“…Unlike GVHD of the skin, liver, and intestine, which displays well-characterized histopathological alterations attributable in part to selective T-cellmediated epithelial destruction, a direct association between lung damage and allo-or autoreactivity in BMT recipients has been more obscure. Here, we demonstrate a restricted pattern of TCR junctional region lengths that indicates less polyclonality of T cells in the lungs of Patient Oligoclonal TCRV gene family detected Unfractionated BAL cells CD4 + BAL T cells CD8 + BAL T cells 1 AV15 BV9, 21 BV9, 21 BV17, 21 2 AV9, 11,14,18,26,27 AV11,12,14,26,27 AV1,4,9,11,13,18,19,26,29 BV16,23,24 BV16,21 BV9,16,21,23,24 3 AV4, 12,14,17,19,21,22 ND a ND BV4, 5S2, 9, 16, 25 6 AV8, 9,18,26 AV5,11 AV4,8,9,11,18,…”