GM-CSF MESSENGER-RNA AND PROTEIN IN HUMAN SKIN-DERIVED LYMPH

GM-CSF together with IL-1 beta and TNF-alpha has been shown to play a key role in the maturation of LC in vitro. To investigate the presence of GM-CSF, IL-1 beta and TNF-alpha in human skin-derived lymph, we ca nnulated microsurgically a superficial lymph vessel on the lower leg o f six healthy volunteers, Messenger RNA levels were estimated by a rev erse transcriptase polymerase chain reaction (RT-PCR) method, From a t otal of 20 different samples, each consisting of 10(6) lymph cells, to tal RNA was extracted, reverse transcribed to cDNA and amplified using specific primers for the target gene. Amplified products were sized b y electrophoresis and visualized by ethidium bromide, Specific transcr ipts for GM-CSF were detected in all lymph samples, indicating that ci rculating human skin-derived lymph cells express GM-CSF mRNA. A mean l evel of 11.5+/-2.1 pg/ml GM-CSF was detected in the lymph samples exam ined, as determined by a sensitive ELISA. In contrast to GM-CSF, occas ional weak mRNA signals together with a mean level of 2.7+/-2.2 pg/ml were found for IL-1 beta, and neither specific transcripts nor protein were detected for TNF-alpha. Thus, our results demonstrate that affer ent skin lymph cells constitutively express GM-CSF.