peripheral CD25+ increased, the CD4+ subpopulation showing significantly higher levels than those in controls. No difference was found between lymphocytes in the diverticular sigmoid mucosa of patients at baseline and those in controls, but there was a significant decrease in CD8+/CD62L+ after treatment. In the normal transverse colon, CD4+/CD62L+ of patient at baseline were significantly lower than in controls. After treatment, CD4+/CD103+ levels significantly increased, while CD8+/CD62L+ levels significantly decreased. CONCLUSIONS: Both central and mucosal immunity may be modified in UDD patients, with an increased recruitment of CD103+ lymphocytes. A 2-month course of rifaximin appears to reduce CD103+ levels, suggesting a decrease in mobilization of mucosal homing.

[Effect of enterosorption on immunologic parameters of patients with colorectal cancer in the postoperative period].

Our investigation was carried out on an assumption that end results among patients radically-treated for colorectal cancer might be improved by use of enteroabsorption. The study group included 17, controls--13 patients with diagnostically verified stage I-III tumors. Mixed sorbent (microcellulose + polysorb) (6g) was administered, once a week, on the average of 20 days after operation. Immunological vigor was assayed 3 weeks after surgery: immunoglobulin levels--by turbodimetric method, cellular profile of lymphocytes--monoclonal antibodies to cell markers CD3, CD4, CD8, CD16 and CD22. As a result of adjuvant treatment CD22 (B-lymphocytes) concentration increased significantly--from 17.70 to 21.66 (22%), while CD16 (innate killers) both in absolute numbers (19%) and by percentage points (9%). Circulating immunocomplex levels in the sorbent-treatment group were significantly lower (37.44 ths units) than in control (48 ths units) (average 28%). No relapse or metastases were reported in either group.

Immunoregulatory mechanisms and CD4-CD8- (double negative) T cell subpopulations in human cutaneous leishmaniasis: a balancing act between protection and pathology.

Cellular immune responses directed against protozoan parasites are key for controlling pathogen replication and disease resolution. However, an uncontrolled, or improperly controlled, response can be deleterious to the host in terms of both allowing for the establishment of pathology, as well as less effective establishment of memory responses. Human cutaneous leishmaniasis is a disease caused by the infection with Leishmania spp. following a bite from the sandfly, the natural vector of this disease. Tens of millions worldwide are currently infected with Leishmania and no effective vaccines have been developed to date. In the face of the complexity presented by the interaction between a host (humans) with the parasite, Leishmania, and the fact that this parasite is inoculated by another complex, biologically active, vector, the sandfly, it is clearly important to study the immunoregulatory mechanisms that are induced in humans naturally infected by this parasite if we hope to develop effective vaccines and immunotherapeutic treatments in the future. Our laboratory has focused over the years on the study of the local and systemic T cell response during the first episode of cutaneous leishmaniasis suffered by individuals before they undergo antimony treatment. The goal of this review is to briefly outline our findings with hopes of putting our most recent studies concerning the dichotomy between alpha/beta TCR and gamma/delta TCR expressing, CD4-CD8- (double negative-DN) T cells in the context of a balanced immune response against Leishmania and to discuss the implications of these findings toward our understanding of human leishmaniasis.

Soluble SLAMF6 Receptor Induces Strong CD8+ T-cell Effector Function and Improves Anti-Melanoma Activity In Vivo.

SLAMF6, a member of the SLAM (signaling lymphocyte activation molecules) family, is a homotypic-binding immune receptor expressed on NK, T, and B lymphocytes. Phosphorylation variance between T-cell subclones prompted us to explore its role in anti melanoma immunity. Using a 203-amino acid sequence of the human SLAMF6 (seSLAMF6) ectodomain, we found that seSLAMF6 reduced activation-induced cell death and had an antiapoptotic effect on tumor-infiltrating lymphocytes. CD8+ T cells costimulated with seSLAMF6 secreted more IFNγ and displayed augmented cytolytic activity. The systemic administration of seSLAMF6 to mice sustained adoptively transferred transgenic CD8+ T cells in comparable numbers to high doses of IL2. In a therapeutic model, lymphocytes activated by seSLAMF6 delayed tumor growth, and when further supported in vivo with seSLAMF6, induced complete tumor clearance. The ectodomain expedites the loss of phosphorylation on SLAMF6 that occurs in response to T-cell receptor triggering. Our findings suggest that seSLAMF6 is a costimulator that could be used in melanoma immunotherapy. Cancer Immunol Res; 6(2); 127-38. ©2018 AACR.

