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.

Abstract

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. 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. 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. 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.