Nephritogenic antigen determinants in epidermal and renal basement membranes of kindreds with Alport-type familial nephritis.

We probed epidermal basement membranes (EBM) of acid-urea denatured skin from members of kindreds with Alport-type familial nephritis (FN) for the presence of antigens reactive with Goodpasture sera (GPS) and serum (FNS) from an Alport patient who developed anti-glomerular basement membrane (GBM) nephritis in a renal allograft. By immunoblotting, GPS reacted primarily with the 28,000 molecular weight (mol wt) monomer but also the 24,000 mol wt and 26,000 mol wt monomers of the noncollagenous globular domain (NC1) of type IV collagen from normal human GBM, while FNS identified only the 26,000-mol wt monomer. FNS reacted with EBM of 12 controls and nine unaffected male kindred members but not EBM of eight affected males. Five affected females exhibited interrupted reactivity of FNS with EBM. GPS showed variable reactivity with EBM and was not discriminating with respect to Alport-type FN. FNS did not stain renal basement members of five affected males. However, the EBM, tubular basement membrane, and Bowman's capsules of affected males contained antigens reactive with GPS. These immunochemical studies suggest that the FNS antigen is distinct from Goodpasture antigen(s). The expression of FNS antigen located on the NC1 domain of type IV collagen is altered in basement membranes of patients with Alport-type FN, and the distribution of this antigenic anomaly within kindreds suggests X-linked dominant transmission of a defective gene.

Alport familial nephritis. Absence of 28 kilodalton non-collagenous monomers of type IV collagen in glomerular basement membrane.

Alport-type familial nephritis (FN), a genetic disorder, results in progressive renal insufficiency and sensorineural hearing loss. Immunochemical and biochemical analyses of the non-collagenous (NC1) domain of type IV collagen isolated from the glomerular basement membranes (GBM) of three males with this disease demonstrate absence of the normally occurring 28-kilodalton (kD) NC1 monomers, but persistence of the 26- and 24-kD monomeric subunits derived from alpha 1 and 2 (both type IV) collagen chains, respectively.

Comparative distribution of the alpha 1(IV), alpha 5(IV), and alpha 6(IV) collagen chains in normal human adult and fetal tissues and in kidneys from X-linked Alport syndrome patients.

We have shown previously that the 5' ends of the genes for the alpha 5(IV) and alpha 6(IV) collagen chains lie head-to-head on Xq22 and are deleted in patients with Alport syndrome (AS)-associated diffuse leiomyomatosis. In this study, we raised a rabbit anti-human alpha 6(IV)chain antibody, demonstrated its specificity by the analysis of recombinant NC1 domains af all six type IV chains, and studied the distribution of the alpha 6(IV) chain in relation to the alpha 1(IV) and alpha 5(IV) chains in human adult and fetal tissues involved in AS and diffuse leiomyomatosis. The alpha 6(IV) chain colocalizes with the alpha 5(IV) chain in basement membranes (BMs) of many tissues, but not in glomerular BM. These data exclude the alpha 6(IV) chain as a site for AS mutations. The head-to-head genomic pairing of the alpha 5(IV) and alpha 6 (IV) genes implies coordinate transcription of the two genes. Differential localization of the alpha 5(IV) and alpha 6(IV) chains shows that the two chains are not always coordinately regulated. The alpha 6(IV) chain, together with the alpha 3(IV)-alpha 5(IV) chains, was absent from all renal BMs in eight patients with X-linked AS while the alpha 1(IV) and alpha 2(IV) chains were increased. The data support the existence of two independent collagen networks, one for the alpha 3(IV)-alpha 6(IV) chains and one for the alpha 1(IV) and alpha 2(IV) chains.

Expression of mRNA for type IV collagen alpha1, alpha5 and alpha6 chains by cultured dermal fibroblasts from patients with X-linked Alport syndrome.

