A Study Of The Effect Of Rare Earth Exposure On Human Immune System

Object:To study the effect of rare earth exposure on human immune system, in order to provide scientific basis for rational management of developing and applying the rich resources of rare earth elements in our country. Metholds:XunWu county rare earth mine lot ,the biggest ion absorptive rare earth mine lot of China was selected as the investigating spot. Shang ping village, another village of XunlVu county, the geologic structure and social environment are comparable to the investigating spot was selected as control spot. One hundred and two healthy adults were randomly selected from the investigating spot as exposure group. Fifty eight healthy adults randomly selected from the control spot acted as control group in this research. The blood content of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, were determined by inductively coupled plasma梥ource mass spectrometry(JCP桵S). The total contents of rare earth elements in the blood were calculated. Flow cytometry(FCM) was carried out to analyzed the lymphocyte subsets(the percentages of CD3~,CD4~,CD8~,NK cells and the ratio of CD4~ to CD8~ cell) in the peripheral blood. Immunoglobulin A,M G and completment C3 and C4 in the serum were determined by turbidimetric immunoassay. Sandwich enzyme linked immunosorbent assay(ELISA) was carried to detected the levels of IL?, IFN梤 and sICAM條 in the serum of 20 of 102 exposure subjects and 20 of 58 control subjects. Results:l. The blood contents of 15 rare earth elements, excepted the element Tm, in the exposure group were significantly higher than those in the control group(P0. 05). The percentage of CD4~ cells and the ratio of CD4~ to CD8t between the two groups showed no significant difference. Multivariate stepwise regression analysis indicated that the blood rare earth content is one of the impacting factors of CD8~ percentages. 3. Humoral immunity. The content of 1gM in exposure group(0.87?.26g/L) was much lower than that in the control group(1. 07 ?0. 29g/L) (P<0. 01) ;On the contrary the content of C3 in the exposure group(1. 41?. 20g/L) was increased compared with that in the control group(1. 30?. 16g/L). The difference was significant (P0. 05); Multivariate stepwise regression analysis revealed that blood rare earth content is an important factor causing the changes in the IL? level. Conclusions:Rare earth exposure has certain inhibitory effects on human cellular immunity as well as on humoral immunity. It promotes the elevation of IL? level in the human serum. Hence it presumed that rare earth exposure has a certain degree of influence o...