URINARY BIOPTERIN LEVELS IN MICE DURING GRAFT-VERSUS-HOST REACTIONS AND DURING EXPOSURE TO 5,5-DIPHENYLHYDANTOIN

Based on evidence that urinary neopterin levels are useful markers of disordered cellular immunity in man, we investigated murine urinary biopterin excretion during acute and chronic graft-versus-host (GvH)-reactions as well as after oral exposure to drugs with documented immune disregulating potential in man. Biopterin levels were determined in urine spot samples by reversed-phase high performance liquid chromatography and expressed in relation to the urinary creatinine content. Similarly increased and decreased biopterin levels were observed during acute and chronic GvH-disease in (C57BL/6J x DBA/2J)F1 (B6D2F1) mice. Increased and/or decreased levels of urinary biopterin were observed during treatment with 5,5-diphenylhydantoin (DPH), methimazole, propylthiouracil and nitrofurantoin, but no consistent pattern could be distinguished. The DPH-induced alterations were similar in B6 and B6D2F1 mice, were dose-dependent, reversible and independent of mature T-cells, as judged by the pronounced biopterin excretion of B6-nu/nu mice in comparison with their T-cell competent litter mates. The results indicate that monitoring of urinary biopterin excretion in mice does not represent a useful biochemical marker for T-cell activation.