Both IgA nephropathy and alcoholic cirrhosis feature abnormally glycosylated IgA1 and soluble CD89-IgA and IgG-IgA complexes: common mechanisms for distinct diseases.

Abnormalities of IgA arise in alcoholic cirrhosis, including mesangial IgA deposits with possible development of secondary IgA nephropathy (IgAN). Since little is known about circulating immune complexes in cases of secondary IgAN, we analyzed IgA-associated parameters in the serum of 32 patients with compensated or advanced alcoholic cirrhosis. Galactose deficiency and decreased sialylation of IgA1, as well as increased amounts of abnormally glycosylated polymeric IgA1, were detected in the serum of patients with advanced alcoholic cirrhosis. Moreover, aberrant IgA1 formed complexes with IgG and soluble CD89 in serum of patients with advanced alcoholic cirrhosis, similar to those found in primary IgAN. The IgA1 of alcoholic cirrhosis, however, had a modified N-glycosylation, not found in primary IgAN. In patients with alcoholic cirrhosis and IgAN, IgA deposits were associated with CD71 overexpression in mesangial areas, suggesting that CD71 might be involved in deposit formation. Although the IgA1 found in alcoholic cirrhosis bound more extensively to human mesangial cells than control IgA1, they differ from primary IgAN by not inducing mesangial cell proliferation. Thus, abnormally glycosylated IgA1 and soluble CD89-IgA and IgA-IgG complexes, features of primary IgAN, are also present in alcoholic cirrhosis. Hence, common mechanisms appear to be shared by diseases of distinct origins, indicating that common environmental factors may influence the development of IgAN.

The spectrum of renal lesions in patients with cirrhosis: a clinicopathological study.

BACKGROUND/OBJECTIVE: Little is known on the morphological changes in the kidneys of cirrhotic patients with abnormal urinalysis and/or high serum creatinine levels. This retrospective, one-point-in-time study aimed to report the results of the analysis of renal biopsy specimens obtained in patients with cirrhosis. METHODS: We retrieved information on 65 patients who underwent transvenous renal biopsy for proteinuria >0.5 g/day and/or microscopic haematuria and/or unexplained renal impairment (defined by serum creatinine levels >1.5 mg/dl). RESULTS: Fifty-one per cent of the patients had proteinuria >0.5 g/day, 58% had haematuria and 83% had renal impairment. Renal biopsy disclosed injury to glomeruli in 77% of the patients, to vessels in 69% and to the tubulointerstitium system in 94% (chronic in 77%; acute in 75%). Fibrous endarteritis was the most common renal vascular lesion. Injuries to different structures were frequently combined. Isolated glomerular alterations were found in only two patients. Acute tubular necrosis was significantly more common in patients with fibrous endarteritis than in those without. Among 18 patients with renal impairment, proteinuria <0.5 mg/day and no haematuria, 10 had glomerular lesions, 13 had chronic tubulointerstitial lesions and 12 acute tubulointerstitial lesions. CONCLUSION: In patients with cirrhosis, various types of renal injuries are frequently combined. Chronic lesions (vascular or tubulointerstitial) may influence the outcome, in particular in patients who subsequently undergo liver transplantation and receive anticalcineurins. Renal vascular lesions may increase the risk of acute tubular necrosis. In patients with renal impairment, the absence of significant proteinuria and haematuria do not rule out the presence of renal lesions.