Spontaneous proliferation of CD4⁺ cells and CD8⁺ cells.

In vitro proliferation of CD4⁺ and CD8⁺ cells, measured by incorporation of BrdU, is shown for a representative patient with HAM/TSP (HAM-4). The data are representative of 4 patients with HAM/TSP tested in the same way. Histograms demonstrate that both CD4⁺ and CD8⁺ cells that were gated by small cell population (R1) or large cell population (R2) incorporated BrdU. Few cells in R1 were labeled with BrdU during culture. Both CD4⁺ and CD8⁺ cells in R2 showed BrdU as being positive during culture. And a larger percentage of CD8⁺cells proliferated than did CD4⁺ cells. The number in each histogram represents the percentage of BrdU-positive cells.