Mechanism by which IL-16 generated by mast cells mediates allergic inflammation

Interleukin-16 aggravates ovalbumin-induced allergic inflammation by enhancing Th2 and Th17 cytokine production in a mouse model

Asthma is a chronic inflammatory disease that involves a variety of cytokines and cells. Interleukin-16 (IL-16) is highly expressed during allergic airway inflammation and is involved in its development. However, its specific mechanism of action remains unclear. In the present study, we used an animal model of ovalbumin (OVA)-induced allergic asthma with mice harboring an IL-16 gene deletion to investigate the role of this cytokine in asthma, in addition to its underlying mechanism. Increased IL-16 expression was observed during OVA-induced asthma in C57BL/6J mice. However, when OVA was used to induce asthma in IL-16^-/- mice, a diminished inflammatory reaction, decreased bronchoalveolar lavage fluid (BALF) eosinophil numbers, and the suppression of OVA-specific IgE levels in the serum and BALF were observed. The results also demonstrated decreased levels of T helper type 2 (Th2) and Th17 cytokines upon OVA-induced asthma in IL-16^-/- mice. Hence, we confirmed that IL-16 enhances the lung allergic inflammatory response and suggest a mechanism possibly associated with the up-regulation of IgE and the promotion of Th2 and Th17 cytokine production. This work explored the mechanism underlying the regulation of IL-16 in asthma and provides a new target for the clinical treatment of asthma.

Conjugated Linoleic Acid: A Functional Food?

Scientific interest in conjugated linoleic acid (CLA) started in 1987 when Michael Pariza's team of Wisconsin University observed its inhibitory effects on chemically induced skin tumors in mice. Numerous studies have since examined CLA's role in cancer, immune function, oxidative stress, atherosclerosis, lipid and fatty acids metabolism, bone formation and composition, obesity, and diabetes. Still it's not clear yet either through which mechanisms CLA produces its numerous metabolic effects.

We now know that CLA contents in cow milk fat can be enriched through dry fractionation, but this knowledge doesn't allow sufficient certainty to qualify this nutrient, as a functional food, capable of increasing well being and reducing the risk of disease.

Theophylline as "add-on" therapy in patients with delayed pressure urticaria: a prospective self-controlled study

Delayed pressure urticaria (DPU) is a skin condition that involves the gradual development of wheals and edema at sites of physical pressure. Its pathogenesis is not clear and histamine-1 receptor (H-1R) antagonists provide only partial relief. In this prospective, clinical study, we investigated the effect of theophylline, which has a long history of benefit in allergic asthma, added to cetirizine in patients with DPU. Twenty three patients received during period 1 cetirizine (10 mg po QD) and theophylline (200 mg po BID) for 6 months, followed by period 2 of 1 month washout with only rescue medication as needed, and then by period 3 with cetirizine (10 mg QD plus placebo (BID) for 5 more months. The addition of theophylline resulted in statistically significant improvement over cetirizine alone by 2 months and continued for the duration of treatment. Treatment of cultured human mast cells with theophylline (10 microM) did not inhibit allergic histamine release, but the in vivo beneficial effect of theophylline may require significant pretreatment period to manifest itself, or may involve inhibition of other mast cell dependent mediators. A double-blind study, accompanied by serum histamine and tryptase levels, should be in order.

Interrelationship between Asthma and Functional Bowel Disease

Gastrointestinal abnormalities have been reported in subjects with bronchial asthma. The aim of this study was to evaluate the presence of irritable bowel syndrome (IBS) in subjects with bronchial asthma. 380 asthmatic patients were selected for body mass index (BMI), sex, and age, before undergoing both methacholine challenge test (MCHt) and skin prick tests. 195 asthmatic patients (51.3%) were positive to MCHt, while 185 (41.6 %) were negative. We also found that 17 (8.7%) of the 276 patients with positive MCHt, and 22 (11.8%) of the 185 patients with negative MCHt were affected by IBS. Therefore, there was no statistical significance between positive MCHt tests and IBS. The results do not demonstrate an interrelationship between asthma and IBS.

