The expression patterns of CD44 and CD45RB on peripheral blood T lymphocytes in the rejection of allogeneic murine skin transplantation.

Until now, the rejection was diagnosed through a biopsy, but this method of diagnosis reflected the advanced tissue damage of the transplanted organ and contained the innate problem of being invasive. In relation, our research attempted to evaluate the viability of analyzing the surface antigens of the peripheral blood activated T lymphocytes after murine skin transplantation as a non-invasive and early diagnostic tool for diagnosis of rejection. After mouse skin was transplanted, the expression patterns of activated T lymphocyte markers, CD44 and CD45RB were analyzed along with T lymphocyte markers, CD3, CD4 and CD8 using flow cytometry. The skins from the tails of allogeneic BALB/c(H2d) mice and syngeneic C57BL/6J mice were transplanted to C57BL/6J(H2b) mice as test and control groups, respectively. Peripheral blood, which was sampled from the tail every other day from day 3 to day 15 was stained with anti-CD44 (or CD45RB), anti-CD4 (or CD8) and anti-CD3 monoclonal antibodies simultaneously, and analyzed by 3-color FACS. Rejection occurred only in the test group from day 8 to day 13 (median: day 10). Although the proportions of CD3(+) lymphocytes, CD4(+) lymphocytes and CD8(+) lymphocytes showed no difference, the total number of peripheral blood lymphocytes and the number of CD3(+) lymphocytes and CD8(+) lymphocytes decreased more sharply in the control after day 7. The proportion and the number of CD44(+)CD3(+)-lymphocytes, CD44(+)CD4(+)-lymphocytes and CD44(+)CD4(+)CD3(+)-lymphocytes began to increase after day 7, to peak on day 11, and then to decrease, showing a significant difference. The proportion and number of CD44(+)CD8(+)-lymphocytes and CD44(+)CD8(+)CD3(+)-lymphocytes showed similar trends. No significant difference was observed in any subsets of the CD45RB antigen. The analysis of the expression patterns of surface antigen CD44 on peripheral blood T lymphocytes using flow cytometry is sensitive, safe, easily repeatable and controllable, and, therefore, can be considered a promising tool for the diagnosis of rejection. However, the clear change in CD44 occurred between day 9 and day 13, when rejection was observed grossly. Therefore, it is regarded more useful as a screening test or follow-up indicator rather than as an early diagnostic tool.