The Presence of Anti-HLA Donor-Specific Antibodies in Lung Allograft Recipients Does Not Correlate With C4d Immunofluorescence in Transbronchial Biopsy Specimens

Abstract

Context.—C4d immunofluorescence (IF) is a surrogate for development of donor-specific antibodies (DSAs) against human leukocyte antigen (HLA) class I and II antigens in kidney and heart biopsy specimens for monitoring of antibody-mediated (humoral) allograft rejection (AMR). Use of C4d IF in monitoring of lung allografts has shown conflicting results. Objective.—To determine if C4d IF can be used as a reliable marker for AMR and if it correlates with the presence of DSAs and histologic findings on biopsy. Design.—All transbronchial biopsies in lung allograft recipients, performed at our institution in a 3-year period, were reviewed. A cohort of 92 patients with 110 corresponding biopsies met the inclusion criteria of (1) having a resulted DSA within 2 weeks of biopsy and (2) having C4d immunofluorescence studies performed and confirmed. Results.—Twenty-nine patients (31.5%) were positive for DSAs and 63 patients (68.5%) did not develop DSAs. Positive C4d capillary IF was seen in 18 of 110 total biopsy specimens (16.4%). Eight of these biopsy samples were from patients positive for DSAs and 10 were from patients negative for DSAs. The correlation coefficient between the presence of DSAs and C4d IF was 0.1628 (P = .09). Conclusions.—A significant proportion of DSA-positive patients had negative C4d IF results and frequently have no histologic changes on biopsy specimens. DSA-negative patients can be positive for C4d and may show the same histologic changes as reported for DSA-positive patients. Diagnosis of AMR in lung may require a collaborative approach combining clinical data, DSA status, and histology.

Antibody-Mediated Rejection in Lung Transplantation: Clinical Outcomes and Donor-Specific Antibody Characteristics

“…There are currently three limitations of C4d staining in LT biopsies: (i) sampling-related limitations (TBB provides randomly limited tissue sampling), (ii) technical constraints, and (iii) positivity interpretation. Previous studies have explored different C4d staining techniques including immunofluorescence (38,39), immunohistochemistry (40)(41)(42) and the use of either frozen or formalin-fixed, paraffin-embedded biopsies, with contradicting results. Besides AMR, C4d positivity can also be due to either nonspecific staining of noncomplement proteins (i.e.…”

Acute rejection

“…The identification of C4d staining on a biopsy sample as a surrogate marker for AMR due to activation of the complement cascade is controversial and its role in the diagnosis of pulmonary AMR may have been overestimated (56,61). It is rarely seen in patients with a diagnosis of pulmonary AMR based on other criteria (26,100), and there is poor inter-pathologist agreement when it comes to recognising a positive stain on trans-bronchial biopsy (101). Notably, C4d is not specific to pulmonary AMR, can be found in any process that is associated with complement activation such as reperfusion injury and infection (86), and studies have shown no little or correlation between positive staining and the presence of DSA (100,102).…”

Practical Applications in Immunohistochemistry: Evaluation of Rejection and Infection in Organ Transplantation

“…Several primary studies reviewed in the summary statement, along with studies published since then, recognize that the correlation of C4d staining and donor-specific antibody studies in lung allografts may be loose, if not controversial, and will certainly require further study. 14,[77][78][79][80][81] Currently, analogous to other solid organ allografts, it is recommended that C4d staining in allograft lung tissue be scored in the interstitial alveolar capillaries only.…”