Abstract A 1-year-old boy with hemophagocyticlymphohistiocytosis exhibited proteinuria 1 month afterunrelated cord blood cell transplantation, which persistedwithout hematuria. Laboratory study showed an increaseof factor VIII-related antigen and total plasminogen acti-vator inhibitor, suggesting endothelial injury. Histologi-cal examination of autopsy materials showed increasedmesangial matrices and double-contoured basementmembranes, and ultrastructurally, swelling of the endo-thelial cells and widening of the subendothelial spacewith mesangial interposition. Thrombosis was not ob-served at any of the sites. This case may be vasculopathydistinct from thrombotic microangiopathy (TMA) or avariant form of TMA following blood stem cell trans-plantation (BSCT). This vasculopathy should be consid-ered in the differential diagnosis of proteinuria in theearly stages after BSCT.

Keywords Blood stem cell transplantation · Complication · Proteinuria · Vasculopathy

Introduction

Blood stem cell transplantation (BSCT) is a treatment forsome inherited metabolic, hematological, and malignantdiseases. However, this procedure is limited by the com-plications of transplantation, such as graft-versus-hostdisease (GVHD) and infection, with a high mortalityrate. Thrombotic microangiopathy (TMA) is also a se-vere complication of BSCT, which encompasses manyclinical conditions, such as hemolytic-uremic syndromeand thrombotic thrombocytopenic purpura [1, 2]. Severalfactors, including intensive conditioning chemotherapy,irradiation, GVHD, cyclosporin A, and infection, are as-sociated with the development of TMA. Vascular injuryleading to activation of the coagulation system and plate-let aggregation constitute the main pathophysiologicalmechanism of TMA [1, 2]. We here report an unusualpatient, who exhibited proteinuria as a clinical manifes-tation of vasculopathy after BSCT. The histological find-ings were not compatible with TMA.

Case report

A 2-month-old boy was referred to our university hospital with fe-ver, hepatosplenomegaly, and pancytopenia. His symptoms spon-taneously regressed with anti-coagulation therapy and platelettransfusion. One month later, he had a recurrence of fever, hepato-splenomegaly, and pancytopenia. Bone marrow aspirate revealedhypocellular marrow with hemophagocytosis. Laboratory studyshowed liver dysfunction and increased levels of serum ferritin,soluble interleukin-2 receptor, and fibrin degradation products. Hewas diagnosed as having a recurrence of hemophagocytic lympho-histiocytosis (HLH), which showed resistance to dexamethasonetherapy. He was treated with dexamethasone, etoposide, and cy-closporin A according to the HLH 94 protocol with slight modifi-cations [3].

After 6 months of remission, laboratory study showed an in-creased mononuclear cell count of the cerebrospinal fluid and amagnetic resonance imaging (MRI) study showed multiple le-sions in the brain. These clinical and laboratory findings (fre-quent recurrence, multiple lesions in the central nervous system,and resistance to treatment) suggested familial HLH, althoughthere was no family history. To obtain complete remission, one-locus-mismatched unrelated cord blood cell transplantation was

C. Imai · T. Kakihara · H. Iwabuchi · A. Tanaka · M. UchiyamaDivision of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medical and Dental Sciences,Niigata, Japan

T. FurukawaDivision of Cardiology, Hematology and Endocrinology/Metabolism,Niigata University Graduate School of Medical and Dental Sciences,Niigata, Japan

T. Kakihara (✉)Division of Pediatrics, Department of Homeostatic Regulation and Development,Niigata University Graduate School of Medical and Dental Sciences,Asahimachi-dori 1, 951–8510 Niigata, Japane-mail: shounika@med.niigata-u.ac.jpTel.: +81-025-2272222, Fax: +81-025-2270778

Pediatr Nephrol (2003) 18:399–402DOI 10.1007/s00467-003-1081-9

B R I E F R E P O RT

Chihaya Imai · Toshio KakiharaHaruko Iwabuchi · Atsushi TanakaTatsuo Furukawa · Makoto Uchiyama

Glomerular vasculopathy after unrelated cord blood transplantation

Received: 22 May 2002 / Revised: 26 September 2002 / Accepted: 15 November 2002 / Published online: 21 March 2003© IPNA 2003

selected because of the absence of an HLA-matched related orunrelated donor.

He received busulfan, cyclophosphamide, and etoposide asconditioning, followed by infusion of cord blood cells(4.8×107/kg) with one locus mismatch of DRB1 genotype (Ta-ble 1). As prophylaxis for acute GVHD, cyclosporin A and short-term methotrexate were administered (Table 1). Cyclosporin Awas continued with a trough level of over 100 ng/ml.

