Mercury-reactive lymphocytes in peripheral blood are not a marker for dental amalgam associated disease

Objectives: The popular press and publications associated with alternative medicine increasingly report that chronic ill health, particularly myalgic encephalitis like conditions, are associated with mercury amalgam fillings. There are no scientifically proven definitive tests to support these claim s. One of the more scientific tests in vogue is to assess the level of bloo d-borne mercury-reactive lymphocytes and to conclude that patients with hig h levels have developed a hypersensitivity reaction to mercury. The objecti ve of this study was to determine the diagnostic value of this test. Methods: This study represents an open comparison of mercury-reactive lymph ocyte levels in healthy control individuals with those in patients complain ing of symptoms associated with adverse effects of dental metal amalgam fil lings. The healthy control group consisted of 51 male and female individual s, aged between 12 and 82 years, with and without dental amalgam fillings. The patient group consisted of 70 male and female individuals, aged between 12 and 87 years, and with the exception of one patient, with three or more mercury amalgam fillings of more than 1 year's duration. In vitro lymphocy te responses to mercury, and to nickel, as an example of a metal commonly a ssociated with hypersensitivity reactions, and to more conventional protein antigens were determined. Results: In the blood of patients and controls, there were similar levels o f specifically reactive lymphocytes to all of the in vitro stimulating agen ts, but there were significantly higher numbers of sub-normal and non-respo nders within the patient group. Conclusions: The incidence and quantity of mercury-reactive lymphocytes in the blood are not pathogenic markers of illness associated with dental meta l amalgams, but may rather reflect exposure to mercury. The clinical releva nce of the decreased in vitro lymphocyte responses in the patient group nee ds further investigation. (C) 2001 Elsevier Science Ltd. All rights reserve d.