Allergic disease, immunoglobulins, exposure to mercury and dental amalgam in Swedish adolescents

 High-dose exposure to inorganic mercury in man can influence the immune system and in rare cases cause immune-related disease. Some experimental animals also react with autoimmunity after low doses of inorganic mercury. Glomerulonephritis and an increased formation of immunoglobulin type E (IgE) are characteristic of these reactions. A recent study of 15-year-old adolescents demonstrated an association between immunoglobulin type A (IgA) and mercury concentration in plasma (P-Hg). There was also an association between allergic disease and IgA levels. The present study included 54 male and 23 female 19-year-old students who were recruited from a cohort that had been previously defined in a survey of allergic disease. Of the students, 39 (51%) had asthma, allergic rhino-conjunctivitis or eczema. Similar amalgam burden and P-Hg levels were observed in students with (n=39) and without (n=38) allergic disease (P=0.48 and P=0.98, respectively). As expected, IgE levels were significantly higher in the group with allergic disease (P=0.006), but there was no association between P-Hg and IgE. The P-Hg levels were very low (median 1.50 nmol/l) and correlated significantly (r=0.31) with the small number of amalgam surfaces (P=0.007). Thirty-seven students had no amalgam fillings. P-Hg levels did not associate significantly with IgA, but did so with IgG₂ (r=0.33; P=0.003). No conclusive correlation was observed between IgG₂ and amalgam fillings. The findings of this study in 19-year-old subjects differ from earlier data obtained in a sample 4 years younger. The possibility of chance in the association between P-Hg levels and IgG₂ must, however, be considered. Received: 15 April 1996/Accepted: 23 August 1996