COL4A5 mutations causing X-linked Alport syndrome (XLAS) are frequently associated with absence of the alpha3, alpha4,alpha5 and alpha6 chains of type IV collagen from basement membranes and increased amounts of the alpha1(IV) and alpha2(IV) chains in glomerular basement membrane. Although many COL4A5 mutations have been described in XLAS, the mechanisms by which these mutations influence the basement membrane appearance of chains other than alpha5(IV) remain poorly understood. In this study, we used dermal fibroblasts from eight normal individuals and nine males with XLAS to test the hypotheses that COL4A5 mutations increase transcription of COL4A1 and suppress transcription of COL4A6. Ribonuclease protection assays revealed that alpha1(IV), alpha5(IV) and alpha6(IV) transcripts were expressed in cultures of dermal fibroblasts. The mRNA levels for alpha1(IV) in eight of nine patients with XLAS were not increased compared to controls; one patient with a large COL4A5 deletion showed significant elevation of alpha1(IV) mRNA levels. No differences in steady-state mRNA levels for alpha6(IV) were found when XLAS fibroblasts were compared with controls, even though little or no alpha6(IV) protein was detectable at the dermal-epidermal junction by immunofluorescence study. This finding suggests that post-transcriptional events account for the absence of alpha6(IV) in the Alport dermal-epidermal junction.

Alport syndrome. An inherited disorder of renal, ocular, and cochlear basement membranes.

Alport syndrome (AS) is a genetically heterogeneous disease arising from mutations in genes coding for basement membrane type IV collagen. About 80% of AS is X-linked, due to mutations in COL4A5, the gene encoding the alpha 5 chain of type IV collagen (alpha 5[IV]). A subtype of X-linked Alport syndrome (XLAS) in which diffuse leiomyomatosis is an associated feature reflects deletion mutations involving the adjacent COL4A5 and COL4A6 genes. Most other patients have autosomal recessive Alport syndrome (ARAS) due to mutations in COL4A3 or COL4A4, which encode the alpha 3(IV) and alpha 4(IV) chains, respectively. Autosomal dominant AS has been mapped to chromosome 2 in the region of COL4A3 and COL4A4. The features of AS reflect derangements of basement membrane structure and function resulting from changes in type IV collagen expression. The primary pathologic event appears to be the loss from basement membranes of a type IV collagen network composed of alpha 3, alpha 4, and alpha 5(IV) chains. While this network is not critical for normal glomerulogenesis, its absence appears to provoke the overexpression of other extracellular matrix proteins, such as the alpha 1 and alpha 2(IV) chains, in glomerular basement membranes, leading to glomerulosclerosis. The diagnosis of AS still relies heavily on histologic studies, although routine application of molecular genetic diagnosis will probably be available in the future. Absence of epidermal basement membrane expression of alpha 5(IV) is diagnostic of XLAS, so in some cases kidney biopsy may not be necessary for diagnosis. Analysis of renal expression of alpha 3(IV)-alpha 5(IV) chains may be a useful adjunct to routine renal biopsy studies, especially when ultrastructural changes in the GBM are ambiguous. There are no specific therapies for AS. Spontaneous and engineered animal models are being used to study genetic and pharmacologic therapies. Renal transplantation for AS is usually very successful. Occasional patients develop anti-GBM nephritis of the allograft, almost always resulting in graft loss.

Chronic renal allograft rejection in the first 6 months posttransplant.

Between May 1, 1986 and May 31, 1992 at the University of Minnesota, we interpreted 129 renal allograft biopsy specimens (done in 48 grafts during the first 6 months posttransplant) as showing changes consistent with chronic rejection. For this retrospective analysis, we reexamined these biopsies together with clinical information to determine: (a) whether a diagnosis other than chronic rejection would have been more appropriate, (b) how early posttransplant any chronic rejection changes occurred, and (c) if the diagnosis correlated with outcome. We found that (1) chronic rejection is uncommon in the first 6 months posttransplant; it was documented in only 27 (2.4%) of 1117 renal allografts and was preceded by acute rejection in all but 3 recipients (for these 3, the first biopsy specimen showed both acute and chronic rejection). (2) Chronic vascular rejection was seen in 1 recipient as early as 1 month posttransplant; the incidence increased over time and was associated with an actual graft survival rate of only 35%. (3) The most frequent cause of arterial intimal fibrosis in the first 6 months posttransplant was arteriosclerotic nephrosclerosis (ASNS) of donor origin. Long-term graft function for recipients with ASNS was 67%. (4) Early-onset ischemia or thrombosis was seen in 14 recipients and predicted poor outcome: only 35.7% of these recipients had long-term graft function. (5) Cyclosporine (CsA) toxicity was implicated in only 3 recipients, who had mild diffuse interstitial fibrosis in association with elevated CsA levels. Other variables (including systemic hypertension, urinary tract infection, obstructive uropathy, neurogenic bladder, cobalt therapy, and recurrent disease) were not significantly associated with chronic renal lesions in the first 6 months posttransplant. A significant number of biopsies were originally interpreted as showing chronic rejection, but the diagnosis was changed upon reevaluation in conjunction with clinical data. We conclude that many factors coexist to produce chronic lesions in biopsies during the first 6 months posttransplant, so clinical correlation is needed before establishing a diagnosis of chronic rejection.

