Objective To analyze the changes of lymphocytes from ileum Peyers pacth from Chinese rhesus monkeys at acute period with SIVmac239 infection. Methods9 rhesus monkeys were used and 5 were infected with SIVmac239 via intravenous injection. The tissues or lymphocytes from ileum Peyers pacth lymph nodes from rhesus monkeys at acute period were collected and analyszed with CD4+, CD8 immunohistochemistry and flow cytometry T-cell subsets labeling with CD3, CD4, CD8, CD28, CD95 monoclonal antibodies respectively. ResultsObviously declined CD4+/CD8+ ratio and increased memory cells (CD4 + & CD8 +) ratio and CD8+ T cells were detected in Peyers lymph nodes, but CD4 counts had no significant change in Peyers lymph nodes. ConclusionDeclined CD4+/CD8+ ratio and increased memory cells (CD4 + & CD8 +) ratio were found in Peyers lymph nodes from rhesus macaques at acute period with SIVmac239 infection, however, the meaning and possible affection to disease need further study. 