Soluble interleukin-5 receptor alpha is increased in acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND: During chronic obstructive pulmonary disease (COPD) exacerbations (AE-COPD), an influx of eosinophils into the bronchial mucosa has been described. Eosinophilic cationic protein (ECP) and soluble interleukin-5 receptor alpha (sIL5Ralpha) are secreted by eosinophils and increased in eosinophilic airway diseases. METHODS: We studied ECP and sIL5Ralpha expression in patients with COPD compared to healthy controls and smokers and investigated a possible association to viral exacerbations of COPD. Expression of sIL5Ralpha in serum was analyzed by ELISA and ECP by the Uni-Cap system. Induced sputum from patients with COPD was analyzed for six different respiratory viruses by nested PCR. RESULTS: ECP and sIL5Ralpha were significantly elevated in AE-COPD subjects (n = 54) compared to healthy controls (n = 11, p = 0.018). Furthermore, there was a significant increase in sIL5Ralpha, but not in ECP, in 30 patients with virus-associated AE-COPD compared to smokers without COPD (n = 16) and healthy controls. The increase in FEV(1) after resolution of the AE-COPD correlated with the decrease in sIL5Ralpha (r = 0.269, p = 0.034). CONCLUSIONS: sIL5Ralpha is increased in AE-COPD and not affected by smoking like ECP. sIL5Ralpha is increased in patients with virus-associated AE-COPD compared to smokers and controls. Concentrations of sIL5Ralpha mirror changes in the clinical status and lung function. These data support the involvement of eosinophils in acute exacerbations of COPD.     

Soluble interleukin-2 receptor release defect in vitro in elderly subjects

The evidence from several studies indicates that as individuals age, they may display immune dysfunctions, mostly T cell dysfunctions. Recently, a soluble form of the receptor for interleukin-2 (IL-2) (sIL-2R) has been demonstrated in human sera and in vitro stimulated culture supernatants from human T lymphocytes. In the present paper, we report in vitro sIL-2R production from peripheral blood mononuclear cells in elderly subjects. The results show that no difference exists for unstimulated cultures, whereas after mitogen stimulation the elderly subjects showed the lowest values compared with young ones. These findings suggest that sIL-2R may provide a new tool for the study of T lymphocyte dysfunctions in old age.     

Soluble interleukin-2 receptor is a thyroid hormone-dependent early-response marker in the treatment of thyrotoxicosis.

Thyrotoxic patients exhibit increased levels of immune activation molecules (soluble interleukin-2 receptor [sIL-2R], intercellular adhesion molecule-1 [ICAM-1], and endothelial-leukocyte adhesion molecule-1 [ELAM-1]) in serum, although the clinical significance of these measurements remains unclear. In a randomized 4-week study, we have recently shown that in the treatment of hyperthyroidism, the combination of cholestyramine and methimazole (MMI) resulted in faster lowering of serum thyroid-hormone levels than did MMI alone. Stored serial serum samples from patients participating in this randomized treatment trial were analyzed for sIL-2R, soluble ICAM-1 (sICAM-1), and soluble ELAM-1 (sELAM-1). The levels of all three molecules were elevated in patients with hyperthyroidism. Although the levels of sICAM-1 and sELAM-1 remained elevated through the 4-week follow-up period in both groups of patients, the sIL-2R levels (normal levels, 1.0 to 4.2 ng/ml) decreased significantly in the 10 patients who received cholestyramine in addition to MMI (week 0, 14.2 +/- 1.5 ng/ml; week 2, 10.8 +/- 1.2 ng/ml; week 4, 8.9 +/- 1.5 ng/ml). In eight patients who received MMI alone, sIL-2R decreased less rapidly (week 0, 12.3 +/- 1.4 ng/ml; week 2, 12.3 +/- 1.3 ng/ml; week 4, 10.9 +/- 1.3 ng/ml). sICAM-1 and sELAM-1 were elevated at baseline but did not decrease during therapy. In the former group, free thyroxine and free triiodothyronine decreased faster. These data show that levels of sIL-2R in serum, but not those of sICAM-1 and sELAM-1, may be of clinical use in the early follow-up evaluation of medically treated patients.     

Soluble interleukin-2 receptor and disease activity in Crohn's disease.

