GAPDH and sarcoidosis: Similar, when CCL2 mRNA levels were expressed as a ratio to ACTB (1.00 ± 0.85; p = 0.46) or to GAPDH (1.37 ± 0.98; p = 0.43), there were not significant differences in mRNA levels in BAL cells between sarcoidosis patients with chest radiographic stage 2 and stage 1 patients.