Acute renal failure and degenerative tubular lesions associated with in situ formation of adenovirus immune complexes in a patient with allogeneic bone marrow transplantation

Deposition of the Membrane Attack Complex in Healthy and Diseased Human Kidneys

The membrane attack complex-also known as C5b-9-is the end-product of the classical, lectin, and alternative complement pathways. It is thought to play an important role in the pathogenesis of various kidney diseases by causing cellular injury and tissue inflammation, resulting in sclerosis and fibrosis. These deleterious effects are, consequently, targeted in the development of novel therapies that inhibit the formation of C5b-9, such as eculizumab. To clarify how C5b-9 contributes to kidney disease and to predict which patients benefit from such therapy, knowledge on deposition of C5b-9 in the kidney is essential. Because immunohistochemical staining of C5b-9 has not been routinely conducted and never been compared across studies, we provide a review of studies on deposition of C5b-9 in healthy and diseased human kidneys. We describe techniques to stain deposits and compare the occurrence of deposits in healthy kidneys and in a wide spectrum of kidney diseases, including hypertensive nephropathy, diabetic nephropathy, membranous nephropathy, IgA nephropathy, lupus nephritis, C3 glomerulopathy, and thrombotic microangiopathies such as the atypical hemolytic uremic syndrome, vasculitis, interstitial nephritis, acute tubular necrosis, kidney tumors, and rejection of kidney transplants. We summarize how these deposits are related with other histological lesions and clinical characteristics. We evaluate the prognostic relevance of these deposits in the light of possible treatment with complement inhibitors.

Sequential adenovirus infection of type 14 hemorrhagic cystitis and type 35 generalized infection after cord blood transplantation

We report a case of a 29-year-old male patient with a generalized adenovirus (AdV) infection after cord blood transplantation (CBT) for acute myelocytic leukemia with maturation at 2nd complete remission. Before engraftment, hemorrhagic cystitis was caused by AdV, which resulted in hydronephrosis, renal failure, and adenoviremia on day 34. Forced diuresis, hemodialysis, withdrawal of cyclosporin A, and administration of gamma-globulin or vidarabine were not effective and the patient died of pulmonary alveolar hemorrhage on day 67. At autopsy, old inflammatory change only was observed in the bladder section. In the lungs and kidneys, granular deposits in the nucleus and a high copy number of AdV-DNA were observed. Molecular diagnosis using PCR-restriction fragment length polymorphism analysis demonstrated that AdV with the serotype 14 caused the cystitis. However, retrospective genome typing using PCR sequencing revealed the infection of AdV serotype 35 in the kidneys, lungs, and serum. The present case suggested that Adv infection could not be always caused by a single AdV serotype, and suggested that multiple serotype infection was very difficult to treat. It is desired that a consensus regarding the treatment of AdV infections is established.

Neutralized adenovirus-immune complexes can mediate effective gene transfer via an Fc receptor-dependent infection pathway

Neutralization of adenovirus (Ad) by anti-Ad neutralizing antibodies in serum involves formation of Ad-immune complexes that prevent the virus from interacting with target cells. We hypothesized that Ad-immune complexes likely contain viable Ad vectors which, although no longer capable of gaining access to receptors on target cells, may be able to express transgenes in cells bearing Fc receptors for immunoglobulins, i.e., that antibody-based "neutralization" of Ad vectors may be circumvented by the Fc receptor pathway. To test this hypothesis, we expressed the Fcgamma receptor IIA (FcgammaR) in A549 lung epithelial cells or human dermal fibroblasts and evaluated gene transfer in the presence of human neutralizing anti-Ad serum. FcgammaR-expressing cells bound and internalized copious amounts of Ad, with a distinct population of internalized Ad trafficking to the nucleus. The dose-response curves for inhibition of gene transfer revealed that FcgammaR-expressing cells required a more-than-10-fold higher concentration of anti-Ad serum to achieve 50% inhibition of Ad-encoded beta-galactosidase expression compared with non-FcgammaR-expressing cells. The discrepancy between neutralization of Ad during infection of FcgammaR-expressing cells and neutralization of Ad during infection of non-FcgammaR-expressing cells occurred with either heat-inactivated or non-heat-inactivated sera, was blocked by addition of purified Fc domain protein, and did not require the cytoplasmic domain of FcgammaR, suggesting that immune complex internalization proceeded via endocytosis rather than phagocytosis. FcgammaR-mediated infection by Ad-immune complexes did not require expression of the coxsackie virus-Ad receptor (CAR) since similar data were obtained when CAR-deficient human dermal fibroblasts were engineered to express FcgammaR. However, interaction of the Ad penton base with cell surface integrins contributed to the difference in neutralization between FcgammaR-expressing and non-FcgammaR-expressing cells. The data indicate that complexes formed from Ad and anti-Ad neutralizing antibodies, while compromised with respect to infection of non-FcgammaR-expressing target cells, maintain the potential to transfer genes to FcgammaR-expressing cells, with consequent expression of the transgene. The formation of Ad-immune complexes that can target viable virus to antigen-presenting cells may account for the success of Ad-based vaccines administered in the presence of low levels of neutralizing anti-Ad antibody.

