Combined immunodeficiency in a calf.

Combined immunodeficiency was documented in a 6-week-old Angus calf. The calf had lymphopenia, undetectable serum IgM or IgA, and low concentrations of serum IgG (420 mg/dl). The calf was treated for diarrhea, pneumonia, and shock, and was given antimicrobial drugs, fluids, and plasma. The calf died of systemic candidiasis and Escherichia coli bacteremia. Aggregated lymphatic folliculi (Peyer patches), lymph nodes, and thymic and splenic lymphoid tissue could not be identified at necropsy.