PLASMA LACTATE-DEHYDROGENASE - A MARKER OF DISEASE-ACTIVITY IN CRYPTOGENIC FIBROSING ALVEOLITIS AND EXTRINSIC ALLERGIC ALVEOLITIS

Total plasma lactate dehydrogenase (LDH) activity may be elevated in c ryptogenic fibrosing alveolitis (CFA) and extrinsic allergic alveoliti s (EAA), and may be a useful monitor of disease progress. In a retrosp ective, primary referral centre study, we compared LDH at presentation , prior to bronchoalveolar lavage BAL, and after treatment and follow- up with changes in pulmonary function, in patients with CFA, EAA and p ulmonary sarcoidosis. Plasma levels of LDH at presentation in CFA (n=4 7) and EAA (n=10) were significantly higher than in patients with sarc oidosis (n=36). LDH activity decreased in patients with improving lung function (EAA, p=0.008; CFA, p-0.02), whereas it increased in CFA pat ients with deteriorating lung function (p=0.015). Total plasma LDH is a simple, though nonspecific test, which appears to reflect changes of disease activity in patients with CFA and EAA.