Angiotensin II receptor on BALF macrophages from Japanese patients with active sarcoidosis.
BACKGROUND
Serum angiotensin converting enzyme (ACE) activity and its changes are important markers for disease activity in patients with sarcoidosis. We earlier reported that ACE and its enzymatic product, angiotensin II (A-II), might play a role in maintaining macrophage/T lymphocyte alveolitis by enhancing an accessory function of macrophages in chronic active cases with sarcoidosis.
We examined whether A-II receptor is present on BALF macrophages by a receptor binding assay using 125I-labeled A-II, and by amplification of A-II receptor gene transcripts using RT-PCR methods and quantification of the amounts of transcripts by HPLC.


RESULTS
The receptor binding assay suggested that specific binding of A-II to BALF macrophages was somewhat more prevalent in active sarcoidosis than in controls. A specific band for A-II receptor was detected by RT-PCR. A-II receptor gene expression was standardized as the ratio to beta-actin. An increased ratio was shown in active sarcoidosis (0.70 +/- 0.19; n = 14) compared to inactive cases (0.14 +/- 0.06; n = 5; p = 0.023) and healthy subjects (0.15 +/- 0.09; n = 5, p = 0.029). The ratio correlated positively with the percentage of BALF T lymphocytes (r = 0.60, p = 0.0056), and negatively with BALF macrophages (r = 0.60, p = 0.0055). No difference was detected between nonsmokers and smokers.


CONCLUSIONS
The amounts of A-II receptor gene expression of BALF macrophages correlated with disease activity in patients with pulmonary sarcoidosis.
Nagai
S
S
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Japan.
Takeuchi
M
M
Morita
K
K
Mikuniya
T
T
Satake
N
N
Mio
T
T
Izumi
T
T
D000328:Adult; D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008264:Macrophages / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011945:Receptors, Angiotensin / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017565:Sarcoidosis, Pulmonary / Q000235:genetics / Q000276:immunology / Q000503:physiopathology*
D011945:Receptors, Angiotensin; D000804:Angiotensin II