both lipoprotein glomerulopathy ( lpg ) and fibrillary glomerulonephritis ( fgn ) are rare causes of end - stage renal disease ( esrd ) .
lpg is a rare disease of renal lipoidosis , first described by saito et al . in 1989 . to date ,
150 cases of lpg have been reported in the literature , with most of them in japan and east asian countries [ 2 , 3 ] .
it has been shown that half of the patients with lpg eventually develop esrd at 127 years after onset of symptoms . however , the literature concerning the outcome of kidney transplantation in patients with lpg was scarce .
only five kidney transplants have been reported and lpg recurred early in all the transplanted allografts [ 48 ] . while usually cases without complications are less likely to be reported , it is noteworthy that cases without lpg recurrence have yet been described . on the other hand ,
fgn is also a rare deposition disease comprising only 1% of native kidney biopsies [ 9 , 10 ] .
it is characterized by the deposition of organized microtubules , measuring 1624 nm in diameter and arranged in a parallel fashion .
fgn usually progresses to esrd within months to a few years but the risk of recurrence in kidney transplant is low according to the limited number of cases . herein we report a patient with coexisting lpg and fgn , who underwent deceased kidney transplant > 10 years ago and did not reveal any clinical features of recurrence of diseases after long - term follow - up .
a 34-year - old chinese man first presented to our hospital with 1-year history of ankle swelling .
laboratory investigations revealed a 24-h urinary protein excretion > 10 g per day , serum albumin 21
g / l , serum creatinine 123 mol / l , total cholesterol 10.1 mmol / l and triglyceride 4.7 mmol / l .
light microscopy revealed 13 out of 36 glomeruli showing advanced sclerosis and another six showing segmental sclerosis .
electron microscopy showed abundant non - branching fibrillary material ranging from 1619 nm in diameter in the mesangium .
electron - lucent areas were noted in the subendothelial space with fragmented filamentous material ranging from 1116 nm in diameter ( figure  1a ) .
1.(a ) electron microscopy showing abundant non - branching fibrillary material in the subendothelial space .
( b ) light microscopy showing marked interstitial inflammation consisting of a large amount of polymorphs in the graft kidney specimen .
( c ) light microscopy showing some vacuolated and stringy materials inside the dilated capillary lumens in the native kidney specimen .
( d ) electron microscopy showing the intraluminal materials composed of fine granular material with small lipid vacuoles , consistent with lipoprotein thrombi .
( a ) electron microscopy showing abundant non - branching fibrillary material in the subendothelial space .
( b ) light microscopy showing marked interstitial inflammation consisting of a large amount of polymorphs in the graft kidney specimen .
( c ) light microscopy showing some vacuolated and stringy materials inside the dilated capillary lumens in the native kidney specimen .
( d ) electron microscopy showing the intraluminal materials composed of fine granular material with small lipid vacuoles , consistent with lipoprotein thrombi .
three years later , he presented with uremic symptoms and blood tests showed urea nitrogen 46 mmol / l , creatinine 2011 mol / l , albumin 28
autoimmune markers including antinuclear , antineutrophil cytoplasmic and antiglomerular basement membrane antibodies were all negative .
three months later , he received deceased kidney transplant and immunosuppression included prednisolone , tacrolimus and mycophenolate mofetil .
his serum creatinine remained stable ( at 120 mol / l ) without any significant proteinuria .
he suffered an episode of acute kidney injury with serum creatinine reaching 201 mol / l during follow - up at 18-months post - transplant .
renal graft biopsy was performed and light microscopy revealed marked interstitial inflammation consisting of a large amount of polymorphs which were also noted within the tubular lumens ( figure  1b ) .
however , subsequent review of his native kidney biopsy specimen showed that in addition to features of fgn , components of lpg which were characterized by some vacuolated and stringy materials inside the dilated capillary lumens ( figure  1c ) were also seen .
positive and stained pale blue under chromotrope - aniline blue ( cab ) stain . on electron microscopy
, these intraluminal materials contained fine granular material with small lipid vacuoles , consistent with lipoprotein thrombi ( figure  1d ) .
these features were not present in the graft biopsy specimen obtained 18 months after transplant .
