Immune aberrations in B and T lymphocytes derived from chronic urticaria patients

The Expression of IL-17, in Chronic Spontaneous Urticaria Is Linked to Semaphorin5A

Background: Patients with chronic spontaneous urticaria (CSU), an autoimmune disorder, show increased skin expression of IL-17A and can benefit from treatment with the anti-IL-17A biologic secukinumab. The mechanisms that drive IL-17A expression in CSU are currently unknown, but may involve Semaphorin5A (Sema5A). Objective: To explore the expression, role, and effects of Sema5A in CSU and its link to IL-17A. Material and Methods: We investigated patients with CSU and healthy controls for skin expression of expressing peripheral T cells. Results: Sema5A was highly expressed in the skin of CSU patients as compared to healthy control skin. Both CD4+ T cells and mast cells in CSU skin expressed Sema5A, and many of them expressed both Sema5A and IL-17A. Patients with CSU had significantly higher rates of IL-17A-expressing CD4+ T cells as compared to healthy controls. Incubation with Sema5A increased the rates of IL-17A-expressing CD4+ T cells in healthy controls to CSU levels. Conclusion: Sema5A may drive the expression and effects of IL-17A in CSU. Further studies in larger cohorts are needed to confirm the role of Sema5A in the pathogenesis of CSU and to explore its potential as a therapeutic target.

The Emerging Role of IL-17 in the Immune-Pathogenesis of Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is considered to be an autoimmune disorder (type I and type II) in 50% of all cases. However, autoreactive T cells and their proximity with activated mast cells in the skin of CSU patients are believed to be the primary event in mast cell degranulation. The finding of anti-FcɛRIα on mast cells or IgE autoantibodies against thyroid antigens should be considered to be a consequence of the auto-reactive T cells’ recognition of the above-mentioned antigens. Our recent finding of increased Th17 and IL-17 expression in both CD4+ T cells and mast cells in the skin of severe CSU patients is supportive for the major role that T cells perform in the pathogenesis of CSU. Supporting this are numerous previous reports in which increased serum IL-17 was found to be in association with CSU disease severity. The beneficial effect of anti-IL-17A (secukinumab) in CSU patients in whom high dose anti-histamines, recurrent course of steroids and omalizumab fail to achieve a reasonable response should be investigated as a new therapeutic strategy in future studies with a large cohort of patients.

Serum Specific IgE to Thyroid Peroxidase Activates Basophils in Aspirin Intolerant Urticaria

Thyroid antibodies are frequently observed in urticaria patients, but their roles in urticaria are not clearly elucidated. We investigated the role of serum specific IgE to thyroid peroxidase (TPO) in patients with aspirin intolerant acute urticaria (AIAU) and aspirin intolerant chronic urticaria (AICU). We recruited 59 AIAU and 96 AICU patients with 69 normal controls (NC). Serum specific IgE to TPO was measured by manual direct ELISA, and CD203c expressions on basophil with additions of TPO were measured to prove a direct role of TPO in effector cells. The prevalences of serum specific IgE to TPO were significantly higher in AIAU (15.2%) and AICU groups (7.5%) compared to NC (0%, P=0.018: P=0.013, respectively). Flow cytometry showed CD203c induction in a dose dependent manner with serial additions of TPO in some AIAU and AICU patients having high specific IgE to TPO. Our findings show that the prevalence of serum specific IgE to TPO was significantly higher in both AIAU and AICU patients than in NC. It is suggested that specific IgE to TPO play a pathogenic role in AIAU and AICU.

Plasma soluble CD40 concentration in patients with delayed pressure urticaria

Very little is known about the immune-inflammatory cascade in delayed pressure urticaria (DPU). It has been suggested that increased activation/expression of CD40 may result in enhanced release of soluble CD40 (sCD40) in chronic urticaria. To investigate release of sCD40 in the course of DPU, plasma sCD40 concentration was measured using ELISA method in 18 adult patients with DPU and 27 age- and sex-matched healthy controls. Plasma sCD40 concentration did not differ significantly in the DPU group as compared to healthy subjects. The present study as well as the earlier contributions, suggest that distinct CD40-signalling activity manifested by sCD40 release may be identified in different types of urticaria. Delayed pressure urticaria is not associated with increased circulating sCD40 concentration, contrary to chronic spontaneous urticaria with positive response to autologous serum skin test.

