Leukocyte chemotactic factor 2 (LECT2)-associated renal amyloidosis: a case series.
BACKGROUND
Renal amyloidosis is characterized by the pathologic deposition within glomeruli and/or interstitium of congophilic fibrils, most often composed of either immunoglobulin light chains or serum amyloid A-related protein and, less commonly, mutated forms of apolipoproteins AI or AII, lysozyme, fibrinogen, gelsolin, or transthyretin.


METHODS
Case series.


METHODS
10 patients with renal amyloidosis who had an amyloidogenic protein that was not identified using routine immunohistochemistry.


RESULTS
Clinical, pathologic, biochemical, and genetic characteristics.


METHODS
Tandem mass spectrometry was used to analyze fibrils extracted from sections of formalin-fixed paraffin-embedded amyloid-containing kidney biopsy specimen blocks.


RESULTS
Chemical analyses showed peptides corresponding to the carboxy-terminal portion of the leukocyte chemotactic factor 2 (LECT2) molecule. In addition, deposits were immunostained using an anti-human LECT2 monoclonal antibody. Plasma specimens were available from 2 individuals for whom LECT2 concentration in these samples was within the reference range. Additionally, in 4 of the cases analyzed at the molecular level, isolation of genomic DNA and polymerase chain reaction amplification of LECT2-encoding exons showed no mutations. However, all were homozygous for the G allele encoding valine at position 40 in the mature protein, a finding confirmed using restriction enzyme analysis of the polymorphic site.


CONCLUSIONS
Causality is not addressed.


CONCLUSIONS
Based on our studies, we posit that LECT2-associated renal amyloidosis represents a unique and perhaps not uncommon disease, especially in Mexican Americans. The pathogenesis, extent, and prognosis remain to be determined.
Human Immunology and Cancer Program, Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA.
Charles L
CL
Murphy
Shuching
S
Wang
Daniel
D
Kestler
Christopher
C
Larsen
Don
D
Benson
Deborah T
DT
Weiss
Alan
A
Solomon
D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D001706:Biopsy; D005091:Exons / Q000235:genetics; D005260:Female; D006720:Homozygote; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D007674:Kidney Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D017058:Mexican Americans / Q000235:genetics; D008875:Middle Aged
D036341:Intercellular Signaling Peptides and Proteins; C103468:LECT2 protein, human