IL-10 subfamily members: IL-19, IL-20, IL-22, IL-24 and IL-26

It has been reported that the CD4+ T cell is a very important source of interleukin 10 (IL-10), while CD8+ cells produce low amounts. IL-10 exerts several immune stimulating, as well as inhibitory effects. There are at least five novel human IL-10 family-related molecules: IL-19, IL-20, IL-22, IL-24, and IL-26. Activated T cells produce IL-19, IL-22 and IL-26, while IL-24 is produced by activated monocytes and T-cells. IL-20 induces cheratin proliferation and Stat-3 signal transduction pathway, while IL-22 induces acute-phase production by hepatocytes and neonatal lethality with skin abnormalities reminiscent of psoriasic lesions in humans. In addition, IL-22 mediates inflammation and binds class II cytokine receptor heterodimers IL-22 RA1/CRF2-4. This cytokine is also involved in immuno-regulatory responses. IL-26 (AK155) is a novel cytokine generated by memory cells and is involved in the transformed phenotype of human T cells after infection by herpes virus. All these new IL-10 subfamily member cytokines are strongly involved in immune regulation and inflammatory responses.

Oxygen supply modulates MCP-1 release in monocytes from young and aged rats: decrease of MCP-1 transcription and translation is age-related

Hyper or hypoxia may affect the immune system's chemokine production. Monocyte chemotactic protein-1 (MCP-1), an important chemotactic cytokine can be activated by active oxygen species. Groups of rats were exposed to hypoxic and hyperoxic environmental conditions for 60 h and MCP-1 was determined in their peripheral blood mononuclear cells by Elisa and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). In this study we evaluated if the ability of monocytes to produce MCP-1 under basal conditions or after stimulation with lipopolysaccharide (LPS) or phytohaemagglutinin (PHA) was differently affected by exposure to hyper or hypoxic conditions in young and aged rats. MCP-1 expression and production in monocyte/macrophages from rats at normoxic conditions was reduced in aged subjects. However, spontaneous, LPS or PHA-induced MCP-1 production was up-regulated by exposure to hyperoxic conditions in both young (62 +/- 8, 99 +/- 7, 102 +/- 8 pg/ml, respectively) and aged rats (79 +/- 4, 112 +/- 9, 117 +/- 10 pg/ ml, respectively). We conclude that hyperoxia is an important regulator of MCP-1 release and support the hypothesis that increased % of O2 may serve to initiate MCP-1 production which then serves to recruit and regulate the distribution of mononuclear cells to the sites of inflammation.

IL-10, an inflammatory/inhibitory cytokine, but not always

IL-10 has been previously called cytokine synthesis inhibiting factor, produced mostly by Th2 cells, macrophages and CD8+ cell clones. IL-10 is capable of inhibiting the synthesis of several cytokines from different cells, antigen or mitogen activated. IL-10 exerts its inhibition at the mRNA transcriptional and translational level. In addition, IL-10 is a co-stimulatory cytokine on activated T cells. For example, IL-10 inhibits NK cell activity, the production of Th1 cytokines, cytokines generated by peripheral blood mononuclear cells, and macrophage activity. On the other hand, IL-10 exerts immunostimulatory effects on B cells, cytotoxic T cell development and thymocytes. In mast cells derived from CD4+/CD133+ cells, IL-10 inhibits IL-6 and TNFalpha, and prostaglandin E(1) and E(2) induced by IL-6. Here, we report for the first time that IL-10 fails to inhibit tryptase and IL-6 from human mast cell-1 (HMC-1) and human umbilical cord blood-derived mast cells.

Inhibitory effect of retinoic acid on proliferation, maturation and tryptase level in human leukemic mast cells (HMC-1)

Mast cells play important role in allergic inflammation by releasing histamine, tryptase and several inflammatory cytokines. Human leukemic mast cells (HMC-1) have been used to study mast cell mediator and their role in inflammatory mechanisms. HMC-1 contain and release several inflammatory mediators, of which the proteolytic enzyme tryptase is most characteristic. Retinoids, including retinoic acid, are naturally occurring and synthetic derivatives of vitamin A. All-trans-retinoic (ATRA) acid had been previously reported to inhibit cell proliferation, differentiation and apoptosis. In the present study, we investigated the effect of ATRA on the proliferation and secretion of tryptase in HMC-1. HMC-1 were treated with ATRA at 10(-4M), 10(-5M) or 10(-6M) for 3, 4 or 5 days in culture. Control HMC-1 were treated with equal amount of culture medium only. ATRA decreased the number of HMC-1 as compared to the control group. The same treatment for 3, 4 or 5 days also decreased intracellular tryptase levels. These results indicate that ATRA significantly inhibits both proliferation and growth as shown by the decreased intracellular tryptase levels in HMC-1. ATRA may be a useful agent in the treatment of mast cell proliferative disorders.

