Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “immunosuppression”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1976

[Modification of the immune reaction by antigen-immunosuppressive-agent conjugates. I. Tentative hypothesis for the induction of antigen-specific suppression by antigen-immunosuppressive-agent conjugates].

The most important mechanisms for the specific depression of immune reactions--immuno-tolerance, enhancement, transfer of antibodies, drug induced tolerance, immunological suicide, application of antibody-toxin-complexes--are discussed with regard to their possible application in the clinical practice. A tentative hypothesis for induction of antigen specific suppression is proposed, basing on the use of antigen-immunosuppressive agent-conjugates (AIC). Antigen binding lymphocytes are supposed to bind the AIC and to pick them up through endocytosis. After breakdown of the AIC in the lymphoid cells the free immunosuppressive agent can become effective causing damage to the specific cell clones.

Animals↗
PubMed1976

[Modification of the immune reaction by antigen-immunosuppressive-agent conjugates. II. Immunogenicity of antigen-immunosuppressive-agent conjugates].

The maintenance of specific immunogenicity of carrier proteins is a necessary condition for the successful use of antigen-immunosuppressive agent-conjugates (AIC) for an antigen specific suppression of the immune response. The experimental results indicate that, in spite of the binding of 6-mercaptopurine (6-MP) and toluyl (T) to bovine gamma globulin (BGG) and human serum albumin (HSA), the carrier specific immunogenicity is not significantly altered. The intradermal application of 6-MP-BGG and T-BGG emulsified with complete Freund's adjuvant in guinea pigs results, in all cases, in a well detectable anti BGG hemagglutination and precipitation titer. This kind of immunization leads also to a formation of anti 6-mercaptopurine and anti new antigen determinants (NAD's) antibodies.

Animals↗
PubMed1976

[Modification of the immune reaction by antigen-immunosuppressive-agent conjugates. IV. Studies on the specific suppression of humoral immune response in guinea pigs by antigen-immunosuppressive-agent conjugates].

Bovine gamma globulin (BGG) antigens were modified by the binding of 6-mercaptopurine and toluyl residues, and their influence on the humoral immune response in guinea pigs was investigated. The antigen-immunosuppressive agent-conjugates (AIC) were different, depending on the method used for their preparation and the number of coupled residues per one molecule of BGG. Conjugates denoted as MPI-n-BGG were prepared by special chemical binding of corresponding thioisocyanates. MPII-n-BGG were synthetized by acetylation, and MPIII-n-BGG conjugates, by reductive alkylation. Pretreatment of guinea pigs with MPIII-19-BGG, MPII-16-BGG resulted in a stimulatory effect on the subsequent humoral immune response induced by BGG application. A significant suppressive influence was detectable if the animals had been pretreated with MPII-6-BGG and MPI-26-BGG. MPI-13-BGG and MPI-36-BGG had no effect on the later induced anti-BGG antibody formation. The immune response against a second antigen (human serum albumin) was not influenced by this kind of pretreatment of the animals. Therefore it seems justified to conclude that both stimulatory and suppressive effects seen here were antigen specific and that both the method for chemical modification and the number of coupled 6-MP residues are very important for their effectivity.

Agglutination↗
PubMed2026

Electronic Nudges to Increase Influenza Vaccination in Immunosuppressed Adults Across the Age Spectrum: A Pooled Analysis of 2 Nationwide Randomized Trials.