mutational analysis of the apolipoprotein ( apoe ) gene by polymerase chain reaction and direct dna sequencing revealed an e3/e3 genotype and a heterozygous mutation c.480_488del , which is predicted to result in deletion of leu - arg - lys at codons 162164 ( reference sequences nm_000041.2 and np_000032.1 ) .
a familial genetic study on his son at 18 years of age showed that he also carries the same mutation , though there was no biochemical evidence of proteinuria or renal disease at the time of testing .
his maintenance immunosuppressive regimen remained prednisolone , tacrolimus and mycophenolate mofetil while he was also put on diltiazem and lisinopril for blood pressure control .
after > 10 years post - transplant , his latest serum biochemistry and other laboratory examination revealed no significant abnormality . these included serum creatinine 125 mol / l , serum albumin 42
g / l , total cholesterol 4.8 mmol / l , triglyceride 1.2 mmol / l and 24-h urinary protein excretion < 0.1 g.
up till now , 12 mutations have been reported in the human gene mutation database ( version 27 september 2013 ) to result in lpg ( http://www.hgmd.org/ ) .
the more common ones include apoe sendai ( arg145pro )   and apoe kyoto ( arg25cys ) .
nevertheless , hyperlipidemia appears not to be an essential prerequisite as lpg has been reported in patients with normolipidemia .
however , serum apoe level was not available in our patient because of a lack of apoe quantitation service in hong kong . as a result ,
once the histopathological diagnosis of lpg has been made , mutational analysis on the apoe gene can be carried out to confirm the diagnosis . since half of the patients with lpg
might eventually develop end - stage renal disease , kidney transplantation should be considered in these patients .
however , the long - term outcome of kidney transplantation in patients with lpg still remains uncertain .
only five kidney transplants have been reported in the literature to date . unfortunately all of them had lpg relapse which was confirmed by renal graft biopsy within 2 years after transplantation . among them , one patient had persistent proteinuria and developed graft failure 1 year later .
two patients developed nephrotic - range proteinuria within 6 months after transplant [ 5 , 8 ] .
one patient had nephrotic syndrome with serum creatinine level reaching 176 mol / l 2 years after transplant   while the last case revealed histological recurrence by protocol biopsy 15-month post - transplant in an asymptomatic patient with proteinuria of 300 mg / day .
it seems that lpg recurrence in a transplanted kidney is inevitable which is also associated with poor prognosis . in our patient ,
renal graft biopsy was performed at 18-months post - transplant which only showed infective component as the cause of acute deterioration in renal function .
since there was no significant proteinuria all along during follow - up , renal graft biopsy was not repeated .
while early relapse had been ruled out by histology at 18-months post - transplant , no biochemical features of lpg or fgn recurrence could be demonstrated in our patient despite having a follow - up for > 10 years .
our case shows that the prognosis of patients with coexisting fgn and lpg who have received a kidney transplant can be good .
prior studies illustrated that the location of apoe mutations is an important determinants for the development of lpg .
however , the relationship between various apoe mutations and lpg recurrence in the kidney graft is not well established because of the limited number of patients . moreover , family studies showed that lpg occurs in some members but not in others even with the same phenotypic and genotypic apoe abnormalities [ 5 , 14 ] . as a result , it has been postulated that some other possibilities such as local mechanisms in the glomeruli or environmental factors in addition to the apoe genotype are required for disease expression .
further studies are thus required for clarification of the exact pathogenic mechanism of lpg . in conclusion
, our experience shows that kidney transplantation remains a viable therapeutic option for patients with esrd secondary to fgn with lpg .
 both lipoprotein glomerulopathy ( lpg ) and fibrillary glomerulonephritis ( fgn ) are rare causes of end - stage renal disease ( esrd ) , and the literature concerning the outcome of kidney transplant in patients with lpg or fgn is scarce . 
 we report a patient who suffered from esrd with coexisting fgn and lpg and received deceased kidney transplant > 10 years ago did not reveal any clinical features of disease recurrence during follow - up . 
 our case shows that the prognosis of patients with lpg component who received kidney transplant can be good . 
 kidney transplantation remains a viable therapeutic option for patients with esrd secondary to fgn with lpg . 
Background
Case history
Discussion
Conflict of interest statement