SP-D as a marker of amiodarone-induced pulmonary toxicity.

Two patients with amiodarone-induced pulmonary toxicity (APT) showed abnormally increased serum SP-D concentrations, although their KL-6 level was within the normal range. In a 59-year-old man with ischemic heart disease, APT progressed rapidly and required steroid pulse therapy. During the clinical course, SP-D was as high as 375 ng/ml, although the KL-6 level was only 289 U/ml. In a 58-year-old man treated for dilated cardiomyopathy, SP-D increased to 289 ng/ml, while KL-6 remained at less than 500 U/ml. These cases indicate that SP-D is a useful and early diagnostic marker for APT even when KL-6 is not elevated.