Ehrlichia-induced hemophagocytic lymphohistiocytosis in a pediatric kidney transplant recipient.

BACKGROUND: Kidney transplant patients are susceptible to a variety of infections in the post-transplant period due to the use of immunosuppressant medications. Ehrlichiosis is a rare infection in solid organ transplant recipients with signs and symptoms that mimic rejection and other viral infections. Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal hyperinflammatory syndrome that can be triggered by infections. METHODS: We describe a pediatric kidney transplant recipient who experienced secondary HLH due to ehrlichiosis within the initial post-transplant month. RESULT: Our patient improved after treatment with doxycycline, corticosteroids, and intravenous immunoglobulin (IVIG). CONCLUSION: Clinicians should consider infections such as ehrlichiosis as a potential cause of illness in febrile solid organ transplant recipients in immediate post-transplant period, especially when accompanied by a compatible exposure history.

Complications of Cryptosporidium infection after pediatric liver transplantation: Diarrhea, rejection, and biliary disease.

BACKGROUND: Cryptosporidium enteritis can be devastating in the immunocompromised host. In pediatric liver transplant recipients, infection may be complicated by prolonged carriage of the parasite, rejection, and biliary tree damage and fibrosis. Herein, we report on six patients and their long-term outcomes following cryptosporidiosis. METHODS: We reviewed all cases of cryptosporidiosis in a pediatric liver transplant population over a 17-year period at a single center. Six patients with infection were identified, and their outcomes were analyzed. RESULTS: Infection was associated with significant diarrhea and dehydration in all cases, and led to hospitalization in one-half of patients. Four of the six patients developed biopsy-proven rejection following infection, with three of those patients developing rejection that was recalcitrant to intravenous steroid treatment. Additionally, three patients developed biliary tree abnormalities with similarity to sclerosing cholangitis. In one patient, those biliary changes led to repeated need for biliary drain placement and advancing fibrotic liver allograft changes. CONCLUSIONS: Cryptosporidiosis in pediatric liver transplant recipients may lead to significant complications, including recalcitrant episodes of rejection and detrimental biliary tree changes. We advocate for increased awareness of this cause of diarrheal disease and the allograft injuries that may accompany infection.

Characterizing the frequency of modifiable histological changes observed on surveillance biopsies in pediatric kidney allograft recipients.

BACKGROUND: Rejection is responsible for just under 50% of graft loss in the pediatric kidney transplant population. Early identification and treatment of allograft injury, specifically modifiable pathologies such as subclinical rejection (SCR), calcineurin inhibitor toxicity, and BK virus nephropathy, may improve allograft survival. Protocol surveillance biopsy (SB) currently offers the earliest opportunity for targeted interventions. METHODS: This is a single-center retrospective review of 215 kidney SBs obtained from 2008 to 2016 in 97 pediatric kidney transplant recipients. SBs were obtained at 6, 12, and 24 months post-transplantation. Frequency of abnormal histologic findings, estimated glomerular filtration rate at time of SB, and SB-related complications were recorded. Data were analyzed to investigate possible time trends and the presence of demographic or clinical associations with abnormal histologic findings. RESULTS: Potentially modifiable histologic findings were seen in 38.1% of all SBs. SCR was found with increasing frequency across all time points with an estimated 49% increase in the odds of a SCR finding per additional 6 months post-transplantation (aOR 1.49, 95% CI 1.06-2.09, p = 0.022). Among follow-up biopsies in patients who underwent treatment for SCR, 50% had no SCR and 18.8% showed histologic improvement. The complication rate associated with SB was 1.9% (4/215 SBs) and consisted of only minor complications. CONCLUSIONS: SBs are safe and offer the opportunity to identify and treat modifiable histologic changes in the pediatric kidney transplant population. The performance of SBs for up to 2 years after transplantation can have meaningful clinical impact.

Bone marrow transplant for X-linked protoporphyria with severe hepatic fibrosis.