BACKGROUND: Immunosuppressed individuals face higher risk of severe influenza complications, yet vaccination coverage remains low. We aimed to assess the effect of electronic letter-based nudges on influenza vaccination uptake by immunosuppression status. METHODS: We performed a participant-level pooled analysis of 2 methodologically harmonized, nationwide, pragmatic randomized clinical trials during the 2023-2024 influenza season. Adults aged &#x2265;65 years (NUDGE-FLU-2) and adults aged 18-64 years with chronic conditions (NUDGE-FLU-CHRONIC) were included, with immunosuppression defined by an immunosuppressive diagnosis or a filled prescription for immunosuppressive therapy. Participants were randomized in a 2.45:1:1:1:1:1:1 ratio to usual care or 1 of 6 electronic letter interventions. The primary outcome was receipt of influenza vaccination by 1 January 2024 ascertained from nationwide administrative health registries. Effect modification by immunosuppression status was assessed using binomial regression. RESULTS: Among 1 181 254 participants (mean age 67 years; 73 830 [6.3%] immunosuppressed), 66.1% were vaccinated. Any letter increased vaccine uptake compared with usual care (absolute difference, 2.79% points; 95% confidence interval [CI], 2.60-2.98; P < .001), with greater effect among immunosuppressed individuals (+4.12 vs +2.70% points; Pinteraction = .002). In younger adults with chronic conditions, letter-based nudges increased vaccination rates by 11.7% points overall and by 13.3% points among those with immunosuppression (Pinteraction = .007). Among immunosuppressed individuals, nudging effects appeared greater for those with immunosuppressive conditions than for those receiving immunosuppressive treatment. CONCLUSIONS: Electronic letter-based nudges increased influenza vaccination rates, with greater benefit among immunosuppressed individuals. These findings support implementation of low-cost, letter-based nudging strategies to improve vaccine uptake in this high-risk population. Clinical Trials Registration. NCT06030726 and NCT06030739.

Adolescent↗
PubMed1979

Correlation between anergy and a circulating immunosuppressive factor following major surgical trauma.

In order to clarify the relationship between anergy and immunosuppressive activity in the serum, we studied 46 previously well patients before and at three, five, seven and 28 days after surgery. Delayed hypersensitivity was measured by skin testing with four common recall antigens, and serum immunosuppressive activity was determined by the ability of the patient's serum in 10% concentration to suppress by 50% or more the phytohemagglutinin (PHA) stimulation of normal human lymphocytes as compared to pooled normal serum. Prior to surgery, all patients manifested delayed hypersensitivity to one or more antigens, and no patient had immunosuppressive serum. Fifteen patients underwent minor surgery under general anesthesia and did not develop anergy or immunosuppressive serum. Thirty-one patients underwent major cardiovascular surgery. Thirteen of these patients became anergic by day 3 after operation, and 11 of the 13 developed immunosuppressive serum. Eighteen patients maintained delayed hypersensitivity after major surgery, and only three developed immunosuppressive serum. The correlation between anergy and immunosuppressive serum was highly significant (p < 0.001). There was a significant difference in the degree of suppressive activity in the serum of the anergic and reactive patient groups for each postoperative day studied until day 28, when there was recovery of delayed hypersensitivity and lack of immunosuppressive serum. The occurrence of postoperative anergy and immunosuppressive serum was not related to the patient's age, sex, number of perioperative blood transfusions or duration of anesthesia but was associated with an increase in postoperative infectious complications (p < 0.05) and in postoperative days in the hospital (p < 0.01). Pooled immunosuppressive serum from anergic patients was fractionated by ion exchange chromatography, gel filtration and preparative high voltage electrophoresis. The majority of the immunosuppressive activity could be accounted for by an electrophoretically homogenous polypeptide-containing fraction not identified in the serum of patients undergoing minor surgery or in normal individuals. We conclude that anergy occurring after major operative trauma is associated with the appearance of a circulating immunosuppressive molecular species and that these events are in turn associated with increased patient morbidity and increased length of hospitalization.

Adult↗
PubMed1978

Effect of immunosuppression on the growth of six murine tumors.

