Immunoglobulin variable region gene analysis to the autoantibody-secreting B cells from tumors in association with paraneoplastic autoimmune multiorgan syndrome

Wang, Jing MDPhD
Bu, Dingfang MD
Zhu, Xuejun MD

From the Department of Dermatology, Peking University First Hospital, Beijing, China

Correspondence Xuejun Zhu, MD Department of Dermatology Peking University First Hospital #8, Xishiku St. Beijing 100034 China E-mail: [email protected]

^*Present address: Department of Dermatology, The Fourth People's Hospital of Shenzhen, Shenzhen 518033, Guangdong, China

International Journal of Dermatology 46(11):p 1146-1154, November 2007.

Objectives

We have studied the role of lymphoproliferative tumors in the pathogenesis of autoimmune and the origin of the autoantibodies in PNP. Objectives of this study is to understand the characteristics of immunoglobulin genes of the B-cells isolated from the tumor which can produce auto-antibody.

Methods

Total RNA of the tumor cells was then isolated and the mRNA was reversely transcribed into cDNA. V_H and V_L genes were amplified and cloned and their sequences were analyzed.

Results

49 V_H genes (527 to 577 bp) and 36 V_L genes (445 to 454 bp) sequences were cloned from five tumors. All of the IgV_L were mostly homologous to IGKV4-01 germ-line gene. The frequency of IgV_H germ-line gene usage in a decreasing order was IGHV3-23 > IGHV3-9 > IGHV4-31 > IGHV4-59. There was more nucleotide changes occurred in complementary determining regions (CDR) than those in the framework regions (FR) in the V_H and V_L of B cell clones. In both V_H and V_L, the probability (P) that the number of observed replacement mutations (R) in the CDRs would occur by random chance was low.

Conclusions

The clones of B-lymphocytes in the tumors carrying possibly functional rearranged immunoglobulin heavy and light chain genes were isolated and there were high incidences of somatic mutations in CDRs and relatively conserved sequences in framework region.