ABSTRACT
BACKGROUND: To use probability theory to establish threshold values for total serum IgE and eosinophil counts that support a diagnosis of allergic rhinitis and to compare our results with previously published data. METHODS: Prospective study of rhinitis patients using a modified version of Bayes' theorem. Study included 125 patients at the West Los Angeles VA Medical Center diagnosed with rhinitis who completed allergy consultation and immediate hypersensitivity skin testing. RESULTS: Eighty-nine of 125 patients were atopic by prick and/or intradermal skin testing. Using a modified version of Bayes' theorem and positive and negative probability weights, calculations for different thresholds of serum IgE and eosinophil counts were summated and a posttest probability for atopy was calculated. Calculated posttest probabilities varied according to the threshold used to determine a positive or negative test; however, IgE thresholds greater than 140IU/ml and eosinophil counts greater that 80cells/ml were found to have a high probability of predicting atopy in patients with rhinitis. Moreover, IgE had a greater influence than eosinophil count in determining posttest probability of allergy in this population. Considerable differences were noted in the IgE levels of atopic and non-atopic patients, including those with asthma or a history of smoking. However, these differences were not observed with eosinophil levels. CONCLUSIONS: Using a modified version of Bayes' theorem to determine posttest probability, IgE threshold levels greater than 140IU/ml and eosinophil counts greater than 80cells/ml in an individual with clinical signs and symptoms of rhinitis are likely to correlate with an atopic aetiology. This model of probability may be helpful in evaluating individuals for diagnostic skin testing and certain types of allergy-modifying treatment.
Subject(s)
Bayes Theorem , Eosinophils/immunology , Immunoglobulin E/blood , Rhinitis, Allergic, Perennial/diagnosis , Rhinitis, Allergic, Seasonal/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Humans , Leukocyte Count , Male , Middle Aged , Prognosis , Rhinitis, Allergic, Perennial/immunology , Rhinitis, Allergic, Seasonal/immunology , Skin Tests , Young AdultABSTRACT
BACKGROUND: Autoimmune disease has been implicated as a cause of chronic urticaria, and anti-thyroid antibodies have been found in patients with chronic urticaria. Because some patients with chronic urticaria and autoimmune hypothyroidism have had clinical resolution with thyroid hormone replacement, we investigated the effect of thyroid hormone in euthyroid patients with chronic urticaria and thyroid autoimmunity. METHODS: Ten euthyroid patients with refractory hives were treated with thyroxine. Seven patients had elevated anti-thyroid antibodies at baseline. Thyroid function and anti-microsomal and anti-thyroglobulin antibody levels were monitored during treatment. If a clinical response was achieved, thyroxine was discontinued and restarted if symptoms recurred. RESULTS: Seven patients with elevated anti-thyroid antibodies reported resolution of symptoms within 4 weeks. Three patients without elevated anti-thyroid antibodies did not respond. Five patients had a recurrence of symptoms after treatment was stopped, which resolved after treatment was restarted. Thyroid-stimulating hormone levels decreased in all patients with a clinical response. No correlation between clinical resolution and anti-thyroid antibody levels was seen. CONCLUSION: Thyroid autoimmunity in euthyroid patients may be associated with chronic urticaria, and treatment with thyroid suppression can result in clinical remission.
Subject(s)
Thyroiditis, Autoimmune/drug therapy , Urticaria/drug therapy , Adult , Aged , Chronic Disease , Female , Humans , Male , Middle Aged , Thyroiditis, Autoimmune/complications , Thyroxine/therapeutic use , Urticaria/etiologySubject(s)
Desensitization, Immunologic , Hypersensitivity/therapy , Self Administration , Humans , InjectionsABSTRACT
The nontranscribed spacer regions (NTS) that adjoin the coding portion of mouse ribosomal DNA are protected in nucleoli against exhaustive DNase I digestion. Since these sequences are degraded by the enzyme after they are extracted by phenol, the protection is suggested to result from the binding of specific proteins. The nucleolar structure would thus be organized to protect NTS sequences and expose the coding sequences for transcription. We show here that these protected sequences include tracts of poly(dG-dT).poly(dA-dC). We also report that these sequences are localized in regions flanking the rRNA transcription unit. These sequences can potentially form Z-DNA. The organized DNase I-resistant NTS structure in which they participate could be involved in structuring the nucleolus or in regulating transcription because poly(dG-dT).poly(dA-dC) sequences and portions of spacer rDNA can serve as transcriptional enhancer elements.
