Effect of arsenic on regulatory T cells.
BACKGROUND
Arsenic (As) affects the function and survival of lymphocytes, and some arsenic compounds exert a relevant antineoplastic effect. We have explored the effect of As on T regulatory cells.


CONCLUSIONS
In vitro experiments with peripheral blood mononuclear cells from healthy subjects showed that low concentrations of As tended to increase the number of natural T regulatory (nTreg) lymphocytes, whereas concentrations >5.0 muM had an opposite effect. Furthermore, rats exposed to As showed redistribution of nTreg cells, and As administration to rats with experimental allergic encephalomyelitis increased the levels of nTreg cells in spleen and diminished the severity of this condition. On the other hand, in 47 apparently healthy subjects chronically exposed to As, we found significant inverse correlation between urinary As levels and the number and function of nTreg lymphocytes. Although most of these individuals showed enhanced levels of apoptotic lymphocytes in peripheral blood, with a diminution of mitochondrial membrane potential, no significant correlation between these parameters and urinary As was detected.


CONCLUSIONS
Our data indicate that As seems to have a relevant and complex effect on nTreg cells.
Hernández-Castro
B
B
Department of Immunology, Facultad de Medicina, UASLP, San Luis Potosí, SLP, México.
Doníz-Padilla
L M
LM
Salgado-Bustamante
M
M
Rocha
D
D
Ortiz-Pérez
M D
MD
Jiménez-Capdeville
M E
ME
Portales-Pérez
D P
DP
Quintanar-Stephano
A
A
González-Amaro
R
R
D000293:Adolescent; D000328:Adult; D000818:Animals; D017209:Apoptosis; D001151:Arsenic / Q000494:pharmacology* / Q000652:urine; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051381:Rats; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000187:drug effects / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000276:immunology; D055815:Young Adult
C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D001151:Arsenic