Significance of peritubular capillary, glomerular, and arteriolar C4d staining patterns in paraffin sections of early kidney transplant biopsies.
BACKGROUND
Although diffuse linear C4d deposition in peritubular capillaries (PTCs) is a well-established criterion of alloantibody-mediated kidney transplant rejection, the actual relevance of focal or granular C4d deposits or staining outside PTC (glomeruli and arterioles) has yet to be established.


METHODS
This study was designed to evaluate the diagnostic significance of such nontypical C4d staining patterns. A total of 539 early indication biopsies (329 kidney transplants) were analyzed by immunohistochemistry using a polyclonal anti-C4d antibody.


RESULTS
We found a close interrelationship between diffuse or focal linear C4d deposition in PTC, linear endothelial deposition in glomeruli, and arteriolar C4d. These specific patterns were also related to transplant glomerulitis and recipient presensitization. No such associations, however, were observed for other patterns, such as granular C4d in PTC. Detection of diffuse but not focal linear C4d in PTC was found to be associated with adverse allograft survival (5-year death-censored graft survival: 48% vs. 82%, 89%, or 84% in patients with focal, minimal, or no C4d, respectively; P<0.0001). Univariate analysis also revealed inferior graft survival in recipients with linear C4d in glomeruli (P=0.02). Applying multivariate Cox regression analysis, however, only diffuse linear PTC staining was found to be predictive of graft loss (hazard ratio 3.95 [95% confidence interval 1.62-9.60]; P=0.002).


CONCLUSIONS
There might be a relationship between humoral alloimmunity and distinct less established staining patterns, such as focal linear C4d in PTC, endothelial C4d in glomeruli, or arteriolar C4d. Nevertheless, our results reemphasize the prognostic value of diffuse linear PTC staining.
Department of Medicine III, Medical University of Vienna, Vienna, Austria.
Zeljko
Z
Kikić
Heinz
H
Regele
Veit
V
Nordmeyer
Markus
M
Wahrmann
Josef
J
Kletzmayr
Gregor
G
Bartel
Georg A
GA
Böhmig
D000328:Adult; D001160:Arterioles / Q000473:pathology; D001706:Biopsy; D002196:Capillaries / Q000473:pathology; D015935:Complement C4b / Q000032:analysis*; D005921:Glomerulonephritis / Q000276:immunology; D006085:Graft Survival / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D016030:Kidney Transplantation / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D007684:Kidney Tubules / Q000276:immunology / Q000473:pathology*; D008875:Middle Aged; D010446:Peptide Fragments / Q000032:analysis*; D012189:Retrospective Studies
D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d