Background
Simian immunodeficiency virus (SIV), a model for HIV pathogenesis, is associated with neuropathology.
Methods
Five SIV‐infected animals were selected following a database search of 1206 SIV‐infected animals for nodular or astrocytic lesions. Two of five had neurologic dysfunction, and 3 of 5 were incidental findings.
Results
Histologic examination revealed multifocal nodular foci in the gray and white matter formed by interlacing astrocytes with abundant cytoplasm and large, reactive nuclei. Nodules were often enmeshed with small capillaries. Immunohistochemistry revealed variable immunoreactivity for a panel of markers: GFAP (4/5), vimentin (5/5), Glut‐1 (1/5), CNPase (0/5), S100 (5/5), Iba1 (0/5), Ki67 (0/5), and p53 (4/4). In situ hybridization failed to detect any SIV RNA (0/5). Immunohistochemistry for simian virus 40, rhesus cytomegalovirus, and rhesus lymphocryptovirus failed to detect any antigen within the lesions.
Conclusion
The immunoreactivity of p53 in the lesions compared with adjacent tissue suggests a local derangement in astrocyte proliferation and function.