EAACI taskforce position paper: evidence for autoimmune urticaria and proposal for defining diagnostic criteria

An autoimmune subset of chronic spontaneous urticaria is increasingly being recognized internationally, based on laboratory and clinical evidence that has accrued over the last 20 years. This evidence has been reviewed by a taskforce of the Dermatology section of the European Academy of Allergy and Clinical Immunology. Functional autoantibodies in chronic urticaria (CU) patient sera have been demonstrated against IgE and FcεRIα by basophil and mast cell histamine release assays and by basophil activation assays. Antibody specificity has been confirmed by immunoassay, but there is a poor correlation between functionality and immunoreactivity. Approximately 25% of CU patients have a positive basophil histamine release assay and show autoreactivity (a positive autologous serum skin test), whereas 50% are negative regarding both. Functionality of CU sera appears to be complement dependent on mast cells but not exclusively on basophils. Basophil activation by CU sera is predominantly restricted to IgG1 and IgG3 subclasses. Circumstantial evidence for CU being an autoimmune disease comes from an observed association with other autoimmune diseases, a strong association between serum functionality and HLA-DR4 haplotype and the good response of CU patients to immunotherapies. It was proposed that a study should be undertaken to prospectively validate potentially relevant clinical criteria (from the history, examination and routinely available clinical investigations) against a new 'gold standard' for the diagnosis of ACU (positive autoreactivity, functional bioassay and immunoassay) to define preliminary criteria sets for the diagnosis of ACU based on clinical and laboratory features with highest individual sensitivity and specificity.

Elevated serum B-cell activating factor in patients with chronic urticaria

The B and T cells abnormalities that have been described among CU patients, lend support to its regard as an autoimmune disease. In this study we compared serum B-cell activation factor (BAFF) levels in 46 CU patients to 24 healthy controls and evaluated a possible association between elevated serum BAFF in CU patients and the presence of autologous serum skin test, anti-thyroid antibodies, antinuclear antibodies, high total IGE levels, and urticaria disease severity. We found that serum BAFF levels is elevated statistically significant in CU patients compared to healthy control (1228±342 pg/ml vs. 758±313 pg/ml, P<0.0001). CU patients with severe disease activity had significantly higher serum BAFF levels compared to patients with mild CU (1394.6±299.6 vs. 1097.6±221.3, P=0.0008). No association was found between the presence of positive autologous serum skin test, anti-thyroid antibodies or antinuclear antibodies or high levels of total IgE and serum BAFF levels in CU Patients. We conclude that CU patients have higher levels of serum BAFF which associate with disease severity.

Cyclosporine-A in severe chronic urticaria: the option for long-term therapy

BACKGROUND

The treatment of severe chronic urticaria (CU) remains a difficult goal to achieve. Many patients do not respond to anti-histamine therapy, even when off-label doses are given. Thus, cyclosporine-A (CsA) becomes a good therapeutic option for severe patients and for some, long-term therapy is required. We evaluated the effectiveness and safety of low-dose CsA, when treatment cannot be discontinued and long-term CsA therapy is needed to maintain severe CU in remission.

METHODS

Among 2000 patients with CU who were referred to our outpatient clinic, 120 patients who suffered from a very severe CU began treatment with CsA 3 mg/kg. A clinical and laboratory followup was performed during this period of treatment.

RESULTS

In 20 patients, CsA was discontinued within 2-15 days after initiation because of side-effects. Among 62 of the remaining 100 patients (62%), CsA was administered for a period of 3 months with a highly beneficial outcome. In another 20 patients (20%), CsA was considered beneficial; however, it was required for a longer period of time, 5-10 years for some of the cases. In all cases, CsA was well tolerated and most important, it was safe. For 18 patients (18%), CsA therapy was reported as failed.

CONCLUSION

A low dose of CsA is a good option for patients who suffer from especially severe CU. In most cases, this therapy regimen is considered effective and safe. For a small group of patients, long-term therapy is needed, and until now it is considered safe.

Immunomodulatory approaches to the management of chronic urticaria: an immune-mediated inflammatory disease

Although commonly encountered in clinical practice, chronic urticaria (CU) remains difficult to treat. In contrast to acute urticaria, neither exogenous triggers nor specific immunoglobulin E are identified in most chronic cases. A body of evidence suggests that CU is represented within the spectrum of immune-mediated inflammatory diseases (IMID). Our understanding of the CU disease pathogenesis now recognizes a role for T cells, B cells, and autoantibodies, and intrinsic abnormalities of histamine-releasing effector cells, thus providing new targets of intervention beyond the current mainstay of often inadequate symptomatic treatment directed against histamine receptors and steroids, with their attendant morbidities. Agents previously used to treat other autoimmune and inflammatory diseases have demonstrated efficacy in CU. Newer biologic and nonbiologic immunomodulatory agents approved for other indications and in clinical development provide potential options for this often severe disease.