Mice have been immunosuppressed with cyclophosphamide, cortisone-acetate, irradiation, or Ehrlich ascitic fluid (EAF) and then grafted with Ehrlich tumor or with one of the following strain-specific tumors: thymoma, methylcholanthrene-induced fibrosarcoma, B-16 melanoma, lymphatic leukaemia, and myeloid leukaemia. Immunosuppression of the host influenced very differently the growth of transplanted malignancies. The growth of thymoma and of Ehrlich tumor was regularly enhanced. The growth of fibrosarcoma and of melanoma, on the other hand, was retarded in mice pretreated with EAF and X-rays, or remained unchanged in mice pretreated with drugs. Leukaemia growth was not influenced by any immunosuppressive treatment; the only exception was enhanced growth of lymphoid leukaemia in animals pretreated with EAF. Thus different tumors grew differently in animals immunosuppressed by the same immunosuppressive agent, while different immunosuppressive treatment changed the growth of one particular tumor always in the same way. From this we concluded: (1) there is no rule as to how immunosuppression of the host will influence tumor growth; and (2) the way in which the malignant growth will be changed depends mainly upon the type of the tumor and probably not very much upon the type of immunosuppressive treatment.

Animals↗
PubMed2025

Immunosuppressants Rewire the Gut Microbiome-Alloimmune Axis Through Time-Dependent and Tissue-Specific Mechanisms.

BACKGROUND: Lifelong immunosuppressive therapy is required to prevent allograft rejection in organ transplantation. Current immunosuppressants effectively suppress adaptive and innate immune responses, but their broad, antigen-non-specific effects often result in severe off-target complications. It remains a significant unmet medical need in transplant medicine. RESULTS: In this study we investigated immunosuppressant effects of four major immunosuppressant classes, including tacrolimus, prednisone, mycophenolate mofetil (MMF), and fingolimod (FTY), on the gut microbiome, metabolic pathways, lymphoid architecture and lymphocyte trafficking after up to 30-day chronic exposure. Despite their distinct mechanisms of action and not designed to target the gut, all immunosuppressive drugs induced profound and time-dependent alterations in both intestine gene expression and gut microbiome composition. Progressive alterations from moderate early, drug-specific changes to a strikingly convergent microbial dysbiosis, marked by significant expansion of pathobionts of Muribaculaceae, occurred across all drug classes. Concurrently, all drugs uniformly induced significant suppression of mucosal immunity including B cell, immunoglobulin, and antigen recognition. Time-dependent changes in lymph node (LN) reorganization and cellular composition were also observed, marked by a progressive shift toward pro-inflammatory phenotypes in gut-draining mesenteric LNs and a gradual loss of tolerogenic architecture in peripheral LNs. Drug-specific metabolic alterations and distinct phases of intestinal transcriptional responses were also characterized. Notably, MMF and FTY demonstrated the most robust immunomodulatory properties, and were able to suppress alloantigen-induced inflammation through mediating regulatory T cell distribution and LN remodeling. CONCLUSIONS: Together, these findings highlight the underappreciated complexity and temporal dynamics immunosuppressants effects, particularly their impact on the gut and compartmentalized regulation of alloimmune in lymphoid tissues. Understanding these relationships offers new opportunities for refining immunosuppressive strategies to reduce treatment-related off-target complications and improve long-term organ transplant outcomes.

gut dysbiosis↗
PubMed1975

[Immunosuppressive therapy in renal disease (author's transl)].

Since immunological events were found to be pathogenetically involved in various forms of glomerulonephritis, corticosteroids and immunosuppressive drugs were introduced in the treatment of nephritis. However, as opposed to the findings in the paediatric nephrotic syndrome, controlled and multicentric trials with immunosuppressive therapy revealed disappointing results in the management of renal disease in adults. Significantly better results under immunosuppressive therapy, were seen only in the nephrotic syndrome based on the so-called "no changes" or "minimal changes" nephritis. In chronic membranous and proliferative glomerulonephritis the clinical course in the treated group was not statistically different from that of the untreated group. In some disorders of connective tissues, such as systemic lupus erythematosus, polyarteritis nodosa and Wegener's granulomatosis, corticosteroids and immunosuppressive agents seem to exert a favourable effect on the course of renal disease. Encouraging results concerning the combined use of immunosuppressive drugs, anticoagulants and platelet aggregation inhibitors in mesangiocapillary (membrano-proliferative) glomerulonephritis and rapidly progressive nephritis have also been presented. Several factors such as incomplete immunosuppression, druginduced antigen tolerance and increased immune complex formation as a consequence of inhibited antibody production may contribute to the fact that many patients with different forms of nephritis do not benefit from long-term immunosuppressive therapy.

