CD40LG and coinfection: Patients diagnosed with borrelial CNS infection were prescribed intravenous ceftriaxone 2 g once daily for 14 days (36 patients) or oral doxycycline 100 mg twice daily for 14 days (3 patients), and 7/25 patients in whom intrathecal synthesis of borrelial IgM was the only laboratory marker of borrelial co-infection were not prescribed antibiotics.