Modulation of cellular-immune responses in vivo and in vitro by histamine receptor-bearing lymphocytes

Integrating the monoamine and cytokine hypotheses of depression: Is histamine the missing link?

Psychiatric diseases, like depression, largely affect the central nervous system (CNS). While the underlying neuropathology of depressive illness remains to be elucidated, several hypotheses have been proposed as molecular underpinnings for major depressive disorder, including the monoamine hypothesis and the cytokine hypothesis. The monoamine hypothesis has been largely supported by the pharmaceuticals that target monoamine neurotransmitters as a treatment for depression. However, these antidepressants have come under scrutiny due to their limited clinical efficacy, side effects, and delayed onset of action. The more recent, cytokine hypothesis of depression is supported by the ability of immune-active agents to induce "sickness behaviour" akin to that seen with depression. However, treatments that more selectively target inflammation have yielded inconsistent antidepressive results. As such, neither of these hypotheses can fully explain depressive illness pathology, implying that the underlying neuropathological mechanisms may encompass aspects of both theories. The goal of the current review is to integrate these two well-studied hypotheses and to propose a role for histamine as a potential unifying factor that links monoamines to cytokines. Additionally, we will focus on stress-induced depression, to provide an updated perspective of depressive illness research and thereby identify new potential targets for the treatment of major depressive disorder.

Inflammation-Induced Histamine Impairs the Capacity of Escitalopram to Increase Hippocampal Extracellular Serotonin

Commonly prescribed selective serotonin reuptake inhibitors (SSRIs) inhibit the serotonin transporter to correct a presumed deficit in extracellular serotonin signaling during depression. These agents bring clinical relief to many who take them; however, a significant and growing number of individuals are resistant to SSRIs. There is emerging evidence that inflammation plays a significant role in the clinical variability of SSRIs, though how SSRIs and inflammation intersect with synaptic serotonin modulation remains unknown. In this work, we use fast in vivo serotonin measurement tools to investigate the nexus between serotonin, inflammation, and SSRIs. Upon acute systemic lipopolysaccharide (LPS) administration in male and female mice, we find robust decreases in extracellular serotonin in the mouse hippocampus. We show that these decreased serotonin levels are supported by increased histamine activity (because of inflammation), acting on inhibitory histamine H3 heteroreceptors on serotonin terminals. Importantly, under LPS-induced histamine increase, the ability of escitalopram to augment extracellular serotonin is impaired because of an off-target action of escitalopram to inhibit histamine reuptake. Finally, we show that a functional decrease in histamine synthesis boosts the ability of escitalopram to increase extracellular serotonin levels following LPS. This work reveals a profound effect of inflammation on brain chemistry, specifically the rapidity of inflammation-induced decreased extracellular serotonin, and points the spotlight at a potentially critical player in the pathology of depression, histamine. The serotonin/histamine homeostasis thus, may be a crucial new avenue in improving serotonin-based treatments for depression.SIGNIFICANCE STATEMENT Acute LPS-induced inflammation (1) increases CNS histamine, (2) decreases CNS serotonin (via inhibitory histamine receptors), and (3) prevents a selective serotonin reuptake inhibitor (SSRI) from effectively increasing extracellular serotonin. A targeted depletion of histamine recovers SSRI-induced increases in extracellular hippocampal serotonin.

FLT-PET At 6 Weeks Predicts Response Assessed by CT at 12 Weeks in Melanoma Patients Treated With Pembrolizumab

PURPOSE

Investigate the ability of F-fluorothymidine (FLT) PET combined with CT at 6 weeks to predict treatment response at 12 weeks after treatment with pembrolizumab.

METHODS

Five patients with unresectable stage IV melanoma were included in this single-institution pilot study. Patients underwent FLT-PET/CT (baseline and 6 weeks) and CT (baseline and 12 weeks). FLT-PET/CT response and CT response were assessed using PET Response Criteria in Solid Tumors and immune Response Evaluation Criteria in Solid Tumors, respectively. Patients were categorized as responders (complete response, partial response) and nonresponders (stable disease, progressive disease). Agreement between 6-week FLT-PET/CT and 12-week CT was calculated using Cohen kappa's agreement. Eight baseline FLT-PET/CT parameters were extracted: SUVmax, SUVpeak, SUVSD, SUVmean, proliferative tumor volume, total lesion proliferation, bone marrow-to-liver SUVmax ratio, and spleen-to-liver SUVmax ratio. Eight delta-parameters were extracted at 6 weeks by calculating variation in FLT uptake as percentage change from baseline.

RESULTS

Agreement between 6-week FLT-PET/CT and 12-week CT was kappa = 0.615, P = 0.025. Three of 5 patients were categorized as responders on CT by immune Response Evaluation Criteria in Solid Tumors. At baseline, responders had a lower mean proliferative tumor volume and a higher bone marrow-to-liver SUVmax ratio. At 6 weeks, responders demonstrated a decrease in tumor volume and tumor proliferation.

CONCLUSIONS

Our study illustrates the potential for FLT-PET/CT as an early predictor of response for patients with metastatic melanoma on anti-PD1 immunotherapy. Larger studies are indicated to confirm these findings.

Allergic contact dermatitis of both eyes caused by alcaftadine 0.25%: a case report

Background

To report the first case of allergic contact dermatitis (ACD) associated with alcaftadine 0.25% ophthalmic solution.

Case presentation

The patient was a 51-year-old woman with no previous history of side effects to ophthalmic antihistamine agents. She had been prescribed alcaftadine 0.25% for allergic conjunctivitis. On first application of the medication, she did not experience any cutaneous reaction. One day later, after the second alcaftadine 0.25% application, both eyelids became swollen, and erythematous changes were evident. On slit-lamp examination, conjunctival injection was noted in the absence of conjunctival swelling or any other findings. Fundus examination was unremarkable. To evaluate the cause of ACD, a patch test was performed and 48 h later was noted to be positive for alcaftadine 0.25%. Based on the positive patch test, the patient was diagnosed with ACD caused by alcaftadine 0.25%. After 9 days of treatment, the swelling and erythema completely resolved.

