The transcripts for the cytokines Tumor necrosis factor-α (Tnf-α), Interleukin-6 (Il-6), Interferon-γ (Ifn-γ) and Monocyte chemotactic protein-1 (Mcp-1) were elevated in all mice after infection, but to a significantly higher degree in B6+/- mice compared to B6-/- mice one day p.i. (Fig 4A–4D; Tnf-α: Z = -2.123, P = 0.0336; Il-6: Z = -2.458, P = 0.0138; Ifn-γ: Z = -2.417, P = 0.0147; Mcp-1: Z = -2.219, P = 0.0261; Wilcoxon test via Monte-Carlo resampling). The gene discussed is CCL2; the disease is infection.