An ELISA was used to measure concentrations of soluble interleukin-2 receptor (sIL-2R) alpha chain in the sera of patients with Crohn's disease. In a group of 56 patients, serum concentrations of sIL-2R were significantly raised in patients with active disease compared with patients with inactive disease and age-matched control populations. There was a significant correlation between serum sIL-2R concentration and disease activity as assessed by the Harvey-Bradshaw index (r = +0.60; P less than 0.001) and laboratory measurements of disease activity including C-reactive protein (r = +0.79; P less than 0.001), ESR (r = +0.64; P less than 0.001) and platelet count (r = +0.533; P less than 0.001). We also found a negative correlation between sIL-2R levels and serum albumin (r = -0.66; P less than 0.001). In longitudinal studies, changes in the concentration of serum sIL-2R reflected the changes in disease activity. Soluble IL-2R, therefore, offers a new measure of disease activity in Crohn's disease with a potential advantage over other laboratory parameters currently available in that it may reflect more accurately the underlying immunopathogenic process.     

Soluble interleukin-2 receptor in sera of patients with Graves' disease.

Recently, in vitro production of interleukin-2 receptor induced by mitogens have been shown to be impaired in autoimmune disorders including organo-specific autoimmune diseases. The aim of this study was to investigate serum levels of soluble interleukin-2 receptor in 20 untreated patients with Graves' disease and to follow up their changes in relation to clinical picture and TSH-receptor-, anti-thyroglobulin-, anti-microsomal as well as anti-eye muscle antibodies. Soluble interleukin-2 receptor level was significantly increased in newly-diagnosed Graves' patients compared to controls (667 +/- 270 vs. 205 +/- 45 U/ml) (P less than 0.001). Among the patients sera those with active infiltrative ophthalmopathy had higher soluble interleukin-2 receptor levels than those without eye symptoms (810 +/- 313 vs. 525 +/- 180 U/ml). Soluble interleukin-2 receptor level was normalized in Methimazole-treatment-induced remission in the majority of patients except those with ophthalopathy. In five patients the soluble interleukin-2 receptor levels were studied after interruption of thyrostatic therapy; an increase was observed in three patients; thereafter hyperthyrosis relapsed in two cases. Furthermore, a correlation was found between soluble interleukin-2 receptor levels and TSH-receptor antibodies, however, the association with other immune parameters examined was not significant. In conclusion, an enhanced level of soluble interleukin-2 receptor was detected in patients with untreated Graves' disease. This finding might play a significant role in regulation of impaired cell-mediated immune mechanism and has a prognostic value for relapse of autoreactive processes.     

Soluble interleukin-2 receptor in sera of patients with Graves' disease.

Activation of T lymphocytes has been found to be associated with an increase in soluble interleukin-2 receptor (sIL-2R) levels. The aim of this study was to investigate serum levels of sIL-2R in 20 untreated patients with Graves' disease and to relate these levels to disease activity and to TSH-receptor, anti-thyroglobulin, anti-microsomal and anti-eye muscle antibodies. sIL-2R levels were significantly increased in newly diagnosed Graves' patients compared with controls (667 +/- 270 vs 205 +/- 45 U/ml) (P less than 0.001). The sIL-2R levels were higher in patients with active infiltrative ophthalmology than in those without eye symptoms (810 +/- 313 vs 525 +/- 180 U/ml). All patients were treated with methimazole for at least 12 months. sIL-2R levels were normalized by methimazole treatment in the majority of patients without ophthalmopathy but not in those with ophthalmopathy. In five patients sIL-2R serum levels were studied after interruption of thyrostatic therapy. An increase was observed in three patients and hyperthyroidism subsequently relapsed in two of these. Furthermore, a correlation was found between soluble interleukin-2 receptor levels and TSH-receptor antibodies but not with other immune parameters examined. Serum sIL-2R represents a useful marker of immunological activity in Graves' disease.     

Soluble interleukin-2 receptor, interleukin-2 and interleukin-4 in sera and supernatants from patients with progressive systemic sclerosis.

We studied the sera of patients with progressive systemic sclerosis (PSS) for elevated levels of soluble interleukin-2 receptor (sIL-2R), interleukin-2 (IL-2) and interleukin-4 (IL-4). We also measured IL-2, IL-4 and B cell growth factor (BCGF) activity in supernatants of peripheral blood mononuclear cells from the same patients. The finding of elevated serum sIL-2R and IL-2, and the increased levels of IL-2, IL-4 and BCGF activity in culture supernatants indicates that T lymphocyte hyperactivity likely play a major role in PSS. The failure to detect under our experimental conditions a direct proliferative effect of recombinant IL-2 on enriched normal B cells might suggest that IL-4 is the cytokine mainly responsible of the BCGF activity recovered in PSS supernatants.     