Conclusions

Although there have been no previous reports of alcaftadine 0.25%-associated ACD, it should be suspected in patients with swelling and erythematous change of both eyes after using alcaftadine 0.25%.

Immunomodulatory effect of cimetidine in common carp (Cyprinus carpio L.)

The main indication of cimetidine is being H₂-receptor antagonist, but studies suggest that cimetidine may also act as a non-specific stimulant of cell-mediated immunity and immunomodulator. In order to determine the immunomodulatory effect of dietary intake of cimetidine in the common carp (100 ± 10 g), subjects were fed diets containing 0 (control), 50, 100 and 200 mg cimetidine kg⁻¹ of dry diet for a period of 6 weeks. TLC and NBT assays were significantly (P < 0.05) stimulated in cimetidine-supplemented groups displaying the highest value in 200 mg kg⁻¹ group. A decrease (P < 0.05) in cortisol and ACH50 value was recorded in fish treated with cimetidine. Serum protein, albumin and serum globulin levels were not significantly changed. The findings of the present investigation suggest that the incorporation of cimetidine in the diet of common carp enhances the non-specific immunity.

Increased sensitivity of lymphocytes from atopic individuals to histamine-induced suppression

Histamine depressed lymphocyte reactivity to phytohemagglutinin and, to a lesser degree, concanavalin A, when administered simultaneously with mitogen to lymphocyte cultures. Addition of histamine at later times to the cultures appeared to have a slightly enhancing effect on the lymphocyte response. Stimulation of lymphocytes with pokeweed mitogen was in some cases enhanced, even by high concentrations of histamine. Lymphocytes from atopic individuals were more sensitive to the inhibitory effect of histamine than lymphocytes from nonatopic individuals. The sensitivity appeared age-dependent, but within each age group histamine evoked significantly more suppression on lymphocytes from atopic than from nonatopic individuals. The possibility that the altered reactivity of lymphocytes to histamine, which appears to be associated with atopic allergy, is of pathogenic importance, is discussed, and a hypothesis for the development of atopic disease is proposed.

Importance of Mast Cells in Human Periapical Inflammatory Lesions

The role of mast cells (MCs) in periapical inflammatory lesions is not well understood. The objective of this work was to quantify MC numbers in human periapical lesions with the aim to clarify their role in the pathogenesis of these lesions. We analyzed the slides of 64 human periapical inflammatory lesions stained with pH 8.0 toluidine blue technique, quantified the number of MCs, and evaluated any correlation with age, gender, size, and location. The results of this study suggest that MCs were more numerous in females (p < 0.01); MC numbers were higher in biopsies from granulomas with proliferating epithelium and lower in biopsies from chronic apical abscesses; MC counts did not correlate with patients' age or size. MCs were observed more commonly in areas containing inflammatory infiltrate and degranulation was a frequent finding in these zones. Our results suggest that MCs play an active role in the pathogenesis of the periapical inflammatory lesions. The potential role of MCs related with the initiation, development, and persistence of the periapical inflammatory process are discussed.

Comparative immunohistochemical study of the presence of mast cells in apical granulomas and periapical cysts: possible role of mast cells in the course of human periapical lesions

Cells other than macrophages and lymphocytes have recently been shown capable of producing cytokines and mediators. Among these are mast cells, a cell population now recognized for its immunoregulatory properties. Little is known about the complex interactions between cells, cytokines, and other inflammatory elements in periapical lesions. The objective of this investigation was to determine the immunohistochemical pattern of expression of mast cells tryptase in periapical lesions based on study of 20 apical granulomas and 20 periapical cysts. Microscopic analysis revealed mast cells to be present in greater numbers in periapical cysts than in apical granulomas, and in cysts were more numerous in regions of active inflammation. Mast cells tended to be more common in the peripheral regions of both periapical lesions, and were often found in close proximity to lymphocytes. These findings lead us to propose a functional relationship between these two cell populations that may facilitate elicitation of an immune response contributory to the pathogenesis of periapical lesions.

Cimetidine modulates the antigen presenting capacity of dendritic cells from colorectal cancer patients

Cimetidine, a H(2) receptor antagonist, has been reported to improve survival in gastrointestinal cancer patients. These effects have largely been attributed to the enhancing effects of cimetidine on the host's antitumour cell-mediated immune response, such as inhibition of suppressor T lymphocyte activity, stimulation of natural killer cell activity and increase of interleukin-2 production from helper T lymphocytes. We conducted an in vitro study on the effects of cimetidine on differentiation and antigen presenting capacity of monocyte-derived dendritic cells from advanced colorectal cancer patients and normal controls. As a result, an investigation of expression of surface molecules associated with dendritic cells by flow cytometric analyses showed that cimetidine had no enhancing effect on differentiation of dendritic cells from cancer patients and normal controls. An investigation of [(3)H]thymidine incorporation by allogeneic mixed lymphocyte reactions revealed that cimetidine increased the antigen presenting capacity of dendritic cells from both materials. Moreover, a higher antigen presenting capacity was observed in advanced cancer patients compared to normal controls. These effects might be mediated via specific action of cimetidine and not via H(2) receptors because famotidine did not show similar effects. Our results suggest that cimetidine may enhance the host's antitumour cell-mediated immunity by improving the suppressed dendritic cells function of advanced cancer patients.

