Elevated D Dimer in the Lungs and Blood of Patients With Sarcoidosis (8)

We were able to detect activation of the coagulation system in the lungs and blood of patients with sarcoidosis. Eight of 10 sarcoidosis patients had detectable levels of BAL D dimer, while none of 18 healthy subjects had detectable BAL D dimer. Our findings are in agreement with those of Nakstad et al who measured FDP by latex agglutination in the unconcentrated BAL fluids of patients with ILD. They found FDP in the BAL fluids of 6 of 22 sarcoidosis and 10 of 29 idiopathic pulmonary fibrosis patients and no FDP in the BAL fluids of 60 healthy individuals. We found a higher prevalence of BAL fluid FDP in our sarcoidosis patients probably because we used EIA, which is more sensitive than agglutination methods for antigen detection.
Since patients with sarcoidosis had higher levels of BAL total protein than normal subjects and recovery of D dimer was greater at high total protein concentrations, levels of D dimer detected in BAL fluids from sarcoidosis patients may have been missed in fluids from healthy volunteers. For this reason, we cannot state that D dimer was absent in the alveolar lining fluids of normal subjects. However, we did not detect fibrinogen or FDP in BAL fluids from normal subjects by autoradiography, suggesting that D dimer is present, if at all, in very low concentrations. In contrast, autoradiography showed that BAL fluids from sarcoidosis patients contained variable amounts of fibrinogen polymeric and degradation products.