RPL32 and pulmonary sarcoidosis: In order to confirm that PSMB2 and RPL32 genes, identified as the most stable genes in the aforementioned analyses in the 1st cohort, has indeed the most stable mRNA expression unaffected by range of tested variables, we investigated gene expression of all ten genes in the second, independent BAL cohort (63 patients with pulmonary sarcoidosis and 17 control subjects) by equivalence test.