Dipeptidyl Peptidase-4 Inhibition With Saxagliptin Ameliorates Angiotensin II-Induced Cardiac Diastolic Dysfunction in Male Mice.

Activation of the renin-angiotensin-aldosterone system is common in hypertension and obesity and contributes to cardiac diastolic dysfunction, a condition for which no treatment currently exists. In light of recent reports that antihyperglycemia incretin enhancing dipeptidyl peptidase (DPP)-4 inhibitors exert cardioprotective effects, we examined the hypothesis that DPP-4 inhibition with saxagliptin (Saxa) attenuates angiotensin II (Ang II)-induced cardiac diastolic dysfunction. Male C57BL/6J mice were infused with either Ang II (500 ng/kg/min) or vehicle for 3 weeks receiving either Saxa (10 mg/kg/d) or placebo during the final 2 weeks. Echocardiography revealed Ang II-induced diastolic dysfunction, evidenced by impaired septal wall motion and prolonged isovolumic relaxation, coincident with aortic stiffening. Ang II induced cardiac hypertrophy, coronary periarterial fibrosis, TRAF3-interacting protein 2 (TRAF3IP2)-dependent proinflammatory signaling [p-p65, p-c-Jun, interleukin (IL)-17, IL-18] associated with increased cardiac macrophage, but not T cell, gene expression. Flow cytometry revealed Ang II-induced increases of cardiac CD45+F4/80+CD11b+ and CD45+F4/80+CD11c+ macrophages and CD45+CD4+ lymphocytes. Treatment with Saxa reduced plasma DPP-4 activity and abrogated Ang II-induced cardiac diastolic dysfunction independent of aortic stiffening or blood pressure. Furthermore, Saxa attenuated Ang II-induced periarterial fibrosis and cardiac inflammation, but not hypertrophy or cardiac macrophage infiltration. Analysis of Saxa-induced changes in cardiac leukocytes revealed Saxa-dependent reduction of the Ang II-mediated increase of cardiac CD11c messenger RNA and increased cardiac CD8 gene expression and memory CD45+CD8+CD44+ lymphocytes. In summary, these results demonstrate that DPP-4 inhibition with Saxa prevents Ang II-induced cardiac diastolic dysfunction, fibrosis, and inflammation associated with unique shifts in CD11c-expressing leukocytes and CD8+ lymphocytes.

Glatiramer acetate (GA) therapy induces a focused, oligoclonal CD8+ T-cell repertoire in multiple sclerosis.

We have demonstrated that GA therapy induces a differential upregulation of GA-specific, cytotoxic/suppressor CD8+ T-cell responses in MS patients. We utilized a novel combination of flow sorting and anchored PCR to analyze the evolving clonal composition of GA-specific CD4+ and CD8+ T-cells. TCRbeta chain analysis revealed the development of an oligoclonal GA-specific CD8+ repertoire with persistence of dominant clones over long periods. Interestingly, some sequences resembled published oligoclonal CD8+ TCR sequences from MS lesions. In contrast, GA-specific CD4+ responses were polyclonal and showed continual evolution of their repertoire. This clonotypic and functional analysis provides mechanistic insights into GA therapy.

Murine txk: a protein tyrosine kinase gene regulated by T cell activation.