On day +10 he developed a skin rash and then hypoproteine-mia (3.3 g/dl), increased body weight, and fever, suggesting en-graftment syndrome or acute GVHD. These findings subsidedwith administration of methylprednisolone. Hypertension was ob-served on day +17 and controlled with amlodipine besilate. Onday +29 proteinuria (151 mg/dl) was first noticed and persistedwith a concentration up to 710 mg/dl. There was no evidence ofincreased body weight, edema, or decreased urine volume.

Laboratory data are shown in Table 2. Hematuria, hypoprotein-emia, increased serum creatinine, and red cell fragmentation inblood smears were not observed post BSCT. Aciclovir, ganciclo-vir, antibiotics, granulocyte-stimulating factor, and heparin weretemporally given. The requirement of red blood cells and platelettransfusion was gradually reduced. On day +86 wheezing and ta-chypnea were observed and his respiratory condition gradually de-teriorated with the need for mechanical ventilation. Chest comput-ed tomography revealed pleural effusion and bilateral consolida-tion lesions, leading to a diagnosis of transplantation-associatedidiopathic pneumonia syndrome. Three days of steroid pulse ther-apy (methylprednisolone 30 mg/kg per day) improved the respira-tory condition and roentgenographic findings. However, he died ofobstructive respiratory failure on day +104.

Some visceral organs were autopsied with the consent of theparents. On light microscopy of the kidney, many of the glomerulishowed increased matrices of the mesangial cells (Fig. 1), but noswelling of the endothelial cells with narrowing of the capillary

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Table 1 Schedule of conditioning chemotherapy and prophylacticregimen for acute graft versus host disease (GVHD) (BUS busul-fan, CY cyclophosphamide, MTX methotrexate, VP-16 etoposide,CsA cyclosporin A, BSCT blood stem cell transplantation)

Day Conditioning Prophylaxis chemotherapy for acute GVHD

-9-8 BUS 1.5 mg/kg×4-7 BUS 1.5 mg/kg×4-6 BUS 1.5 mg/kg×4-5 CY 50 mg/kg-4 CY 50 mg/kg,

VP-16 300 mg/m2

-3 CY 50 mg/kg, VP-16 300 mg/m2

-2 CY 50 mg/kg, VP-16 300 mg/m2

-1 Initiation of CsA (5.0 mg/kg per day)

0 BSCT1 MTX 10 mg/m2

23 MTX 10 mg/m2

456 MTX 10 mg/m2

Table 2 Laboratory data of patient (WBC white blood cell count,RBC red blood cell count, NAG N-acetylglucosaminidase, Epi epithe-lial cell count, hpf high-power field, GOT glutamic oxaloacetic trans-aminase, GPT glutamic pyruvic transaminase, LDH lactate dehydro-

genase, BUN blood urea nitrogen, aPTT activated partial thrombo-plastin time, PT prothrombin time, FDP fibrin degradation product,α2-PI·PM α2-plasmin inhibitor-plasmin complex, TAT thrombin an-tithrombin III, PAI-1 total plasminogen activator inhibitor)

Hematological findings Urinalysis

WBC 1,910/mm3 pH 6Neutrophil 29% Specific gravity 1.02Lymphocyte 45% Protein 151 mg/dlMonocyte 26% Selectivity index 0.45RBC 324×104/mm3 Na 84 mEq/lHemoglobin 9.5 g/dl K 42 mEq/lPlatelet 36×103/mm3 Cl 92 mEq/l

Creatinine 14 mg/dlNAG 19.5 U/lβ2-Microglobulin 22,924 µg/lSedimentWBC <1/hpfRBC 1–2/hpfEpi <1 hpf

Blood biochemical studyTotal protein 7.8 g/dl FDP 6.1 µg/mlGOT 29 IU/l D-Dimer 2.0 µg/mlGPT 27 IU/l Fribrinogen 334 mg/dlLDH 1261 IU/l Normal valueTotal bilirubin 0.9 mg/dl Antithrombin III 133% (80–130)BUN 26 mg/dl Factor VIII-related antigen 211% (50–155)Creatinine 0.3 mg/dl α2-PI·PM 0.4 µg/ml (<0.8)Cholesterol 257 mg/dl TAT complex 1.7 ng/ml (<3.0)Triglyceride 225 mg/dl PAI-1 75 ng/ml (<50)aPTT 28.4 s (control 32.5 s) Haptoglobulin <12 mg/dl (41–273)PT 10.4 (108%)C-reactive protein <0.1 mg/dl

lumens or thrombus formation. Double-contoured basement mem-brane was observed (Fig. 2). No pathological change was ob-served in the tubules or interstitium. Furthermore, thrombosis wasnot observed in any sites of the kidney, lung, heart, liver, pancreas,spleen, or digestive tract. The lung showed interstitial pneumoni-tis. Electron microscopy of the kidney revealed swelling of the en-dothelial cells and widening of the subendothelial space with theinterposition of the mesangial cells (Fig. 3). Electron-dense depos-its and fibrin deposition were not observed.

