CD8 SERUM LEVELS IN ACUTE GRAFT-VERSUS-HOST DISEASE DIAGNOSIS

Attempts to identify an early and discriminating marker of acute graft -versus-host disease (aGvHD) have been unsuccessful. The levels of sol uble CD4 and soluble CD8 in serum correlate with T cell subset activat ion and may be important in monitoring and characterizing immunologica l processes. We determined serum soluble CD4 (sCD4) and sCD8 levels wi th a two-site sandwich enzyme immunoassay on patients' serum samples c ollected prior to bone marrow transplantation and weekly after transpl antation until day +28. No significant increment of sCD4 was documente d in each determination. sCD8 rose significantly before diagnosis or d evelopment of maximal clinical symptoms in patients with grade II-III aGvHD than grade 0-I aGvHD [at day +21-median value 447 IU/ml; range 9 4-713; versus 1136 IU/ml, range 790-1416 (P = 0.002); at day +28--medi an value 443 IU/ml, range 73-992, versus 1164 IU/ml, range 625-1960 (P = 0.005)]. On the day of marrow infusion the sCD8 levels were signifi cantly higher in patients who subsequently developed grade II-III than in patients with grade 0-I aGvHD (median value 155 IU/ml, range 10-33 2, versus 350 IU/ml, range 283-830; P = 0.003). Careful monitoring of sCD8 is a useful tool for a prompt aGvHD diagnosis and may be used in a clinical bone marrow transplantation setting.