Histamine inhibits chemotaxis, phagocytosis, superoxide anion production, and the production of TNFalpha and IL-12 by macrophages via H2-receptors

Histamine is released from stimulated basophils and mast cells, and plays an important role in the pathogenesis of allergic inflammatory processes. In vitro treatment of macrophages with histamine resulted in inhibition of chemotaxis. Moreover, histamine at l0(-5) M markedly inhibited the production of superoxide anions by both opsonized zymosan-A and phorbol 12-myristate 13-acetate (PMA) stimulated macrophages and histamine at a concentration range of 10(-7) to 10(-5) M significantly inhibited phagocytosis of Escherichia coli by macrophages. In addition, H2-selective receptor agonist dimaprit resulted in inhibition of macrophage chemotaxis and markedly inhibited the production of superoxide anion by PMA-stimulated macrophages and phagocytosis of E. coli by macrophages. On the other hand, histamine and dimaprit both resulted in a concentration-dependent inhibition of lipopolysaccharide-induced production of TNFalpha and IL-12 by macrophages. These results suggest that histamine and dimaprit may inhibit chemotaxis, phagocytosis, superoxide anion production, and the production of TNFalpha and IL-12 by macrophages via H2-histamine receptors. reserved.

Nephrotoxicity and hepatotoxicity of histamine H2 receptor antagonists

The extensive use of selective histamine H2 receptor antagonists provides a unique opportunity to describe very rare adverse drug reactions. Although mild elevation of serum creatinine level following the administration of cimetidine is relatively common, acute interstitial nephritis (AIN) is a rare hypersensitivity reaction. There have been 25 published reports of AIN associated with H2 antagonist therapy and we also identified 16 cases from the Australian Adverse Drug Reaction Advisory Committee (ADRAC) database. AIN was reported most commonly following cimetidine administration. AIN was supported by renal biopsy in 28 patients and by rechallenge in 6. H2 antagonist-induced AIN was more commonly reported in men older than 50 years. In the majority of cases the onset was within 2 weeks of initiation of therapy (1 day to 11 months). The clinical manifestations were nonspecific including sterile pyuria, elevated erythrocyte sedimentation rate, fatigue, proteinuria and leucocytosis whereas rash, arthralgia and flank pain were rarely reported. There were 170 cases of hepatotoxicity following H2 antagonist administration reported to ADRAC. These were more common following ranitidine and included cholestatic, hepatocellular and mixed reactions. Hepatotoxicity was proven following liver biopsy in several cases published in the literature and in 15 cases reported to ADRAC. Hepatotoxicity recurred upon rechallenge in 6 cases. Generally, renal and hepatic adverse effects resolved quickly after cessation of H2 antagonist therapy and did not require specific treatment. Nephrotoxicity and hepatotoxicity following administration of an H2 antagonist is rare and a high index of suspicion is necessary for early detection. Now that many H2 antagonists are available over the counter, awareness of these conditions and early detection with cessation of H2 antagonist therapy would appear paramount.

Efficacy of topical sensitizers in the treatment of alopecia areata

It has been more than 2 decades since the first report of the use of dinitrochlorobenzene to induce hair growth in 2 patients with alopecia areata. Other topical sensitizers, namely squaric acid dibutylester and diphenylcyclopropenone, have been used with variable success. This article reviews the efficacy and safety of the use of topical sensitizers in the treatment of alopecia areata.

Pharmacological analysis of the inflammatory exudate-induced histamine production in bone marrow cells

The inflammatory exudate at the post-anaphylaxis phase of allergic inflammation in rats has an ability to enhance histamine production by bone marrow cells. To analyze the mechanism of the inflammatory exudate-induced histamine production pharmacologically, the effects of several drugs were examined in cultures of bone marrow cells. Incubation of the bone marrow cells in the presence of the inflammatory exudate that had been centrifuged and dialyzed against Hanks' balanced salt solution increased histidine decarboxylase activity in the cells and histamine concentration in the conditioned medium. The induction of histamine production by the inflammatory exudate was inhibited by actinomycin D (0.01-1 microM), an inhibitor of RNA synthesis, and cycloheximide (0.1-10 microM), a protein synthesis inhibitor. The protein kinase C inhibitors staurosporine (2-20 nM), K-252a (6-200 nM), and H-7 (10.3-103 microM) also inhibited the inflammatory exudate-induced histamine production in a concentration-dependent manner. The tyrosine kinase inhibitor genistein (3.7-37 microM) also inhibited the inflammatory exudate-induced histamine production, but the protein kinase A inhibitor H-89 (0.2 microM), and the adenylate cyclase activator forskolin (0.1 microM) showed no effect. These findings suggest that histamine production induced by the inflammatory exudate is mediated by the de novo synthesis of histidine decarboxylase and by the activation of protein kinase C and tyrosine kinase.

Evidence of enhanced type 2 immune response and impaired upregulation of a type 1 response in frail elderly nursing home residents

Peripheral blood mononuclear cells (PBMC) of frail elderly nursing home residents had significantly higher PHA-induced interleukin-10 (IL-10) production compared to PBMC's from young control subjects. No correlation was observed between IL-10 production and interleukin-12 (IL-12) p40 production, proliferative response or with the proportion of CD28-negative T cells. To better characterize the host response to a ubiquitous pathogen, the dose response and time-dependent (kinetic) production of IL-10 and IL-12 p40 of PBMC stimulated with Staphylococcus aureus Cowan (SAC) was studied. IL-10 production continued to increase at 48 h, while IL-12 p40 levels declined or remained stable, in both young and elderly subjects. In analyzing how excessive IL-10 production might influence antigen presenting cell functions, IL-12 was markedly inhibited by recombinant IL-10 (rIL-10), while anti-IL-10 enhances IL-12 p40 production in cultures from young controls; but the PBMC cultured from an elderly cohort were not able to generate similar absolute levels of IL-12 p40 even in the presence of anti-IL-10. These preliminary data suggest that there may be both over production of IL-10 in some individuals, as well an an impaired ability to upregulate a T Helper 1 (type 1) reaction. These age-related changes could even be more dramatic at the tissue level and contribute to the impaired delayed type hypersensitivity (DTH) and failed host defense to infection, such as to primary and reactivation tuberculosis.

Cimetidine for mucosal warts in an HIV positive adult

An HIV-positive adult presented with recalcitrant mucosal warts which failed to respond to therapies including curettage and cautery, cryocautery and oral etretinate. There was an apparent complete resolution of intra- and peri-oral warts with the histamine H2 antagonist, cimetidine.

