Characterization of c4d immunostaining utilizing paraffin-embedded tissue of nonpresensitized pediatric heart transplant XXXX .

@entity1 @entity982 @entity63
Immunoperoxidase techniques for demonstration of complement split product C4d on @entity982 -embedded endomyocardial biopsy samples have been used for the evaluation of humoral rejection mainly in adult heart transplantation. Interpretation of suspected humoral rejection in @entity1 requires knowledge of the pattern and frequency of C4d deposition in nonpresensitized pediatric heart transplantation @entity1 . @entity982 -embedded endomyocardial biopsy samples of 65 @entity1 with no rejection, acute cellular rejection (ACR), or early @entity63 /reperfusion injury were studied. Six biopsies within each grade of ACR both early (<6 months) and late (>6 months) after heart transplantation were reviewed, as were 5 biopsies of @entity63 /reperfusion injury. None of the subjects was sensitized prior to transplant. All slides were blindly evaluated for histologic features traditionally associated with humoral rejection. C4d staining was quantified by counting the number of positive capillaries in 10 random high-power fields (hpf). C4d positivity (C4d+) was defined as >10 capillaries/10 hpf. C4d+ was observed in 6 (9%) endomyocardial biopsy samples; 2 in the early and 4 in the late ACR groups. Four had ACR grades 1A/B, and 2 had grade 3B/4. Thirteen (20%) endomyocardial biopsy samples had histologic features suggestive of humoral rejection. Of these, only 2 were C4d+ and both had ACR grade 3B/4. No C4d+ staining was found in the @entity63 /reperfusion injury group. C4d immunostaining was negative in endomyocardial biopsy samples of the majority of our @entity1 (91%). Endomyocardial biopsy samples with C4d+ did not show consistent ACR grade or time specificity. Contrary to previously reported data, none of the @entity63 /reperfusion injury endomyocardial biopsy samples was C4d+, and histologic features alone were poor predictors of C4d+.
