We report a case of IgA kappa light chain deposition disease and combined adult Fanconi syndrome with Auer rod-like intracytoplasmic inclusions in plasma cells and proximal renal tubular cells in a 54-yr-old female. Cytochemical stainings revealed a strong acid phosphatase activity of the inclusions and weak periodic acid-Schiff positivity, whereas the reactions for peroxidase and alpha-naphthyl acetate esterase were negative. An immunostaining verified IgA-kappa inside the plasma cells. Kidney biopsy revealed Bence Jones cast nephropathy with kappa light chain positivity, and Congo red staining was negative. Electron microscopy showed needle-shaped crystals located in tubular epithelial cells.
Fanconi Syndrome/diagnosis/etiology/*pathology ; Female ; Humans ; *Immunoglobulin A/analysis ; Immunoglobulin kappa-Chains/analysis ; Inclusion Bodies/*ultrastructure ; Kidney Tubules, Proximal/pathology/*ultrastructure ; Middle Aged ; Paraproteinemias/*pathology ; Plasma Cells/pathology/*ultrastructure

No abstract available.
Asymptomatic Diseases ; Biological Markers/analysis ; Biopsy ; Crystallization ; Fluorescent Antibody Technique ; Humans ; Immunoglobulin Light Chains/*analysis ; Kidney Diseases/*diagnosis/immunology/pathology ; Kidney Tubules, Proximal/*immunology/ultrastructure ; Male ; Microscopy, Electron ; Proteinuria/*diagnosis/immunology/pathology

BACKGROUNDIntrarenal activation of the renin angiotensin system (RAS) plays an important role in mediating renal fibrosis. Both angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II (AngII) receptor antagonists have been shown to exert a protective role against diabetic and non-diabetic nephropathy. However, the exact mechanism of how blocking local RAS prevents renal fibrosis is unclear. The present study was to investigate the influence of a new AngII receptor antagonist, irbesartan (Irb), on AngII-induced hypertrophy in human proximal tubular cell line (HK-2).

METHODSThe cell line, HK-2, was grown in Dulbeccos's Modified Eagle's Medium containing 10% heat-inactivated fetal calf serum. After rested in serum-free medium for 24 hours, the effects of Irb on AngII (10(-7) mol/L)-induced [(3)H]-leucine incorporation, total protein content (measured by the Coomassie brilliant blue G250 method), and change in cell size (determined by scanning electron microscopy) were observed. The influence of Irb on the cell cycle was analyzed by fluorescence activated cell sorter (FACS) flow cytometry.

RESULTSAngII induced cell hypertrophy in a time and dose dependent manner. Stimulation of cells with AngII for 48 hours resulted in a increase in [(3)H]-leucine incorporation [0 hour: (5584 +/- 1016) cpm/10(5) cells vs 48 hours: (10741 +/- 802) cpm/10(5) cells, P < 0.05], which was significantly attenuated by treatment with Irb. AngII significantly increased the total protein content in HK-2 cells [control: (0.169 +/- 0.011) mg/10(5) cells vs AngII group: (0.202 +/- 0.010) mg/10(5) cells, P < 0.05], which was also markedly inhibited by cotreatment with Irb (P < 0.01). Scanning electron microscopy showed that AngII induced an increase in average physical cell size, which was significantly inhibited by Irb [control: (11.92 +/- 1.62) microm; AngII group: (20.63 +/- 3.83) micro m; AngII + Irb group: (13.59 +/- 3.15) micro m; P < 0.01 vs control, respectively]. Furthermore, flow cytometry revealed that AngII arrested cells in the G(0)-G(1) phase, which was significantly reversed by treatment with Irb [G(0)-G(1) cells in AngII group: (76.09 +/- 1.82)%, in AngII + Irb group: (67.00 +/- 2.52)%, P < 0.05].

CONCLUSIONIrb can inhibit AngII-induced hypertrophy in HK-2 cells.

Angiotensin II ; pharmacology ; Angiotensin II Type 1 Receptor Blockers ; Biphenyl Compounds ; pharmacology ; Cell Cycle ; drug effects ; Cells, Cultured ; Humans ; Hypertrophy ; Kidney Tubules, Proximal ; drug effects ; pathology ; ultrastructure ; Protein Biosynthesis ; Tetrazoles ; pharmacology