CYTOKINE MESSENGER-RNA GENE-EXPRESSION IN ACTIVE AND NONACTIVE PULMONARY SARCOIDOSIS

Sarcoidosis is a multisystem granulomatous disease associated with the expansion and activation of CD4+ T-lymphocytes and macrophages. To in vestigate the immunopathology of active and nonactive pulmonary sarcoi dosis, we have examined the expression of cytokine gene transcripts in bronchoalveolar lavage cells from 15 patients with active pulmonary s arcoidosis, eight patients with nonactive pulmonary sarcoidosis, and n ine normal controls. Using in situ hybridization, the percentage of ce lls expressing messenger ribonucleic acid (mRNA) for interleukin (IL)- 1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, IL-12 and interferon-gamm a (IFN-gamma) were compared in the groups studied. In individuals with active sarcoidosis, there were significantly greater proportions of c ells expressing mRNA for IL-2, IL-10, IL-12 and IFN-gamma than in subj ects with nonactive disease and normal controls (p < 0.01). There was no significant difference in the percentage of positive cells expressi ng IL-10 and IL-12 mRNA in the nonactive group compared to the normal controls (p > 0.05), No significant differences in the percentages of IL-3, IL-4 and IL-5 mRNA positive cells were observed between active a nd nonactive sarcoidosis patients and normal centrols (p > 0.05). Thes e results demonstrate that there is a preferential expression of T-hel per type 1 cytokines in pulmonary sarcoidosis, and that cytokines rela ted to macrophage activation are the most prominent. In addition, thes e data implicate an elevated expression of interleukin-2, -10 and -12 and interferon-gamma in active compared to nonactive sarcoidosis.