Exacerbation of glomerulonephritis in subjects with chronic hepatitis C virus infection after interferon therapy

We previously reported the glomerular deposition of hepatitis C virus (HCV) core antigen (Ag) in HCV-related nephropathy. In this study, we analyzed 23 HCV-positive subjects with exacerbation of proteinuria and/or hematuria during interferon (IFN) therapy and measured urinary protein selectivity. We also examined the involvement of HCV-related Ag using anti-HCV core (capside) Ag murine monoclonal antibody (Ab) and anti-core2 rabbit polyclonal Abs in nine subjects. Of 17 subjects, 13 (78%) showed low selective proteinuria. We found mesangial proliferative glomerulonephritis in 9 subjects, membranoproliferative glomerulonephritis in 1 subject, and nephrosclerosis in 1 subject. Immunofluorescence study showed the glomerular deposition of immunoglobulin G (IgG) or IgA and complements in all 9 subjects examined. Trace amounts only of HCV core Ag were detected along the glomerular capillary wall in 3 of 9 subjects (33%). Electron microscopy showed subendothelial or mesangial electron-dense deposits and also foot process effacement (20% to 72.5% of glomerular capillary walls) in all subjects and endothelial swelling in 4 subjects. In conclusion, IFN therapy for HCV may exacerbate the underlying glomerulopathies, unrelated to HCV Ags, through direct or indirect effects on glomerular endothelial and epithelial cells. Physicians should carefully distinguish HCV-related nephropathy from other glomerular diseases when they administer IFN therapy to HCV-positive subjects.

Eotaxin contributes to renal interstitial eosinophilia

BACKGROUND

A potent eosinophil chemotactic cytokine, human eotaxin, is directly chemotactic for eosinophils. Therefore, the specific expression of eotaxin in tissue might play a crucial role in tissue eosinophilia. However, the precise molecular mechanism of the recruitment and activation of eosinophils in human renal diseases remains to be investigated. We evaluated the role of eotaxin in the pathogenesis of human diffuse interstitial nephritis with marked infiltration of eosinophils.

METHODS

In this study, we examined 20 healthy volunteers. 56 patients with primary or secondary glomerular diseases and two hypereosinophilic syndrome patients without renal involvement. Urinary and serum eotaxin levels were determined by an enzyme-linked immunosorbent assay. We also detected the presence of eotaxin protein immunohistochemically.

RESULTS

On the one hand, urinary levels of eotaxin were significantly higher before the initiation of glucocorticoid administration in the patient with interstitial nephritis with marked infiltration of eosinophils. On the other hand, urinary eotaxin levels were not detected in any patients with nephrotic syndrome, interstitial nephritis without eosinophils, hypereosinophilic syndrome without renal involvement or other renal diseases. Serum eotaxin levels were not detected in any of the patients. Therefore, the detection of eotaxin in the urine was specific for renal interstitial eosinophilia. Moreover, endothelial cells, infiltrating mononuclear cells and renal epithelial cells in the tubulointerstitial lesions were immunostained with specific anti-eotaxin antibodies. Furthermore, the elevated urinary levels of eotaxin decreased dramatically during glucocorticoid-induced convalescence.

HYPOTHESIS

We hypothesize that in situ expression of eotaxin may provide a new mechanism to explain the renal interstitial eosinophil infiltration.

Urinary levels of chemokines (MCAF/MCP-1, IL-8) reflect distinct disease activities and phases of human IgA nephropathy

Leukocytes have been implicated to be involved in the pathogenesis of IgA nephropathy (IgAN). To clarify the precise molecular mechanism of recruitment and activation of leukocytes in the subgroups of IgAN, latent, acute, and chronic types, we studied monocyte chemotactic and activating factor (MCAF/MCP-1) and interleukin (IL)-8 in urines and renal expression of these cytokines. Urinary MCAF levels were significantly higher in chronic type, and were correlated with pathological progressive factors such as mesangial proliferation and interstitial cellular infiltration associated with CD68-positive macrophage. On the other hand, urinary IL-8 elevated only in acute type and were correlated with glomerular endocapillary proliferation and the degree of hematuria. In immunohistochemical study, IL-8 was mainly observed in glomeruli, otherwise MCAF in vascular endothelial cells, tubular epithelial cells, and infiltrated mononuclear cells in the interstitial lesions. These observations demonstrated that MCAF and IL-8 were differentially expressed in kidneys with IgAN, and their subtypes, and suggest that chemokines may be involved in the pathogenesis of IgAN at distinct phases or pathological lesions, possibly through the recruitment and activation of a distinct type of leukocyte.