Skin reactions due to anti-epileptic drugs: several case-reports with long-term follow-up

In this study, the clinical findings and management of allergic skin reactions induced by the most used antiepileptic drugs, Lamotrigine (LMT) and Carbamazepine (CBZ), were evaluated. Lamotrigine is an antiepileptic drug recently released in several countries; it is effective for a variety of seizure types in adults and children, both as an add-on agent and in monotherapy, and it is generally well tolerated. Clinical and epidemiologic evidence suggest serious cutaneous reactions to antiepileptic drugs are more likely to occur during the first 8 weeks and they appear to increase when drugs are administered with other anticonvulsants, such as Valproate (VPA). We selected 10 patients who presented an idiosyncratic skin rash when treated with carbamazepine (8 patients) and lamotrigine (2 patients) administered as monotherapy, and we followed up on these patients for several years. Seven reactions were mild/severe cutaneous eruptions; one Toxic Epidermal Necrolysis, a case of Stevens-Johnson and a case of Hypersensitivity Syndrome. All severe skin drug reactions were induced by Carbamazepine. In five patients the AEDs were ceased abruptly (sometimes with the administration of a different molecule), tapered in four and continued unchanged in one. We conclude that the discontinuation of the drug with substitution with another is the most effective treatment and that corticosteroids are helpful in mild cutaneous reactions, while in severe skin reactions, such as Toxic Epidermal Necrolysis, corticosteroids are only a complementary therapy since intravenous immunoglobulins are the first choice treatment.

The role of substance P in cerebral ischemia

Tackykinins are involved in the inflammatory process of a large number of diseases. The role of the tachykinins in ischemic brain injury was evaluated by the serum levels of Substance P (SP), one of the most known tachykinins and detected by a competitive enzyme immunoassay. The study was performed in 15 human females and 3 human males with typical manifestation of complete stroke (12 cases) or transient ischemic attack (6 cases). The mean SP level in the serum of patients with transient ischemic attack (0.53+/-0.25 ng/ml) and of patients with complete stroke (0.31+/-0.14 ng/ml), showed significantly higher values than in controls (0.10+/-0.02 ng/ml). Moreover, in transient ischemic attack, the SP values were significantly higher than in cerebral complete stroke. But SP levels, based on the timings of classification of patients (i.e. before 12 hours: 0.34+/-0.15 ng/ml vs. 12 to 24 hours: 0.26+/-0.11 ng/ml) with brain injury, did not show any significant difference. Both values anyway were significantly higher than in controls. Our original results demonstrate the SP increase during cerebral ischemia. Further studies are necessary to verify if SP has an effective physiopathological role in the neurological ischemic damage, or if it is only a concomitant phenomenon. Our data, if confirmed, will be particularly important, not only to improve the knowledge of cerebral ischemic injury, but also for diagnosis and therapeutic approaches.

Some aspects of Parasitology and Immunology in general Medicine

The objective of these studies is to review the role of some parasites and their components in inflammation, allergy and immune system. We also report recent results published by others group as well as our own.

The role of antileukotrienes in the treatment of asthma

Cysteinyl leukotrienes (Cys-LTs) are mediators released in asthma and are both direct bronchoconstrictors and proinflammatory substances that mediated several steps in the pathophysiology of chronic asthma, including inflammatory cells recruitment, vascular leakage, and possibly airway remodelling. Available evidence from clinical trials and real world experience derived from managing patients with asthma justifies a broader role for antiLTRAs in asthma management than that recommended in the National Asthma Education and Prevention Programm (NAEPP) and National Health Lung and Blood Institute (NHLBI) treatment guidelines. Leukotriene-receptor antagonist drugs (LTRAs) seem to be effective alternatives to inhaled corticosteroids (ICS) either as monotherapy or as adjunctive therapy that reduces the need for higher doses of ICS in patients with mild-to-moderate persistent asthma. LTRAs may be used as adjunctive therapy for al levels of disease severity because they are effective in combination with ICS during long-term maintenance therapy. The agents seem especially effective in preventing aspirin-induced asthma, exercise-induced asthma (EIA) and they may provide an additional advantage of reducing nasal congestion in patients with both asthma and rhinitis.

