QUANTITY AND STRUCTURE OF SURFACTANT PROTEINS VARY AMONG PATIENTS WITH ALVEOLAR PROTEINOSIS

Alveolar proteinosis (AP) is an idiopathic condition characterized by excess alveolar surfactant. Although the surfactant proteins (SP) are known to be aberrant, little is known of their variation between patie nts or their abundance relative to the lipids. We have examined surfac tant composition in lavage fluid from 16 normal subjects and 13 patien ts with AP, one of whom was lavaged on 11 occasions over similar to 13 mo. In this patient we have examined composition on each occasion and in each sequential lavage aliquot. Composition was constant between r ight and left lung, but it differed markedly between patients. The cho lesterol/disaturated phospholid ratios (CHOL/DSP) were invariably elev ated, on average by similar to 7-fold, whereas the SP-A/DSP and SP-B/D SP ratios were generally elevated, in some cases by as much as similar to 40- and similar to 100-fold, respectively. Although AP ravage gene rally contained more non-thiol-dependent SP-A aggregates and low M-r i soforms, the two-dimensional immunochemical staining patterns varied b etween patients and right and left lung. In the patient lavaged on mul tiple occasions, the SP-A/DSP and SP-B/DSP ratios progressively decrea sed as the patient's condition resolved. Because the SP-B/SP-A ratio w as normal in all cases, we suggest that structural changes to the prot eins occurred secondarily and that caution must be used in comparing f unctional data derived using SP-A obtained from patients with AP.