Expression of multiple alpha1-antitrypsin-like genes in hibernating species of the squirrel family

In the chipmunk, a mammalian hibernator, a 140 kDa protein complex found in the blood, drastically decreases in concentration during hibernation. This complex contains four species of proteins, HP-20, -25, -27 and -55. In the present study, cDNA clones coding for the chipmunk HP-55 were isolated from a liver cDNA library. Sequence analysis revealed that HP-55 is produced as a precursor protein of 413 amino acids (aa), that it has a signal peptide of 24 aa, and that it contains four potential N-glycosylation sites. The deduced aa sequence shows 63% identity with that of rat alpha1-antitrypsin (alpha1-AT); however, the sequence corresponding to the reactive center P1-P1' residues was found to be Met-Leu, whereas it is Met-Ser in the rat alpha1-AT. During screening of the chipmunk liver cDNA library, four other related classes of cDNA clones were obtained, each also coding for an alpha1-AT-like protein. In spite of more than 86% overall aa sequence identity among the five chipmunk alpha1-AT-like proteins, they are highly divergent in the putative reactive center region; the putative P1-P1' sequences are Met-Leu (HP-55 or CM55-ML), Met-Met (CM55-MM), Met-Ser (CM55-MS), Ser-Ile (CM55-SI) and Ser-Thr (CM55-ST). Each of the alpha1-AT-like protein mRNAs was expressed in chipmunk liver, and the HP-55 mRNA level was greatly reduced during hibernation. Genomic Southern blot analysis and screening of a liver cDNA library from another hibernating squirrel species, the ground squirrel, also revealed expression of multiple members of the alpha1-AT gene family, whereas analysis of a cDNA library from a non-hibernating species, the tree squirrel, found only a single alpha1-AT gene.

In situ expression and soluble form of P-selectin in human glomerulonephritis

To clarify the early involvement of cellular adhesion molecules in human glomerulonephritis, we investigated P-selectin and high endothelial venules' (HEVs) marker MECA-79 expression in kidney specimens by immunohistochemical and in situ hybridization analyses, and measured serum and urinary soluble P-selectin levels by enzyme-linked immunosorbent assay. In normal controls, P-selectin and MECA-79 expression were negative in glomeruli (N = 4), and serum soluble P-selectin levels were 114.3 +/- 36.8 ng/ml (mean +/- SEM, N = 12). Soluble P-selectin was not detectable in urine of all cases. In proliferative glomerulonephritis involving rapidly progressive glomerulonephritis (N = 6), IgA nephropathy (N = 26), lupus nephritis (N = 7) and acute glomerulonephritis (N = 2), both glomerular and interstitial P-selectin expression were up-regulated. Glomerular P-selectin expression correlated positively with local cellular accumulation, endocapillary proliferation and CD41b (platelet) staining. Interstitial P-selectin expression showed a positive correlation with the grade of local cellular infiltrates. P-selectin mRNA signals detected by in situ hybridization were only observed on capillary or venous endothelium in the interstitium, but not in glomeruli. In addition, MECA-79 was expressed on the plump endothelial cells at the cortico-medullary junction (outer medulla). Serum soluble P-selectin levels were significantly higher in patients with proliferative glomerulonephritis, especially in glomerular and interstitial P-selectin positive staining, and correlated with glomerular endocapillary proliferation. These observations suggested that P-selectin was associated with both glomerular and interstitial leukocyte accumulation in human glomerulonephritis, and might be expressed by two distinct mechanisms that are the activated platelets in glomeruli and the de novo expression in the interstitial lesions that correlated with MECA-79 expression as HEVs like vessels, and serum soluble P-selectin may be a useful marker for predicting in situ P-selectin expression associated with glomerular endocapillary proliferation in nephritis.