Adult↗
PubMed2026

Spatial biology reveals altered macrophage states in immunosuppressed non-melanoma skin cancer.

Immunosuppressed patients with non-melanoma skin cancer experience worse clinical outcomes, yet the tumor immune microenvironment associated with systemic immunosuppression remains incompletely defined. Using integrated single-cell, spatial transcriptomic, multiplex immunofluorescence, and spatial epigenomic profiling across immunocompetent and immunosuppressed tumors, we found that overall immune-cell composition was largely preserved despite differences in immune-cell distribution, spatial organization, and T cell clonality. Immunosuppressed tumors demonstrated reduced intratumoral macrophage densities, decreased T cell clonal diversity, altered antigen-presenting cell and T cell spatial interactions, and distinct fibroblast- and macrophage-associated spatial niches. Multi-cohort validation across complementary spatial and single-cell platforms identified consistent alterations in innate-adaptive immune organization in immunosuppressed tumors. Together, these findings define spatial and functional remodeling of the tumor immune microenvironment under systemic immunosuppression and provide a framework for future therapeutic investigation in high-risk patients.

Humans↗
PubMed1976

Cytomegalovirus infection in patients receiving immunosuppressive therapy for rheumatologic disorders.

Evidence of cytomegalovirus infection was sought in 131 patients attending a rheumatology clinic, 211 blood donors, and 14 patients before and after the initiation of cytotoxic immunosuppressive therapy for a rheumatologic condition. The titer of complement-fixing antibody to cytomegalovirus was significantly related to age and sex, but not to rheumatologic disease. After adjustment for age and sex differences, the proportion of patients treated with corticosteroids who had measurable antibody was lower than that of controls (P less than 0.025). Immunosuppressive therapy with azathioprine or cyclophosphamide did not affect the proportion of patients with antibody, but there was a significantly increased titer of antibody in those who were seropositive (P = 0.04). Cytomegalovirus was isolated from the urine of 20% of patients receiving cytotoxic immunosuppressive drugs, but not from any of the patients receiving corticosteroids or neither form of therapy (P = 0.001). Eight of 14 patients followed prospectively after the initiation of therapy with immunosuppressive drugs became infected with cytomegalovirus as demonstrated by a fourfold or greater rise in complement-fixing titer, viruria, or both. Seven of the eight patients were seropositive before therapy, a finding suggesting that immunosuppression acts largely by reactivating latent infection. It is postulated that immunosuppressive agents alone may account for a large proportion of cytomegalovirus infections seen after allograft transplantation.

Adrenal Cortex Hormones↗
PubMed1978

[Immunosuppression as a concomitant effect].

1. It is becoming increasingly clear that besides traditional immunosuppressive agents, an array of miscellaneous influences and conditions, as well as drugs used for other purposes, can affect the immune system. The potential pathogenetic role of immunity in an ever growing number of diseases, including infections, cancer, and autoimmune processes, confers on the concept of concomitant immunosuppression or immunotoxicology its due place in the discipline of immunopharmacology. 2. Microorganisms such as viruses, bacteria, and protozoa (and their products), as well as parasites, may depress immune reactivity. The mechanism of action, dose-response dependency, effect of timing, and relation to bacterial adjuvanticity need more thorough exploration. 3. The efficacy of immunosuppressive drug protocols can be improved by combining immunosuppressants without bone marrow toxicity, such as niridazole or free fatty acids, with the standard antiproliferative immunosuppressive agents. 4. Prostaglandin is a likely candidate for an essential role as an immunosuppressive effector. Its release from T-suppressor cells is triggered for example by microorganisms. Moreover, dietetic and metabolic factors, such as free fatty acids, and nervous impulses affect prostaglandin formation. If thus constitutes a link between the nervous system and, on the other hand, immunity and possibly cancer.

Adjuvants, Immunologic↗
PubMed1979

Immunosuppressive antilymphocyte serum. III. Different subpopulations of T lymphocytes are influenced at different doses of antilymphocyte serum.

