PROTEIN PROFILE IN BRONCHOALVEOLAR LAVAGE FLUID FROM PATIENTS WITH SARCOIDOSIS AND IDIOPATHIC PULMONARY FIBROSIS AS REVEALED BY SDS-PAGE ELECTROPHORESIS AND WESTERN-BLOT-ANALYSIS
M. Uebelhoer et al., PROTEIN PROFILE IN BRONCHOALVEOLAR LAVAGE FLUID FROM PATIENTS WITH SARCOIDOSIS AND IDIOPATHIC PULMONARY FIBROSIS AS REVEALED BY SDS-PAGE ELECTROPHORESIS AND WESTERN-BLOT-ANALYSIS, Scandinavian journal of clinical & laboratory investigation, 53(6), 1993, pp. 617-623
So far bronchoalveolar lavage (BAL)-protein in interstitial lung disea
se (ILD) is evaluated by measuring concentrations of single proteins.
Due to the high dilution of most proteins in BAL, analysis of protein
profile has been disappointing. This study describes a new method to o
vercome this problem and to reveal a highly differentiated picture of
BAL proteins. Eighteen patients with pulmonary sarcoidosis, 18 patient
s with idiopathic pulmonary fibrosis (IPF) and 22 patients with no cli
nical, roentgenologic or functional evidence of ILD underwent BAL. Tot
al and differential cell count was performed. Normal values for the co
ntrol group, a lymphocytic alveolitis in sarcoidosis and a granulocyti
c alveolitis in IPF-patients were found. Median total protein concentr
ation in sarcoidosis showed an increase five times higher than that of
the controls (150 mg l-1 and 27 mg l-1, respectively) with p < 0.001,
IPF protein concentration (58 mg l-1) exceeded twice the control valu
es (0.01 > p > 0.001). Analysis of electrophoretic protein profile in
controls with Western blot analysis and the biotin/streptavidin staini
ng system revealed a highly differentiated range of bands. Staining wi
th immunoglobulin antibody identified six bands. Four proteins with mo
lecular weight < 21.000 dalton were present only in sarcoidosis patien
ts. These proteins may be identical with fragmented serum proteins or
different cell mediators detected in alveolar cell supernatants. Furth
ermore, in sarcoidosis the intensity and number of bands with molecula
r weight more than 67.000 dalton was increased. This gives strong evid
ence for an injury of the alveolar membrane integrity in the alveoliti
s during the course of sarcoidosis. The uniform protein profile in IPF
compared to the highly variable profile and increased band intensity
in sarcoidosis stresses the different pathogenesis of these ILDs. West
ern blot analysis of BAL-protein profile is a highly promising method
to assess pathogenetic changes, alveolar membrane integrity, and leaka
ge in interstitial lung disease.