[IGHV mutational statue in patients with splenic marginal zone lymphoma].

Objective

To investigate the IGHV mutational status and its differences from Caucasian in splenic marginal zone lymphoma (SMZL).

Methods

A retrospective study on 40 SMZL cases were performed to detect the V-D-J sequence of IGHV by plasmid cloning sequencing, comparing the data with the most homologous germ line V sequence in database, identifying the stereotype of patients through cluster analysis and alignment. The clinical and laboratory characteristics were compared between the patients with IGHV mutation and without mutations.

Results

In SMZL patients, the proportion of IGHV mutations was 75%, consistent with data from Caucasian. In V region, the usage of V3-23 subtype was lower in Chinese patients compared with Caucasian (2.6% vs 18.0%, P=0.006), whereas the V2-70 subtype was used with high proportion (10.3% vs 0.8%, P=0.002). In D region, the D2-21 and D6-13 gene were used frequently (17.9% vs 2.3%, P<0.001; 12.8% vs 3.8%, P=0.046). One new stereotype was found, and the SMZL-biased V1-2 gene was mostly used (25.6%). The levels of IgG and IgA were significantly increased in IGHV without mutations as compared with mutations [10.70 (5.28-15.50) g/L vs 12.90 (7.71-23.50) g/L, 1.06 (0.21-3.13) g/L vs 1.66 (0.81-2.93) g/L, P=0.038, 0.040]. The only two 17p deletion patients were IGHV without mutaions. The progression free survival (PFS) was significantly prolonged in IGHV mutations (P=0.009), and there was no significant difference regarding to the overall survival between the two subgroups (P=0.430).

Conclusion

The proportion of IGHV mutaions was similar to the data in Caucasian. There was disparity in the usage of V and D regions between Chinese and Caucasian, and the SMZL-biased V1-2 gene were used more frequently in Chinese patients. One new stereotype was identified. In the IGHV without mutations group, the levels of IgG and IgA were significantly increased.