Discussion

Acute nephropathy, including tubular necrosis and TMA,is observed in the early stages after BSCT. Chronicnephropathy, with proteinuria, hematuria, and nephroticsyndrome, is also found. Several factors such as condi-tioning chemotherapy, immunosuppressant drugs, radia-tion, GVHD, and infection are involved in the pathogen-esis of renal complications of BSCT.

In this patient, proteinuria was first observed 29 daysafter unrelated BSCT and persisted without hematuria.Laboratory studies revealed an increase of factor VIII-re-lated antigen and tissue plasminogen activator, suggest-ing endothelial cell damage. However, other laboratorystudies did not show evidence of TMA (hematuria, redcell fragmentation in blood smears, and a falling plateletcount). Histological examination of autopsy materials re-vealed increased mesangial matrices and double-con-toured basement membrane. Ultrastructurally, swellingof the endothelial cells and widening of the subendothe-lial space with the interposition of the mesangial cellswere observed. These pathological findings were in partsimilar to TMA. However, thrombi in the capillary lu-mens and mesangiolysis are common in TMA [4]. Cruzet al. [5] reported a slowly progressive case with histo-logical findings similar to TMA, in which extensivemesangiolysis, aneurysmal capillary dilatation, andthrombus formation were found. Ultrastructurally, wid-ening of the subendothelial space with amorphous mate-rial consistent with fibrin and mesangiolytic materialswas observed. However, several clinicopathologicalfindings [late onset (6 months), conditioning with radia-tion, thrombus formation, and mesangiolysis] were dif-ferent from those of the present patient. The pathologicalfindings of this patient were more similar to the glomer-ular lesions in patients with preeclampsia and eclampsia.In these patients enlargement of the glomeruli withswelling and vacuolation of the cytoplasm of the endo-thelial cells, double contour of the basement membrane,and increased mesangial matrices were observed [6, 7].The glomerular change with narrowing of the capillarylumens is termed “endotheliosis”. Electron-microscopicstudy showed subendothelial widening with the mesan-gial interposition, electron-dense and fibrin deposits, aswell as the pathological findings observed on light mi-croscopy. Considering these clinicopathological findings,this case might be a mild form of TMA following BSCTor a distinct entity of vasculopathy after BSCT. Infec-tion, conditioning therapy, prophylactic therapy for acuteGVHD, and immunological reactions could be consid-

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Fig. 1 Glomeruli show increased mesangial matrices (periodic ac-id-Schiff stain, ×750)

Fig. 2 Double contour of the basement membrane is found (peri-odic acid-silver methenamine stain, x1,500)

Fig. 3 Electron micrograph showing the swelling of the endotheli-al cells and the widening of the subendothelial space with the in-terposition of the mesangial cells (X9,660)

ered in the pathogenesis of the glomerular vasculopathy.Cyclosporin A may have played an important role, sinceit is an inducer of endothelial cell injury and predisposesto TMA [1, 8]. The mechanism of glomerular changes inpregnancy-associated renal diseases could also be oper-ating in this patient [6]. Endothelial damage may be theprimary cause, which then leads to endothelial dysfunc-tion, hypertension, and glomerular changes with protein-uria.

Other glomerular lesions of nephrotic syndrome afterBSCT (minimal change, membranous nephropathy, andfocal glomerular sclerosis) have been reported [9, 10, 11,12, 13]. These were observed more than 6 months afterBSCT and a relationship between the nephrotic syn-drome and chronic GVHD was suggested. These clinico-pathological findings were different from those of thepresent patient.

Selby et al. [14] reported vasculopathy withoutthrombosis formation after bone marrow transplantation,which was observed in the digestive tract and lung. Mi-croscopic vascular changes consisted of concentric inti-mal or medial hyperplasia and myxoid change in thesmall muscular arteries [14]. Electron-microscopic ex-amination showed lucent expansion of the subendothelialspace [14]. These findings suggest distinct forms of vas-culopathy after BSCT.

To our knowledge, glomerular vasculopathy such asin this patient, presenting with proteinuria but not hema-turia, and with similar histological features to pregnan-cy-related glomerular disease, has not been reported.This patient may represent a distinct entity of microangi-opathy or a variant form of TMA following BSCT. Thisglomerular vasculopathy should be borne in mind in thedifferential diagnosis of proteinuria in the early stagesafter BSCT to clarify the etiology and establish preven-tive and treatment strategies of BSCT-associated neph-ropathy.

Acknowledgements We thank Soichiro Okubo and Itaru Kiharafor their advice and Michiko Oba, Beaut Okada, and Yuko Sogafor their help in preparing this manuscript.

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