CD4/CD8

The CD4 + /CD8 + (helper/suppressor) lymphocyte ratio, quantified as the ratio of CD4 fluorescein isothiocyanate (FITC)-positive lymphocytes to CD8 phycoerythrin (PE)-positive lymphocytes, has been used to evaluate the immune status of patients with, or suspected of developing, autoimmune disorders or immune deficiencies. In many cases, the relative percentages of helper lymphocytes decline and suppressor lymphocytes increase in immune deficiency states. These states may also be marked by T-cell lymphopenia. In addition, the ratio has been used to monitor bone marrowtransplant patients for onset of acute GVHD. While a useful indicator, the CD4 + /CD8 + (helper/ suppressor) lymphocyte ratio has specific limitations.