Altered biosynthesis of tumour necrosis factor (TNF) alpha is involved in postburn hypertrophic scars.

The present study shows that the decrease of TNF alpha in postburn hypertrophic scars is due to a decrease in the steady-state level of TNF alpha mRNA and thus to an altered biosynthesis of the cytokine. Thirteen scars, including seven hypertrophic and six normotrophic scars, were tested for TNF alpha mRNA production by a semiquantitative reverse polymerase chain reaction (PCR) method. TNF beta and beta actin were tested as a control. Six out of six normotrophic scar samples amplified with primers for TNF alpha showed a positive PCR signal up to the 1:32 dilution. On the contrary all the hypertrophic tested samples (7/7) had a positive PCR signal only at the 1:1 or 1:2 dilution. All samples, both normotrophic and hypertrophic, were homogeneous as to TNF beta production.