抄録
Among immunoglobulin free light chains (FLCs), kappa and lambda isotypes exist mainly in monomeric and dimeric forms. Under pathological conditions, the levels of total FLCs as well as the ratios between mono- and dimeric FLCs significantly change in samples from patients with monoclonal immunoglobulin gammopathy (MMG). The MALDI-TOFMS technique, which would be correspond to the electrophoresis of proteins under a high vacuum, can be used to easily and rapidly detect any target proteins in body fluids without any specific antibodies. We compared the effectiveness of MALDI-TOF MS and immunoelectrophoresis techniques to detect FLCs in MMG patients. Our preparations were only treated with desalts and concentration using the SpinFilter 3KTM and Affi-GelTM Blue resin without any antibodies. The ratios of the relative ion intensities between [ca 45 kDa] and [ca 23 kDa] by MALDI-TOF MS were 0.054+/−0.05 (n=26) of the κ-type, and those of the λ-type were 0.572+/−0.45 (n=12), respectively. The ratios of [ca 45 kDa] / [ca 23 kDa] were consisted with those of dimers and monomers in patients’ samples by immunoelectrophoresis techniques. Conclusion: The ratios of the relative ion intensity at m/z ca 23 kDa and ca 45 kDa of FLCs in patients’ urine may facilitate the rapid discrimination between BJP κ- and λ-types in MMG.