In these experiments, we have examined the effect of antilymphocyte serum (ALS) on T lymphocyte subpopulations in animals receiving nonimmunosuppressive, weakly immunosuppressive, and strongly immunosuppressive doses of different pools of ALS. Nonimmunosuppressive (inactive) sera were defined by their inability to prolong Fischer skin grafts on Lewis recipients. Weak immunosuppression was considered to have been achieved at doses of active ALS that induced prolonged survival of Fischer skin homografts but not the more strongly antigenic Wistar-Furth homografts. Similarly, strong immunosuppression was induced with doses of active ALS that resulted in prolonged survival of not only Fischer but also the Wistar-Furth grafts. Examination of Lewis rats treated under these conditions indicated that weakly immunosuppressive ALS created a shift in peripheral T lymphocyte subpopulations with an increase in the absolute numbers of one subpopulation (lymphocytes capable of forming rosettes with guinea pig red blood cells in fetal calf serum). This population shift induced by active ALS was dose dependent and occurred in spleen slightly before lymph nodes. Nonimmunosuppressive antisera failed to induce this change. Moreover, although these doses of ALS were capable of prolonging the survival of Fischer skin grafts and inducing the population change, there was no loss of reactivity to phytohemagglutinin (PHA) and concanavalin A (Con A) in vitro. However, at doses of antiserum capable of prolonging the survival of Wistar-Furth skin grafts, the in vitro reactivity of T lymphocytes to these mitogens was more consistently suppressed. These data suggested that the degree of immunosuppression achieved with different pools or doses of ALS was attributable to variation in the susceptibility of different T lymphocyte subpopulations to suppression by ALS.

Animals↗
PubMed1979

Suppression of T cell-mediated immunity by tumor cells: immunogenicity versus immunosuppression and preliminary characterization of the suppressive factors.

In studying the immunogenicity of spleen cells and tumor cells in the generation, of cytotoxic T lymphocyte (CTL) in the allogeneic mixed lymphocyte culture (MLC) or mixed lymphocyte tumor cell culture (MLTC) reactions, we have found that the tumor cells not only appear to be poorly immunogenic, but are also immunosuppressive. This was shown by the ability of the tumor cells or their cell-free extracts to suppress standard MLC reactions. This suppression was acting mainly at the induction phase of the cytotoxic response. It could not interfere with the killing activity of the fully generated CTLs. In a Friend virus-induced leukemia FBL-3 system, at least two major components could be attributed to the cause of immunosuppression; one was of viral origin and the other was of non-viral origin. The viral component was sensitive to UV-irradiation and could be pelleted after ultracentrifugation at 100,000 g. The non-viral component was UV-resistant and was retained in the supernatant fraction after ultracentrifugation. Friend virus and 12 commonly found murine viruses have been excluded as the possible candidates causing the immunosuppression. The immunosuppressive viruses are very likely of endogenous origin and are defective in replication as shown by electromicroscopy, and by the virus focus-inducing and reverse transcriptase assays. These findings indicate that probably all tumor cells possess the immunosuppressive factor(s) which may account for their apparent lack of immunogenicity and the lack of proper immune responses in the tumor-bearing hosts.

Animals↗
PubMed1979

Quantitative stereological studies on the mechanism of immunosuppressive effect of nitrogen mustards of benzimidazole derivatives: the role of polymorphonuclear leukocytes and mononuclear phagocytes.

The effect on antigen uptake and digestion in macrophages and polymorphonuclear leukocytes (PMNL) of 2 compounds of a series of benzimidazole nitrogen mustard derivatives has been investigated by ultrastructural quantitative stereological techniques in order to enlighten some mechanisms of the immunosuppressive effect of especially one of the chemicals. One compound, ZIMET 3393 (Cytostasan), is a powerful cancerostatic with only moderate immunosuppressive side effects while ZIMET 3164 proved an effective immunosuppressant with low cytostatic action. Results of a recent study (FRITSCH and GOTHE 1979) have lent support to the hypothesis that immunosuppression can be induced by an inhibition of antigen processing by macrophages through a membrane-stabilizing effect of the chemicals under investigation. It can be shown in the present study that in the case of ZIMET 3164 an increased competitive antigen phagocytosis and digestion takes place in PMNL. This alternative pathway of antigen processing is suggested to be ineffective with respect to enhancement of immune responses compared with that through macrophages, thus providing an additional possible mechanism of chemical immunosuppression.

