Quaternary epitopes of α345(IV) collagen initiate Alport post-transplant anti-GBM nephritis

Multidisciplinary and multidimensional approaches to transplantation in children with rare genetic kidney diseases

In this review, we describe the multidisciplinary, multidimensional care required to optimize outcomes for pediatric transplant recipients with rare genetic kidney diseases. Transplant success, recipient survival, and improvement in quality of life depend on collaboration between patients, families, and a team of specialists with medical, as well as nonmedical expertise. A multidisciplinary transplant team composed of experts from medicine, surgery, nursing, nutrition, social services, transplant coordination, psychology, and pharmacology, is now standard in most transplant centers and is critical to the success of a transplant. In addition to these professionals, other specialists, such as cardiologists, urologists, geneticists, metabolic disease specialists, occupational therapists, case management, child life, chaplain, and palliative care services, have a crucial role to play in the preparation, surgery, and follow-up care, especially when a pediatric patient has a rare genetic disorder leading to renal involvement, and the need for transplantation. In order to describe this multidisciplinary care, we divide the genetic renal diseases into five subgroups-metabolic and tubular disorders, glomerular diseases, congenital anomalies of the kidney and urinary tract, ciliopathies including cystic diseases, and miscellaneous renal conditions; and describe for each, the need for care beyond that provided by the standard transplant team members.

Maternal alloimmune IgG causes anti-glomerular basement membrane disease in perinatal transgenic mice that express human laminin α5

Mammalian immune systems are not mature until well after birth. However, transfer of maternal IgG to the fetus and newborn usually provides immunoprotection from infectious diseases. IgG transfer occurs before birth in humans across the placenta and continues after birth across the intestine in many mammalian species, including rodents. Transfer, which is mediated by the neonatal IgG Fc receptor, occurs by transcytosis across placental syncytiotrophoblasts and intestinal epithelium. Although maternal IgG is generally beneficial, harmful maternal allo- and autoantibodies can also be transferred to the fetus/infant, resulting in serious disease. To test this we generated transgenic mice that widely express human laminin α5 in their basement membranes. When huLAMA5 transgenic males were crossed with wild-type females, there was a maternal anti-human laminin α5 immune response. Maternal IgG alloantibody crossed the yolk sac and post-natal intestine invivo and bound in bright, linear patterns to kidney glomerular basement membranes of transgenic fetuses/neonates but not those of wild-type siblings. By postnatal day 18, most transgenic mice were proteinuric, had glomerular C3 deposits and inflammatory cell infiltrates, thickened and split glomerular basement membranes, and podocyte foot process effacement. Thus, our novel model of perinatal anti-glomerular basement membrane disease may prove useful for studying pediatric glomerulopathies, formation of the fetomaternal interface, and maternal alloimmunization.

Clinicopathological features and outcome of antibody-negative anti-glomerular basement membrane disease

AIM

To explore the clinicopathological characteristics of patients with anti-GBM antibody-negative anti-GBM disease.

METHODS

The clinical and renal pathological findings were retrospectively studied in 19 patients. All patients met the following inclusion criteria: linear GBM IgG deposition on immunofluorescence(IF); and lack of serum anti-GBM antibodies by ELISA and indirect immunofluorescence assay.

RESULTS

There were 17 male and two female patients, with a median age of 36 years (range 15-61 years). Hypertension was present in 68% of cases, nephrotic-range proteinuria (> 3.5 g/24 hours) in 42%, nephrotic syndrome in 37%, microhaematuria in 95%, renal insufficiency in 63% and lung involvement in 16%. On biopsy all patients had linear GBM staining for polyclonal IgG by IF. The dominant IgG subtype was IgG4 or IgG1. By light microscopy, mesangial proliferative GN without crescents was seen in four patients; proliferative GN (mesangial proliferative GN in eight; endocapillary proliferative GN in two; and membranoproliferative GN in two) with crescents (focal in 11; diffuse in one) in 12 patients; and crescentic GN without mesangial or endocapillary proliferative or membranoproliferative changes in three patients. By electron microscopy, six patients showed scarce electron dense deposits in glomeruli and 11 patients had global podocyte effacement. Totally, 10 (53%) patients received immunosuppressive therapy. The median follow-up was 15 months and six (32%) patients progressed to end-stage renal disease.

CONCLUSIONS

Anti-GBM antibody-negative anti-GBM disease was different from classic anti-GBM disease clinically and pathologically. The pathogenesis of the renal injury in these patients has not been elucidated until now and it should be studied and identified further.

Alport syndrome: a rare cause of uraemia

Alport syndrome (AS) is a heterogeneous basement membrane disease characterised by haematuria with progressive hereditary nephritis, high-frequency sensorineural hearing loss (SNHL) and pathognomonic ocular lesions. It is one of the spectra of diseases representing hereditary nephritis, which inevitably leads to end-stage renal disease (ESRD). Microscopic or frank haematuria persistent from childhood constitutes the clinical clue for its early recognition. It occurs as a result of genetically inherited or de novo mutations in type IV collagen genes. The most common mode of inheritance is X-linked and men are more severely affected. We report a case of a young woman, in her fourth decade of life presenting with overt nephropathy, having persistent haematuria associated with SNHL and lenticonus with dot and fleck retinopathy on detailed clinical examination, diagnosed as a previously undetected case of Alport syndrome.