CD40LG and macrophage activation syndrome: Surveillance CT chest, abdomen, and pelvis did not show any signs of pneumonia or intra-abdominal infection but demonstrated bilateral pleural effusions and anasarca, consistent with capillary leak secondary to MAS. Remaining infectious evaluation including respiratory viral pathogen panel, repeat blood cultures, urine culture, tuberculin skin testing, Epstein Barr virus viral capsid antigen immunoglobulin (Ig) M, coxsackie IgM, and IgG testing, urine Histoplasma galactomannan antigen, serum aspergillus antigen, and serum human polyomavirus 2 were negative as noted in Table 3.