1:  Westphal G, Hallier E.
Mercury in infants given vaccines containing thiomersal.
Lancet. 2003 Feb 22;361(9358):699; author reply 699. No abstract available.

2: Arch Toxicol  2003 Jan;77(1):50-5
Thimerosal induces micronuclei in the cytochalasin B block micronucleus test
with human lymphocytes.
Westphal GA, Asgari S, Schulz TG, Bunger J, Muller M, Hallier E.
Department of Occupational Health, Georg-August-University Gottingen, Waldweg
37, 37073 Gottingen, Germany, gwestph@gwdg.de

Thimerosal is a widely used preservative in health care products, especially in
vaccines. Due to possible adverse health effects, investigations on its
metabolism and toxicity are urgently needed. An in vivo study on chronic
toxicity of thimerosal in rats was inconclusive and reports on genotoxic effects

in various in vitro systems were contradictory. Therefore, we reinvestigated
thimerosal in the cytochalasin B block micronucleus test. Glutathione
S-transferases were proposed to be involved in the detoxification of thimerosal
or its decomposition products. Since the outcome of genotoxicity studies can be
dependent on the metabolic competence of the cells used, we were additionally
interested whether polymorphisms of glutathione S-transferases (GSTM1, GSTT1, or

GSTP1) may influence the results of the micronucleus test with primary human
lymphocytes. Blood samples of six healthy donors of different glutathione
S-transferase genotypes were included in the study. At least two independent
experiments were performed for each blood donor. Significant induction of
micronuclei was seen at concentrations between 0.05-0.5 micro g/ml in 14 out of
16 experiments. Thus, genotoxic effects were seen even at concentrations which
can occur at the injection site. Toxicity and toxicity-related elevation of
micronuclei was seen at and above 0.6 micro g/ml thimerosal. Marked individual
and intraindividual variations in the in vitro response to thimerosal among the
different blood donors occurred. However, there was no association observed with

any of the glutathione S-transferase polymorphism investigated. In conclusion,
thimerosal is genotoxic in the cytochalasin B block micronucleus test with human

lymphocytes. These data raise some concern on the widespread use of thimerosal.

3: Int J Hyg Environ Health  2001 Jul;203(5-6):479-81
Inhibition of the human erythrocytic glutathione-S-transferase T1 (GST T1) by
Muller M, Westphal G, Vesper A, Bunger J, Hallier E.
Department of Occupational and Social Medicine, Georg-August-University
Gottingen, D-37073 Gottingen, Germany. mmuelle3@gwdg.de

We have investigated the interaction of thimerosal, a widely used antiseptic and

preservative, with the human erythrocytic GST T1 (glutathione-S-transferase T1).

This detoxifying enzyme is expressed in the erythrocytes of solely the human
species and it displays a genetic polymorphism. Due to this polymorphism about
25% of the individuals of the caucasian population lack this activity
("non-conjugators"), while 75% show it ("conjugators") (Hallier, E., et al.,
1993). Using our newly developed HPLC-fluorescence detection assay (Muller, M.,
et al., 2001) we have profiled the kinetics of enzyme inhibition in erythrocyte
lysates of two individuals previously identified as "normal conjugator" (medium
enzyme activity) and "super-conjugator" (very high activity). For the normal
conjugator we have determined a 2.77 mM thimerosal concentration to inhibit 50%
of the GST T1 activity. In the case of the super-conjugator a 2.3 mM thimerosal
concentration causes a 50% inhibition of the enzyme activity. For both
phenotypes a 14.8 mM thimerosal concentration results in residual enzyme
activities equal to those typically detected in non-conjugator lysates. Thus,
sufficiently high doses of thimerosal may be able to change the phenotypic
status of an individual--at least in vitro--by inhibition of the GST T1 enzyme.

4: Int Arch Occup Environ Health  2000 Aug;73(6):384-8
Homozygous gene deletions of the glutathione S-transferases M1 and T1 are
associated with thimerosal sensitization.
Westphal GA, Schnuch A, Schulz TG, Reich K, Aberer W, Brasch J, Koch P,
Wessbecher R, Szliska C, Bauer A, Hallier E.
Abteilung fur Arbeits- und Sozialmedizin, Georg-August-Universitat Gottingen,
Germany. gwestph@gwdg.de

