Monitoring serum free light chains in patients with multiple myeloma who achieved negative immunofixation after allogeneic stem cell transplantation

Monitoring of serum free immunoglobulin light chains (FLC) in 26 myeloma patients who achieved immunofixation negativity after allografting showed a decrease of FLC at a median of 128 days before immunofixation negativity. In patients who subsequently relapsed, a 25% increase of FLC was observed at a median of 98 days before immunofixation positivity.