Soluble interleukin-2 receptor and soluble CD8 antigen in active rheumatoid arthritis

Concentrations of soluble interleukin-2 receptor (sIL-2R) and of soluble CD8 antigen (sCD8) in sera and in supernatants of phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) derived from patients with active rheumatoid arthritis (RA) were studied. sIL-2R concentrations in sera derived from patients with RA (1484 +/- 382 U/ml) were significantly higher than in sera derived from healthy controls (380 +/- 110 U/ml; P less than 0.0005). In contrast, supernatants of PHA-stimulated PBMC derived from patients with RA contained similar amounts of sIL-2R (727 +/- 467 U/ml) as those derived from healthy control individuals (833 +/- 508 U/ml; P greater than 0.1). When investigated for the presence of sCD8 antigen, sera derived from patients with RA contained significantly lower amounts (30 +/- 28 U/ml) than sera derived from healthy controls (405 +/- 136 U/ml; P less than 0.0005). Similarly, PHA stimulation of PBMC derived from patients with RA resulted in a significantly lower production of sCD8 (35 +/- 46 U/ml) as compared to the one obtained by PHA stimulation of PBMC derived from healthy controls (177 +/- 59 U/ml; P less than 0.0005). This difference could not be explained by a lower proliferative response to PHA by PBMC derived from patients with RA (21,474 +/- 14,022 cpm) as compared to healthy controls (29,549 +/- 11,188 cpm; P greater than 0.05). Our data demonstrate that PBMC derived from patients with active RA differ from PBMC derived from healthy individuals concerning their ability to produce sIL-2R and sCD8.     

Soluble interleukin-6 receptor (sIL-6R) in cerebrospinal fluid of patients with inflammatory and non inflammatory neurological diseases

IL-6 acts on target cells via the ligand-binding protein interleukin-6 receptor (IL-6R) and the affinity-converting and signal-transducing glycoprotein 130 (gp130). Soluble interleukin-6 receptor (sIL-6R) has an agonistic role because the soluble complex (IL-6/sIL-6R) can activate cells that do not express IL-6R and an antagonistic role as it enhances the inhibitory activity of sgp130. Soluble forms of both receptors, sIL-6R and sgp130, regulate the action of IL-6. sIL-6R was measured by a sensitive enzyme-linked immunosorbent assay in paired sera and cerebrospinal fluid (CSF) from 46 patients with inflammatory neurological diseases (IND), 45 patients with relapsing-remitting multiple sclerosis (RR-MS), 13 patients with primary progressive multiple sclerosis (PP-MS), 17 patients with other non inflammatory neurological diseases (NIND) and 13 mentally healthy individuals--healthy controls (HC). Patients with RR-MS had CSF sIL-6R levels comparable to those from patients with IND, but higher than patients with NIND and HC. A positive correlation between the CSF/serum albumin (QAlb) and CSF sIL-6R levels was observed in IND but not in RR-MS patients indicating that CSF sIL-6R levels in IND patients could be influenced by serum sIL-6R and blood brain barrier (BBB) permeability properties. RR-MS patients had higher values of [CSF/serum sIL-6R:CSF/serum albumin] (sIL-6R index) than IND patients suggesting that in multiple sclerosis (MS), the increase in CSF sIL-6R could be due to intrathecal synthesis of sIL-6R. The finding of increased CSF sIL-6R concentrations (>979 pg/ml) with sIL-6R index (>4.66), in correlation with positive oligoclonal bands in RR-MS patients, suggests that values of sIL-6R index > 4.66 indicate intrathecal increase of sIL-6R and might be used as an indicator of neuroimmunoregulatory and inflammatory processes in the central nervous system (CNS).     