Comparison of antiproliferative effects of 1-histamine-2 receptor antagonists, cimetidine, ranitidine, and famotidine, in gastric cancer cells

In the immune system, histamine is known to suppress cytotoxic T-lymphocytes and nitrogen induced lymphocyte thymidine uptake, down-regulate some cytokines, and activate suppressor T-lymphocytes, and in the gastrointestinal system, histamine was reported to have trophic effects on gastrointestinal epithelial cells. Enhanced rates of cell proliferation by histamine are implicated in the pathogenesis. This study was designed since there is a lack of comparative data about the cell proliferations of histamine-2 receptor antagonist (H2-RA), cimetidine, ranitidine, and famotidine, in gastric cancer. KATO-III and AGS cell lines were used in this experiment. The concentrations of the histamine and cimetidine were 10(-5)-10(-8) M, respectively and those of ranitidine and famotidine were 10(-6)-10(-9)M, respectively. Cell proliferation after drug treatment was evaluated by direct cell counting, [3H]thymidine incorporation, and MTT assay. Activities of ornithine decarboxylase (ODC), a rate limiting enzyme in polyamine synthesis, were measured after each drug treatment. Protein kinase A, a cAMP-dependent protein kinase system, was assayed using [alpha-32P]ATP. Histamine showed statistically significant cell proliferating effects in a dose-dependent manner (P < 0.001), the maximal effect in 10(-5) M concentration. ODC activities were increased in accordance with the increment of cell numbers after histamine treatment. Cimetidine reversed the histamine-stimulated cell proliferation significantly, the maximal effect in 10(-5) M concentration (P < 0.01). Although ranitidine showed the tendency to attenuate the cell proliferation dose-dependently, but without statistical significance, famotidine did not show such an effect at all. cAMP-dependent protein kinase activities were significantly increased following 10(-5) M histamine treatment, also reversed significantly by cimetidine co-administration (P < 0.01). Beneficial clinical outcomes could be anticipated from cimetidine treatment in patients with gastric cancer by anti-proliferating effects against gastric cancer cells. These effects of H2-RA are likely to be mediated by specific interactions at the H2-receptor.

Effects of metronidazole and its metabolites on histamine immunosuppression activity

We have previously reported that metronidazole treatment increases human lymphocyte proliferation showing individual differences. This drug and its metabolites are imidazole compounds like histamine and cimetidine. The first is an endogenous amine that inhibits T-helper lymphocyte proliferation, and the second is a histamine antagonist. We presently report the in vitro effects of histamine, cimetidine, imidazole, metronidazole and its two principal metabolites (the acetic acid and hydroxy forms), on the mitogenic response to phytohemagglutinin (PHA) stimulation of human peripheral blood lymphocytes. Histamine decreased lymphocyte proliferation while (in order of potency) cimetidine, the hydroxy metabolite of metronidazole, imidazole and metronidazole, increased the mitogenic response to PHA in a dose-response fashion. The acetic acid metabolite lacked immunomodulatory effects. Competitive studies showed that cimetidine, metronidazole, and the hydroxy metabolite blocked the inhibitory effect of histamine on lymphocyte proliferation in a dose-related manner. This blockage was non-competitive, suggesting that the target of the imidazole compounds was not the active site of the H2 receptor.

Comparison of immunomodulative effects of the histamine-2 receptor antagonists cimetidine, ranitidine, and famotidine on peripheral blood mononuclear cells in gastric cancer patients

BACKGROUND

Histamine-2 receptor antagonist (H2-RA) have been shown to improve the function of various parts of the immune system. The proposed mechanism of the immunomodulative effects of H2-RA has been considered to be the inhibition of suppressor T-lymphocyte activity, an increase in interleukin-2 production, and an enhancement of natural killer cell activity. Most of these studies were done with cimetidine. Comparative data with other H2-RA are limited and conflict on immunomodulative effects. Comparison of the actions of H2-RA on the immune system is required.

METHODS

We compared the immunodulative effect of the H2-RAs cimetidine, ranitidine, and famotidine on peripheral blood mononuclear cells (PBMC) in normal controls and patients with gastric cancer. DNA synthesis, cytotoxicity against K562 cells, and the levels of soluble interleukin-2 receptor (sIL-2R) in supernatant were measured after addition of the various H2-RA to PBMC cultures.

RESULTS

Subjects with gastric cancer showed significantly higher levels of suppressor lymphocyte activity than normal controls. These levels were restored to levels of normal controls by the addition of cimetidine. Statistically significant lymphoblastogenesis and cytotoxicity against K562 cells were observed only in cimetidine-treated PBMC (p < 0.05); such effects were not observed in ranitidine- or famotidine-treated PBMC. Significantly increased levels of sIL-2R were found in supernatants obtained from culture flasks treated with cimetidine and phytohemagglutinin or ranitidine and phytohemagglutinin (p < 0.01).

CONCLUSIONS

Of the three H2-RAs tested, cimetidine had the strongest and famotidine the weakest immunomodulating effect. Only cimetidine augmented the cytotoxicity and proliferative response of lymphocyte to mitogen; neither ranitidine nor famotidine had such an effect. These results might be due to their structural differences. In addition, the immunologic effects of H2-RA are unlikely to be mediated via specific interaction at the H2 receptor.

The clinical effect of percutaneous histamine on allergic contact dermatitis elicited to fragrance mix

Histamine (2-(4-imidazol)ethylamine) has been shown to downregulate cell-mediated reactions in vitro. However, the rôle of such downregulation in vivo has not yet extensively been studied in humans. In an attempt to gain more insight into this, we studied in vivo the effect of percutaneous histamine on an allergic contact reaction elicited to fragrance mix in 28 human volunteers with previously-known sensitization (patch tests) to this allergen. Histamine (0.1 mg/ml) was administered either via subcutaneous injections or by scratching at the site of patch tests to one concentration (8% pet.) of fragrance mix at different times. Histamine and control solution were administered immediately before patch testing (0 hours) or 2x at 0 and 24 h (after application). No significant differences were observed in the grade of delayed-type hypersensitivity reaction (DTHR) to fragrance mix (8% pet.) by visual reading when histamine or control solution was administered. This study did not exclude the possibility that histamine could inhibit DTHR to lower concentrations of the allergen used, and therefore additional in vivo studies are required.

