Are CD34+ cells found in renal interstitial fibrosis?

Background: The CD34 antigen is a marker of precursor myeloid cells and endothelial cells, but also of a subset of spindle cells. Methods: To establish the possible role of CD34+ cells in the progression of glomerulonephritis, 30 renal biopsies were investigated. Immunohistochemistry for CD34 and smooth muscle actin ( SMA) were performed by standard methods. The results were assessed semiquantitatively. The relative interstitial volume ( RIV) was evaluated by the point counting method. Clinical data such as sex, age, serum creatinine and urea levels were taken into account. Results: CD34+ spindle cells and SMA+ myofibroblasts were present in the renal interstitium in all but one case. In membranous, membranoproliferative and segmental- proliferative glomerulonephritis, CD34+ cells were seen in clusters, while in IgA nephropathy and in segmental and focal glomerulosclerosis, single, scattered cells were seen. The density of CD34+ cells showed a positive correlation with the myofibroblast density and the RIV. Serum creatinine and urea levels were associated with the RIV of the kidney and to a smaller degree with the number of myofibroblasts and CD34+ cells. Conclusion: These results show that in glomerulonephritis, CD34+ spindle cells appear in the interstitium. At present, their possible role can only be speculated. Copyright (C) 2003 S. Karger AG, Basel.