Patients with early B. burgdorferi infection also diagnosed with fibromyalgia showed the highest levels of anxiety and depression. The results showed that serological markers of infection could act as indicators of depression level in patients with B. burgdorferi infection. Patients with IgM- and IgG+ serological markers, showing more advanced infection, had the lowest levels of anxiety and depressive symptoms. The gene discussed is CD40LG; the disease is depressive disorder.