Recurrence of disease in patients retransplanted for focal segmental glomerulosclerosis.

The natural history of focal segmental glomerulosclerosis in patients retransplanted after loss of a primary allograft is not well established. We studied 14 patients with FSGS who were retransplanted between April 1964 and September 1990 to determine if recurrence in a second or subsequent allograft could be predicted. In this group, 8 of the primary allografts were lost to recurrent disease and 6 to rejection. None of the 6 patients who lost their primary allograft to rejection without evidence of recurrent FSGS suffered recurrent disease after retransplantation. In contrast, 3 of the 8 patients who lost their primary allograft rapidly to FSGS suffered recurrent disease and loss of function in all subsequent allografts. The remaining 5 patients had prolonged function of the primary allograft ranging between 4 and 10.5 years, despite recurrence of FSGS. Of these 5 patients, 2 have excellent renal function after retransplantation without recurrence of FSGS in the secondary allograft at 9 and 10.5 years posttransplant; 2 have lost their secondary allograft to recurrent FSGS, but are free of recurrence in the third allograft at 0.5 and 5.8 years postoperatively; 1 maintains a serum creatinine level of 1.9 mg% despite recurrence of FSGS in the secondary allograft at 1 year postoperatively. Our data show that, without recurrence of FSGS in the primary allograft, further renal transplants will be free of recurrent disease. Based on this finding, we advocate use of living-related donors for second transplants in these patients. With rapid recurrence of FSGS and subsequent accelerated loss of the primary allograft, further renal transplants carry a high likelihood of recurrent FSGS and graft loss. A substantial proportion of patients with recurrent FSGS in the primary allograft will have prolonged renal function, and are likely to have excellent results with subsequent allografts.

Pediatric renal transplants--results with sequential immunosuppression.

Cyclosporine has improved the results of renal transplantation. In 1984, we began using it as part of a sequential immunosuppression protocol (MALG, AZA, P, and delayed administration of CsA) in our pediatric renal transplant recipients. We studied the outcome of the 131 pediatric renal transplants (less than or equal to 18 years of age at transplant) performed at our institution between June 1984 and March 1991. We compared these results with the 144 similar transplants performed since January 1980 that did not involve CsA immunosuppression. In the sequential immunosuppression group, there were 97 primary (74%) (26 [27%] cadaver, 71 [73%] living donor [LD]) and 34 (26%) retransplant (23 [68%] CAD, 11 [32%]) recipients. Age at transplant (mean +/- SD) was 7.4 +/- 5.5. Overall, 1-year actuarial graft survival was 93%; 1-year patient survival was 100%. The mean number of hospital readmissions was 3.0 +/- 3.5; 26 (20%) were readmission-free. The mean number of rejection episodes was .87 +/- 1.3 per patient; 73 (56%) were rejection-free. Importantly, LD (vs. CAD) recipients had fewer rejection episodes (P = 0.06). In the first post-transplant year, the serum creatinine level was significantly lower in primary (vs. retransplant) recipients and in LD (vs. CAD) recipients (P less than 0.05). In the 144 patients not receiving CsA, there were 129 (90%) primary (27 CAD, 102 LD) and 15 (10%) retransplant (7 CAD, 8 LD) recipients. Age at transplant was 6.9 +/- 5.3 years. The 1-year actuarial graft survival rate was 82%; the 1-year patient survival rate was 94%. The mean number of hospital readmissions was 3.3 +/- 2.3; 5 (8%) were readmission-free. The mean number of rejection episodes was 1.2 +/- 1.5; 27 (45%) were rejection-free. There was no difference in the serum creatinine level based on donor source or transplant number. Sequential immunosuppression has significantly improved patient (P = 0.003) and graft survival (P = 0.004) rates. Comparing sequential vs. non-CsA immunosuppression, there was no difference in the number of readmissions (P = 0.47), number of rejection episodes (P = 0.17), or serum creatinine level. The number of rejection-free patients was significantly lower in LD (vs. CAD) recipients (P less than 0.05). There was no evidence of progressive deterioration in renal function in the sequential (vs. non-CsA) recipients.

