Relative cytokine mRNA expression in splenocytes of heavy metal-exposed BALB/c mice. Data represent mRNA relative expression values ± SEM in spleen cells of mice exposed to Cd acetate or Hg chloride for 3 or 5 weeks (3-w, 5-w). Data were analyzed using the REST© software as described in Materials and Methods. Control values were assigned to 1, values of relative gene expression > or < 1 indicate the up- or down-regulation of this gene relative to control mice. The asterisks (*) indicate significance relative to controls as obtained by the pair-wise fixed reallocation randomization test at p < 0.05; the horizontal lines indicate significant differences between the connected groups.