C4d Immunostaining Research Articles

Pancreas Allograft Rejection: Analysis of Concurrent Renal Allograft Biopsies and Posttherapy Follow-Up Biopsies

Pancreas and kidney allograft function is routinely monitored with serum studies (amylase, lipase, and creatinine). Increased levels commonly prompt tissue biopsy, to diagnose cause of graft dysfunction. Historically, pancreas allografts were infrequently biopsied, although serum enzymes and renal rejection may be poor surrogates for pancreas status. Pancreas allograft biopsies at our center were reviewed and reclassified according to University of Maryland (UMD) and Banff criteria; C4d immunostaining was performed. Findings were correlated with clinical data and renal allograft biopsies. Fifty-six pancreas allograft biopsies from 27 patients were evaluated. UMD and Banff grading were similar, although two UMD "indeterminate" biopsies were Banff grade 1 rejection. There were 21 concurrent pancreas and renal biopsies, all from simultaneous pancreas-kidney allograft recipients. Thirteen pairs were concordant for rejection; eight pairs were discordant for rejection (38%); six pairs showed pancreas rejection without kidney rejection, and two pairs showed the converse. Fourteen patients had a total of 21 follow-up pancreas allograft biopsies. Seven biopsies showed a lower grade of rejection on follow-up biopsy, 4 biopsies showed more severe rejection, and 10 had unchanged grade. In only 9 of these 21 (43%) cases, did the interval serum amylase or lipase trend parallel the subsequent biopsy diagnosis. With a high biopsy discordance rate, our data suggest that renal allograft rejection is a poor surrogate for pancreas allograft status. Likewise, serum amylase and lipase levels do not predict response to rejection therapy. Surveillance or posttherapy pancreas allograft biopsies may be a useful means to monitor pancreas allograft status.

C4D Immunostaining in Surveillance Endomyocardial Biopsies From Well-Functioning Heart Allografts

Objective The meaning of biopsy C4d detection in heart allografts without dysfunction or morphologic changes suggesting antibody-mediated rejection (AMR) is not clear. The aim of this study was to search for an association between C4d detection in allograft biopsies of well-functioning hearts without changes suggestive of AMR, and clinical outcomes. Methods Endomyocardial protocol biopsies from 44 heart transplant patients with well-functioning grafts and without changes suggesting AMR were performed at 1 month and 1 year after transplantation and analyze the presence of C4d deposition using immunohistochemistry. Two-year follow-up was based on clinical parameters and echocardiographic information. Heart graft function was categorized as good vs. poor. The presence of C4d, using diverse schemes to graduate the extension of the deposition, was correlated with clinical graft outcomes. Results C4d deposition was observed in the capillary walls of 33 biopsies (37.5%; n = 25 patients; 56.8%). No biopsy had diffuse (>50%) immunostaining. Six patients presented with multifocal capillary C4d immunostaining in at least 1 biopsy. Capillary positivity for C4d (if focal or multifocal) showed no statistical association with cellular rejection or graft function. Perimyocytic C4d detection was neither associated with rejection nor graft outcome. Conclusion Our work failed to demonstrate an association between C4d detection in protocol biopsies of heart grafts and clinical outcomes. The clinical utility of C4d staining in solid organ transplantation may vary by organ. Our results suggest that C4d did not have clinical utility in surveillance biopsies of well-functioning heart grafts without morphological changes suggesting AMR.

Does a positive lymphocyte cross-match contraindicate living-donor liver transplantation?

There is still no consensus on the importance of lymphocyte cross-matching (LCM) in the field of living-donor liver transplantation (LDLT). LCM examinations are routinely performed before LDLT, and the results of complement-dependent cytotoxicity were used in this study. A total of 1157 LDLT cases were evaluated. The recipients were divided into four groups based on the LCM and ABO compatibilities: (1) negative LCM and identical/compatible ABO; (2) negative LCM and incompatible ABO; (3) positive LCM and identical/compatible ABO; and (4) positive LCM and incompatible ABO. The diagnosis of antibody-mediated rejection (AMR) was made based on the clinical course, immunological assays and histopathological findings. C4d immunostaining was added if AMR was suspected. The LCM-positive LDLT recipients showed significantly poorer outcomes than the LCM-negative recipients. Among the LCM-positive recipients, 44.1% of recipients eventually died and 85.2% of recipients revealed positive C4d findings. The survival rate of LCM-positive and ABO-incompatible group was 0.50. The survival days were compared with the LCM-negative and ABO-identical/compatible group, and the LCM-positive and ABO-identical/compatible group clearly showed early death after LDLT, although the ABO-incompatible groups did not show significant. The factors of age, disease, pre-transplant scores, LCM, ABO compatibility and graft-recipient weight ratio showed statistical significance in multivariate analysis for important factors of LDLT outcomes. However, the LCM and ABO compatibilities had no synergetic effects on the LDLT survival. HLA antigens are more widely expressed than ABO antigens, and advanced immunological strategies must be established for LCM-positive LDLT as well as for ABO-incompatible LDLT.