Azelastine is more potent than olopatadine n inhibiting interleukin-6 and tryptase release from human umbilical cord blood-derived cultured mast cells

BACKGROUND

Mast cells are involved in early- and late-phase reactions by releasing vasoactive molecules, proteases, and cytokines. Certain histamine-1 receptor antagonists and other antiallergic drugs seem to inhibit the release of mediators from rat and human mast cells.

OBJECTIVE

Azelastine and olopatadine are antiallergic agents present in the ophthalmic solutions azelastine hydrochloride (Optivar, Asta Medica/Muro Pharmaceuticals, Tewksbury, MA), and olopatadine hydrochloride (Patanol, Alcon Laboratories, Fort Worth, TX), respectively. We investigated the effect of these drugs on interleukin-6 (IL-6), tryptase, and histamine release from cultured human mast cells (CHMCs).

METHODS

CHMCs were grown from human umbilical cord blood-derived CD34+ cells in the presence of stem cell factor and IL-6 for 14 to 16 weeks. Sensitized CHMCs were pretreated with various concentrations of azelastine or olopatadine for 5 minutes. CHMCs were then challenged with anti-immunoglobulin E, and the released mediators were quantitated.

RESULTS

The greatest inhibition of mediator release was seen with 24 microM azelastine; this level of inhibition was matched with the use of 133 microM olopatadine. At this concentration, these drugs inhibited IL-6 release by 83% and 74%, tryptase release by 55% and 79%, and histamine release by 41% and 45%, respectively. Activated CHMCs were characterized by numerous filopodia that were inhibited by both drugs as shown by electron microscopy.

CONCLUSIONS

These results indicate that azelastine and olopatadine can inhibit CHMCs activation and release of IL-6, tryptase, and histamine. On an equimolar basis, azelastine was a more potent inhibitor than olopatadine.

Monocyte chemotactic protein-1 in a randomized placebo controlled study of canine plasmacytic-lymphocytic colitis

The purpose of this study was to determine serum and colonic monocyte chemotactic protein-1 (MCP-1) concentration in dogs with plasmacytic-lymphocytic (PL) colitis, as well as to demonstrate if the concentration of MCP-1 may be an accurate diagnostic and prognostic marker for PL colitis in dogs receiving three different therapeutic protocols. Serum and colonic MCP-1 concentration were measured in 18 dogs with PL colitis and in 6 controls. Dogs with PL colitis were randomly divided in 3 groups and for a period of 30 days received the following: Group 1, sulfasalazine, prednisone and placebo; Group 2, placebo and &#x03C93/&#x03C96 fatty acids, and Group 3, sul-fasalazine, prednisone and &#x03C93/&#x03C96 fatty acids. Colonic and serum MCP-1 concentration were de-termined at the beginning and at the end of this period. Serum MCP-1 concentrations at the be-ginning were not significantly increased in dogs with PL colitis compared to the controls. On the contrary, colonic tissue MCP-1 concentrations at the beginning were significantly increased in the same dogs compared to the controls. Moreover, the colonic tissue MCP-1 concentration in the dogs of group 3 was significantly decreased (P&#x003C0.001) at the end of the experiment. The same observations were obtained from dogs of groups 1 and 2, in which the colonic MCP-1 concentra-tion also significantly decreased (P&#x003C0.01). These data demonstrate that in canine PL colitis, colo-nic MCP-1 concentration is increased in comparison to those of controls and suggest that the colonic MCP-1 concentration may aid in the diagnosis of canine PL colitis.