To identify genes involved in signal transduction pathways that regulate T cell activation and development, murine fetal thymocytes were screened for expression of protein tyrosine kinase family members by the polymerase chain reaction. Using this approach, a non-receptor protein tyrosine kinase, txk, was identified and cloned. Tsk is expressed in thymocytes as early as fetal day 13.5 and its expression at the mRNA level continues throughout development. Txk transcripts are present in thymocytes, peripheral T cells and mast cell lines, but are not detectable in B cell macrophage/monocyte cell lines or in non-hematopoietic fetal or adult tissues. In both thymocytes and T cells, txk transcripts are down-regulated after activation with PMA and ionomycin, concanavalin A or T cell receptor cross-linking. Sequence analysis indicates that txk contains SH2, SH3 and kinase catalytic domains and belongs to the tec family of cytoplasmic protein tyrosine kinases which includes tec, itk and btk. Its unique N-terminus contains a proline-rich region, but unlike the other tec family members, does not contain a pleckstrin homology domain. The restricted expression pattern of txk and its regulation by T cell activation make it an excellent candidate for involvement in signal transduction during thymocyte development.

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.

[Administration of the immunomodulator gepon after tonsillectomy].

The study included 37 patients with chronic tonsillitis. Before and after tonsillectomy all the patients' humoral and cellular immunities were studied. Local thermometry and physiological test "pharynx" were made. For optimization of early postoperative period, all the tonsillectomized patients were given a domestic immunomodulator with local anti-inflammatory activity gepon. The results of gepon therapy allowed conclusion that local use of immunomodulator gepon early after bilateral tonsillectomy is justified and can be recommended for wide clinical practice.

Requirements for activation of CD8+ murine T cells. I. Development of cytolytic activity.

Cytolytic effector function fails to develop if proliferation of allospecific cytolytic T lymphocyte precursors is inhibited, but the requirements for generation of cytolytic activity have not been fully defined. In contrast, the cytolytic effector function of cytolytic T lymphocyte clones does not change during the cell cycle, and the level of cytolytic activity is independent of cellular proliferation. The requirement for proliferation by primary responding populations may reflect the need for clonal expansion of a few inherently cytolytic effector cells in order to reach a threshold number which can readily be detected in conventional cytolytic assays. Alternatively, proliferation may be required for cytolytic T lymphocyte precursors to differentiate into mature, functional cytolytic cells. Using CD8+ T cells which express an antigen-specific transgenic alpha/beta T cell receptor, we have studied the requirements for acquisition of cytolytic capacity. Stimulation of the T cell receptor alone appears to be sufficient to render naive, CD8+ transgenic T cells sensitive to the growth effects of interleukin-2 (IL-2), and in some circumstances to interleukin-4 (IL-4), but not to induce either lymphokine production or cytolytic activity. Costimulatory molecules expressed by allogenic stimulating cells appear to be required for lymphokine production, and CD8+ transgenic T cells initially appear to secrete only IL-2 and interferon-gamma. Stimulation of the T cell receptor of naive, CD8+ transgenic T cells appears to induce cytolytic activity only if cell proliferation occurs, either in response to IL-2 produced by the stimulated cells themselves when costimulatory molecules are present, or to IL-2 or IL-4 from exogenous sources if costimulatory molecules are absent.

Virus encoding an encephalitogenic peptide protects mice from experimental allergic encephalomyelitis.

The association of viral infections with autoimmune central nervous system (CNS) diseases such as post-infectious encephalomyelitis and possibly multiple sclerosis (MS) prompted the investigation to understand how virus infection could modulate autoimmune responses. Recombinant vaccinia viruses encoding an encephalitogenic portion of myelin basic protein (MBP) were evaluated in an animal model for human demyelinating disease, experimental allergic encephalomyelitis (EAE). We have determined that mice vaccinated with recombinant viruses encoding an encephalitogenic region of MBP were protected from EAE. In vivo depletion of CD8+ T cells did not abrogate this protection, suggesting lack of regulation by this cell type. These studies demonstrate that virus infection may be a means to modulated immune responsiveness to CNS disease.

Analysis of cell surface antigens on glucocorticoid-treated rat thymocytes with monoclonal antibodies.