OBJECTIVE: Thimerosal is an important preservative in vaccines and
ophthalmologic preparations. The substance is known to be a type IV sensitizing
agent. High sensitization rates were observed in contact-allergic patients and
in health care workers who had been exposed to thimerosal-preserved vaccines.
There is evidence for the involvement of the glutathione system in the
metabolism of thimerosal or its decomposition products (organomercury alkyl
compounds). Thus detoxification by polymorphically expressed glutathione
S-transferases such as GSTT1 and GSTM1 might have a protective effect against
sensitization by these substances. METHODS: To address this question, a case
control study was conducted, including 91 Central European individuals with a
positive patch-test reaction to thimerosal. This population was compared with
169 healthy controls and additionally with 114 individuals affected by an
allergy against para-substituted aryl compounds. The latter population was
included in order to test whether possible associations were due to
substance-specific effects, or were a general feature connected with type IV
immunological diseases. Homozygous deletions of GSTT1 and GSTM1 were determined
by polymerase chain reaction. RESULTS: Glutathione S-transferase M1 deficiency
was significantly more frequent among patients sensitized to thimerosal (65.9%,
P = 0.013) compared with the healthy control group (49.1%) and the
"para-compound" group (48%, P = 0.034). Glutathione S-transferase T1 deficiency
in the thimerosal/mercury group (19.8%) was barely elevated versus healthy
controls (16.0%) and the "para-compound" group (14.0%). The combined deletion
(GSTT1-/GSTM1-) was markedly more frequent among thimerosal-sensitized patients
than in healthy controls (17.6% vs. 6.5%, P = 0.0093) and in the "para-compound"

group (17.6% vs. 6.1%, P =0.014), revealing a synergistic effect of these enzyme

deficiencies (healthy controls vs. thimerosal GSTM1 negative individuals, OR =
2.0 [CI = 1.2-3.4], GSTT1-, OR = 1.2 [CI = 0.70-2.1], GSTM1/T1-, OR = 3.1 [CI =
1.4-6.5]). CONCLUSIONS: Since the glutathione-dependent system was repeatedly
shown to be involved in the metabolism of thimerosal decomposition products, the

observed association may be of functional relevance.

5: Lancet  2002 Nov 30;360(9347):1737-41
Comment in:
     Lancet. 2002 Nov 30;360(9347):1711-2.
     Lancet. 2003 Feb 22;361(9358):698-9; author reply 699.
     Lancet. 2003 Feb 22;361(9358):698; author reply 699.
     Lancet. 2003 Feb 22;361(9358):699; author reply 699.
Mercury concentrations and metabolism in infants receiving vaccines containing
thiomersal: a descriptive study.
Pichichero ME, Cernichiari E, Lopreiato J, Treanor J.
Department of Microbiology/Immunology, University of Rochester, Rochester, New
York, NY, USA. michael_pichichero@urmc.rochester.edu

BACKGROUND: Thiomersal is a preservative containing small amounts of
ethylmercury that is used in routine vaccines for infants and children. The
effect of vaccines containing thiomersal on concentrations of mercury in
infants' blood has not been extensively assessed, and the metabolism of
ethylmercury in infants is unknown. We aimed to measure concentrations of
mercury in blood, urine, and stools of infants who received such vaccines.
METHODS: 40 full-term infants aged 6 months and younger were given vaccines that

contained thiomersal (diptheria-tetanus-acellular pertussis vaccine, hepatitis B

vaccine, and in some children Haemophilus influenzae type b vaccine). 21 control

infants received thiomersal-free vaccines. We obtained samples of blood, urine,
and stools 3-28 days after vaccination. Total mercury (organic and inorganic) in

the samples was measured by cold vapour atomic absorption. FINDINGS: Mean
mercury doses in infants exposed to thiomersal were 45.6 microg (range
37.5-62.5) for 2-month-olds and 111.3 microg (range 87.5-175.0) for
6-month-olds. Blood mercury in thiomersal-exposed 2-month-olds ranged from less
than 3.75 to 20.55 nmol/L (parts per billion); in 6-month-olds all values were
lower than 7.50 nmol/L. Only one of 15 blood samples from controls contained
quantifiable mercury. Concentrations of mercury were low in urine after
vaccination but were high in stools of thiomersal-exposed 2-month-olds (mean 82
ng/g dry weight) and in 6-month-olds (mean 58 ng/g dry weight). Estimated blood
half-life of ethylmercury was 7 days (95% CI 4-10 days). INTERPRETATION:
Administration of vaccines containing thiomersal does not seem to raise blood
concentrations of mercury above safe values in infants. Ethylmercury seems to be

eliminated from blood rapidly via the stools after parenteral administration of
thiomersal in vaccines.



A.    Toxic Effects of Thimerosal on Vital Mammalian Enzymes and Enzyme Systems

B.    Chromosomal Aberrations Induced by Thimerosal Exposure

C.    Disruption of Calcium Homeostasis by Thimerosal

D.    Allergic Responses to Thimerosal in Vaccines and Opthalmics