Association between Diffuse Panbronchiolitis and HTLV-I Infection

To determine whether HTLV-I infection is associated with diffuse panbronchiolitis (DPB), we investigated T-cell surface markers of peripheral blood and bronchoalveolar lavage fluid (BALF) in 9 healthy volunteers, 6 HTLV-I seronegative DPB patients (HTLV-I(-)DPB) and 8 HTLV-I seropositive DPB patients (HTLV-I(+)DPB). In peripheral blood, no significant difference was observed between HTLV-I(-)DBP and healthy volunteers. However, in BALF, HTLV-I(-)DPB showed a significant decrease of the CD4/CD8 ratio and an increase of CD8+HLA-DR+ cells compared with healthy volunteers. CD3+CD25+ and CD4+HLA-DR+ cells in peripheral blood were significantly increased in HTLV-I(+)DPB compared with those in HTLV-I(-)DPB. No significant difference was observed in BALF cells between HTLV-I(-) and HTLV-I(+)DPB with the exception of CD3+CD25+ cells. The most striking result was a marked elevation of CD3+CD25+ cells in 2 of 8 HTLV-I seropositive patients. Microscopic findings of open lung biopsy specimens obtained from the 2 patients differed from the typical microscopic findings in DPB. From these findings, we consider that HTLV-I infection may be associated with pulmonary lesions like DPB, but of a different, pathologically distinct, type.