[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.