Long-term quality of life after kidney transplantation in childhood.

Transplantation is the treatment of choice for children with end-stage renal disease. However, the long-term quality of life and socioprofessional outcome for those with successful transplants have not previously been reported. We studied these factors in patients transplanted when less than 18 years old who currently have greater than or equal to 10 years of graft function. A total of 57 questionnaires were sent out; 57 (100%) responded [24 female and 33 male patients; average (+/- SD) age at tx = 10 +/- 5 years (0.9-17.7); average f/u = 15.6 +/- 3 years (10-26); current age = 26 +/- 5 years (12-38); 26 had greater than 1 transplant]. Of the 57 respondents, 9 are less than 18 (all are in school); 48 are greater than or equal to 18 (7 in school, 37 employed, 4 unemployed); 12 are married, 1 engaged, and 2 divorced; and 9 have children. While in school, 43 (75%) had participated in sports, 37 (65%) in other extracurricular activities; 7 (12%) were A and 33 (58%) B students; 15 (26%) received awards or scholarships. For those working, the range of occupations is broad (average work week = 41 +/- 5 hr). Health-related absence from work has been nonexistent for 93%. Health is rated as good to excellent by 91% and fair by 9%. The future is regarded as hopeful or promising by 80%. Similarly, 89% are satisfied with life in general; 95% said health never or seldom interferes with family life; 95% feel health and drug side effects are of no or minor concern in sexual relationships. Only 3% feel health is a problem in maintaining a sexual relationship (41% are not sexually active). Only 4% stated that health often interferes with social life; 98% meet with friends on a regular basis; 76% are satisfied with personal relationships and 8% dissatisfied; 91% are satisfied with their ability to perform at work or school and 5% dissatisfied. Of note, 32% are dissatisfied with body appearance. Major concerns are short stature and brittle bones. Major suggestions include education/support groups to deal with teasing at school and peer problems. We conclude that transplanted children with long-term graft function have a favorable social and professional outcome. Overall, quality of life seems excellent.

Influenza B virus infection in pediatric solid organ transplant recipients.

OBJECTIVE: Influenza B virus causes epidemic infection in normal children, but only one case of infection in an immunocompromised solid organ transplant (SOT) recipient has been reported. Characterization of the clinical course of influenza B virus infection in pediatric SOT recipients may increase the utilization of preventive and therapeutic interventions by pediatricians caring for these immunocompromised children. DESIGN: Retrospective chart review of patients whose respiratory viral cultures yielded influenza B from January 1989 through March 1992. PATIENTS: Twelve pediatric SOT recipients with influenza B virus infection were identified. These included five renal, four hepatic, and three cardiac allograft recipients, ranging from 19 months to 17 years 9 months of age (median 6 years 2 months). The posttransplant interval ranged from 6 weeks to 4 years 6 months (average 26.7 months). No patient had been immunized against influenza. Exposure histories were documented for eight children; five of these occurred in the hospital. RESULTS: Clinical symptoms included fever (12/12), respiratory (11/12), or gastrointestinal complaints (8/12). Five patients had neurologic involvement; one died of uncal herniation. Ten children were hospitalized (median duration, 3 days; range, 2 to 79 days). Two patients (post-transplant interval, 3 to 8 months) required mechanical ventilation, and one of these received aerosolized ribavirin. Three children had concurrent allograft rejection. CONCLUSIONS: Influenza B infection is potentially life-threatening in pediatric SOT recipients. We recommend annual immunization of pediatric SOT recipients, their household contacts, and health care workers. Prospective studies are needed to evaluate the efficacy of influenza vaccination in pediatric SOT recipients.

Aortic dissection in young patients with chronic hypertension.