Increased serum levels of circulating CD40 ligand in patients with bullous pemphigoid: preliminary results

BACKGROUND

Autoimmune bullous diseases are characterized by autoantibodies against specific adhesion molecules of the skin and/or mucous membrane. While these autoantibodies are known to play a primary role in the disease manifestation, it remains unknown how disease-specific autoreactive B cells and autoantibodies are induced. Recent studies have indicated the importance of the CD40 and CD40 ligand (CD40L) receptor-ligand pair in the immunopathogenesis of autoimmune diseases. CD40L circulates in soluble form, and some reports suggest that serum soluble CD40L (sCD40L) levels are increased in various autoimmune diseases.

OBJECTIVES

To determine serum sCD40L levels in patients with pemphigus vulgaris (PV) and bullous pemphigoid (BP), and to determine their correlation with clinical findings and laboratory findings.

PATIENTS AND METHODS

Sera from 10 PV patients, 35 BP patients and 12 normal controls were subjected to ELISA assays to measure serum levels of sCD40L, anti-desmoglein-3 antibody and anti-BP180 antibody.

RESULTS AND CONCLUSIONS

Circulating sCD40L levels were significantly elevated in BP patients, but not in PV patients. Serum sCD40L levels increased in the early stage of disease onset and recurrence in BP patients. In conclusion, circulating sCD40L levels may be a useful marker for early activation of autoimmune diathesis and, furthermore, an effective therapeutic target in patients with BP.

Elevated levels of soluble CD40 ligand (sCD40L) in serum of patients with systemic autoimmune diseases

The CD40-CD40L costimulatory pathway is involved in the evolution of many autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren's syndrome (SS). Increased levels of sCD40L in the serum have been associated with disease activity in SLE. The aim of this study was to investigate the role of sCD40L in the development of lupus nephritis and examine its possible association with cryoglobulinemia in Sjögren's syndrome. We used a 2-site sandwich ELISA to measure the levels of sCD40L in sera, from 64 patients with SLE, RA and SS and 17 healthy blood donors. Biological specimens from the affected tissues such as urine from patients with lupus nephritis and saliva from patients with SS were also tested. In this regard, paired sera and first morning urine samples from 6 SLE patients (3 with active lupus nephritis and 3 with inactive lupus nephritis) were tested with the sCD40L ELISA protocol as well as paired sera and salivary samples from 5 patients with SS and cryoglobulinemia, 5 patients with SS and anti-Ro or anti-La autoantibodies and 5 age-matched healthy control donors. We also examined possible correlations of sCD40L levels with several laboratory and clinical parameters in SS and SLE. We found that sera from SLE and SS patients had significantly higher levels of sCD40L compared to sera from healthy control donors. No sCD40L was detected, in urine samples of patients with either active or inactive nephritis and in salivary samples from SS patients or normal subjects. Soluble CD40L is elevated in sera of SS and SLE patients but further investigation is needed to determine its possible role in SLE nephritis and Sjögren's syndrome.

Significant correlation between the CD63 assay and the histamine release assay in chronic urticaria

BACKGROUND

Antibodies directed to the alpha subunit of the high affinity IgE receptor and the IgE molecule are proposed to be of pathogenetic relevance in a group of patients with chronic urticaria (CU). The diagnosis of autoimmune chronic urticaria (ACU) is difficult; the autologous serum skin test (ASST) seems to be a useful screening test, but reliable, additional confirmatory methods are needed.

OBJECTIVES

To assess the diagnostic value of a modified serum-induced basophil activation test, the CD63 expression assay, in the diagnosis of ACU by comparing the results of the CD63 assay with the results of the histamine release (HR) test, the ASST and serum levels of soluble CD40 ligand (sCD40L).

METHODS

Using basophils from an atopic (DA) and a nonatopic (DNA) donor the activity of sera of 72 patients with CU were measured in HR assay by enzyme-linked immunosorbent assay and in CD63 expression assay by flow cytometry. An ASST was carried out in all patients; in 30 of the 72 patients sCD40L was detected and correlations were derived between the different assays. Sera of 20 normal controls and 26 patients with systemic autoimmune diseases were also tested in the HR assay and in the CD63 expression assay.