Serum procalcitonin, adenosine deaminase and its isoenzymes in the aetiological diagnosis of pneumonia in children

A prospective study was undertaken to assess the usefulness of leukocyte count, serum C-reactive protein (CRP), procalcitonin (PCT), and the activities of total adenosine deaminase (tADA) and its isoenzymes ADA1 and ADA2, in the aetiological diagnosis of pneumonia in children. The study included three groups. Group A consisted of 23 children with bacterial pneumonia, group B of 50 children with viral and mycoplasmal pneumonia and group C of 46 healthy children. On the first day of admission in the clinic, blood samples were collected before the start of antimicrobial treatment, for culture, serological tests, leukocyte count and for the determination of CRP and PCT levels as well as tADA activity and its isoenzymes ADA1 and ADA2. According to our results, the mean leukocyte count and the mean concentrations of PCT and CRP were significantly higher in the children of group A than those in groups B and C. The admission serum PCT concentration has a higher sensitivity, specificity and positive predictive value for bacterial pneumonia than either CRP or the leukocyte count. The mean serum tADA, ADA1 and ADA2 activity in children of group A was not significantly different from those in group C, while the difference between groups B and C was statistically significant. In conclusion, we found that CRP is a good marker for screening various infectious diseases, but it cannot be used to distinguish between bacterial and viral infections. Serum PCT measurement might be a useful tool for the physician for the aetiological diagnosis of pneumonia in children. Measurements of serum tADA and ADA2 activity may provide useful additional diagnostic information on the aetiology of pneumonia so that appropriate antibiotic therapy can be given promptly. Further studies with larger patients groups are required to confirm our results.

Bronchial hyperresponsiveness in adults with seasonal and perennial rhinitis: is there a link for asthma and rhinitis?

Epidemiological studies have shown that asthma and rhinitis often coexist in the same patients and the prevalence of asthma is greater in patients with rhinitis. The aim of this study was to evaluate the differences in bronchial reactivity in subjects with seasonal and perennial rhinitis. We enrolled 128 subjects with seasonal or perennial allergic rhinitis divided into three groups: A with perennial rhinitis and allergy to Dermatophagoides Pteronissynus; B with seasonal rhinitis and allergy to Graminae and Parietaria, who underwent methacholine challenge test (MCHt) during the exposure period (fron March until May); C with seasonal rhinitis and allergy to Graminae and Parietaria, who underwent MCHt during the non exposure period (from June until February). The PC20 mean values of group A (1774.8 ± 20.7) and group B (1740.7 ± 38.8) were not significantly different, but significantly lower than those of group C (3010.0 ± 56.9) (p=0.001). The subjects with group A were positive to the MCHt in 54.54%, against 29.28% of group B and 11.62% of group C (p=0.007). The results show differences in the degree of bronchial responsiveness. The dose-response curves documented a lower value of PC20 in the group with perennial rhinitis and a statistically significant difference of bronchial hyperresponsiveness prevalence between the three groups (p=0.007).

Steroid and antihistamines modulate RANTES release in cultured peripheral blood mononuclear cells of atopic patients

RANTES plays a crucial role in cell recruitment in allergic inflammation. We investigated the pharmacological modulation of RANTES release in cultured peripheral blood mononuclear cells obtained from allergic patients with active asthma. Chemokine production was assessed before and after 15 day treatment with histamine-1 receptor antagonists (antihistamines) (Loratadine or Cetirizine) and a steroid (Deflazacort), both in unstimulated and PHA-stimulated cell cultures. Results were compared with those obtained from placebo-treated patients. During the treatment period, patients recorded morning and evening peak expiratory flow (PEF) by the mini-Wright procedure. PEF absolute values and diurnal variability significantly improved respect to the pre-treatment in steroid-treated patients, in comparison to the placebo and antihistamine-treated groups (p<0.001 and 0.01, respectively). PEF diurnal variability in the antihistamine-treated group were lower than placebo-treated group without statistical significance (p=0.06). No differences could be found in RANTES levels in supernatants of all cultures between the two antihistamines. RANTES release significantly decreased in supernatants of all cell cultures from steroid (p<0.01) and antihistamine (p=0.03 and 0.04) groups after treatments, compared to the basal values; whereas it increased slightly in controls. Co-variance analysis on RANTES levels, adjusting for pre-treatment values, showed a significant reduction of RANTES release by PHA-stimulated PBMCs from steroid (p=0.003) and anti-histamine (p=0.03) groups, with respect to the placebo group. The same statistical tool applied between the steroid and the antihistamine groups showed, after therapy, the lowest levels of RANTES to be associated with steroid treatment (p=0.005). The study shows that the steroid is the most effective drug in modulating RANTES release from PBMCs. However, antihistamines, which are able to reduce cell recruitment due to chemokine release, avoiding important side effects, may be useful in long term therapy in controlling and preventing allergic inflammation.