Nephrotic syndrome and immune complex glomerulonephritis associated with chlorpropamide therapy

Understanding the relationship between HCV infection and progression of kidney disease

Hepatitis C virus (HCV) can cause a range of kidney diseases. HCV is the primary cause of mixed cryoglobulinaemia, which leads to cryoglobulinaemic vasculitis and cryoglobulinaemic glomerulonephritis (GN). Patients with acute cryoglobulinaemic vasculitis often exhibit acute kidney disease due to HCV infection, which typically progresses to acute kidney injury (AKI). HCV also increases the risk of chronic kidney disease (CKD) and the likelihood of developing end-stage renal disease (ESRD). Currently, direct-acting antiviral agents (DAAs) can be used to treat kidney disease at different stages. This review focuses on key findings regarding HCV and kidney disease, discusses the impact of DAAs, and highlights the need for further research and treatment.

Drug-induced glomerulopathies

Normal renal function depends upon an intact glomerular apparatus. Many drugs and chemicals are capable of damaging the glomerulus, causing its increased permeability to large molecules. Glomerular lesions are usually responsible for proteinuria and the nephrotic syndrome. This also holds true for the drug-induced glomerulopathies, of which membranous glomerulo-nephritis is the most frequent type of lesion encountered. Apart from this, several cases of different glomerular changes such as focal segmental glomerulosclerosis and crescentic glomerulonephritis have also been reported. The drug-induced glomerulopathies are probably immune mediated. This is, for instance, reflected in the fact that patients with drug-induced nephritic syndrome frequently have the HLA-B8 and DR3 antigens. In depth information is provided for the previously mentioned disorders.

High prevalence and adverse effect of hepatitis C virus infection in type II diabetic-related nephropathy

Over a 4-yr period in the northeast region of Japan (Tohoku), 3643 patients for whom a renal biopsy was available were screened. In addition, 2370 biopsied patients for whom hepatitis C virus (HCV) serology was available were evaluated. The prevalence of HCV infection was investigated in the 2370 biopsied patients. The highest prevalence of HCV infection was found in type II diabetic-related glomerulosclerosis (II-DGS) (24 of 123; 19.5%). At renal biopsy, clinical and laboratory findings and histologic parameters were comparable between the HCV-positive and -negative II-DGS groups. After renal biopsy, the decline of renal function reflected by the slope of reciprocal serum creatinine (1/S(Cr)) was significantly greater in the HCV-positive group than in the HCV-negative group (P = 0.001). The log-rank test performed on the renal survival curves showed a significant difference in the two groups (P = 0.019). According to a multiple linear regression analysis adjusted for the effect of age, gender, BP, HbA1c, urinary protein excretion, and histologic parameters as covariates, urinary protein excretion (P = 0.011), severe arteriolar hyalinosis (P = 0.006), and HCV infection (P < 0.001) were significantly associated with 1/S(Cr) slope. Finally, HCV infection was randomly examined in 545 outpatients and inpatients with type II diabetes mellitus who did not undergo renal biopsy. Of these, 56 patients were positive for HCV antibody (10.3%), and their proteinuria was heavier than in 489 HCV-negative patients (P = 0.001). This study reveals that HCV infection is present at a high rate in type II diabetic-related nephropathy and may have an adverse effect on the progression of the disease.

Renal vascular lesions as a marker of poor prognosis in patients with lupus nephritis. Gruppo Italiano per lo Studio della Nefrite Lupica (GISNEL)

The frequency of renal vascular lesions (RVL) and their relevance in the progression of renal damage were evaluated by the Pathology Group of the "Gruppo Italiano per lo Studio della Nefrite Lupica" (GISNEL). Of 285 patients with lupus nephritis collected from 20 nephrology centers in Italy and classified according to World Health Organization (WHO) criteria, 79 cases (27.7%) with RVL were identified and classified as follows: (1) lupus vasculopathy (n = 27); (2) hemolytic-uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP) malignant hypertension-like lesions (n = 24); (3) vasculitis (n = 8); (4) arterio-arteriosclerosis (n = 20). At the time of renal biopsy, patients with RVL had mean serum creatinine levels significantly higher than patients without RVL (201.8 +/- 195.9 mumol/L [2.2 +/- 2.2 mg/dL] v 108.1 +/- 108.0 mumol/L [1.2 +/- 1.2 mg/dL]; P less than 0.01). Hypertension was more frequent in patients with RVL than in those without (68.4% v 30.5%; P less than 0.01). The probability of kidney survival assessed according to the Kaplan-Meier method at 5 and 10 years was, respectively, 74.3% +/- 5.9% and 58.0% +/- 8.9% in patients with RVL, compared with 89.6% +/- 2.7% and 85.9% +/- 3.7% in patients without RVL. However, the two groups did not differ significantly as regards overall survival, the probability of survival at 5 and 10 years being 86.5% +/- 4.5% and 78.8% +/- 6.6% in patients with RVL and 92.2% +/- 2.2% and 83.3% +/- 4.4% in patients without RVL.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic significance of hypocomplementemia

Hypocomplementemia is an important marker for the presence of IC-mediated disease and can be used to assess disease activity. However, in interpreting the clinical significance of hypocomplementemia, the following must be kept in mind: 1) There are numerous non-immunologic conditions that also can cause hypocomplementemia. Furthermore, some of these conditions can cause a multisystem disease that, along with the hypocomplementemia, can closely resemble an IC-mediated systemic vasculitis. Furthermore, these nonimmunologic conditions that lower serum complement levels can complicate the course of patients with inactive IC-mediated disease, spuriously indicating that the disease is active. The most relevant of these differential diagnostic problems are listed in Table 2. 2) There are a few conditions (for example, pregnancy) that can raise serum complement levels, thereby possibly obscuring the presence of a disorder (such as, active SLE) that is lowering complement levels. 3) There are some conditions that might be expected to lower serum complement levels, because of their effect on protein metabolism, but do not. Nephrotic syndrome, and moderately poor nutrition are examples. All of these factors should be considered when interpreting results of serum complement levels in a given patient.

Nondiabetic renal disease in patients with diabetes mellitus

Renal diseases other than diabetic nephropathy were found in 10 of 122 diabetic patients who underwent renal biopsy between 1960 and 1982. These diseases included lupus glomerulonephritis, acute post-streptococcal glomerulonephritis, membranoproliferative glomerulonephritis (type I), focal glomerulosclerosis, idiopathic membranous nephropathy, and nonspecific immune complex glomerulonephritides. Because some of these disorders can alter the management and prognosis of renal disease in diabetic patients, the appearance of urinary abnormalities or deterioration in renal function inconsistent with the natural history of diabetic nephropathy raises the possibility of a nondiabetic renal disease and should lead to a more detailed evaluation.