Serum free light chains and post-transplant lymphoproliferative disorder in patients with renal transplant.

The aim of the present study was to determine whether there is an association between serum free light chains (sFLC) quantification and the development of post-transplant lymphoproliferative disorder (PTLD), using serum samples from a nested case control cohort of patients with renal transplant. Ten new cases of PTLD and 46 controls were enrolled. Additional comparison groups consisted of five human immunodeficiency virus (HIV)-infected individuals, five with untreated Hodgkin lymphoma and six normal individuals. Serum kappa and lambda FLC concentrations were measured by nephelometry and compared with reference ranges (normal and renal ranges). kappa and/or lambda were above the normal range in 90% of cases and in 65% of matched controls. There was no statistically significant difference between all groups, except for lambda FLC concentrations between cases of PTLD and normal individuals (p = 0.016). The kappa/lambda sFLC ratios of cases and controls were within the renal range and normal range. Our results suggest that sFLC are not useful to predict PTLD development in renal transplant recipients.