Immunologic Aspects of Lung Diseases and Cystic Fibrosis

Abstract

Immunologic lung disorders are accompanied by an array of laboratory abnormalities, some of which contribute to disease pathogenesis. Allergic bronchopulmonary aspergillosis, which complicates asthma and cystic fibrosis, causes mucous plugging of airways, eosinophilic pneumonia, and bronchiolitis obliterans. Aspergillus fumigatus, growing saprophytically in bronchial mucus, is responsible for most cases, and prednisone, not antifungal agents, is the drug of choice because it controls the immunologic responses of the lung. In cystic fibrosis, epithelial surface fluid from the lung does not kill Pseudomonas aeruginosa, in part because antibodies to P aeruginosa are plentiful but ineffective in opsonizing bacteria. Neutrophil-derived elastase cleaves immunoglobulins and digests the C3b receptor on neutrophils, which limits phagocytosis of pathogens. In helminth infections and infestations, pulmonary and peripheral blood eosinophilia can be accompanied by increases in total and antiparasite IgE concentrations and generate T(H)2 CD4+ T-lymphocyte responses. Understanding the immunologic abnormalities of lung disorders may lead to more effective therapies.

Allergic Bronchopulmonary Aspergillosis in Cystic Fibrosis—State of the Art: Cystic Fibrosis Foundation Consensus Conference

“…The classic case of ABPA fulfills the following criteria [244][245][246]: (1) asthma; (2) chest roentgenographic infiltrates-current or in the past-may be detectable on CT when chest radiography is unremarkable; (3) immediate cutaneous reactivity to Aspergillus species; (4) elevated total serum IgE (1417 IU/mL or 11000 ng/mL); (5) serum precipitating antibodies to A. fumigatus; (6) central bronchiectasis on chest CT; (7) peripheral blood eosinophilia; and (8) elevated serum IgE and/or IgG to A. fumigatus.…”

Aspergillus in the lung: diverse and coincident forms

“…Type-I reaction results in elevated serum IgE, eosinophilia in the blood, sputum, and lung tissue, and immediate skin test reactivity to Aspergillus antigens. Confusingly, approximately 25% of patients with chronic asthma show an immediate cutaneous reactivity to Aspergillus species, whether or not they have other features of ABPA; however, patients with ABPA have consistently far greater levels of isotypic antibodies to Aspergillus fumigatus ( IgE-a-Af, IgG-a-Af, and IgA-a-Af) than patients with allergic asthma or non-atopic controls [16]. The immune complex driven type-III reactions accounts for a positive late (Arthrus) skin reaction.…”

Central Bronchiectasis in Allergic Bronchopulmonary Aspergillosis

“…4 The essential minimal criteria for the diagnosis of ABPA with central bronchiectasis include asthma, immediate cutaneous reactivity to Aspergillus, serum IgE levels greater than 1000 ng/mL, and proximal bronchiectasis. 5 A diagnosis of ABPA without central bronchiectasis (ABPA-sero positive) can be made if the following minimal criteria are met, including the presence of asthma: immediate cutaneous reactivity to Aspergillus, serum IgE level greater than 1000 ng/mL, history of pulmonary infiltrates, and elevated levels of serum IgE and IgG antibodies to A. fumigatus. 5…”