A cDNA encoding fish fibroblast growth factor-2, which lacks alternative translation initiation

Here, we describe the isolation of a rainbow trout cDNA clone that contains the entire fibroblast growth factor-2 (FGF-2; basic FGF) coding region. Interestingly, the rainbow trout cDNA contains a translation stop codon just upstream of the primary initiating methionine codon and so cannot give rise to the longer forms of FGF-2 that are produced in mammals by alternative translation initiation at leucines farther upstream. Transfection of human FGF-2 cDNA into fish cells shows that fish cells can initiate protein synthesis at an upstream leucine CUG codon; surprisingly, however, synthesis is initiated only at the most 5' CUG and not at the two subsequent CUG codons or the methionine AUG codon also used in mammalian cells. Like other FGF-2 proteins, bacterially produced rainbow trout FGF-2 protein binds tightly to heparin-Sepharose and also promotes the proliferation of fibroblast cells. However, the protein differs from all others previously identified at amino acids 121-123, which are part of the proposed highly conserved receptor-binding domain. Comparisons of the efficacies of recombinant wild-type and mutant rainbow trout FGF-2 proteins demonstrate that these three amino acids are critical to the activity of FGF-2.

Glomerular ICAM-1 expression related to circulating TNF-alpha in human glomerulonephritis

To clarify the in vivo involvement of cellular adhesion molecules and cytokines in human glomerulonephritis, we have investigated the glomerular and interstitial expression of intercellular adhesion molecule 1 (ICAM-1) in 69 kidney biopsy specimens by immunohistochemical methods and its correlation with serum bioactive tumor necrosis factor alpha (TNF-alpha) and soluble ICAM-1 (sICAM-1) levels in 43 cases. In normal controls, glomerular ICAM-1 expression and serum TNF-alpha and sICAM-1 levels showed a mean score of 1.0 (n = 7) and were 12.1 +/- 1.5 and 187 +/- 5 ng/ml (mean +/- SEM, n = 25), respectively. ICAM-1 was positive in 68 kidneys except in 1 patient with membranous nephropathy at various degrees in glomeruli and in 72% of peritubular capillaries or venules in the interstitium. Serum-bioactive TNF-alpha levels increased in the patients with IgA nephropathy, purpura nephritis, and lupus nephritis (LN) (18.9 +/- 4.1, 32.6 +/- 13.3, and 20.9 +/- 3.5 pg/ml) and were positively correlated with the grade of glomerular ICAM-1 expression (n = 43, r = 0.57, p < 0.001), endocapillary proliferation with exudative lesions (r = 0.72, p < 0.001) and hematuria (r = 0.62, p < 0.001). Serum sICAM-1 levels were elevated in patients with LN and purpura nephritis and decreased from 312 +/- 40 to 226 +/- 21 ng/ml after methylprednisolone pulse therapy in LN (n = 9, p = 0.0285). sICAM-1 levels were positively correlated with the grade of interstitial ICAM-1 expression (r = 0.46, p < 0.05), and sICAM-1 levels (>210 ng/ml) showed high odds ratios in the interstitial ICAM-1-positive cases and systemic vasculitides such as purpura nephritis and LN (6.00, p = 0.0355; 6.50, p = 0.0216, respectively). These results suggest that bioactive TNF-alpha might relate to glomerular ICAM-1 expression associated with endocapillary lesions in human glomerulonephritis and that sICAM-1 levels may be used as a clinical marker to assess interstitial lesions in human nephritis and systemic vasculitides.

A method for direct DNA amplification of uncharacterized DNA viruses and for development of a viral polymerase chain reaction assay: application to the red sea bream iridovirus

A method is described for isolating a DNA segment of a virus for which no protein or DNA sequence information is available. This segment can then be used to develop a PCR-based assay for the virus. The method is based on the widespread presence and strong conservation of the ribonucleotide reductase gene among DNA viruses. The validity of the procedure is demonstrated by development of an assay for the fish iridovirus. We report the direct isolation from infected fish of a 738-bp segment of the iridovirus ribonucleotide reductase small subunit gene without prior virus purification. Using the sequence information obtained, a PCR-based diagnostic system was developed for detecting iridovirus infection.

Mother to fry, successful transfer of immunity against infectious haematopoietic necrosis virus infection in rainbow trout

We have tested whether immunity can be transferred from a mother fish to its fry. Rainbow trout mother fish were inoculated against infectious haematopoietic necrosis virus (IHNV) by intraperitoneal injection of a fragment of the IHNV glycoprotein spanning amino acids 31 to 310. This protein fragment was obtained by isolating the specific cDNA from Japanese IHNV strain HV7601 and expressing it in Escherichia coli. Fry from immunized and control fish were exposed to IHNV at various intervals after hatching, and their mortality monitored. Survival of the fry of immunized fish was significantly greater when exposure to virus occurred 7 days after hatching, and some immunity appeared to persist until at least 25 days after hatching.