XLP is an erythroid porphyria that results in variable cutaneous photosensitivity due to accumulation of protoporphyrin. The genetic defect in XLP is mutation of the gene ALAS2, resulting in gain of function for the erythroid enzyme 5-aminolevulinate synthase 2. Previous reports have shown that protoporphyrin-induced liver disease may also occur in XLP, occasionally severe enough to warrant liver transplantation; however, transplantation may be followed by injury to the graft due to continued presence of the underlying metabolic disorder in the bone marrow. We present a case of XLP with severe liver disease successfully treated with HPCT to avoid liver transplantation. The case also demonstrates the feasibility of reduced intensity transplant to provide engraftment sufficient for correction of porphyria and tolerability of reduced intensity conditioning containing TLI in the face of severe liver injury.

Cyclooxygenase-2, prostaglandin E2, and prostanoid receptor EP2 in fluid flow shear stress-mediated injury in the solitary kidney.

Hyperfiltration subjects podocytes to increased tensile stress and fluid flow shear stress (FFSS). We showed a 1.5- to 2.0-fold increase in FFSS in uninephrectomized animals and altered podocyte actin cytoskeleton and increased synthesis of prostaglandin E2 (PGE2) following in vitro application of FFSS. We hypothesized that increased FFSS mediates cellular changes through specific receptors of PGE2. Presently, we studied the effect of FFSS on cultured podocytes and decapsulated isolated glomeruli in vitro, and on solitary kidney in uninephrectomized sv129 mice. In cultured podocytes, FFSS resulted in increased gene and protein expression of cyclooxygenase (COX)-2 but not COX-1, prostanoid receptor EP2 but not EP4, and increased synthesis and secretion of PGE2, which were effectively blocked by indomethacin. Next, we developed a special flow chamber for applying FFSS to isolated glomeruli to determine its effect on an intact glomerular filtration barrier by measuring change in albumin permeability (Palb) in vitro. FFSS caused an increase in Palb that was blocked by indomethacin (P < 0.001). Finally, we show that unilateral nephrectomy in sv129 mice resulted in glomerular hypertrophy (P = 0.006), increased glomerular expression of COX-2 (P < 0.001) and EP2 (P = 0.039), and increased urinary albumin excretion (P = 0.001). Activation of the COX-2-PGE2-EP2 axis appears to be a specific response to FFSS in podocytes and provides a mechanistic basis for alteration in podocyte structure and the glomerular filtration barrier, leading to albuminuria in hyperfiltration-mediated kidney injury. The COX-2-PGE2-EP2 axis is a potential target for developing specific interventions to ameliorate the effects of hyperfiltration-mediated kidney injury in the progression of chronic kidney disease.

Fluid flow shear stress upregulates prostanoid receptor EP2 but not EP4 in murine podocytes.

Podocytes in the glomerular filtration barrier regulate the passage of plasma proteins into urine. Capillary pressure and ultrafiltration impact the structure and function of podocytes. The mechanism of podocyte injury by fluid flow shear stress (FFSS) from hyperfiltration in chronic kidney disease (CKD) is not completely understood. Recently, we demonstrated increased synthesis of prostaglandin E2 in podocytes exposed to FFSS. Here, we determine the effect of FFSS on prostanoid receptors EP1-EP4 in cultured podocytes and in Os/+ mouse kidney, a model of hyperfiltration. Results of RT-PCR, qRT-PCR, immunoblotting and immunofluorescence studies indicate that cultured podocytes express EP1, EP2 and EP4 but not EP3. FFSS resulted in upregulated expression of only EP2 in podocytes. Kidney immunostaining showed significantly increased expression of EP2 in Os/+ mice compared with littermate controls. These novel results suggest that EP2 may be responsible for mediating podocyte injury from hyperfiltration-induced augmented FFSS in CKD.

