Abstract. Planck A, Eklund A, Yamaguchi E, Grunewald J. (Karolinska Hospital, Stockholm, Sweden; and Hokkaido University School of Medicine, Sapporo, Japan). Angiotensin‐converting enzyme gene polymorphism in relation to HLA‐DR in sarcoidosis. J Intern Med 2002; 251: 217–222. Objectives. To investigate if an insertion/deletion (I/D) polymorphism in the angiotensin‐converting enzyme (ACE) gene associates with HLA‐DR alleles previously found to be of prognostic interest in Scandinavian sarcoidosis patients. This may contribute to characteristics associated with these HLA‐DR alleles, such as a good (DR17) or poor (DR14 or 15) prognosis. Design, settings and subjects. Polymerase chain reaction (PCR) was used for analysing an I/D polymorphism in the gene coding for ACE in 138 subjects; 65 controls and 73 sarcoidosis patients, and for HLA‐DR genotyping 67 patients. Serum ACE level (S‐ACE) was measured in all controls and 72 patients. Sixty‐one patients were classified as chronic or nonchronic after 2 years follow‐up. All patients were recruited and followed at our outpatient clinic. Results. No significant differences in ACE alleles or genotypes were seen between controls and patients or between patients positive and negative for DR17 or DR14/15. The ACE genotype did not differ between nonchronic and chronic patients. The ACE genotype tended to influence the S‐ACE in patients, whilst in controls S‐ACE significantly differed between the ACE genotypes. Conclusion. This study does not support an association between ACE genotype and sarcoidosis or disease outcome. However, because significantly (P < 0.001) more DR17 positive (17 of 19) than DR14/15 positive (seven of 26) patients were classified as nonchronic, these results instead strengthen the prognostic importance of HLA‐DR alleles in Scandinavian sarcoidosis patients.