RESULTS

Histamine-releasing activity was detected in the sera of 51% (DA) and 32% (DNA) of CU patients and 57% (DA) and 28% (DNA) of sera upregulated CD63 expression on the surface of basophils from the different donors. There was a significant correlation between the HR and the CD63 assays carried out on both donors, but the ASST showed a strong correlation with the HR assay only for basophils from the DA. The serum level of sCD40L was significantly higher in patients with CU compared with controls, but the difference between the autoimmune and the nonautoimmune groups was not significant.

CONCLUSIONS

The CD63 expression assay seems to be a reliable functional test in the diagnosis of ACU, particularly if highly sensitive donor basophils are used, but the determination of the sCD40L serum level was not sufficient to differentiate between the autoimmune and the nonautoimmune patient groups.

Increased plasma levels of matrix metalloproteinase-9 are associated with the severity of chronic urticaria

BACKGROUND

Matrix metalloproteinase (MMP)-9 is produced by many inflammatory cells such as macrophages, neutrophils, mast cells, eosinophils and T lymphocytes. Activated T cells are capable, through cell-cell contact, of inducing MMP-9 expression in human mast cells.

OBJECTIVE

To investigate the activation status of peripheral CD4+ T cells and the level of MMP-9 in the plasma of patients with chronic urticaria (CU), and whether MMP-9 levels are in association with CU severity.

METHODS

Study subjects included 29 patients with CU and 30 healthy control subjects. At the time of assessment, patients were divided into subgroups according to urticarial severity. Plasma levels of total MMP-9 (free pro-MMP-9 and free MMP-9) were determined by ELISA. CD4+ lymphocytes were positively selected with magnetic microbeads. After 48 h of activation, CD4+ T cells were assayed for both nuclear factor-kappa B (NF-kappa B) expression and proliferation.

RESULTS

Plasma levels of MMP-9 were found to be significantly higher in 29 CU patients compared with 18 healthy controls (186 +/- 174 vs. 31 +/- 21 ng/mL, P<0.0001). We also found a significant correlation between MMP-9 levels and urticarial severity (r = 0.92, P<0.001). In addition, CD4+ T cells from CU patients expressed higher levels of NF-kappa B than CD4+ T cells from healthy controls (82 +/- 30 vs. 69 +/- 20 optical density, P = 0.007). Finally, as compared with seven healthy individuals, DNA synthesis in CD4+ T cells from seven CU patients was found to be significantly elevated (1000 +/- 240 vs. 751 +/- 166 counts per minute, P = 0.01).

CONCLUSION

Increased levels of MMP-9 are found in CU patients, and particularly among those with severe disease. We also demonstrated that CD4+ T cells from such patients are highly activated.

Increased CD8+ T cell apoptosis in scleroderma is associated with low levels of NF-kappa B

Our objectives were (1) to compare lymphocyte subpopulation apoptosis rates in SSc patients versus healthy controls and (2) to compare Bcl-2 and NF-kappa B expression in cultured CD8 lymphocytes of SSc patients versus controls. Peripheral blood samples were obtained from 27 SSc patients meeting the American College of Rheumatology criteria for SSc and 28 healthy individuals. Mononuclear cells were isolated by Ficoll-Hypaque density gradient separation and cultured for 48 hr. For determination of apoptosis within specific cell populations, samples were labeled with PE-conjugated monoclonal antibody to CD8, CD4, and a FITC-conjugated monoclonal antibody to Annexin V. Flow cytometry was carried out with a FACS operating with Cellquest software. CD8+ lymphocytes were positively selected with magnetic microbeads conjugated to antihuman CD8. CD8 T cells were separated, then incubated with activation for 48 hr, and NF-kappa B and Bcl-2 analysis was carried out using Western immunoblotting. The CD4:CD8 ratio was increased in SSc compared to controls (2.6 +/- 1.13 vs.1.87 +/- 0.76; P = 0.018). The spontaneous apoptosis rate of SSc CD8 lymphocytes was increased compared to that of controls of (21.9 +/- 13.7 vs. 13.3 +/- 9.9; P = 0.019). No difference was found in the rate of CD4 apoptosis of SSc patients versus controls (9.8 +/- 5.2 vs. 7.18 +/- 4.89%; P = ns). The expression of NF-kappa B in SSc CD8 lymphocytes was decreased compared with that of CD8 lymphocytes from healthy controls (144 +/- 13 vs. 188 +/- 11; P = 0.018). Whereas expression of Bcl-2 was similar in activated CD8+ T cells of SSc patients and healthy controls, CD8+ T cell apoptosis rate was found to be in reverse correlation with expression of NF-kappa B in these cells ( r = - 0.53, P = 0.029). The increased CD4:CD8 ratio in SSC may result from increased CD8+ T cell apoptosis. Increased SSc CD8 T cell apoptosis is associated with low levels of NF-kappa B.

