Pathology of the spleen in the acquired immunodeficiency syndrome.

The pathologic findings of the spleen at autopsy in 101 patients with the acquired immunodeficiency syndrome are described. Grossly visible lesions were present in 52 patients. Microscopically, the histologic patterns of red and/or white pulp could be classified into five groups: group 1, in white pulp only, was characterized by lymphoid depletion; group 2, in red or white pulp, by a proliferation of histiocytes; group 3, in red or white pulp, by a plasma cell/immunoblastic reaction; group 4, in red or white pulp, by a mixture of cells in malpighian corpuscles or trabeculae without significant proliferation or depletion; and group 5, in red pulp only, by packed cords with empty sinuses. These patterns of reaction could be correlated with infectious agents. Disseminated opportunistic infections involved the spleen in 27 cases; of these, the red pulp had a histiocytic or mixed pattern in 89%, and the white pulp showed lymphoid depletion in 52%. Other lesions, including neoplasms in five patients, did not predominate in any group. Splenic opportunistic infections in acquired immunodeficiency syndrome may correlate with histologic patterns of reaction and give an indication of immune response.