Neopterin and interferon gamma serum levels in renal allograft recipients.

In the follow-up of children receiving renal allografts the early differential diagnosis of infections and rejection episodes is the main problem. Serum levels of neopterin (N), a pteridine released from stimulated macrophages, was determined by radioimmunoassay. Also interferon-gamma (IF) serum levels, a marker of T lymphocyte activity, were determined with an immunoradiometric assay in 19 kidney-transplanted children. Both, infections and rejection episodes, are accompanied by distinct increases in N. The IF are elevated 1-3 days earlier than N, the median values during infections being significantly (p less than or equal to 0.001) higher than those during rejection crises. The routine measurement of N and IF allow the simple, quick and reliable monitoring of the immune status, which seems to be of a high relevance for the daily monitoring of transplant recipients.