We describe four patients aged 14 to 21 years who developed acute aortic dissection. In three of the four patients, the course was fatal, despite aggressive medical and surgical intervention. All four patients had sustained systemic hypertension related to chronic renal insufficiency. The patients had no other identifiable risk factors for aortic dissection, including congenital cardiovascular disease, advanced atherosclerosis, vasculitis, trauma, pregnancy, or family history of aortic dissection. Although aortic dissection is rare in individuals younger than 40 years of age, young patients with sustained systemic hypertension are at increased risk for this serious and often fatal condition. Physicians must be aware of this rare complication of hypertension and consider aortic dissection in the differential diagnosis of unusual chest, abdominal, and back pain in hypertensive children, adolescents, and young adults.

Autosomal dominant optic nerve colobomas, vesicoureteral reflux, and renal anomalies.

We describe a father and 3 sons with optic nerve colobomas, vesicoureteral reflux, and renal anomalies. The youngest son had congenital renal failure and ultimately underwent renal transplantation. The father and one son had high frequency hearing loss. There were no other affected relatives. We conclude that the association of optic nerve colobomas, renal anomalies, and vesicoureteral reflux comprises a unique autosomal dominant syndrome. Molecular investigations have determined this disorder to be associated with a single nucleotide deletion in the PAX2 gene.

Glomerular disease.

This review focuses on recent insights into the genetics and pathogenesis of several inherited glomerular diseases. Investigation of these disorders has resulted in the identification of proteins that play important roles in glomerular development, structure, and function.

The genetic basis of pediatric renal disease.

The goals of this brief review are to provide current information on the pathogenesis of important genetic renal diseases that present in childhood and to discuss the impact of these fresh insights on the diagnosis of these conditions. Space limitations preclude detailed consideration of each disorder.

X-linked Alport syndrome in females.

Alport syndrome (AS) is in the differential diagnosis of hematuria. Variability in clinical presentation and in the ultrastructural changes of the glomerulus can make the diagnosis of AS a challenge in female patients. The purpose of this report is to present immunostaining for glomerular basement membrane (GBM) expression of alpha5(IV) as an adjunctive diagnostic method. Renal biopsy specimens from eight female patients with clinical presentation suggestive of AS were studied. The patients were between 7 and 36 years of age; six were between 12 and 15 years. Light microscopy and immunohistochemistry using a monoclonal antibody to alpha5(IV) were performed. Controls showed a continuous linear pattern along the GBM in normal kidneys and absence in renal biopsy specimens from male X-linked AS patients. To express the variability of the ultrastructural GBM changes among the patients in the series, we developed a semi-quantitative Alport Index, obtained by quantification of severity and extent of ultrastructural GBM changes. With immunohistochemistry, we showed an interrupted, discontinuous linear pattern for alpha5(IV) in glomeruli from the eight patients in the series, confirming the diagnosis of X-linked AS. The ultrastructural Alport Index varied between 6 and 47, showing the heterogeneity in the severity of the GBM changes, even among the six patients aged between 12 and 15 years. In three of the eight biopsy specimens, the predominant change was thin GBM, and the Alport Index was below 20. Immunohistochemistry for alpha5(IV) in renal biopsy specimens can identify female patients heterozygous for X-linked AS. In this series, the method led to the diagnosis of AS in female patients in whom the predominant ultrastructural change was thin basement membrane.

Outcome of dialysis for acute renal failure in pediatric bone marrow transplant patients.

We have reviewed the clinical course of 30 pediatric bone marrow transplant (BMT) recipients requiring dialysis for acute renal failure early after BMT. Patients requiring dialysis were not significantly different from the general pediatric BMT population except for: (1) a greater proportion of neuroblastoma patients in the dialysis group, and (2) fewer autologous and more unrelated BMT donors in the dialysis group. Twenty-three patients (77%) died without recovering renal function 1-72 days (mean 12 days) after dialysis was begun. Sepsis was the most commonly cited cause of renal failure and death in these patients. Seven patients (23%) recovered sufficient renal function to stop dialysis; all long-term survivors were in this group. Factors at the onset of dialysis associated with persistent renal failure were weight gain of > or = 10% of baseline body weight, requirement of three or more drugs for blood pressure support and hyperbilirubinemia. Although acute renal failure requiring dialysis is an ominous development following BMT, recovery of renal function is possible with aggressive supportive care.

