NGFR and rheumatoid arthritis: The observed decrease in cytokine production, induced by LM11A-31 blocking of p75NTR activity, is not due to any toxic effect of the p75 inhibitor or decreased survival of RA-FLS: neither 30% v/v SF nor different LM11A-31 concentrations (the highest dose was 10-fold that used in the neutralization experiments) induced an increase in the percentage of apoptotic cells in RA-FLS (Figure 5E).