Association between angiotensin II receptor gene polymorphism and serum angiotensin converting enzyme (SACE) activity in patients with sarcoidosis

Background-Serum angiotensin converting enzyme (SACE) is considered to reflect disease activity in sarcoidosis. SAGE activity is increased in many patients with active sarcoid lesions. The mechanism for the increased SAGE activity in this disease has not been clarified. ACE insertion/deletion (I/D) gene polymorphism has been reported to have an association with SAGE levels in sarcoidosis, but no evidence of an association between angiotensin II receptor gene polymorphism and SAGE in this disease has been found. A study of the association of angiotensin II receptor gene polymorphisms with sarcoidosis was therefore undertaken. Methods-ACE (I/D), angiotensin II type 1 receptor (AGTR1), and angiotensin II type 2 receptor (AGTR2) gene polymorphisms were investigated by polymerase chain reaction (PCR) and SAGE levels were measured in three groups of patients: those with sarcoidosis or tuberculosis and normal controls. Results-There was no difference in allele frequency of AGTR1 and AGTR2 polymorphism among the three groups. Neither AGTR1 nor AGTR2 polymorphisms were associated with sarcoidosis. SAGE activity was higher in patients with sarcoidosis with the AGTR1 AIC genotype than in others. However, this tendency was not detected in patients with tuberculosis. Conclusions-The AGTR1 allele C is associated with high activity of SAGE in patients with sarcoidosis. It is another predisposing factor for high levels of SAGE in patients with sarcoidosis and is considered to be an independent factor from the ACE D allele for high levels of SAGE in sarcoidosis. This fact could be one of the explanations for the increased SAGE activity in sarcoidosis.