Autoimmune urticaria

A growing body of evidence shows that at least 40% of patients with unexplained (idiopathic) chronic urticaria have clinically relevant functional autoantibodies to the high-affinity IgE receptor on basophils and mast cells. The term "autoimmune urticaria" is used for this subgroup of patients presenting with continuous ordinary urticaria. This article reviews the evidence for the autoimmune hypothesis and other nonantibody serum histamine-releasing factors in the etiopathogenesis of urticaria; defines autoimmune urticaria; looks at how autoimmune urticaria fits into existing classifications of urticaria; proposes diagnostic criteria that may be useful to the clinician; and reviews the management implications for patients with this subset of chronic disease.

Clinical and laboratory parameters in predicting chronic urticaria duration: a prospective study of 139 patients

BACKGROUND

Despite the disabling nature of chronic urticaria (CU), little is known about the disease's duration or the efficacy of adopting aggressive therapeutic regimens such as cyclosporine A.

OBJECTIVES

The aim of this study was to evaluate whether parameters such as angioedema, autologous serum test, anti-thyroid antibodies, and total IgE could predict both CU duration and severity.

PATIENTS AND METHODS

One hundred and thirty-nine patients suffering from CU were prospectively followed over a 5-year period for disease duration, severity and the presence of angioedema. Also investigated was the association between these clinical parameters and the subsequent detection of autologous serum test, anti-thyroid antibodies, and total IgE.

RESULTS

CU lasted over 1 year in more than 70% of cases and in 14% it still existed after 5 years. Angioedema co-existed or appeared during the course of CU in 40% of patients and was associated with disease duration. Autologous serum test and anti-thyroid antibodies were found positive in 28 and 12% of patients, respectively, compared to none of normal individuals, P = 0.001. CU duration was associated with the presence of both autologous serum test and anti-thyroid antibodies; however, autologous serum test and not anti-thyroid antibodies was found in association with CU severity.

CONCLUSION

We demonstrate for the first time that CU duration is associated with clinical parameters such as severity and angioedema, and with laboratory parameters such as autologous serum test and anti-thyroid antibodies. The ability to predict CU duration may facilitate decisions regarding the possible early initiation of cyclosporine A as a means by which to reduce disease severity and duration.

Blood basophil numbers in chronic ordinary urticaria and healthy controls: diurnal variation, influence of loratadine and prednisolone and relationship to disease activity

BACKGROUND

The basopenia of chronic urticaria relates to histamine releasing autoantibodies in the serum of patients with autoimmune urticaria. This reduction in circulating basophils may be due to active recruitment into weals. If so, it might be expected that numbers in blood would be reduced when urticaria is active and increased after treatment. The primary aim of this study was to look at diurnal variation of basophil numbers in patients with chronic ordinary urticaria (not physical or vasculitic) in relation to disease activity and the effect of treatment with antihistamines and corticosteroids, and to compare the results with healthy controls. A secondary aim was to compare a standard manual counting method with automated basophil counts and to look at numbers of other circulating leucocytes that might be relevant to urticaria pathogenesis.

METHODS

Manual basophil counts using a toluidine blue stain and automated 5-part differentials (Coulter Gen. S) were performed at 4-hourly intervals from 08.00 to 20.00 in 10 healthy controls (six women, age 24 to 63 years) and seven chronic urticaria patients (five women, 24 to 50 years). All chronic urticaria patients had severe daily or almost daily urticaria. Only one of six chronic urticaria sera showed in vitro basophil histamine releasing activity. Counts were performed without treatment, after a week of taking loratadine 10 mg daily and after 3 days of adding prednisolone at 0.6 mg/kg/day (maximum 40 mg). Daily urticarial activity scores (UAS) were derived from weal numbers and itch, maximum 7.

