Transfer of99mTc DTPA andbronchoalveolar lavage findings inpatients withasymptomatic extrinsic allergic alveolitis

An investigation was performedto determinewhether symptom free patientswith previouslydiagnosed extrinsic allergic alveolitis hadsignsof inflammation inthelung.Pulmonary clearanceof inhaledtechnetium-99m labelleddiethylene triaminepentaaceticacid(DTPA) was measuredin sevenpatients withahistory ofextrinsic allergic alveolitis butwithnosymptoms atthetimeofthestudyandin12control subjects. Monoexponential clearance curveswereobtained inall12control subjects. Incontrast, lungclearance was abnormalinfiveofthesevenpatients: biexponential clearancecurveswere notedinfourandanabnormally rapid monoexponential curvein one.Bronchoalveolar lavagewasperformedinall patients. Fluidfrom thesecondand thirdaliquots showedincreased concentrations ofalbuminandureainfluids fromthepatients, suggesting increased plasmaleakagethroughthealveolocapillary membranes.Moreeosinophils and more eosinophil cationic protein werealsofoundinthelavage fluid from thepatients. The trendtowardsincreasednumbers of eosinophils in patients withabnormallungclearance of DTPA suggests thatthismay beduetoa continuing inflammatory reaction. Lung inflammation wasalsosuggested bythe factthatlessleukotriene B4wassecreted by cultured alveolar macrophages obtainedfrom patients thanby control macrophages. Itisconcluded thatsymptomfreepatients withprevious extrinsic allergicalveolitis have continuing alveolardiseaseas shown by lung clearance andlavage findings.