Parathyroid-hormone-related protein-mediated hypercalcemia in benign congenital mesoblastic nephroma.

Parathyroid hormone-related protein (PTHrP) mediated hypercalcemia of malignancy is rare in children, and even more so in the setting of a benign tumor. We report two infants with PTHrP-mediated hypercalcemia secondary to congenital mesoblastic nephroma and their outcome after removal of the benign tumor. Pre-operatively hypercalcemia was corrected with saline hydration, furosemide, calcitonin and/ or pamidronate. Following resection of the tumor serum PTHrP normalized. Immunohistochemical staining of tumor cells was positive for PTHrP. Post-operatively the infants developed elevated serum parathyroid hormone with low- normal serum Ca and P, and undetectable urinary Ca and P, probably due to their movement into bone. Children needed treatment with calcitriol, Ca and P supplementation for 6-12 weeks until PTH normalized and urinary Ca and P were detected, suggesting bone replenishment. We conclude that benign congenital mesoblastic nephroma can secrete PTHrP that can cause severe hypercalcemia; and following excision one should anticipate the development of a transient modified "hungry bone"-like condition requiring Ca, P and calcitriol therapy for several weeks accompanied by careful monitoring of mineral homeostasis.

Pediatric Ovarian Growing Teratoma Syndrome.

Ovarian immature teratoma is a germ cell tumor that comprises less than 1% of ovarian cancers and is treated with surgical debulking and chemotherapy depending on stage. Growing teratoma syndrome (GTS) is the phenomenon of the growth of mature teratoma elements with normal tumor markers during or following chemotherapy for treatment of a malignant germ cell tumor. These tumors are associated with significant morbidity and mortality due to invasive and compressive growth as well as potential for malignant transformation. Current treatment modality is surgical resection. We discuss a 12-year-old female who presented following resection of a pure ovarian immature teratoma (grade 3, FIGO stage IIIC). Following chemotherapy and resection of a pelvic/liver recurrence demonstrating mature teratoma, she underwent molecular genetics based chemotherapeutic treatment. No standardized management protocol has been established for the treatment of GTS. The effect of chemotherapeutic agents for decreasing the volume of and prevention of expansion is unknown. We review in detail the history, diagnostic algorithm, and previous reported pediatric cases as well as treatment options for pediatric patients with GTS.

Granular cell tumors and congenital granular cell epulis in children: Similar entities.

BACKGROUND/PURPOSE: Granular cell tumor (GCT) is an unusual lesion thought to originate from Schwann cells. Congenital granular cell epulis (CGCE) is a rare fibroma-like lesion arising from the alveolar ridge in newborns. These entities have been described as distinct entities. METHODS: A retrospective review was performed of children with a histopathologic diagnosis of GCT or CGCE from 1991-2014. Data were recorded and analyzed. All values reported as the mean±standard deviation. RESULTS: GCT or CGCE was identified in 41 patients with a mean age of 7.8±6.1years. Thirty-one patients had GCT, and 10 had CGCE. All patients underwent excisional biopsy, except 1 who underwent incisional biopsy only. Fifteen patients had positive margins after excision (12 GCT and 3 CGCE). Only 1 had a local recurrence, and this same patient had multifocal GCT. Only 1 patient had an invasive lesion without recurrence after wide local excision. All patients survived, with a median follow-up of 42.5months (0.2-204.2months). CONCLUSION: In children, both GCT and CGCE exhibit benign behavior, and complete excision does not appear to be mandatory, as recurrence or invasive disease is rare. When invasive features are present, wide local excision should be undertaken.

LPS and PAN-induced podocyte injury in an in vitro model of minimal change disease: changes in TLR profile.

