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A double-blind cross-over trial was carried out on 83 sequential out-patients presenting with adult onset chronic airflow obstruction who were not clearly asthmatic. The study consisted of three treatment phases each lasting two weeks with a two week interval between each phase. The treatment phases were prednisolone 40 mg daily, beclomethasone dipropionate 500 ug three times a day and placebo, administered in a random order. FEV1 and FVC were measured at the end of each of the treatment phases and peak expiratory flow rate five times a day throughout. Over the study period 25 (30%) patients responded with an improvement of greater than or equal to 20% in at least one of the parameters measured as compared with the best of either baseline or placebo measurements. A further eight patients were classified as partial responders with an improvement of greater than 15% in any single parameter or greater than 10% in any two parameters. A similar number responded to beclomethasone [15] as responded to prednisolone [16]. Only six patients, however, responded fully to both forms of steroid therapy. A number of patients responded to one form of steroid treatment only which was also comparable between the two groups (prednisolone 10, beclomethasone 9). For full and partial responders mean improvement in FEV1, FVC and PEFR was greater during the prednisolone phase than during the beclomethasone phase, however, the difference did not achieve statistical significance.

Three workers developed classical extrinsic allergic alveolitis while working in a printing works that had a contaminated cold water humidifier. All had nodular shadows on their chest radiographs, reduced gas transfer measurements, and lung biopsy specimens that showed an alveolitis with giant cells and cholesterol clefts. In two subjects bronchoalveolar lavage was performed and the lavage fluid contained more than 70% lymphocytes in each case. Bronchial provocation tests with the humidifier antigen in these two workers reproduced their symptoms. Unlike previously reported cases, where exposure was to humidifiers working at generally higher temperatures, challenge with thermophilic actinomycetes in our two patients produced no reaction. Tests for precipitins to the humidifier antigen gave strongly positive reactions in the three workers but no single organism isolated from the humidifier produced a significantly positive reaction.