Fish glucocorticoid receptor with splicing variants in the DNA binding domain

Here we describe the isolation of a rainbow trout cDNA containing an entire GR coding region. Although the encoded protein is highly homologous to other GRs, especially in its DNA binding domain, it contains a nine amino acid insertion between the two zinc fingers. This novel form is found in all rainbow trout tissues examined; however, the testis also contains a splice variant lacking this insert, making it completely continuous to other GRs. In transient transfection assays of cultured cells, the two rainbow trout GR variants activated transcription from the glucocorticoid-responsive mouse mammary tumor virus promoter to comparable levels.

A rare case of arteriosclerosis obliterans without prominent risk factors complicated by idiopathic thrombocytopenic purpura. A case report

An eighty-four-year-old man was admitted to the hospital because of pain at rest in the lower extremities. On physical examination, trophic changes of the skin and petechiae in the limbs were observed. Computed tomographic scan of the abdomen showed focal renal infarctions and calcification of the descending aorta. Moreover, radionuclide imaging of the arterial system revealed complete obstructions of the two right iliac arteries and the left external iliac artery, where collateral flows were observed. Laboratory examination showed a severe thrombocytopenia caused by immunoglobulin G (IgG)-type autoantibody against platelets. He was diagnosed as having arteriosclerosis obliterans complicated by idiopathic thrombocytopenic purpura, although no known risk factors promoting atherosclerosis other than age were evident. In such a case with hemorrhagic diathesis, a hemorheologic agent and the vasodilator prostaglandin could confer advantages in relieving and controlling the ischemic leg pain without hemorrhagic complications. Moreover, small doses of the initial prednisolone therapy for ITP might also be recommended to avoid thrombus formations in the atherosclerotic lesions.

Monitoring urinary levels of monocyte chemotactic and activating factor reflects disease activity of lupus nephritis

Monocytes/macrophages (M phi) have been implicated in the pathogenesis of lupus nephritis (LN), but the precise molecular mechanism of recruitment and activation of M phi in LN remains unclear. To clarify the involvement of chemotactic cytokines (chemokines) in those events, we measured levels of monocyte chemotactic and activating factor (MCAF, also termed monocyte chemoattractant protein-1, MCP-1) in urines and sera derived from 42 patients with LN. Both urinary and serum MCAF levels were significantly higher in patients with LN as compared with 22 healthy volunteers (10.3 +/- 3.2 vs. 1.0 +/- 0.1 pg/ml . creatinine, 212.2 +/- 75.8 vs. 66.1 +/- 15.5 pg/ml, respectively, P < 0.05, mean +/- SEM). Histological examination of renal lesions from 41 patients classified 19 as active according to the WHO-defined classes IIIb, IVb and IVc, and 22 as inactive by the WHO-defined classes I, II, IIIc, IVd and V. Urinary MCAF levels in the patients with active lesions were significantly higher than those with inactive lesions (20.3 +/- 6.4 vs. 1.7 +/- 0.3 pg/ml . creatinine, P < 0.01). Moreover, elevated urinary MCAF levels were dramatically decreased during steroid therapy-induced convalescence in 29 patients examined serially (13.9 +/- 4.5 vs. 5.3 +/- 1.7 pg/ml . creatinine, P < 0.001), whereas serum MCAF levels did not change significantly. Endothelial cells, renal epithelial cells and infiltrating mononuclear cells in the tubulointerstitial regions were MCAF-positive in immunohistochemical as well as in situ hybridization analysis. These observations suggest that MCAF is probably involved in the pathogenesis of LN with active lesions, possibly through the recruitment and activation of M phi, and that measurement of urinary MCAF levels may be a useful clinical tool for monitoring the disease activity of LN.

Steroid pulse therapy in lupus cystitis

A middle-aged woman with lupus cystitis showed no other symptoms of lupus vasculitis. Cystoscopic findings revealed mucosal hemorrhage and hyperemia. Histological studies of the bladder showed mucosal edema, inflammatory cellular infiltration and the deposition of immune complexes along the vessels. She was treated with a combination of intravenous methylprednisolone pulse therapy and oral prednisolone. Cystoscopy and histological findings showed appreciable improvement. Elevated urinary levels of chemokines such as interleukin-8 (IL-8) and monocyte chemotactic and activating factor (MCAF) decreased during convalescence. These results suggest that the early diagnosis and treatment with steroid pulse therapy achieves improvement of an unusual vasculitis symptom, lupus cystitis.