Abstract
The combination therapy of carcinurin inhibitor (CNI), and inhibitor of nucleic acid production, has been widely utilized in clinical kidney transplantation. Mycophenolate mofetil (MMF) has a strong immunosuppressive effect as compared with azathioprine. As a result, over immunosuppression is often experienced under the combination therapy of MMF and CNI. It is very difficult to adjust each immunosuppressive drug without knowing how much the immunosuppression and how much each drug affects the immunosuppression. The method of monitoring the immunosuppression has not yet become available for transplant patients under the combination therapy. We investigated the usefulness of flow cytometry of the lymphocyte stimulation test under the immunosuppressive drug in vitro. The peripheral blood from four healthy volunteers was separated by density gradient centrifugation. After lymphocytes were dyed with 5(and 6)-carboxy fluorescein diacetate succinimidyl ester(CFSE), cells were cultured with Staphylococcus enterotoxin B (SEB) for 4 days under the Mycophenolic acid (MPA) and/or Cyclosporine (CsA) in various concentrations. After cultured, Division Index (DI) was measured by FACS, and Stimulation Index (SI) was calculated using DI. From a series of multiple concentrations of MPA or CsA, SI 25, 50 and 75 of MPA groups were 54, 18 and 6 ng/ml, and SI 25, 50 and 75 of CsA groups were 250, 100 and 30 ng/ml. We defined the medium concentration of each drug as MPA 30 ng/ml and CsA 100 ng/ml, then 1/5 of these results as low concentration and concentration 5 times as high (setting up MPA: 6, 30 and 150 ng/ml, and CsA: 20, 100 and 500 ng/ml). The mean S.I. of MPA group was 71.27±11.55 at 6 ng/ml, 23.63±13.44 at 30 ng/ml and 4.87±1.33 at 150 ng/ml. The mean S.I. of CsA group were 78.02±9.05 at 20 ng/ml, 44.14±4.89 at 100 ng/ml and 16.51±5.17 at 500 ng/ml. At the combination of low doses of CsA and MPA, S.I. was 61.03±8.03. The addition of a medium dose of MPA to the low dose of CsA decreased S.I. to 12.23±0.75, which is almost the same result of the high dose of CsA group. These results have us conclude that the dose of CsA could be decreased when the medium dose of MMF is combined with CsA treatment. In addition, patterns of the histogram in Flow cytometry found that there were differences between CsA and MPA, leading to a better understanding as to which drug contributed to the over-immunosuppression.
