Micronucleus evaluation in mitogen-stimulated lymphocytes of narrow-band (311 nm TL01) UVB-treated patients
Narrow-band UVB (311 nm) lamps (TL01) are being increasingly used for phototherapy of psoriasis and other dermatoses, for their excellent effect compared with broad-band UVB sources and photochemotherapy. It is acknowledged that the TL01 lamp is probably two to three times more carcinogenic per minimum erythema dose than broad-band UVB, but the cumulative dose is considerably less than broadband UVB sources. Micronucleus (MN) test is used to detect both clastogenic (breaking) and aneugenic (abnormal segregation) effect of physical/chemical agents on chromosomes. The aim of this study is to evaluate MN frequencies in mitogen-stimulated lymphocytes of narrow-band UVB-treated patients. Methods:
Frequency of micronuclei in 72 h cultivated/mitogen-stimulated lymphocytes of 36 patients (age 7–73 years, mean±SD: 25.33±18.54) have been evaluated at pretreatment and after 20, 40, 60 sessions of narrowband UVB treatment. Results:
While the beginning MN frequency ±SD (%) was 1.07±0.63, it increased to 1.47±0.92, 1.47± 0.77, 1.41±0.31 corresponding, respectively, to 20, 40, 60 sessions. These sessions reciprocally correspond to 0.85±0.23, 2.97±0.72, 5.68±1.46 J/cm2 doses of narrow-band UVB. Difference of MN frequency was statistically significant (P=0.002). Significant differences have been observed between the initial MN frequency and after that of 20, 40, 60 sessions (P=0.001, 0.004, 0.002, respectively). Conclusion:
The results of this study show that narrow-band UVB treatment causes a detectable chromosome damaging effect.