Renal function following hematological stem cell transplantation in childhood

Renal function greatly influences mortality rates in the early phase following hematological stem cell transplantation (HSCT) in childhood, as well as the quality of life in long-term survivors. Nevertheless, the number of studies in pediatric populations is limited and some important aspects of kidney function after HSCT have only been elucidated in adults. The incidence of acute renal failure (ARF) immediately after HSCT in pediatric patients is between 25% and 50%, with 5%-10% of children requiring renal replacement therapy. Doubling of serum creatinine is associated with a twofold increase in mortality. However, the need for dialysis leads to a further increase in mortality rates to 80%-90%. Specific renal syndromes appear at different times following HSCT, revealing a similar pattern in children and adult patients. In both children and adults, impaired renal function associated with liver impairment (hepatorenal syndrome) is the most important cause for ARF. Therapeutic approaches have not been able to reduce the frequency or to improve outcome so far. In adults surviving long term, bone marrow transplant (BMT) nephropathy is the most frequent renal complication, although a considerable variation in incidence (up to 70%) has been published, partly due to various definitions and manifestations. Little is known about the long-term outcome of renal function in patients treated with HSCT in childhood. However, chronic renal failure has been reported in 0%-28%, but no end-stage renal failure has been published so far. Tubular function following HSCT is rarely investigated, although its impact on long-term survivors of BMT in childhood might be of some importance, especially for growth and bone metabolism.

Adenovirus infection of a renal allograft

One month after renal transplantation, a 60-year-old man developed acute allograft dysfunction associated with gross hematuria and dysuria. Urinary cytological examination showed viral inclusion-bearing epithelial cells. A renal transplant biopsy specimen showed granulomatous interstitial nephritis, tubular necrosis, and ground glass-like intranuclear viral inclusion bodies in tubular cells caused by an adenovirus (ADV) infection. A reduction in baseline immunosuppressive therapy resulted in rapid normalization of allograft function and ultimately viral clearance. We report this case not only to illustrate an exceptional manifestation of an ADV infection in a renal allograft, but also to highlight the beneficial effect of reduction in immunosuppressive therapy on viral replication and clinical outcome.

P-selectin-dependent macrophage migration into the tubulointerstitium in unilateral ureteral obstruction

BACKGROUND

Interstitial infiltration of macrophages (Mø) is one of the main causal factors for the tubulointerstitial injury. However, precise mechanisms of Mø infiltration into tubulointerstitium have not been fully explored. The purposes of this study were to assess the role of selectins in the acute infiltration of Mø in rats with unilateral ureteral obstruction (UUO) and to evaluate the role of vasa recta, that is, whether they facilitate massive influx of Mø into the interstitium by functioning as specialized vessels.

METHODS

To evaluate the role of selectins in Mø infiltration into tubulointerstitium, the expression of selectins and L-selectin ligands was examined by immunohistochemistry and immunoelectron microscopy. The functional role of P-selectin in vasa recta was studied by Stamper-Woodruff assay, in vivo p-Mø migration assay and in vivo blocking experiments with the monoclonal antibody (mAb) ARP2-4.

RESULTS

Selective expression of P-selectin was detected in vasa recta as early as one hour after UUO, and the expression increased thereafter for 96 hours. In contrast, endothelial expression of L-selectin ligands and E-selectin were not detectable. In the Stamper-Woodruff assay on kidney sections of rats with UUO, the adhesion of isolated rat peritoneal Mø (p-Mø) to vasa recta was significantly inhibited by the mAb ARP2-4 (P-selectin blocker; P < 0.01), but not by mAb ARE-5 (E-selectin blocker) or rLECIg (rat L-selectin chimeric protein). In the in vivo transfer experiments with fluorescein-labeled p-Mø into rats 48 hours after UUO, labeled p-Mø had accumulated around vasa recta at three minutes and had infiltrated predominantly into the outer medulla at 180 minutes. The number of labeled p-Mø was reduced when the rats were pretreated with ARP2-4 (P < 0.01). Finally, ARP2-4 (10 mg/kg), injected 15 minutes before UUO, reduced the number of infiltrated Mø (P < 0.01).

CONCLUSION

The results suggest that vasa recta, which express P-selectin, contribute to massive infiltration of Mø into the interstitium by functioning as specialized post-capillary venules.