Comparison of immunomodulative effects of histamine-2 receptor antagonists in gastric cancer patients: focus on the lymphoblastogenesis and cytotoxicity of peripheral blood mononuclear cells

A proposed mechanism of the immunomodulative effects of histamine-2 receptor antagonist (H2-RA) has been considered to be the inhibition of suppressor T-lymphocyte activity, an increase in interleukin-2 production of helper T-lymphocytes, and an enhancement of natural killer cell activity. Since there is a lack of comparative data about the immunomodulative effects of various H2-RAs, cimetidine, ranitidine and famotidine on peripheral blood mononuclear cells (PBMC), study of the comparison of the actions of H2-RA will be required. We compared the immunomodulative effect of each H2-RA on PBMC in patients with gastric cancer. DNA synthesis, cytotoxicity of PBMC against K562 cells and gastric cancer cell lines, and the levels of supernatant soluble interleukin-2 receptor (sIL-2R) were measured after the addition of each H2-RA, respectively. Increased suppressor cell activities were attenuated and restored to the levels of normal controls by the addition of cimetidine to H2-RA. Statistically significant lymphoblastogenesis and cytotoxicity against K562 cells were observed only in cimetidine-treated PBMC (P < 0.05). Such effects were not observed in ranitidine- or famotidine-treated PBMC. Neither cimetidine- nor ranitidine-activated activated PBMC showed any significant cytotoxicity against gastric cancer cells. Significantly increased levels of sIL-2R were found in supernatants obtained from culture flasks treated with cimetidine or ranitidine and phytohemagglutinin (P < 0.01). A significant correlation was found between the cytotoxicity of cimetidine- or ranitidine-treated PBMC and supernatant sIL-2R (P < 0.05). In conclusion, the most strongly modulative substance among H2-RAs was cimetidine and the least modulative drug was famotidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-6 biosynthesis is increased by histamine in human B-cell and glioblastoma cell lines

An enhancing effect of histamine on the biosynthesis and gene expression of interleukin-6 (IL-6) by human cell lines, Epstein-Barr virus (EBV)-infected human B lymphoma line BMNH and the glioblastoma line SK-MG4 has been found. No similar effect of histamine has been detected on the IL-6 production by any other B-cell line, CESS or human peripheral monocytes. Histamine stimulates the IgM production of BMNH cells by autocrine action of IL-6 induced by histamine, since either neutralization of IL-6 by polyclonal antibody or blocking the IL-6 receptor by specific monoclonal antibody abolished the effect of histamine.

Histamine-induced inhibition of neutrophil chemotaxis and T-lymphocyte proliferation in man

Histamine inhibits in vitro human neutrophil chemotaxis and T-lymphocyte proliferation via H2 receptors. The aim of this study was to verify these inhibitory effects of histamine in man in vivo. Healthy volunteers were challenged with histamine by intravenous (1 mg), subcutaneous (1 mg) and inhalatory (2.4 mg) routes. Venous blood was taken before and at different times after challenge. Neutrophil chemotaxis was studied by the Boyden assay and T-lymphocyte proliferation by counting H3-thymidine incorporation in cultured mononuclear cells. Plasma histamine was measured by radioimmunoassay. Histamine infusion caused transient systemic symptoms as well as a significant decrease of neutrophil chemotaxis (mean - 26% +/- 6) and of PHA-pulsed T-lymphocyte proliferation (mean - 16% +/- 6) 4 h after histamine challenge. Subcutaneous injection of histamine caused only a significant decrease of neutrophil chemotaxis (mean - 24% +/- 15) 4 h after injection. Histamine inhalation was well tolerated and caused a significant depression of neutrophil chemotaxis (mean - 40% +/- 15) and of T-lymphocyte proliferation (mean - 27% +/- 6) 2 and 4 h after the challenge. Histamine challenges were always accompanied by a rapid and transient rise in plasma histamine. Inhalation of an H2 agonist (impromidine) but not of an H1 agonist (betahistine) caused a decrease of neutrophil chemotaxis and of T-lymphocyte proliferation. Oral pretreatment with an H2 antagonist (cimetidine) before histamine inhalation prevented histamine-induced decrease of neutrophil chemotaxis and T-lymphocyte proliferation, whereas astemizole, an H1 antagonist, had no effect. In conclusion, during the few hours following administration, exogenous histamine in man causes a depression of neutrophil chemotaxis and T-lymphocyte proliferation via H2 receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in cell-mediated immune responses after experimentally-induced anaphylaxis in dogs

Experimentally-induced type 1 hypersensitivities were induced in normal dogs to either ovalbumin or Ascaris antigen. In vitro and in vivo cell-mediated immune responses were measured before sensitization and again at 1 and 6 days after induction of anaphylaxis by intravenous challenge with antigen. Histamine-modulated lymphocyte functions, such as histamine-induced suppression, histamine co-mitogen induced blastogenesis and the in vivo cutaneous responses to intradermally injected mitogens decreased post anaphylaxis. Spontaneous suppression of the autologous mixed-lymphocyte reaction increased post anaphylaxis. Lymphocyte blastogenic response to Concanavalin A (Con A) decreased at 6 (but not at 1) days post anaphylaxis probably due to a mediator other than histamine. Blastogenesis of 24 h preincubated cells by suboptimal concentration of Con A, declined post anaphylaxis, but Con A-induced suppression was not significantly altered. Dogs with atopic dermatitis have some altered cell-mediated immune responses. Altered histamine-induced and spontaneous suppression, histamine suppression of mitogenesis and decreased contact sensitivity observed in this experimental type 1 hypersensitivity mimicked that of atopic dogs. Increased cutaneous response to mitogens observed in atopic dogs was not reproduced in the type 1 hypersensitive dogs. These findings suggest some of the altered cell-mediated immune functions observed in dogs with atopic dermatitis result from type 1 hypersensitivity. The other abnormalities may be intrinsic to the atopic state.

