Abstract The patient was a 61-year-old man diagnosed with rheumatoid arthritis (RA) in 2001. He initially received treatment at a nearby clinic, but his condition could not be satisfactorily controlled. He subsequently consulted our hospital during the same year. Although his symptoms improved in response to treatment at our hospital, slight fever, cough, and then high fever and dyspnea subsequently developed. A diagnosis of interstitial pneumonia was made on the basis of findings of diagnostic imaging. The time course of changes in serological markers, including surfactant protein A (SP-A), surfactant protein D (SP-D), and KL-6, as well as markers of inflammatory reaction and lactate dehydrogenase was examined to determine the clinical significance of serological markers in the management of interstitial pneumonia.