Adenovirus infections in adult recipients of blood and marrow transplants

Adenoviruses are increasingly recognized pathogens that affect blood and marrow transplant (BMT) recipients. Experiences with 2889 adult BMT recipients were reviewed to study the incidence, clinical spectrum, risk factors for dissemination, response to therapy, and outcome of adenovirus infections. Eight-five patients (3%) were diagnosed by means of culture (n=85) or culture and histopathological examination (n=6). Nine patients had asymptomatic viruria, and 76 had symptomatic infections, which included upper respiratory tract infection (n=20), enteritis (n=18), hemorrhagic cystitis (n=10), pneumonia (n=15), and disseminated disease (n=13). The overall mortality rate was 26%. A higher mortality rate was observed among patients with pneumonia (73%) and disseminated disease (61%). Risk factors for dissemination included receipt of an allogeneic transplant, presence of graft-versus-host disease (GVHD), and receipt of concurrent immunosuppressive therapy. Intravenous ribavirin was not associated with an appreciable benefit among 12 patients who received this treatment. In conclusion, adenovirus infections are an important cause of morbidity and mortality in adult BMT recipients, particularly allogeneic transplant recipients with GVHD who are receiving immunosuppressive therapy. The need for an effective, nontoxic antiviral therapy is apparent.

Hematopoietic cell transplantation-related nephropathy in Japan

To clarify the incidence and characteristics of hematopoietic cell transplantation (HCT)-related nephropathy (HCT-N) in Japan, we sent questionnaire letters to 188 hematologic divisions of 91 hospitals and analyzed the responses. Of 2,136 Japanese hematopoietic cell transplant recipients, 51 patients (2.4%) had HCT-N. The early-onset (</=30 days after HCT), middle-onset (31 to 120 days after HCT), and late-onset (>180 days after HCT) groups included 20, 16, and 15 patients, respectively. The early-onset group mainly consisted of patients with acute renal failure (ARF) and hemolytic uremic syndrome and/or thrombotic thrombocytopenic purpura. ARF was the dominant type in the middle-onset group. The main phenotype of the late-onset group was nephrotic syndrome, which correlated with chronic graft-versus-host disease (P=0.008). The total amounts of irradiation for patients with chronic renal failure and urinary abnormality were significantly greater than those for patients with ARF (P=0.004). The survival rate of the early-onset and middle-onset groups was 47.2%, whereas 87% of patients in the late-onset group survived (P=0.002). HCT-N is expected to become a serious and important problem in Japan because of the increasing number of HCTs from unrelated donors.

Adenovirus infection of the renal allograft with sparing of pancreas graft function in the recipient of a combined kidney-pancreas transplant

We report a case of adenovirus infection of the renal allograft in a combined kidney/pancreas transplant recipient. The clinical presentation was renal allograft failure, which eventually reversed. The pancreatic graft function remained stable. A renal biopsy showed massive tubular necrosis associated with a prominent granulomatous reaction. The process had a striking regional distribution within the kidney with the injury and inflammation limited to the outer medulla. Adenovirus type 11 was isolated from renal tissue by culture, and adenovirus was demonstrated by immunofluorescence and electron microscopy in the kidney biopsy. Immunosuppression may result in unusual patterns of response to infectious agents. This case demonstrated tropism of the adenovirus to only selected tubules within the kidney, with sparing of other organ function including, specifically, the pancreas allograft. The differential diagnosis of a granulomatous reaction in the transplant kidney must be expanded to include viral infection, in particular, adenovirus.

Cytokines in adenoviral disease in children: association of interleukin-6, interleukin-8, and tumor necrosis factor alpha levels with clinical outcome

To explore the pathogenic mechanisms involved in adenovirus infection, we evaluated total levels of immunoglobulins, antiadenovirus antibodies, adenovirus-specific circulating immune complexes, and cytokines in serum samples obtained from 38 hospitalized children with adenovirus infection. According to their clinical findings and outcome, the infections were classified as follows: (1) moderate (group I, n = 10), (2) severe (group II, n = 12), and (3) fatal (group III, n = 16). About 60% of the children had elevated IgM levels. IgG-containing adenovirus-specific circulating immune complexes were initially detected in 7 of 16 group III patients, 4 of whom had low serum levels of the third component of complement. A decrease in initial antiadenovirus IgG antibodies was observed in 3 of 10 patients in group III. Serum interleukin-6 was not detected in group I (none of 10), but was present in group II (7 of 12, p = 0.016) and group III (13 of 16, p < 0.001). Interleukin-8 was detected in all groups; values in fatal cases were significantly higher than in surviving children. Tumor necrosis factor alpha was not observed in group I (none of 10) and was uncommon in group II (2 of 12) but was frequently detected in group III (9 of 15, p = 0.01). Interleukin-1 and interleukin-4 were rarely detected in serum samples. Increased concentrations of interleukin-6, interleukin-8, and tumor necrosis factor alpha were associated with hypoperfusion, febrile peaks, tonic-clonic seizures, and septic shock. In 5 of 10 patients in groups II and III, autoantibodies specific for smooth muscle were found. Our findings indicate that high serum values for interleukin-6, interleukin-8, and tumor necrosis factor alpha are associated with severity of adenovirus infection.