In 1983, Eggleston reported increases in the percentage of lymphocytes (white blood cells) that were T-lymphocytes after removing amalgam restorations in two patients . One of these patients had four amalgams replaced and the percentage of lymphocytes that were T-lymphocytes decreased. This study is widely cited by anti-amalgamists as proof that amalgam fillings are harmful to the immune system, but it has been criticized for several reasons. Only two patients were examined, and although it was only a "preliminary report," no subsequent report was forthcoming. Furthermore, lymphocytes were given as percentages, not as numbers of cells, and the methods of counting the lymphocyte cells were not stated. Most importantly, the changes in lymphocyte levels were within the range that would be expected for normal variation and measurement error .
Controlled scientific studies have been unable to document damage to the immune system from amalgam fillings. In 1998, Loftenius et al studied ten healthy subjects who had acute mercury exposure by having all their amalgam fillings removed. Although the plasma levels of mercury increased after amalgam removal, there was no significant influence on peripheral blood lymphocytes within the first 48 hours . Although serum interleukin-6 levels increased significantly within 48 hours, the levels were still low and within the normal range. Mackert could find no significant differences in three populations of lymphocytes in 21 patients with amalgams versus 16 patients without .
Herrström et al examined cellular immune factors including B- and T-lymphocytes, T4, T8, monocytes, netruophilic, eosinophilic, and basophilic granulocytes, and large unstained cells and humoral immune factors including immunoglobulins IgG, IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE, albumin, alfa-1-antitrypsin, orosomucoid, haptoglobin, and antinuclear antibodies in a group of 41 healthy schoolchildren . Although there was a low correlation between plasma mercury levels and the number of amalgam surfaces, there was no relationship except random findings between cellular and humoral immune factors and the number of amalgam surfaces. Herrström and Högstedt found no correlation between number or presence of amalgam fillings and eczema, allergic rhino-conjunctivitis, or asthma in a group of 348 teenage children . Interestingly, the children with no amalgam fillings had a significantly greater frequency of asthmatic symptoms than children with amalgam fillings.
Langworth et al examined 21 subjects with self-diagnosed "amalgam illness" from mercury in their amalgam fillings but found no immunologic abnormalities except that one subject had an increase in spontaneous DNA synthesis. Further examination of this subject revealed no sign of rheumatologic disease, collagenosis, or malignancy . In a 1997 study comparing 44 dentists and dental nurses with 44 hospital employee controls, Langworth et al reported that the white blood cell count was normal in both groups 
Dr. Wahl practices dentistry in Wilmington, Delaware. This article was originally published in Quintessence International 32:696-710, 2001, and is reproduced here with the kind permission permission of Quintessence Publishing Co. The author thanks Drs. J. Rodway Mackert, Ivar A. Mjör, and Fred Eichmiller for reading the manuscript and offering several helpful suggestions.