The fasciitis-panniculitis syndrome: clinical spectrum and response to cimetidine

The term fasciitis-panniculitis syndrome (FPS) is proposed as a novel compilation encompassing several disorders, common to which is subcutaneous induration caused by cicatrizing fasciitis as well as septal and lobular panniculitis and perimysial fibrosis. Included herein are Shulman's eosinophilic fasciitis, morphea profunda, lupus profundus, venous lipodermatosclerosis, toxic oil syndrome, altered tryptophane-related eosinophilic myositis, graft-versus-host reaction, and fasciitis reactive to subjacent basal cell carcinoma. FPS should be differentiated from scleroderma, which primarily affects the dermal structures and in which arterioles are injured. In contrast, vasculopathy of the subcutaneous medium-sized veins accompanies the hypodermal lesions of FPS. The importance of recognizing and grouping these disorders lies in their different histopathology, characterization as reactive phenomena, enhanced responsiveness to treatment, and better prognosis than scleroderma. In view of the excellent prognosis of FPS, steroid treatment is not warranted. Long-term therapy with cimetidine appears to benefit the majority of patients.

In vitro augmentation of the cytotoxic activity of peripheral blood mononuclear cells and tumor-infiltrating lymphocytes by famotidine in cancer patients

We investigated the in vitro effects of famotidine on the cytotoxic activity of peripheral blood mononuclear cells (PBMC) and tumor-infiltrating lymphocytes (TILs). The cytotoxic activity of PBMC was augmented by famotidine at a concentration of 10 ng/ml, which is equivalent to the serum level achieved by the intravenous administration of a dose of 20 mg. This response to famotidine was seen only in cancer patients. Both the cytotoxic activity and DNA synthesis of activated TILs were increased by the combination of interleukin-2 and 1 microgram/ml of famotidine. Augmentation of cytotoxic activity by famotidine occurred independently of any decrease in the population of suppressor T-cells. Thus, famotidine may have the potential to be used in adoptive immunotherapy with TILs for cancer patients.

Immunomodulatory effect of cimetidine on the proliferative responses of splenocytes from T. cruzi-infected rats

The immunomodulatory effect of cimetidine (CIM), a histamine type-2 receptor antagonist, was evaluated in respect to the blastogenic response to Con A of Wistar Furth (WF) rats infected by the Y strain of Trypanosoma cruzi (T. cruzi). Enhancement of blastogenesis of normal splenocytes was observed at a concentration of 10(3) M. However, the splenocytes from infected animals responded to concentrations of CIM ranging from 10(-8) to 10(-3) M. The mitogenic response to Con A of cells from infected animals was restored in the presence of CIM. The results show that CIM modulates the "in vitro" proliferative response of cells from T. cruzi-infected rats and suggest an immunoregulatory role of histamine and/or of cells that express H2 receptors in this infection.

Immune cells in periapical granuloma: morphological and immunohistochemical characterization

Samples of periapical granulomas obtained from 12 patients were examined using light and electron microscopes and monoclonal antibodies. Monocytes/macrophages, lymphocytes, and plasma cells were nearly always the most abundant cell populations. Ultrastructural analysis showed close contacts between macrophages and cells of the lymphoid lineage, with the lymphoid cells frequently demonstrating blastic features. Immunohistochemical staining with the anti-interleukin 2 receptor antibody showed that the concentration of labeled cells was quite low. The vast majority were lymphocytes, though some mast cells were also labeled. Mast cells were chiefly located in perivascular areas and interleukin 2 receptor-positive mast cells were frequently associated with lymphoid cells. mast cells could be part of a negative feedback mechanism in the immune response. By releasing histamine, they would block the immune response and by absorbing interleukin 2 they would remove it as an immune system stimulant.

Histamine and its congener derivatives as immune modulators

Our knowledge of the function of histamine as an immunoregulatory autacoid is expanding. The presence of histamine in many tissues in which the immune response takes place and its release during immune response lend credibility to the notion that histamine's role in the immune response could be an important one. In this report we present data that demonstrate the immune modulatory role of histamine. We also describe the synthesis and novel pharmacologic effects of congener derivatives of histamine. These new lymphocyte specific histamine H1 and/or H2 agonists make it feasible to assess the potential of histamine as a selective in vivo immune modulator.

In vivo augmentation of local xenogeneic graft-versus-host reaction by cimetidine and Bacillus Calmette-Guerin

Histamine-2 receptor blocker therapy (cimetidine) was combined with nonspecific Bacillus Calmette-Guerin (BCG) immunomoderation in order to obtain a more directed immunostimulatory response. To establish this the local xenogeneic graft-versus-host reaction (XGVHR) was used as objective in vivo parameter. In this placebo-controlled experiment the lymphocytes of inbred Sprague-Dawley rats were transferred intradermally to partially immunosuppressed guinea pigs after treatment with either or both of the test substances. The surface areas of the local XGVHRs were evaluated 48 and 72 h later. The local XGVHRs caused by lymphocytes obtained from rats treated with either cimetidine or BCG alone did not differ significantly from those caused by lymphocytes obtained from placebo-treated rats. Combination therapy, however, resulted in significant augmentation of the local XGVHR, clearly indicating a synergistic effect between cimetidine and BCG. The XGVHR appears to be a satisfactory model for evaluating drug effect on cell-mediated immune reaction in vivo.

Treatment with cimetidine of atypical fasciitis panniculitis syndrome

Three patients presented with septal fasciitis and panniculitis, associated with clinical and laboratory features which precluded straight-forward classification into eosinophilic fasciitis, localised scleroderma, or lupus erythematosus profundus. Treatment with cimetidine caused the remission of cutaneous manifestations and the extracutaneous abnormalities, such as nailfold capillary disturbances and the presence of antithyroid antibodies, improved. It is concluded that features of eosinophilic fasciitis or localised scleroderma and certain additional atypical elements should be categorised as atypical fasciitis-panniculitis syndrome.

