Because the patient lives in an area endemic of coccidioidomycosis, Coccidioides spp. immunoglobulin M (IgM) and immunoglobulin G (IgG) detected using enzyme-immunoassay (EIA) (manufactured by Premier, Inc., Charlotte, North Carolina) on the patient’s serum were requested on admission and came back negative. Here, CD40LG is linked to coccidioidomycosis.