CD40LG and infection: Pathogen detection showed positive Mycoplasma pneumoniae immunoglobulin M (IgM), positive parainfluenza virus (types 1–3) IgM (indicating possible active infection), Epstein-Barr virus (EBV) viral capsid antigen IgG 67.8 AU/mL (normal range: 0–2 AU/mL), EBV nuclear antigen IgG 89.34 AU/mL (normal range: 0–2 AU/mL), and cytomegalovirus (CMV) IgG 4.55 AU/mL (normal range: <4.2 AU/mL) (IgM was negative for all 3, indicating previous infection).