Serum C-reactive protein concentrations in patients with pulmonary sarcoidosis.

In a prospective study serum C-reactive protein concentrations were measured in nine patients with "active" pulmonary sarcoidosis (as assessed by bronchoalveolar lavage lymphocyte counts, gallium-67 lung scanning, and serial pulmonary function testing), and in five patients with "inactive" disease. Active pulmonary sarcoidosis was associated either with no rise or with only a modest rise in serum C-reactive protein concentrations. In contrast, serum C-reactive protein concentrations in 12 patients with sputum positive pulmonary tuberculosis were considerably raised. Serum C-reactive protein may thus provide a valuable test in the differentiation of sarcoidosis from conditions which it may mimic and which are known to induce an acute phase response.