AIDS-ASSOCIATED VACUOLAR MYELOPATHY AND TUMOR-NECROSIS-FACTOR-ALPHA (TNF-ALPHA)

The spinal cords from 15 patients with AIDS-associated vacuolar myelop athy (VM). 4 AIDS patients without VM, and 5 HIV-seronegative controls , were studied with immunocytochemistry for TNF alpha. CSF and blood f rom HIV-seropositive patients with VM (n = 16), non-vacuolar myelopath ies (n = 8). CNS infection but no clinical myelopathy (n = 31), no cli nical or radiological evidence of CNS disease (n = 9), and from 7 HIV- seronegative controls with motor neurone disease were assayed for TNF alpha using an ELISA technique. TNF alpha was present on immunostainin g in all the 15 cords with VM studied. The stained cells were macropha ges, microglia and endothelial cells. The amount of immunostaining was higher in cords with VM compared with cords from HIV-seropositive pat ients without VM (p = 0.001). the distribution of staining corresponde d to the areas of pathology but did not correlate with the severity of the VM. Immunostaining was also higher in the HIV-seropositive group compared to the HIV-seronegative controls (p = 0.001). There was no si gnificant difference in the levels of TNF alpha in the CSF of patients with VM compared to any of the other groups studied. Blood levels of TNF alpha were lower in the HIV-seropositive controls without CNS dise ase and in the HIV-seronegative MND controls, than in patients with VM , non-vacuolar myelopathies and CNS disease. CSF TNF alpha levels did not appear to a reliable indicator of intramedullary levels. The findi ngs support the hypothesis that TNF alpha may be relevant in the patho genesis of vacuolar change in VM.