The absolute number of CD14+ cells, as determined by IHC, increased from 1.8 cells/HPF in controls to 55 cells/HPF (p = 0.004) in patients with AIDS; the percentage of CD14+ cells, as assessed by flow cytometry using CD33, increased from a median 6.5 to 21.2 % (p =0.007) (Fig. 4). Here, CD33 is linked to AIDS.