CD5 and myeloid sarcoma: MS patients tended to lack myeloid markers (myeloperoxidase was present in 63.2%, CD68 in 51.3%, CD13 in 48.7%, and CD33 in 48.7% of patients) and express T-cell markers such as CD3 in 20.7% and CD5 in 34.2%. In immunohistochemistry, all T-cell marker-positive MS subjects were negative for T-cell receptors.