2.5 μM of NKL 22 increases frataxin protein concentrations in the FRDA ymphoid cell line. Incubation for 2 d in culture with NKL 22 increases the FXN mRNA level in lymphocytes from the affected individual to about 80% of that in lymphocytes from the unaffected individual. NKL 22 is highly active in increasing FXN mRNA levels in cells obtained from both carrier C and affected AC, bringing the FXN mRNA level in the FRDA lymphocytes to about 160% of that found in the untreated carrier lymphocytes..