Identification and purification of mesenchymal stem cells (MSCs) expanded in culture for therapeutic use is crucial for improved yield and optimal results. Fibroblasts are the most common cell type in connective tissue and are commonly found as contaminants of MSC cultures, affecting cell yield and potentially causing tumor formation after cell transplantation. In the current study, we wished to identify cell surface markers that can differentiate MSCs of different origins from fibroblasts.

Material and methods:
MSCs were isolated from bone marrow, adipose tissue, Wharton’s jelly and placental tissue and fibroblasts were isolated from foreskin (as a negative control) in order to examine the differences in the expression of a panel of 14 different cell surface markers using multiplex flow cytometry.

Our results indicate that the following markers could be useful in differentiating between fibroblasts and MSCs derived from: adipose tissue - CD79a, CD105, CD106, CD146, and CD271; Wharton’s jelly - CD14, CD56 and CD105; bone marrow - CD105, CD106, and CD146; placental tissue - CD14, CD105, and CD146. Furthermore, we found that, contradictory to previous studies, CD26 is not fibroblast-specific.

In conclusion, the results of our study indicate that cell surface markers may prove to be a useful tool in the discrimination between MSCs of different origins and fibroblasts and thus may be used to authenticate the identity of the isolated cells.