[The relation between Bence Jones protein gene polymorphism and function of renal tubular-epithelial cell in multiple myeloma].

Objective: Bence Jones protein (BJP) plays an important role in multiple myeloma (MM) renal lesion, we try to study the relation between the characteristics of BJP variable gene and the function of renal tubular-epithelial cell (TEC).
Methods: MM patients whose function of TEC was abnormal at diagnosis constituted a group damage and patients whose function of TEC was normal for a long period a group normal. We also collected MM patients and divided them into a group BJPkappa and a group BJPlambda. Total RNAs were isolated from the mononuclear cells of bone marrow and reverse transcription was carried out with an oligo dT18 primer; these cDNAs were then amplified with PCR, cloned and sequenced, the comparison and analysis of the sequences were made according to current ESBC/Gen Bank sequence directories.
Results: 3/5 cases of BJPlambda use V3-4 gene in the group damage, the replacement R mutation ratio of CDRS in the group damage (7.57 +/- 3.40) was higher than that in the group normal (4.25 +/- 1.90) and higher than that of FWRS in the group damage (3.29 +/- 1.25); R mutation ratio of CDRS region in the group BJPlambda (6.64 +/- 2.38) was higher than that in the group BJPkappa (4.10 +/- 2.13) and higher than that of FWRS in the group BJPlambda (2.91 +/- 0.94), R mutation ratio of CDRS both in the group BJPkappa or BJPlambda was higher than that of FWRS respectively.
Conclusions: The higher ratio of renal lesion in some MM patients and BJPlambda patients is correlated with the high ratio of their variable gene R mutation which result in changing organization and physicochemical activity of BJP. BJP translated by some subtype genes may incline to injure the function of TEC.