Normal immunosuppressive potential of synovium-derived mesenchymal stem cells of patients with rheumatoid arthritis (RA-SMSCs). (A1) The differences of absorbance between 0 days and 5 days were not statistically significant for the allogeneic peripheral blood mononuclear cells (PBMCs) from a healthy donor (P > 0.05) and the PBMCs from another unrelated healthy donor (P > 0.05); for the mixed PBMCs, however, the absorbance at 5 days was significantly higher than the value at 0 days (P < 0.05). (A2), (A3) Compared with synovium-derived mesenchymal stem cells of healthy donors (HD-SMSCs), no statistically significant reduction in suppressive potential (% inhibition) on mixed PBMCs reaction (MLR) was found at all five ratios (P > 0.05). (B1) In autologous or allogeneic PBMCs proliferation assay, the differences of absorbance between 0 days and 5 days without PHA were not significant (P > 0.05), whereas the value for 5 days with PHA was significantly higher than the value at 0 days (P < 0.05). (B2,B3) Percentage inhibition of RA-SMSCs on PBMCs proliferation induced by PHA was similar with the values of HD-SMSCs at varied ratios (P < 0.05). Results were recorded as mean absorbance (optical density (OD)) ± standard deviation (SD) and as mean counts per minute (CPM) ± SD, respectively. The percentage inhibition values were calculated by using the following formulae: %inhibition = 1 − (OD(exp) − OD(adj))/OD(bla) or %inhibition = 1 − (CPM(exp) − CPM(adj))/CPM(bla). OD(exp), OD(adj) and OD(bla) represent the mean absorbance of experimental wells, adjusted wells (only SMSCs), and blank wells, respectively, and CPM(exp), CPM(adj), and CPM(bla) represent the mean counts per minute of the corresponding wells. Results were finally expressed as the mean (% inhibition) ± SD.
Zhang et al. Arthritis Research & Therapy 2013 15:R169 doi:10.1186/ar4355