The central role of nuclear factor-kappa B in mesangial cell activation.

BACKGROUND: Nuclear factor-kappa B (NF-kappa B) is a family of transcription factors that is recognized by the kappa B enhancer element. Numerous proinflammatory genes have binding sites for NF-kappa B, and the products of these genes are an integral part of cellular activation and inflammatory response systems. Because there is a close relationship between NF-kappa B and mediators of cell activation, it is possible that a disruption of NF-kappa B-activating pathways may effectively influence mesangial cell activation. METHODS: We reviewed available studies related to both NF-kappa B and mesangial cells in order to provide evidence for the role of NF-kappa B in mesangial cell activation. RESULTS: Studies reported by this laboratory and others showed that various experimental maneuvers that modulate NF-kappa B activation result in a parallel modulation of proinflammatory molecule production in cultured mesangial cells. Likewise, the ability of the inhibitors of NF-kappa B activation to down-regulate the inflammatory response in animal models of renal disease has been recently demonstrated. CONCLUSIONS: These data suggest a pivotal role of NF-kappa B in mesangial cell activation and designate it as an obvious target for the modulation of this activation. Studies are necessary to characterize the role of NF-kappa B in human renal injury.

Recipient evaluation, preparation, and care in pediatric transplantation: the University of Minnesota protocols.

At the University of Minnesota, outcome of renal transplants for infants and young children is the same as outcome for older children and adults. We reviewed our decision-making process in the pre-, peri-, and postoperative care of these recipients.

Long-term follow-up of patients with steroid-dependent, minimal change nephrotic syndrome.

A subgroup of patients with steroid-responsive minimal change nephrotic syndrome (MCNS) is classified as steroid-dependent because of repeated relapses of proteinuria during prednisone taper, or within four weeks of withdrawal of prednisone. The long-term outcome of this subgroup of patients has not been documented. Thirteen patients with onset of steroid-dependent MCNS (biopsy-proven) in childhood have been followed for 10-22 years (mean 15.6 years); 8 patients have been in stable remission for 2-13 years (mean 5.5 years); 3 remain steroid-dependent 12, 18 and 22 years after onset; and 2 had steroid-responsive relapses after 5 and 8 years of remission. In 3 patients steroid-dependent MCNS remitted without cytotoxic therapy 7-11 years after onset. Cyclophosphamide was administered to the remaining 10 patients: 8 had prolonged remissions (1.1-13 years, mean 4.3 years) and 2 relapsed shortly after cyclophosphamide therapy. Of the 8 patients who had prolonged remissions after cyclophosphamide, 3 have had no relapses 5-13 years after therapy. In 5 of these 8 patients steroid-dependency recurred 1.1-3 years after cyclophosphamide and a second course was given, resulting in remissions of 1.4-8 years in 3 patients, change to a frequently relapsing pattern in 1 patient and remission of 3 months in one patient who then became steroid-dependent again. We conclude that the long-term outcome of steroid-dependent MCNS is favorable. Cyclophosphamide is useful in the management of these patients and a prolonged course of alternate-day prednisone therapy after cyclophosphamide may be helpful in maintaining remission.

Dense intramembranous deposit disease: a clinical comparison of histological subtypes.

The accumulation of osmiophilic dense deposits in glomerular mesangial and basement membranes (dense intramembranous deposit disease, or DIDD) is associated with variable histologic alterations of the kidneys. We compared clinical features and long-term renal outcome in 21 patients representing two histologic subtypes of DIDD, namely membranoproliferative glomerulonephritis (MPGN) and focal segmental glomerulonephritis (FSGN). We found that MPGN-type DIDD in 12 patients was associated with nephrotic syndrome in 12, persistent hypocomplementemia in 10 and progression to chronic renal insufficiency in 8. In 9 patients with the focal segmental variety of DIDD, nephrotic syndrome was observed in 3, persistent hypocomplementemia in none, and progression to renal insufficiency in 2 (significance: nephrotic syndrome, p = 0.001; persistent hypocomplementemia, p = 0.0001; chronic renal insufficiency, p = 0.02). In one patient transition from focal segmental to MPGN-type DIDD was observed. We conclude that DIDD is a heterogeneous disorder, and that certain clinical and histologic features may be useful in predicting ultimate outcome.