RESULTS

There was no significant overall diurnal variation of basophil numbers in healthy controls or chronic urticaria patients. Mean (SE) manually counted basophil were higher in healthy controls than chronic urticaria (43.4/ microL (2.1) vs. 4.4 (0.8), P < 0.001). Basophil counts were reduced in healthy controls on steroids (19.2 (1.9), P < 0.001) but increased in chronic urticaria (8.9 (1.9), P < 0.001). Loratadine did not influence them. UAS fell on treatment (3.3 (0.4) baseline, 1.4 (0.5) on loratadine and 0.5 (0.2) on prednisolone with loratadine, P < 0.001). There was a negative linear correlation between basophil numbers and UAS in untreated chronic urticaria patients (P = 0.001, Spearman rank correlation). Manual and automated basophil counts showed poor agreement. Lymphocyte numbers were lower in chronic urticaria than healthy controls. Neutrophils increased whereas lymphocytes and eosinophils decreased in all subjects on prednisolone. They were unaffected by loratadine.

CONCLUSION

The results are consistent with the hypothesis that circulating basophils may be recruited from blood into urticarial weals during disease activity. Automated counts are not suitable for assessing basophil numbers in chronic urticaria. The relevance of reduced lymphocyte numbers in chronic urticaria needs to be explored.

Enhanced peripheral T-cell apoptosis in chronic hepatitis C virus infection: association with liver disease severity

BACKGROUND/AIMS

It has been suggested that enhanced T-cell apoptosis in hepatitis C virus (HCV) infection may lead to down-regulation of their cellular immune response, thus contributing to the persistency of HCV infection. In the present study we have investigated the role of bcl-2 and nuclear factor kappa B (NFkappaB) in dexamethasone-induced apoptosis of peripheral T cells in chronic HCV infection.

METHODS

The expression of bcl-2 and NFkappaB in peripheral T cells as well as spontaneous and dexamethasone-induced T-cell apoptosis were studied in HCV-infected patients (n=21), hepatitis B virus (HBV)-infected patients (n=14) and healthy individuals (n=19). These parameters were correlated with markers of autoimmunity and disease severity.

RESULTS

NFkappaB, but not bcl-2 expression, was significantly decreased in the HCV-infected patients. This decrease was associated with the presence of mixed cryoglobulins (MC) and rheumatoid factor and was positively correlated with alanine aminotransferase (ALT) levels and histological activity index (HAI). Both spontaneous and dexamethasone-induced T-cell apoptosis were enhanced in HCV-infected patients; however, only the latter was correlated with the presence of MC, ALT levels and HAI.

CONCLUSIONS

We confirm previous reports that enhanced T-cell apoptosis in HCV infection may play an important role in disease severity. Decreased expression of NFkappaB is important in the development of peripheral T-cell apoptosis, thus contributing to viral persistence and autoimmunity in these patients.

Evaluation of chronic urticaria in patients with Hashimoto thyroiditis

The coincidence of Hashimoto thyroiditis (HT) and chronic idiopathic urticaria (CIU) is a commonly observed phenomenon in western New York. Previous literature suggested that there may be a direct relationship between them. We undertook these studies to determine whether humoral or cell-mediated mechanisms might link HT and CIU. Skin biopsies from patients with CIU, with or without HT, were indistinguishable by light microscopy. No immune complex deposition was observed, although only the skin from patients with CIU and HT contained perivascular fibrin deposits. Similarly, immunohistochemical studies evaluating cellular expression of CD3, CD4, CD8, CD20, and CD68 failed to differentiate between CIU with or without HT. Analysis of Vbeta restriction in thyroid tissue of patients with HT and the skin of patients with CIU and HT by in situ polymerase chain reaction failed to reveal any oligoclonal T-lymphocyte subpopulations. In contrast, only patients with CIU and HT had anti-FcepsilonRI antibodies in their sera that could induce degranulation of normal basophils. Some sera from patients with CIU and HT caused degranulation of normal basophils in the absence of anti-FceRI. The factor causing basophil degranulation in these sera was not determined. Patients with CIU and HT failed to improve clinically with thyroid replacement therapy. All CIU patients were equally well managed with symptomatic therapies. In conclusion, HT likely represents a marker of other autoimmunity, rather than being a direct causative agent in CIU. Management of CIU, with or without HT and with or without anti-FceRI antibodies, should be the same. Future studies will have to examine whether cell-mediated responses participate in CIU, especially in association with HT.