Soluble interleukin-6 receptor is elevated during influenza A virus infection and mediates the IL-6 and IL-32 inflammatory cytokine burst

Influenza A virus (IAV) infection is a major worldwide public health problem. However, the factors involved in mediating the inflammatory response to this infection and their relationships remain poorly understood. Here, we show that IAV infection stimulates the expression of the soluble IL-6 receptor (sIL-6R), a multifunctional protein involved in IL-6 signaling. Interestingly, sIL-6R expression upregulated the levels of its own ligand, IL-6 and those of the pro-inflammatory cytokine IL-32. shRNA-mediated knockdown of sIL-6R suppressed IL-6 and IL-32, indicating that this regulation is dependent on sIL-6R during IAV infection. Furthermore, our results demonstrate that IL-32 participates in a negative feedback loop that inhibits sIL-6R while upregulating IL-6 expression during IAV infection. Therefore, we show that sIL-6R is a critical cellular factor involved in the acute inflammatory response to viral infection.     

Plasma and tissue interleukin-2 receptor levels in inflammatory bowel disease.

Plasma and tissue interleukin-2 receptor (IL-2R) levels were determined in patients with active ulcerative colitis and Crohn's disease. Compared with healthy controls (median 440 U/ml; range 240-900), significantly higher levels of plasma IL-2R were present in patients with active ulcerative colitis (median 1180 U/ml; range 580-7150; P less than 0.002) and Crohn's disease (median 1340 U/ml; range 480-9000; P less than 0.002). Compared with other laboratory parameters, plasma IL-2R levels were related most closely to clinical score of disease activity in Crohn's disease. Plasma IL-2R levels also reflected the clinical course and may provide a more accurate assessment of disease activity in Crohn's disease. In plasma of patients undergoing intestinal resection of active inflammatory bowel disease, raised levels of IL-2R were present in samples from mesenteric vein (draining inflamed intestine) compared with those from peripheral vein. In tissue homogenates of colonic biopsies, significantly higher levels of IL-2R were present in specimens from colons with active ulcerative colitis compared with healthy controls (median 230.2, range 20.7-581.5 versus 77.9, range 34.2-291.3; P less than 0.02).     

Astrocytic alterations in interleukin-6/Soluble interleukin-6 receptor alpha double-transgenic mice

Interleukin-6 (IL-6), a major cytokine with diverse effects on cells mainly of the immune and hematopoietic systems, has been linked to several neurological disorders such as acquired immune deficiency syndrome dementia, multiple sclerosis, and Alzheimer's disease. Central nervous system (CNS)-specific expression of IL-6 caused neurodegeneration, massive gliosis, and vascular proliferation in transgenic mice. However, the effects of systemically circulating IL-6 and its receptor IL-6Ralpha on the CNS are unknown. IL-6Ralpha is the specific component of the IL-6 receptor system and hence an important co-factor of IL-6. IL-6Ralpha is bioactive in a membrane-bound and in a soluble (s) form. We investigated the effects of systemically elevated levels of either human IL-6 or human sIL-6Ralpha or both on the CNS of transgenic mice. Although IL-6 and sIL-6Ralpha single transgenic mice were free of neurological disease, IL-6/sIL-6Ralpha double-transgenic mice showed neurological signs, such as tremor, gait abnormalities, and paresis. However, these mice also frequently showed prominent general weakness probably because of the systemic effects of IL-6/IL-6Ralpha such as liver damage and plasmacytomas. IL-6/sIL-6Ralpha transgenic mice exhibited massive reactive gliosis. Lack of signs of neuronal breakdown versus ample astrogliosis suggested that astrocytes were selectively affected in these mice. There was neither vascular proliferation nor inflammatory infiltration. Ultrastructural analysis revealed blood-brain barrier (BBB) changes manifested by hydropic astrocytic end-feet. However, albumin immunohistochemistry did not reveal major BBB leakage. Our results indicate that increased and constitutive systemic expression of IL-6 together with its soluble receptor sIL-6Ralpha is less harmful to the brain than to other organs. The BBB remains primarily intact. IL-6/IL-6Ralpha, however, might be directly responsible for the selective activation of astrocytes.     

Soluble interleukin-2 receptor and interleukin-4 in sera of asthmatic children before and after a prednisolone course.

