Lymphocytic pulmonary infiltrates. (A) A 40-year-old woman with gradually worsening severe lung disease. Computed tomography of the chest revealed massive infiltrates composed of lymphocytic collections and fibrotic scars. (B) On biopsy, the infiltrating T cells in the lung, obliterating normal architecture, were revealed as CD4⁺ by the brownish monoclonal peroxidase conjugated monoclonal anti-CD4⁻ staining pattern (magnification ×25).