[en] Radiation induced cell damages were analyzed from an aspect of an inflammation along with DNA damages to progress a molecular-immunological analysis of the mechanism for spreading of such cell damages. Human fibroblast cell line, NB1RBG at confluent stage was exposed to X-ray at 40 Gy and the spreading of radiation-induced damages was monitored. It is well known that cytokines are generally produced by the cells in immune system, but those are also expressed in the cells of non-immune system such as HeLa cell, fibroblast cell, etc. Therefore, cytokine expression in NB1RBG cells exposed to radiation was investigated by RT-PCR method. However, it was found that the expression of IL-1βinduced by radiation irradiation became maximum 8 hours after the irradiation and any expression of IL-6, IL-10 or TNF-α was not induced by X-ray radiation. Meanwhile, expressions of IL-1ββ and TNF-α of various inflammatory cytokines were inducible by UV exposure. These results suggested that the spreading factor might be IL-1β or TNF-α for UV-induced damages and IL-1β for X-ray induced ones. (M.N.)