Animals↗
PubMed1975

Response to primary infection with Herpesvirus saimiri in immunosuppressed juvenile and newborn squirrel monkeys.

Immunosuppression of juvenile squirrel monkeys with combined azathioprine, prednisolone, and antilymphocyte globulin resulted in decreased antibody responses to viral antigens after primary infection with Herpesvirus saimiri (HVS). The virus was repeatedly isolated from the oropharynx of immunosuppressed monkeys but not from untreated infected controls. Thus immune factors are important in inhibiting shedding of HVS from the oropharynx. HVS could be isolated from the peripheral blood lymphocytes of infected control monkeys but not from the lymphocytes of immunosuppressed monkeys. Immunosuppressed monkeys also had decreased percentages of lymphocytes capable of forming rosettes with sheep erythrocytes. These results indicate that the immunosuppressive agents had inhibitory effects on lymphocytes (presumably thymus derived) capable of being latently infected with HVS. Antibody responses in newborn monkeys infected with HVS were delayed compared with juvenile monkeys. Treatment of newborn monkeys with antilymphocyte globulin had no suppressive effect on antibody responses to HVS.

Animals↗
PubMed1977

Contrasting effects of immunosuppression on Theiler's virus infection in mice.

In the present study, cyclophosphamide and rabbit anti-mouse thymocyte serum were used to immunosuppress SJL/J mice infected with Theiler's mouse encephalomyelitis virus (TMEV) in order to delineate the potential mechanism(s) of virus-induced cellular injury in this infection. Whereas both immunosuppressive agents produced a significant increase in mortality, this treatment had differing effects on the pathological involvement of gray and white-matter structures in the central nervous system. The central nervous system of immunosuppressed TMEV-infected mice had increased microglial cell proliferation and neuronal necrosis, longer maintenance of high virus levels and spread of virus antigen to involve the neocortex and hippocampal complex. These observations indicate that TMEV causes a cytolotic infection of neurons and possibly other cells in gray matter. In contrast, immunosuppression produced a dramatic reduction in mononuclear inflammatory cells in the leptomeninges and spinal cord white matter of infected mice and prevented demyelination. Further, virus antigen was not detected in the leptomeninges and white matter of immunosuppressed and infected mice. These findings suggest that demyelination of TMEV infection is immune mediated.

Animals↗
PubMed1979

Skin cancer development in mice exposed chronically to immunosuppressive agents.

Inbred female C3Hf/HeN, murine mammary tumor virus-negative mice exposed to either UV light or benzo[a]pyrene (BP), were subjected to four different chronic immunosuppressive regimens to determine their effect on skin cancer development. The immunosuppressive agents were cyclophosphamide, methotrexate, cortisone, and heterologous antilymphocyte globulin. Because of an unexpectedly high morbidity and mortality of mice exposed to chronic immunosuppressive measures, the dosages were kept at a level that permitted them to survive but did not prolong allogeneic skin graft survival and lower antibody titers, nor did this level diminish proliferative responses of lymphocytes to mitogens or allogeneic lymphocytes. Nevertheless, the latency periods (time interval between beginning of medication and appearance of skin tumors) of tumors in mice exposed to immunosuppressant measures were significantly shortened in several groups of mice exposed to UV and subjected to cyclophosphamide, cortisone, or antilymphocyte globulin and mice exposed to BP and subjected to cortisone acetate. In 3 groups, spindle cell tumors (fibrosarcomas) shifted to squamous cell carcinomas. A suppressed immune function would not be regarded as the mechanism for the observed responses because immunosuppression was not detected in the experimental mice.

Animals↗