Minimal change disease (MCD), the most common idiopathic nephrotic syndrome in children, is characterized by proteinuria and loss of glomerular visceral epithelial cell (podocyte) ultrastructure. Lipopolysaccharide (LPS) and puromycin aminonucleoside (PAN) are used to study podocyte injury in models of MCD in vivo and in vitro. We hypothesized that LPS and PAN influence components of the innate immune system in podocytes such as the Toll-Like Receptor (TLRs), TLR adapter molecules, and associated cytokines. Our results show that cultured human podocytes constitutively express TLRs 1-6 and TLR-10, but not TLRs 7-9. LPS (25 µg/ml) or PAN (60 µg/ml) caused comparable derangement of the actin cytoskeleton in podocytes. Quantitative RT-PCR analysis show that LPS differentially up-regulated the expression of genes for TLRs (1 > 4 ≥ 2 > 3 > 6 > 5), the adapter molecule, MyD88, and transcription factor NF-κB within one hour. LPS also caused increased levels of IL-6, IL-8 and MCP1 without exerting any effect on TNF-α, IFN-α or TGF-ß1 at 24 h. Immunofluorescence intensity analysis of confocal microscopy images showed that LPS induced a significant increase in nuclear translocation of NF-κB by 6 h. In contrast, PAN-induced only small changes in the expression of TLRs 2-6 that included a persistent increase in TLRs 2 and 5, a transient increase in TLR-4, and a gradual increase in TLRs 3 and 6 between 1 and 6 h. Correspondingly, it did not alter pro-inflammatory cytokine levels in podocytes. However, PAN induced a low but significant increase in NF-κB nuclear translocation within one hour that remained unchanged up to 6 h. In summary, these novel findings show that LPS, a known TLR-4 ligand, induced the gene expression of multiple TLRs with maximum effect on the expression of TLR-1 suggesting a loss of receptor selectivity and induction of receptor interactions in podocytes. A comparable derangement of the podocyte cytoskeleton and significant increase in the nuclear translocation of NF-κB by PAN suggest that disparate but complementary mechanisms may contribute to the development of podocytopathy in MCD.

Patterns of glomerular injury in kidneys infiltrated by lymphoplasmacytic neoplasms.

Glomerular injury may occur as a result of immune dysfunction in patients with remote lymphoplasmacytic neoplasms. Glomerular injury concurrent with direct infiltration of the kidney by lymphoplasmacytic neoplasms has been reported but is not extensively characterized. We identified 18 patients, all presenting with elevated serum creatinine and many with proteinuria, whose renal biopsies showed direct involvement of kidney by a variety of neoplasms, including chronic leukocytic leukemia/small lymphocytic lymphoma (n = 7), diffuse large B-cell lymphoma (n = 6), multiple myeloma (n = 4), or B-cell lymphoblastic lymphoma (n = 1). In 10 cases (55%), there was coexistent glomerular pathology: 5 of these cases, including glomerulonephritis with membranoproliferative glomerulonephritis-like pattern of injury (n = 4) and membranous nephropathy (n = 1), featured deposition of immune complexes; 2 demonstrated deposition of monoclonal immunoglobulin components: λ light chain amyloidosis (n = 1) and light chain deposition disease (n = 1); 2 showed minimal change disease; and, in 1 case, there was focal crescentic pauci-immune-type glomerulonephritis. In addition, 1 biopsy revealed diabetic nephropathy and 3 showed nonspecific ischemic changes. In the remaining 4 cases, there were no significant glomerular abnormalities. In 11 cases (61%), the diagnosis of lymphoproliferative disease was established following the kidney biopsy. Our study indicates that lymphoplasmacytic neoplasms may be first diagnosed in renal biopsies performed for evaluation of renal dysfunction with or without proteinuria. Concurrent glomerular injury may be a direct result of the lymphoplasmacytic disorder through a paraprotein deposition process resulting in amyloid or monoclonal immunoglobulin deposition disease, or may be caused indirectly through immune-mediated mechanisms, as in the cases of glomerulonephritis with membranoproliferative glomerulonephritis-like pattern of injury, membranous nephropathy, and possibly minimal change disease.