In this study, patients with diffuse panbronchiolitis (DPB) and bronchiolar type of HTLV-I associated bronchiolo-alveolar disorder (HABA-B) were evaluated in regard to regulation of interleukin-2 receptor (IL-2R) and lymphocyte subsets. The levels of soluble IL-2R in sera and lymphocyte culture supernatant, the responsiveness of lymphocytes to IL-2 and the percentage of IL-2R positive lymphocytes and helper-T lymphocytes were higher in DPB than in normal controls. Furthermore in HABA-B, the levels of IL-2R were much higher than those of DPB. The correlation coefficient between the percentage of IL-2R positive lymphocytes or helper-T lymphocytes and the CD4/CD8 ratio were statistically significant. In the patients with DPB, the percentage of IL-2R positive lymphocytes and helper-T lymphocytes were increased with the progress in clinical stage of DPB or the serum titer of cold hemagglutinin increase. Therefore, the cellular immunity regulated by the IL-2 and IL-2R system might play an important role in the pathogenesis of DPB and HABA-B.
interleukin-2 receptor soluble interleukin-2 receptor