Transcript level of erythroid differentiation-related factor, a candidate surrogate marker for transmissible spongiform encephalopathy diseases in blood, shows a broad range of variation in healthy individuals.

Background: In 2001, it was demonstrated that the expression of the erythroid differentiation-related factor (EDRF) is reduced in lymphatic tissues of rodents and cattle as well as in whole blood of sheep that suffer from transmissible spongiform encephalopathy.

Study Design And Methods: To determine whether the normal range of EDRF expression varies in healthy individuals, mRNA levels were measured in whole blood samples from 106 healthy blood donors by quantitative real-time RT-PCR. Furthermore, the correlations of transcript levels with individual physical characteristics were analyzed. In addition, EDRF expression was examined in total RNA samples from a lymph node and the intestine.

Results: The data show that EDRF mRNA levels in healthy persons vary within a total range of 2 log units as well as they display a weak correlation with body height. Furthermore, it was found that EDRF is also expressed in lymph nodes and the intestine.

Conclusion: Owing to its broad range of variation, measuring the EDRF expression does not seem to be a good surrogate marker, unless an altered expression is distinctively different from the varying level in healthy humans.