Ceruloplasmin and transferrin levels are altered in serum and bronchoalveolar lavage fluid of patients with the adult respiratory distress syndrome

The respiratory burst of neutrophils generates oxygen radicals that can result in lipid peroxidation and may contribute to acute lung injury in the adult respiratory distress syndrome (ARDS). Because ceruloplasmin and transferrin are inhibitors of lipid peroxidation and may play a role in regulating tissue injury, antigen levels of ceruloplasmin and transferrin and ceruloplasmin oxidase levels were measured in the serum and bronchoalveolar lavage fluid (BALF) of ARDS patients (n = 28), patients at risk for ARDS (n = 22), and normal control subjects (n = 45). Serum ceruloplasmin levels were similar in ARDS (mean ± SEM) (3.8 ± 0.3 μM) and at-risk (3.3 ± .04 μM) patients compared with control subjects (3.2 ± 0.2 μM). Serum transferrin levels were decreased in ARDS (14.9 ± 1.7 μM) and at-risk (20.4 ± 1.7 μM) patients compared with normal control subjects (32.9 ± 1.2 μM), and serum transferrin levels correlated with serum unsaturated iron binding capacity (UIBC). Ceruloplasmin was detected in only one of 38 normal BALF samples (0.002 ± 0.002 μM) and two of 13 at-risk BALF samples (0.15 ± 0.1 μM), yet it was present in 17 of 23 ARDS BALF samples (0.9 ± 0.2 μM). Transferrin was also increased in ARDS BALF (5.4 ± 1.1 μM) compared with at-risk (0.7 ± 0.5 μM) and normal (0.4 ± 0.1 μM) samples. Ceruloplasmin that was present in the BALF and serum samples had functional oxidase activity, and purified human ceruloplasmin inhibited hydroxyl radical formation by phorbol myristate acetate (PMA)-stimulated neutrophils. We conclude from this study that ceruloplasmin and transferrin, which are both present in ARDS BALF, may play a role in regulating oxidant-mediated inflammation in the lung.