The effects of glucocorticoid (GC) on thymocytes have been utilized to investigate the maturation and differentiation of thymocytes, but these experiments have mainly been performed on mouse thymocytes. We investigated the cell surface antigens expressed by LEW rat thymocytes during thymic reconstitution after GC treatment. Three-color flow cytofluorometric analysis of CD4, CD8 and the T cell antigen receptor (TCR alpha beta) clearly demonstrated that normal rat thymocytes contain CD4-8+ TCR alpha beta- and CD4+8- TCR alpha beta- cells. After GC treatment, we observed significant increases in the percentages of CD4-8+ TCR alpha beta- and CD4+8- TCR alpha beta- cells. The extent of the increase in the percentage of CD4-8+ TCR alpha beta- cells was greater than that of CD4+8- TCR alpha beta- thymocytes. Two-color analysis of TCR alpha beta and major histocompatibility complex (MHC) class I antigen showed that GC treatment significantly increased the percentage of TCR alpha beta- MHC class Ihi cells. Three-color analysis of CD4, CD8 and MHC class I demonstrated that normal rat thymocytes contain CD4-8- MHC class Ihi cells, which increased in number after GC treatment. These results indicate that rat thymocytes contain no fewer CD4-8+ TCR alpha beta- and CD4+8- TCR alpha beta+ cells than do mouse thymocytes, and that CD4-8+ TCR alpha beta- cells predominate over CD4+8- TCR alpha beta- cells in LEW rat thymus. Rat CD4-8- cells seemed to be divided into two subsets of TCR alpha beta- MHC class Ihi and TCR alpha beta- MHC class I- cells.

In vivo immunomodulatory effects of clozapine in schizophrenia.

Recently, there have been some reports that schizophrenia is accompanied by an immune-inflammatory response, characterized by increased secretion of interleukin-6 (IL-6), soluble IL-2 receptor (sIL-2) and lower plasma levels of CC16 (Clara cell protein), an endogenous anti-cytokine. It was shown that clozapine, an atypical antipsychotic drug, may increase the plasma levels of sIL-2R and pro-inflammatory cytokines. This study was carried out in order to examine serum IL-6, IL-6R, CC16, IL-1R antagonist (IL-1RA), transferrin receptor (TfR) and sCD8 antigen, both before and after treatment with clozapine in schizophrenic subjects versus normal controls. Schizophrenic patients showed significantly higher plasma IL-6R and IL-1RA and lower plasma CC16 than normal controls. Treatment with clozapine significantly increased plasma sCD8, IL-6, CC16 and IL-1RA concentrations. The clozapine-induced increments in plasma IL-6 and CC16 appeared during the first 2 weeks of treatment, whereas the increases in plasma sCD8 and IL-1RA appeared after 5 weeks. Clozapine appears to have complex in vivo immunomodulatory effects.

In vivo modulation of the circulating lymphocyte subsets and monocytes by androgen.

Androgens influence some immunological processes, including alternation of the number and function of the circulating lymphocytes and monocytes. In the present study, the effects of three different doses of testosterone on the numbers and percentages of the peripheral blood cells were investigated; the lymphocyte subsets were determined and the proliferation of lymphocyte was detected. Groups of Sprague-Dawley rats were treated with 0.5, 2.5, 12.5 mg/kg or only vehicle, respectively. Compared with controls, the results of complete blood counts showed that the absolute and relative numbers of monocytes decreased. The lymphocyte subpopulations determined by flow cytometry indicated an increase in CD8+ T cells, whereas the CD3+, CD4+ and CD4+CD8+ T cells remained unchanged. Thus, the immunoregulatory index (CD4+/CD8+ ratio) decreased. The proliferative activities determined by MTT assay were down-regulated. In conclusion, the immunosuppressive effects of testosterone may be attributed to a decline in number of monocytes, CD4+/CD8+ ratio and proliferative activities together with an increase of CD8+ T cells in Sprague-Dawley rats.

Low-level sarin-induced alteration of immune system reaction in inbred BALB/c mice.

