Mesangial cell Fas ligand: upregulation in human lupus nephritis and NF-kappaB-mediated expression in cultured human mesangial cells.

BACKGROUND: Fas ligand (FasL) is a well-known death factor; however, the role of FasL in the regulation of human glomerulonephritis remains unclear. METHODS: We investigated the renal expression and localization of FasL in various forms of human glomerulonephritis by immunohistochemistry, utilizing confocal laser scanning microscopy. We further evaluated cytokine-induced FasL expression via nuclear factor (NF)kappaB in cultured human mesangial cells (HMC). The level of soluble FasL was measured by a specific enzyme-linked immunosorbent assay (ELISA). RESULTS: The frequency of glomerular FasL-positive cases was higher in lupus nephritis (37.9%) as compared with other forms of glomerulonephritis (8.7%). The glomerular FasL score in proliferative lupus nephritis was significantly higher than that in nonproliferative forms. Patients with a high apoptosis score, severe microhematuria, proteinuria, or decreased renal function had a high FasL score. Double immunolabelling demonstrated that the most prevalent phenotypes of FasL-positive cells were mesangial cells. In cultured HMC, interleukin (IL)1beta, lipopolysaccharide (LPS), or gamma interferon (IFN) upregulated membrane-bound FasL. IL1beta significantly, and LPS or gammaIFN weakly activated NFkappaB, but none of these agents activated NFkappaB/Rel-related nuclear factor of activated T cells (NFATc) or IFN regulatory factor-1. IL1beta-mediated NFkappaB was completely inhibited in the presence of lactacystin, a potent inhibitor of NFkappaB. Lactacystin-mediated inhibition of NFkappaB reduced FasL protein levels. Matrix metalloproteinase (MMP)-7, but not other MMPs (1, 2, 3, 8, or 9), significantly sensitized HMC to release soluble FasL after IL1beta stimulation. CONCLUSIONS: The results suggest that: (1) upregulation of mesangial FasL may contribute to the glomerular inflammation in proliferative lupus nephritis in vivo; (2) proinflammatory cytokines, in particular IL1beta, produced in nephritis can upregulate FasL via the transcription factor NFkappaB in HMC; and (3) MMP-7-mediated release of soluble FasL could control the mesangial inflammation.

Angiocentric immunoproliferative lesions of the lung associated with diffuse renal involvement.

A 62-year-old Japanese man presented with high fever, cough, and sputa. Computed tomography (CT) scan of the chest revealed lung infiltrates with air bronchogram of the right middle lobe and mediastinal lymphadenopathy. Bronchoscopic examination was performed, and Mycobacterium avium complex was detected from bronchoalveolar lavage fluid. Although the administration of clarithromycin and levofloxacin improved the patient's symptoms, the lung infiltrates on chest CT scan gradually worsened. Lung biopsy of segments 4 and 8 by video-assisted thorachoscopy revealed angiocentric and angiodestructive massive lymphoplasmocytic infiltrations with multinucleated giant cells, which were compatible with grade II angiocentric immunoproliferative lesions. The patient was found to have deterioration of renal function, and glomerular filtration rate was 32.6 mL/min. His kidneys were enlarged and showed prominent and diffuse uptake of gallium-67 citrate. Percutaneous renal biopsy revealed massive infiltration of CD4+ mononuclear cells, plasma cells, and eosinophils in the interstitium and destruction of normal structure of tubules. Blood vessels were destroyed and replaced by inflammatory cells. The combination chemotherapy achieved a remission, and the patient has remained free of disease at 2 years after onset of the illness. We recommend the imaging of kidneys for diagnosis and following renal biopsy to evaluate the renal involvement of angiocentric immunoproliferative lesions.