Glomerular crescent-related biomarkers in a murine model of chronic graft versus host disease.

BACKGROUND: We examined the alterations in gene expression associated with the development of crescentic glomerulonephritis in murine chronic graft-versus-host disease, a model for human systemic lupus erythematosus. METHODS: The disease was induced in (C57BL/6 x DBA/2) F(1) hybrids by injection of DBA/2 lymphocytes leading to deposition of auto-antibodies in the glomeruli, and a lupus type of nephritis morphologically. After extensive crescent formation at week 9 of disease, cDNA microarray analysis was performed and highly expressed genes were evaluated as molecular markers by real-time reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization, immunohistochemistry and immunoassay of urine proteins. RESULTS: Six genes, secreted acidic cysteine-rich glycoprotein (Sparc), thymosin beta 10 (Tmsb10), S100 calcium-binding protein A6 (S100a6), annexin A2 (Anxa2), osteopontin (OPN) and lipocalin 2 (Lcn2), were quantified by real-time RT-PCR in laser microdissected glomeruli in a time course manner. Sparc was detected early before the onset of proteinuria and continued to increase throughout the course of the disease. The expression of Tmsb10, S100a6 and Anxa2 coincided with heavy proteinuria. By week 9, OPN and Lcn2 were highly expressed. The expression of proteins encoded by these genes was predominant in the glomerular crescent. The protein levels of Sparc, OPN and Lcn2 in urine were significantly elevated. CONCLUSIONS: These findings implicate these six genes in the development of glomerular crescents. More importantly, detection of Sparc, OPN and Lcn2 in urine may mean that these molecules could serve as important biomarkers for non-invasive diagnosis of glomerular crescents.

Autocrine expression of platelet-derived growth factor B in B cell chronic lymphocytic leukemia.

Platelet-derived growth factor (PDGF) regulates clonal proliferation of malignant pre-B cell lines, but little is known about its role in normal B lymphocyte differentiation and malignant transformation. To understand the expression of PDGF-A, PDGF-B and the beta-receptor (PDGF-Rbeta) in B cell lymphoproliferative disorders, we used an immunohistochemical method to stain formalin-fixed, paraffin-embedded tissues in 5 patients with reactive lymphoid hyperplasia, 15 with non-Hodgkin's lymphoma and 23 with B cell chronic lymphocytic leukemia (B-CLL). Abundant PDGF-A, rather than PDGF-B, was expressed in normal B cell differentiation. There was no difference in the expression of PDGF-A and PDGF-B between patients with reactive lymphoid hyperplasia and patients with malignant lymphoproliferative disorders. Among the patients with B-CLL, the expression of PDGF-B was much stronger than the expression of PDGF-A, and 18 of the patients had coexpression of PDGF-B and PDGF-Rbeta. A larger proportion of patients with B-CLL than with non-Hodgkin's lymphoma had expression of PDGF-B and PDGF-Rbeta. In conclusion, PDGF-A expression in all stages of B lymphocyte differentiation suggests that it is important in B cell differentiation and proliferation. Expression of PDGF-B and PDGF-Rbeta suggests that autocrine signaling of PDGF may be important in malignant transformation of B-CLL. However, further studies are necessary to confirm these conclusions.