To study the influence of low-level sarin inhalation exposure on immune functions, inbred BALB/c mice were exposed to low concentrations of sarin for 60 min in the inhalation chamber. Two concentrations of sarin were chosen-asymptomatic concentration (LEVEL 1) and non-convulsive symptomatic concentration (LEVEL 2). The evaluation of immune functions was carried out using phenotyping of CD3 (T-lymphocytes), CD4 (helper T-lymphocytes), CD8 (cytotoxic T-lymphocytes) and CD19 cells (B-lymphocytes) in the lungs, blood and spleen, lymphoproliferation of spleen cells stimulated in vitro by various mitogens (concanavalin A, lipopolysaccharides), phagocyte activity of peritoneal and alveolar macrophages, production of N-oxides by peritoneal macrophages and the measurement of the natural killer cell activity at 1 week following sarin exposure. The results were compared to the values obtained from control mice exposed to pure air instead of sarin. The results indicate that not only symptomatic but also asymptomatic dose of sarin is able to alter the reaction of immune system at 1 week following exposure to sarin. While the number of CD3 cells in the lungs was slightly decreased, an increase in CD19 cells was observed especially in the lungs and blood. The reduced proportion of T-lymphocytes is caused by decay of CD4 positive T-cells. Lymphoproliferation was significantly decreased regardless of the mitogen and sarin concentration used. The production of N-oxides by peritoneal macrophages was stimulated after exposure to LEVEL 2 of sarin whereas their ability to phagocyte the microbes was increased after exposure to LEVEL 1. The natural killer cell activity was significantly higher in the case of inhalation exposure of mice to LEVEL 2 of sarin. Thus, not only organophosphorus insecticides but also nerve agents such as sarin are able to alter immune functions even at a dose that does not cause clinically manifested intoxication following the inhalation exposure. Nevertheless, the alteration of immune functions following the inhalation exposure to a symptomatic concentration of sarin seems to be more pronounced.

In vitro exposure effects of cyclosporin A and bis(tri-n-butyltin)oxide on lymphocyte proliferation, cytokine (receptor) mRNA expression, and cell surface marker expression in rat thymocytes and splenocytes.

Rat thymocytes and splenocytes were exposed in vitro to the model compounds Cyclosporin A (CsA), an immunosuppressive drug, and bis(tri-n-butyltin)oxide (TBTO), an immunotoxic environmental contaminant. The lymphocyte transformation test (LTT), cytokine (receptor) mRNA expression (RT-PCR and dot blot hybridisation), and flow cytometry were evaluated as assays for in vitro immunotoxicity, at dose levels that did not show effects on viability, this being the aim of the study. LTT and RT-PCR proved useful assays. Lymphocyte transformation was suppressed by both compounds, while IL-2 mRNA expression was suppressed by CsA but not by TBTO, and both compounds suppressed IL-2R mRNA expression in splenocytes but not in thymocytes. Furthermore, the data obtained suggest that antiproliferative effects may be more relevant than apoptosis induction for TBTO induced thymus atrophy.

Dexamethasone-induced effects on lymphocyte distribution and expression of adhesion molecules in treatment-resistant depression.

Alterations in immune function are associated with major depression and have been related to changes in endocrine function. We investigated whether alterations in immune function were associated with altered basal hypothalamic-pituitary-adrenal (HPA) function (salivary cortisol) and lymphocyte sensitivity to dexamethasone (DEX) intake (1 mg PO). The latter was explored by comparing the impact of DEX-induced changes on peripheral lymphocyte redistribution and expression of adhesion molecules (beta2 integrins and L-selectin). The study included 36 inpatients with treatment-resistant major depression (unipolar subtype) and 31 matched healthy controls. The dexamethasone suppression test (DST) was carried out and used to classify 10 patients as HPA axis non-suppressors. The latter presented significantly higher post-DEX salivary cortisol levels than DST suppressors, 82.0 vs. 8.9 nM l(-1) h(-1). No differences in basal salivary cortisol levels were found between patients and controls. Changes in cell redistribution (CD4(+), CD8(+), CD19(+), CD56(+) and HLADR(+) cells) after DEX administration were more prominent in controls than in patients, but the effects of DEX varied dependent on whether patients exhibited DEX-induced suppression of cortisol secretion. Glucocorticoid-induced suppression of adhesion molecule expression was also generally less marked in patients than controls. Our data indicate that alterations in immune function and steroid regulation associated with depression are not related to elevated basal levels of cortisol and further suggest that lymphocyte steroid resistance is associated with drug-resistant depression.