[Atopy and autoimmunity -- a case report].

Atopy, immunodeficiency and autoimmunity are manifestations of immune system dysfunction. Classically atopy and autoimmunity are referred as distinct immunological reactions. Recent studies suggest the existence of common pathogenic mechanisms. We report the case of a teenager with familial history of asthma and miasthenia gravis in her mother (HLA- B8+) and personal history of recurrent upper respiratory infections from two to four years old, and pneumonia since five years old (3 or 4 episodes/ year, in three consecutive years), with associated dyspnoea and hypoxemia, requiring frequently hospital admission. Investigation was initially negative for atopy markers, and excluded other hypothesis as tuberculosis, cystic fibrosis, -1 antitrypsin deficiency, congenital heart disease, bronchopulmonary malformations or foreign body aspiration. Latter, further exams finally confirmed atopy with a raised IgE, positive RAST and cutaneous sensitivity tests (for house dust mites and pollen) and revealed circulating immune complexes and IgG 2, 3 e 4 deficit. Most frequent autoantibodies and precipitins study were negative, and histocompatibility antigens study revealed HLA- B8 (as her mother). Ventilation-perfusion scintigraphy and respiratory function tests were normal. Antihistamines, topical corticoids and bronchodilators were done with an excellent clinical response. At 16 years- old she is admitted again with the diagnosis of erythema nodosum and the clinical suspicion of Sweet's syndrome, having a good evolution. The relation between atopy and autoimmunity is enfatized by the authors. This simultaneous occurrence does not correspond merely to a statistical association, but may represent a global immune system impairment, with the involvement of different types of hypersensibility.