The effect of histamine on the immune response of hamsters to infection with Ancylostoma ceylanicum

The role of histamine in modulating the immune response of hamsters infected with Ancylostoma ceylanicum (hookworm) was investigated. Histamine administration (20 mg base/hamster x 6 ip) made the immune hamsters susceptible to challenge infection, and on assay the humoral as well as the cell-mediated responses were found to be suppressed. An adverse effect of histamine was observed on lymphocytes but the macrophage function remained unaltered, since the latter lack histamine receptors. These findings provide definite evidence that histamine suppresses specific immune responses, and that contrary to earlier reports this neurotransmitter does not play a direct role in the 'self-cure' phenomenon.

Lymphocyte-mediated inhibition of platelet cytotoxic functions during Hymenoptera venom desensitization: characterization of a suppressive lymphokine

Recently, it has been shown that platelets, through a receptor for the Fc fragment of IgE, could be specially triggered by venom allergens in hypersensitivity to hymenoptera, generating cytocidal mediators toward Schistosoma mansoni larvae, and oxygen metabolites measured by chemiluminescence. After rush immunotherapy, a depressed platelet response was demonstrated to be associated with the production of lymphokine(s). Here we report the characterization of a factor present in supernatants of antigen-stimulated T cells from patients after hymenoptera venom desensitization which is able to inhibit platelet cytotoxic functions in a dose-dependent manner. The optimal inhibition was observed with supernatants obtained after T lymphocyte stimulated with 10(-5) micrograms venom allergen/ml. Once specifically produced the platelet-suppressive effect of lymphocyte supernatants was not antigen specific. The producing T cell subpopulation was identified as CD8+. This lymphokine had an approximate molecular mass of 25 kDa and a pI of 4.8. It was heat and acid stable and sensitive to trypsin and proteinase K but not to neuraminidase. This platelet inhibitory activity was absorbed by platelet membrane suggesting its binding to a receptor. These properties were very similar to a previously described platelet activity suppressive lymphokine, suggesting the participation of this lymphokine in the mechanisms of rush desensitization.

Cimetidine-induced augmentation of allergic contact hypersensitivity reactions in mice

BALB/c mice were treated with cimetidine (100 mg/kg) or saline, intraperitoneally, twice daily, from days 0-2 or days 7-9 after sensitization with 0.1%, 2,4,6-trinitro-1-chlorobenzene (TNCB) on day 0. On day 7, the mice were challenged with 1% TNCB to one ear. Ear swelling responses (as an index of sensitization), serum histamine levels, and biopsy specimens of challenged ears were evaluated in groups of cimetidine- or saline-treated mice at 0, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, and 48 h after challenge. Additional controls included mice injected with saline or cimetidine and challenged with, but not sensitized to, TNCB (irritant controls). Treatment with cimetidine during the induction but not the elicitation of allergic contact hypersensitivity (ACH) produced a significant enhancement of the response throughout the first 48 h. There was no effect of cimetidine on antigen-presenting cells within the epidermis which might account for this enhancement. Similarly, no difference in mast cell morphology or serum histamine levels between cimetidine- and saline-treated groups was observed. Histologically, the cimetidine-treated animals showed a more intense cellular infiltrate, which was most noticeable at 24 to 48 h, at which time numerous subcorneal and perifollicular neutrophilic abscesses were observed. To further investigate the mechanism of action of cimetidine, mice were injected with cyclophosphamide (150 mg/kg) 2 d prior to sensitization. Mice treated with cyclophosphamide alone or in combination with cimetidine showed no additive or synergistic effect upon the ear swelling response. We conclude that enhancement of ACH by cimetidine is independent of any effect on mast cells or antigen-presenting cells, but may relate to a cimetidine-induced inhibition of the induction of T-suppressor cells at the time of sensitization.

Enhancement of suppressor T cell activity by lymphocyte promoting factor of Bordetella pertussis

Lymphocyte promoting factor (LPF), a bioproduct of Bordetella pertussis shown previously to exert immunosuppressive effects, was examined for its effect on Concanavalin A (Con A) induced T lymphocyte suppressor activity by human lymphocytes. Suppressor cells (5 x 10(4) cells/well) first generated with Con A (10 micrograms/ml) for 24h were co-cultured with responder cells (5 x 10(4) cells/well) for another 72h in the presence of Con A (2.5, 5, 20 micrograms/ml). In this culture condition, LPF (20 micrograms) and/or histamine 10(-5) M or 10(-6) M/well were added for comparison. The suppressor activity was assessed by the reduction of the uptake of radioactivity of [3H] thymidine compared to that of Con A alone. Lymphocytes treated with LPF exhibited increase of suppression by 22 to 41%, while LPF and histamine (10(-5) M) together further increased the suppression by 35 to 63% compared to controls. Serial studies on cell population in the culture indicated OKT8(+) cells proliferated after day 6 in culture. These results indicated LPF exerts selective enhancement of T cell suppressor activity by 72h in culture, prior to cell expansion, and that activity can be further strengthened by sensitizing cells to histamine.

Angiotensin-converting enzyme inhibitors and their influence on inflammation, bronchial reactivity and cough. A research review

Synthetic orally active angiotensin-converting enzyme (ACE) inhibitors have been successfully used in the treatment of congestive heart failure and hypertension, particularly in hypertensive subjects with increased renin-angiotensin-aldosterone-system activity. Adverse skin reactions, angioneurotic oedema and rapidly decreasing lung function in asthmatics have been reported following medication with ACE inhibitors. Furthermore, these drugs have been associated with a persistent dry cough in subjects without previous known bronchial hyper-reactivity. There is reason to believe that an ACE inhibitor-induced cough is due to an increased inflammatory state in the airways of susceptible individuals, and that this cough might thereby have pathophysiological features in common with the cough seen as an early symptom of asthma. All inflammatory responses, wheal and flare reactions, infiltration of neutrophils, eosinophils, basophils and monocytes were enhanced by ACE inhibitors. A dose-response relationship for the proinflammatory effect of the ACE inhibitor has been demonstrated.

