Thrombotic microangiopathy and peritubular capillary C4d expression in renal allograft biopsies.

Abstract

BACKGROUND AND OBJECTIVES:

This study characterizes the pathologic and clinical relationships of thrombotic microangiopathy (TMA) to antibody-mediated rejection (AMR) in renal allograft biopsies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:

Consecutive renal allograft biopsies, routinely stained for C4d over a period of 51 months (n=1101), were reviewed. For comparative analysis of histology and clinical features, additional patients with TMA and peritubular capillary (PTC) C4d (n=5) were combined with those identified in the 51-month period of review (n=6).

RESULTS:

One hundred eighty-two of 1073 adequate biopsies from 563 allografts had PTC C4d in the study period. Six of 37 biopsies with TMA had PTC C4d (five at ≤90 days and one at 213 days). Early (≤90 days) C4d+ biopsies (n=5) had more frequent TMA (11.9% C4d+ versus 3.4% C4d-; odds ratio, 3.84; P=0.03). Graft loss was significantly greater in an early C4d+TMA+ group (n=5 study+2 archival patients) than in C4d+ controls without TMA (n=21) (57% versus 9.5%; P=0.02). Early TMA+C4d+ biopsies had more severe glomerulopathy and less severe arteriolopathy than TMA+C4d- and had more frequent neutrophilic capillaritis than TMA-C4d+ biopsies.

CONCLUSIONS:

TMA was infrequent in this series of unselected, consecutive, renal allograft biopsies (3.4%). PTC C4d may be a significant risk factor for early TMA, and TMA is associated with glomerular thrombi and neutrophilic capillaritis. TMA in allografts with suspected AMR may portend a higher risk of graft loss.

• Authors: Shane M Meehan, Joseph Kremer, Farah N Ali, Jessica Curley, Susana Marino, Anthony Chang, Pradeep V Kadambi
• Journal: Clinical journal of the American Society of Nephrology : CJASN (Clin J Am Soc Nephrol) Vol. 6 Issue 2 Pg. 395-403 (Feb 2011) ISSN: 1555-905X [Electronic] United States
• PMID: 20966124 (Publication Type: Journal Article)

Chemical References

• Peptide Fragments
• Complement C4b
• complement C4d

Topics

• Adult
• Biopsy
• Capillaries (immunology, pathology)
• Case-Control Studies
• Chi-Square Distribution
• Chicago
• Complement C4b (analysis)
• Female
• Graft Rejection (immunology, pathology)
• Graft Survival
• Humans
• Immunohistochemistry
• Kidney Transplantation (immunology)
• Male
• Middle Aged
• Odds Ratio
• Peptide Fragments (analysis)
• Retrospective Studies
• Risk Assessment
• Risk Factors
• Thrombotic Microangiopathies (immunology, pathology)
• Time Factors
• Transplantation, Homologous