Influence of aluminium on the immune system - an experimental study on volunteers

The purpose of this study was to examine whether oral exposure to aluminum (Al) can affect the human immune system. Eighteen healthy volunteers (mean age 42, 28-57 yr) were divided into a test group (9 females, 4 males) and a referent group (3 females, 2 males). Over 6 weeks, the test subjects inges ted 10 ml of antacid (aluminum hydroxide, 59 mg Al/ml) three times daily. A luminum was analyzed in urine before and during the exposure period (ICP-MS ). Blood samples were used for analysis of lymphocyte subpopulations, mitog en-induced lymphocyte proliferation and in vitro production and circulating plasma concentrations of immunoglobulin (Ig) A, IgG, IgM, interleukin (IL) -2 and IL-4. Urinary Al concentration in the test subjects was approximate ly 10- to 20-fold higher than in the referent group during exposure. This i ndicates that ingestion of an Al-containing antacid is associated with an A l absorption far above that originating from food and drinking water. In bo th referents and test subjects the lymphocyte subpopulations, lymphocyte pr oliferation and the in vitro Ig and IL production showed similar, time-depe ndent changes before as well as during the exposure period. No major differ ences were seen between the referent and test groups regarding the immune p arameters, except for a slightly smaller CD8+CD45R0+ population (primed cyt otoxic T-cells), in the exposed individuals as compared to the referents. T he results also show that subjects on antacid therapy may constitute a suit able population for studying biological effects of high-dose oral exposure to Al.