Allergic Bronchopulmonary Aspergillosis

Noninvasive pulmonary Aspergillus infections

Aspergillus can cause several forms of pulmonary disease ranging from colonization to invasive aspergillosis and largely depends on the underlying lung and immune function of the host. This article reviews the clinical presentation, diagnosis, pathogenesis, and treatment of noninvasive forms of Aspergillus infection, including allergic bronchopulmonary aspergillosis (ABPA), aspergilloma, and chronic pulmonary aspergillosis (CPA). ABPA is caused by a hypersensitivity reaction to Aspergillus species and is most commonly seen in patients who have asthma or cystic fibrosis. Aspergillomas, or fungus balls, can develop in previous areas of cavitary lung disease, most commonly from tuberculosis. CPA has also been termed semi-invasive aspergillosis and usually occurs in patients who have underlying lung disease or mild immunosuppression.

Current pharmacotherapy of allergic bronchopulmonary aspergillosis

Although no well-designed studies have been carried out, the available data support the use of corticosteroids for acute exacerbations of allergic bronchopulmonary aspergillosis (ABPA). Neither the optimal steroid dose nor the duration of therapy has been standardised but limited data suggest the starting dose should be prednisone (approximately 0.5 mg/kg/day). The decision to taper steroids should be made on an individual basis, depending on clinical course. The available data suggest that clinical symptoms alone are inadequate to make such decisions, since significant lung damage may occur in asymptomatic patients. Increasing serum IgE levels, new or worsening infiltrate on chest radiograph and worsening spirometry suggest that steroids should be used. Multiple asthmatic exacerbations in a patient with ABPA suggest that chronic steroid therapy should be used. Itraconazole appears useful as a steroid sparing agent.

Pulmonary eosinophilia with systemic features: therapy and prognosis

Of 65 patients presenting with pulmonary eosinophilia to one Respiratory Unit during a 20-year period, 12 (18%) had systemic features associated with their pulmonary disease. Eleven had fever, three night sweats, three arthralgia, three vasculitic rashes and two weight loss. Anaemia, myalgia, peripheral neuropathy, mononeuritis, pericardial effusion and photosensitivity rash were each recorded in single patients. None had evidence of hypersensitivity to drugs, helminthes or other allergens. Ten of the 12 patients could be classified as cryptogenic pulmonary eosinophilia and two as Churg Strauss syndrome. Ten were female. The maximum recorded eosinophil counts were higher in the 12 patients with systemic features compared with the remaining 53 patients [mean (SD) 5613 (3883) vs. 2359 (3046) x 10(6) 1(-1), P < 0.02], whereas both asthma and recurrent episodes of eosinophilia were significantly less common. Steroid therapy achieved a good clinical response and radiological clearing in the majority of patients. All 12 patients were treated with prolonged duration oral prednisolone [mean (SEM) dose 8.5 (3.8) mg day-1 duration 5.5 (1.3) years]. The two patients with Churg Strauss syndrome required azathioprine in addition to long-term prednisolone. There were no deaths and currently four patients are off all steroids and six receive less than 5 mg day-1. During a median follow-up period of 11 years, there was no significant decline in FEV1 or VC, measured as percent predicted values. Persistent radiographic abnormalities consistent with fibrosis or bronchiectasis were not seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary eosinophilia with and without allergic bronchopulmonary aspergillosis

Sixty five patients with pulmonary eosinophilia attending one respiratory unit were reviewed. All had fleeting radiographic abnormalities and peripheral blood eosinophil counts greater than 500 x 10(6)/l. Eighteen had a single episode and 47 recurrent episodes during a median follow up period of 14 years. Thirty three patients had allergic bronchopulmonary aspergillosis on the basis of a positive skin test response to Aspergillus fumigatus, serum precipitins, or culture of A fumigatus from sputum, or a combination of these. All but seven patients had asthma, six of the seven being in the group who did not have allergic bronchopulmonary aspergillosis. The patients with allergic bronchopulmonary aspergillosis were more often male and had a greater incidence of asthma and an earlier age of onset of asthma than those without aspergillosis. The patients with aspergillosis had lower mean blood eosinophil counts and more episodes of pulmonary eosinophilia and more commonly had radiographic shadowing that suggested fibrosis or bronchiectasis (20 v 7). Pulmonary eosinophilia associated with allergic bronchopulmonary aspergillosis appears to be a distinct clinical syndrome resulting in greater permanent radiographic abnormality despite lower peripheral blood eosinophil counts.

Corticosteroid treatment and prognosis in pulmonary eosinophilia

The acute and long term responses to corticosteroid treatment in 65 patients with pulmonary eosinophilia have been reviewed. Of the 247 episodes of pulmonary eosinophilia that were documented during a median follow up period of 14 years, 186 were treated with prednisolone. Complete clearing of chest radiographic infiltrates occurred in 65% of the 247 episodes, partial clearing in 25%, and no response in 9%. Blood eosinophil counts were monitored during 194 episodes and returned to normal in 72%, decreased in 19%, and remained raised in 9%. Complete radiological clearing and a reduction in blood eosinophil counts were more common in episodes treated with prednisolone. Long term prednisolone was given to 28 of the 33 patients with allergic bronchopulmonary aspergillosis (mean 7.4 mg/day for 11 years) and to 29 of the 32 "non-aspergillosis" patients (mean 8.1 mg/day for 4.6 years). Initial pulmonary function, measured between episodes, was worse in patients with allergic aspergillosis than in those without (mean % predicted: FEV1 57% v 83%, vital capacity (VC) 76% v 88%). During a mean follow up period of 12 years neither group displayed further decline in FEV1 or VC.

Immunologic mechanisms in pulmonary disease

This article reviews some concepts about the organization of the immune system and the immunopathologic mechanisms of hypersensitivity. This is followed by a discussion of the effect of excessive or inappropriate immunologic resources on the respiratory tract.