Primary T-cell and combined immunodeficiencies
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A 4-month-old infant has persistent thrush, diarrhea, poor weight gain, and Pneumocystis pneumonia. Both CD4-positive and CD8-positive T-cell counts are markedly reduced. B cells, monocytes, and neutrophils are present. Two assays compare patient and control lymphocyte preparations with the same total lymphocyte input and viability. After matched ex vivo antigen-priming and activation conditions, the preparations are added to either healthy macrophages containing intracellular organisms or healthy virus-infected target cells. Each donor’s macrophages and targets are HLA matched to that donor’s lymphocytes, and the relevant test antigens are identical across patient and control conditions.