BACKGROUND: Cytokine-mediated interactions among inflammatory cells may play a role in the pathogenesis of bronchial asthma. OBJECTIVE: To understand the role of soluble interleukin-2 receptor (sIL-2R) and interleukin-4 (IL-4) in the disease activity of acute asthma, changes in serum concentrations of sIL-2R and IL-4 elaborated by activated T-lymphocyte before and after prednisolone therapy with clinical improvement were determined in the present study. METHODS: Circulating levels of sIL-2R and IL-4 in sera from 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in a stable condition were determined by using commercially available ELISA kits. RESULTS: The mean concentration of serum sIL-2R was significantly higher in acute exacerbation than in children with stable asthma (368.9 +/- 395.4 pg/mL vs 291.2 +/- 361.0 pg/mL; P < .01) or in control subjects (124.6 +/- 17.8 pg/mL; P < .001). The mean concentration of serum IL-4 was higher in acute exacerbation (5.82 +/- 1.10 pg/mL) and in stable asthmatic patients (6.73 +/- 2.83 pg/mL) versus control group subjects (5.54 +/- 1.20 pg/mL). However, the difference was not statistically significant among the three study groups. CONCLUSIONS: This study provides further evidence that changes in serum IL-2R may serve as an objective indicator for clinical outcome of allergic asthmatic patients.     

Soluble interleukin-2 receptor and soluble CD8 in liver cirrhosis and obstructive jaundice.

Activated lymphocytes secrete soluble interleukin-2 receptor (sIL-2R); CD8-positive lymphocytes secrete soluble CD8 (sCD8). Liver dysfunction in cirrhosis and obstructive jaundice is known to result in depressed cellular immunity. To evaluate whether this is due to real inactivation of the immune system, we measured sIL-2R and sCD8 in the serum of 46 patients with liver cirrhosis, 25 patients with obstructive jaundice, 32 patients with alcoholic liver disease without evidence of cirrhosis, 23 healthy persons and 43 patients with unrelated disease. sIL-2R in patients with cirrhosis (mean +/- s.e.m. 1499 +/- 140 U/ml) and obstructive jaundice (1517 +/- 204) was significantly increased compared with healthy subjects (363 +/- 29) and patients with unrelated diseases (685 +/- 92); sCD8 was significantly increased in patients with cirrhosis (737 +/- 63) but not in patients with obstructive jaundice (419 +/- 32) compared with healthy subjects (322 +/- 23) and patients with unrelated diseases (375 +/- 22). No difference was found between patients with cirrhosis due to alcohol abuse (n = 15) and chronic hepatitis B (n = 6). The Child-Pugh score had no significant influence on the sIL-2R or sCD8 value. In obstructive jaundice, sIL-2R correlated with alkaline phosphatase as marker of cholestasis (r = 0.43). These data show that in spite of the apparent depressed cellular immune defense both in liver cirrhosis and obstructive jaundice there is a general activation of the immune system but the CD8+ cell compartment is only activated in liver cirrhosis. The great changes of sIL-2R and sCD8 in liver dysfunction are important for the interpretation of studies using these serum proteins as markers for immune activation.     

Soluble interleukin-2 receptors in plasma cell dyscrasias

Levels of the soluble form of the interleukin-2 receptor (sIL-2R) were evaluated in the peripheral blood of 69 patients with plasma cell dyscrasias. A close relationship was seen between serum sIL-2R levels and clinical features. Among patients with normal BUN and creatinine levels, the mean (+/- 1SD) level of sIL-2R in 44 patients with multiple myeloma (MM) was higher than that of normal controls (457 +/- 227 U/ml vs 288 +/- 124 U/ml, P = 0.01). The mean level of sIL-2R in eight patients with primary macroglobulinemia was 722 +/- 251 U/ml. In MM, those with active or refractory disease showed a significantly higher mean level of sIL-2R than those in the remission phase (577 +/- 240 U/ml vs 335 +/- 103 U/ml, P = 0.01). There was a negative correlation between sIL-2R and hemoglobin levels in MM patients (r = -0.45, P = 0.01). Five patients with complications of renal insufficiency had elevated levels of sIL-2R. In a longitudinal study of a patient with plasmacytoma and an extremely high sIL2-R level, the sIL-2R level showed a strong relationship with tumor burden. Patients with high sIL-2R levels generally had a poor prognosis than those with normal levels. Thus a high sIL-2R level may be an indicator of a poor prognosis in MM.     

