RESUMO
Waldenström's macroglobulinemia (WM) is a clonal B-cell lymphoproliferative disorder (LPD) of post-germinal center nature. Despite the fact that the precise molecular pathway(s) leading to WM remain(s) to be elucidated, a hallmark of the disease is the absence of the immunoglobulin heavy chain class switch recombination. Using two-dimensional gel electrophoresis, we compared proteomic profiles of WM cells with that of other LPDs. We were able to demonstrate that WM constitutes a unique proteomic entity as compared with chronic lymphocytic leukemia and marginal zone lymphoma. Statistical comparisons of protein expression levels revealed that a few proteins are distinctly expressed in WM in comparison with other LPDs. In particular we observed a major downregulation of the double strand repair protein Ku70 (XRCC6); confirmed at both the protein and RNA levels in an independent cohort of patients. Hence, we define a distinctive proteomic profile for WM where the downregulation of Ku70-a component of the non homologous end-joining pathway-might be relevant in disease pathophysiology.
Assuntos
Aberrações Cromossômicas , Dano ao DNA , DNA de Neoplasias/genética , Leucemia Linfocítica Crônica de Células B/genética , Repetições de Microssatélites/genética , Idoso , Idoso de 80 Anos ou mais , Apoptose , Feminino , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Hibridização in Situ Fluorescente , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Pessoa de Meia-Idade , Mutação/genética , Reação em Cadeia da PolimeraseAssuntos
Perfilação da Expressão Gênica , Imunoglobulinas/genética , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/patologia , Linfócitos B , Análise Mutacional de DNA , Progressão da Doença , Humanos , Reação em Cadeia da Polimerase , Análise de Componente Principal , PrognósticoRESUMO
B-cell lymphoproliferative disorders (BCLD) have been associated with chronic hepatitis C virus (HCV) infection. The HCV glycoprotein E2 (gpE2) hypervariable region I (HVR-I) may be a potential antigenic candidate to promote B-cell proliferation. The purpose of this study was to analyze the influence of HVR-I sequence variability in the development of BCLD. HVR-I sequences were studied in 29 chronically HCV-infected patients with (n=15) or without (n=14) BCLD. After PCR amplification of the gpE2 region, analysis of the 81 bp HVR-I encoding fragment was performed on 7-18 clones per patient. HVR-I sequence complexity was slightly lower in patients with BCLD (mean 0.347) than without (0.468) (P=0.2), though, sequence diversities were similar (0.0370 vs 0.0954, P=0.239). Phylogenetic analysis did not reveal any BCLD-associated clustering. In our population, neither the recently described insertion between positions 1 and 2 of HVR-I nor residues at positions 4 and 13 were particularly linked to BCLD. As previously described, we confirm the high degree of conservation of HVR-I residues T-2, G-6 and G-23 in our patients. Contrary to recent findings, our analysis based on multiple clones per patient analysis did not reveal any particular motif associated with BCLD.