Cimetidine as an immunomodulator in the treatment of herpes zoster

As there is evidence of a possible immunoregulatory role for H2-histamine receptor antagonists, we carried out a prospective randomized trial to evaluate the in vivo and in vitro effect of cimetidine, an H2-blocker, in the treatment of herpes zoster infection. Cimetidine treatment shortened the median interval until the first decrease in pain, the median interval until the complete resolution of pain and promoted faster complete healing of skin lesions than symptomatic treatment. The immunological trends observed in vitro support an important role for histamine in the induction of immunosuppression, as measured by the response to the mitogen phytohemagglutinin. This effect of histamine was antagonized by cimetidine.

Ranitidine for prevention of postoperative suppression of delayed hypersensitivity

Cell-mediated immunity was assessed by skin testing with seven delayed-type common antigens in 20 patients undergoing major abdominal surgery and in 20 nonoperative control subjects. The 20 surgical patients were randomized to perioperative ranitidine (50 mg every 6 hours for 72 hours) or no ranitidine. The 20 control subjects received either no ranitidine or ranitidine in the same dosage as the surgical patients. Skin tests were performed 2 days before and 1 day after operation with the same time schedule in the control subjects. Postoperatively, the diameter of the positive skin test area decreased in each of 10 patients without ranitidine (p less than 0.006) but increased in 9 and was unchanged in 1 of the ranitidine-treated patients (p less than 0.01). The skin test changes were similar during the two tests in ranitidine-treated surgical patients and the nonoperative control subjects. Ranitidine did not amplify the response in the nonoperated group. The potential role of histamine blockade in reversal of other aspects of postoperative immunosuppression and reduction in the risk of infection should be explored.

T cell responses in allergic rhinitis, asthma and atopic dermatitis

Although clinical responses to allergens have been shown to primarily involve IgE antibodies, there is often no clear correlation between the amount of allergen-specific IgE present in the serum and the nature and severity of allergic symptoms. This observation raises the question of the possible role of non-IgE mediated types of immune responses in this reaction. It is not known to what extent components of T cell-mediated immunity are involved in IgE-mediated reactions but several observations suggest an association between atopic disease and alterations in cellular immune function. These include the frequent association of high serum IgE levels with: (i) several of the primary and acquired immunodeficiencies characterized by partial T cell deficiency; (ii) the defective cell-mediated immunity and resultant recurrent infections seen in the hyper-IgE syndrome; and (iii) the sudden rise in serum IgE levels associated with reduced numbers of suppressor T cells in bone marrow transplant recipients during the acute graft vs host disease. In this review, we will examine the recent evidence suggesting that the T lymphocyte may play a primary role in the pathogenesis of atopic disorders.

Adjuvant effects of prostaglandin D2 to cisplatin on human ovarian cancer cell growth in nude mice

Adjuvant effects of prostaglandin D2 to cisplatin on tumor growth were studied by using nude mice bearing HR cells derived from human ovarian carcinoma. Combinations of 0.2 or 0.4 microgram/ml cisplatin and 0.05 or 0.1 microgram/ml prostaglandin D2, which did not affect the HR cell proliferation alone, resulted in a significant inhibition of cell proliferation. In addition, tumor take of HR cells by nude mice in groups treated with a combination of cisplatin and prostaglandin D2 was inhibited. Although there was no significant difference between tumor volumes in mice treated with prostaglandin D2 alone or cisplatin alone and untreated mice, when cisplatin was administered with 1 mg/kg prostaglandin D2 the tumor volume was significantly smaller on days 21 and 35, compared to that of untreated mice. When cisplatin and 2 or 4 mg/kg prostaglandin D2 were combined, the tumor growth was significantly inhibited after day 21, compared not only to that of untreated mice but also of mice treated with cisplatin alone or prostaglandin D2 alone. Such a combination therapy by cisplatin and prostaglandin D2 seemed to result in prevention by prostaglandin D2 of immunological suppression which may be induced by cisplatin. Thus, such a combination therapy brought about a significant prolongation to the survival time.

Inhibitory effects of histamine on interleukin 2 and gamma interferon production of different human T helper cell subsets

We have previously demonstrated that histamine can inhibit human helper T cells by direct interaction with these cells. It has now been investigated whether histamine inhibits lymphokine production by various subsets of CD4+ human T cells separated with the Leu-8 (p80) and Leu-18 (anti-CD45R;p220) monoclonal antibodies (MoAb). Histamine was shown to suppress to a similar extent the production of interleukin 2 (IL-2) and gamma interferon (IFN-gamma) by Leu 3+, Leu 3+8+, and Leu 3+8- cell subsets. Mitogen-activated, unseparated Leu 3+ and purified Leu 3+8- cells produced maximal amounts of IL-2 after 24 h and IFN-gamma after 72 h of culture. In contrast, the Leu 3+18+ subset produced no IL-2 after 24 h, and maximal amounts of IL-2 no sooner than 48 h of culture, and only small amounts of IFN-gamma during the entire culture period of 96 h. Histamine suppressed the production of IL-2 by both subsets, both when produced early (after 24 h), as in the case of the Leu 3+18- subset, and late (after 48 h of culture), as for the Leu 3+18+ subset. The IFN-gamma production by the Leu 3+ and Leu 3+18- cells and the marginal production by Leu 3+18+ cells were significantly suppressed by histamine. Dual staining with Leu 8 and Leu 18 MoAb demonstrated that the Leu 18- cell compartment included both Leu 8+ and Leu 8- cells. It was shown that the inhibitory effect of histamine on the early production of IL-2 and the major production of IFN-gamma by T helper cells is mediated via action on both the Leu 3+18-8- and the Leu 3+18-8+ cells. The inhibitory effect of histamine on the late production of IL-2 is mediated mainly via action on Leu-18+ cells.