Soluble interleukin-2 receptor secretion defect in vitro in HLA-B8, DR3 positive subjects

Several studies have shown that HLA-B8,DR3 positive subjects may display T cell dysfunctions. Recently, a soluble form of the receptor for IL-2 (sIL-2R) has been demonstrated in human sera and in vitro-stimulated culture supernatant from human T lymphocytes. In the present paper we report sIL-2R serum levels and sIL-2R production from peripheral blood mononuclear cells in HLA-B8,DR3 positive subjects. We found that HLA-B8,DR3 positive subjects have the highest values of serum sIL-2R, but comparing the values of these subjects with those of negative ones no significant difference was observed. As regards the in vitro production of sIL-2R, no difference exists for unstimulated cultures, whereas after stimulation, the HLA-B8,DR3 positive subjects showed the lowest values compared with negative ones. It is noteworthy that these changes are observed in autoimmune diseases linked to this HLA phenotype.     

Soluble type-I interleukin-1 receptor blocks chicken IL-1 activity

The ligand-binding domain of the chicken type-I interleukin-1 (IL-1) receptor (soluble IL-1R(I); sIL-1R(I)) was cloned into a Pichia pastoris expression system and the resulting sIL-1R(I) binding protein was used to produce antisera in rabbits (anti-IL-1R(I)). Two experiments were conducted to determine the capacity of sIL-1R(I) or anti-IL-1R(I) to block the IL-1 bioactivity (thymocyte co-stimulation) in conditioned media (CM) from HD11 chicken macrophages stimulated with lipopolysaccharide. In the first experiment, pre-incubation of CM with unpurified sIL-1R(I) significantly decreased its thymocyte co-stimulation activity by 57%. Further purification of sIL-1R(I) from other proteins secreted or shed from P. pastoris expression system by size exclusion filtration or ammonium sulfate (60%) precipitation did not influence its capacity to neutralize IL-1 bioactivity. These partially purified sIL-1R(I) preparations significantly decreased thymocyte co-stimulation activity in CM by 70.7 and 77.3%, respectively. In the second experiment, pre-incubation of thymocytes with antisera against the sIL-1R(I) decreased IL-1 activity in CM by 70% relative to control thymocyte cultures that received no antibody and by 59% relative to thymocyte cultures incubated with pre-immune sera. Presumably anti-sIL-1R(I) diminished the IL-1 bioactivity in CM by blocking IL-1 binding to its type-I receptor on thymocytes. Thus, 30% of the IL-1-like activity released by LPS-stimulated HD11 macrophages is probably due to at least one other cytokine. Our data are consistent with the type-I receptor being the primary IL-1 receptor on chicken thymocytes that is capable of providing a signal for proliferation.     

Atopy and interleukin-4 receptor]

Both IL-4 and IL-13 induce IgE synthesis in B cells by binding to their functional receptors on target cells. These receptors are considered to be composed of heterodimers and both share the IL-4R alpha chain (IL-4R alpha) as a component. Atopy is an inherited tendency, underlying asthma, rhinitis and eczema, and generating high nonspecific IgE and/or high specific IgE against common antigens. Based on findings concerning the molecular mechanism of the signal transduction of IL-4 and IL-13, IL-4R alpha was considered a gene that gave rise to atopy. One polymorphism in the IL-4R alpha gene, Ile50Val, has been correlated with atopy by both genetic and functional assessment. The strategy used in these studies should lead to identification of other genes involved in atopy. Furthermore, these studies should be useful for gene diagnosis of atopy and development of new therapies for atopy in the future.     

Soluble interleukin-4 receptor (sIL-4R) in allergic diseases

The mediator interleukin-4 (IL-4) plays an important role in the development of allergic inflammatory responses. IL-4 controls the production of IgE, expands IL-4 producing T cell subsets and stabilises effector cells functions. Based on this concept, it was aimed to neutralize secreted IL-4 molecules using recombinant soluble IL-4 receptors. The molecular characterization of soluble IL-4 receptors allowed the design of a recombinant drug initially evaluated in cell culture, then in animal models, followed by investigations of T cell functions from allergic patients in vitro. Based on these data, phase I/II studies have been initiated to take this approach from bench to bedside. Initial data reveal that this approach is safe and without drug-related toxicity. Stabilization of lung functions in moderate asthma patients has been reported. These results have proven the concept for a central role of IL-4 in the immunopathogenesis of allergic diseases. The immediate future will reveal whether neutralization of IL-4 with suitable drugs will provide an additional tool in the management of allergic patients.