Cutaneous lymphocyte antigen-positive T cells may predict the development of acute GVHD: alterations and differences of CLA+ T- and NK-cell fractions.

Acute GVHD (aGVHD) is a serious complication after allogeneic SCT (allo-SCT). However, an adequate immunological index is not yet available for assessing its severity. We analyzed the fraction of cutaneous lymphocyte antigen (CLA)+ cells in peripheral blood T and natural killer (NK) cells in 33 patients and evaluated its association with aGVHD. The CLA+ T-cell fraction often increased 3-7 days before the onset of aGVHD, and the maximum percentage of CLA+ T cells in grades II-IV aGVHD cases was significantly higher than that in grade 0 or I aGVHD (P<0.01). When the cutoff value of the maximum CLA+ T-cell percentage was set at 20%, any higher percentage was a significant risk for the development of severe aGVHD (P<0.0001). The maximum CLA+ T-cell percentage was significantly correlated with a high body temperature, low percutaneous oxygen saturation, and fibrinogen/fibrin degradation product D-dimer level. The post-allo-SCT CLA+ T cells exhibited a high ability to produce IL-2 and IFN-gamma, and may be the effectors and immunological markers for aGVHD. The CLA+ NK-cell-fraction steadily increased 2-4 weeks after allo-SCT but was not influenced by aGVHD. The CLA+ T-cell percentage may predict the development of severe aGVHD in clinical settings.