Subclinical peritubular capillaritis in serial graft biopsies in cadaveric kidney transplant recipient with pre‐transplant anti‐HLA antibodies

National Fukuoka-Higashi Medical Center, Koga, Japan A 63-yr-old Japanese woman on 18-yr hemodialysis (HD) program underwent cadaveric kidney transplantation from non-heart beating donor. Pre-transplant lymphocytotoxicity test was negative, but flow cytometric cross-match and flow-cytometric panel reactive antibody (PRA) screening tests were positive. Flow-PRA single-antigen test revealed several anti-HLA antibodies including donor-specific antibody (DSA). She was treated with plasma exchange (PEX) and rituximab to prevent antibody-mediated rejection (AMR). Urinary output increased from post-operative day (POD) 5 and HD was discontinued from POD8. Graft biopsy performed on POD11 showed severe peritubular capillaritis (PTCitis), numerous polymorphonuclear neutrophils (PMNs), and moderate glomerulitis. Although C4d immunostaining on PTC was negative, the case was diagnosed as subclinical AMR based on the presence of pre-transplant DSA and PTCitis with predominant PMNs. The patient was treated with additional PEX and rituximab, which increased urinary output and reduced serum creatinine (sCr). Graft biopsy repeated on POD39 showed persistent severe PTCitis, moderate interstitial infiltration, and mild tubulitis. C4d on PTC was negative again. The patient was discharged from the hospital on POD40. During the seven months follow-up at the outpatient clinic, the sCr level has shown a slight increase. In this case, the patient had DSA, which can be detected only by flow-PRA. In both graft biopsies, C4d on PTC was negative despite the presence of severe PTCitis, and thus the diagnosis of AMR could not be established. However, the significance of subclinical PTCitis is reported perhaps as an early marker for chronic AMR and to emphasize the importance of close follow-up.

37: The Role of C4d Immunostaining in the Evaluation of Microvascular Damage in Heart Transplantation

37: The Role of C4d Immunostaining in the Evaluation of Microvascular Damage in Heart Transplantation

Diagnostic efficacy of C4d immunostaining in the detection of the humoral component of renal allograft rejection and therapeutic implications

In the current scenario of renal transplantation, the role of immunological methods in the detection of C4d has emerged as a useful adjunct in the recognition of acute humoral rejection (AHR). Few reports of this nature are available from the Indian context although there are several from the Western literature. To study the humoral component of renal allograft rejection in patients presenting clinically with graft dysfunction by histopathological detection of polymorphs in the peritubular capillaries and the expression of C4d using immunological techniques, as well as the response of patients to appropriate antirejection therapy. This study from a tertiary care center reemphasizes the importance of recognition of AHR as a cause of renal allograft dysfunction. Percutaneous renal biopsies were obtained from 40 postrenal transplant patients and evaluated for C4d using immunofluorescence and immunohistochemical methods. SPSS software. Positive expression of C4d was seen in a total of 19/40 cases (44.4%) indicating immunological evidence of AHR. Diffusely positive cases were treated with IV immunoglobulin therapy, plasmapheresis and Rituximab following which graft function was restored. Patients with minimal to focal positive expression of C4d responded well to pulse steroids and change in immunosuppressive therapy. C4d staining is a useful adjunct to routine histopathological methods in evaluating the humoral component of acute renal allograft dysfunction and helps in planning appropriate antirejection therapy with the goal of achieving long-term graft survival.

Acute Antibody-mediated Rejection After Lung Transplantation

The role of humoral immunity after lung transplantation remains unclear. In this report, we describe the pathologic findings and clinical course of a case of acute antibody-mediated rejection (AMR) after lung transplantation. After an uncomplicated early course, a 31-year-old man with cystic fibrosis developed acute graft dysfunction 1 month after bilateral lung transplantation. Lung biopsies showed acute pneumonitis with capillary injury, neutrophilic infiltration and nuclear dust. Immunostaining for C4d demonstrated endothelial cell deposition, and circulating donor-specific human leukocyte antigen (HLA) antibodies were identified. Despite severe hypoxemic respiratory failure, he responded well to a regimen consisting of methylprednisolone, plasma exchange, intravenous immunoglobulin and rituximab therapy. He completely recovered clinically although donor-specific HLA antibodies have remained detectable. The incidence of acute AMR after lung transplantation is unknown, but this case fulfills all of the consensus diagnostic criteria, and we suggest that AMR could be an under-recognized cause of acute graft dysfunction.

Measurement of Human Erythrocyte C4d to Erythrocyte Complement Receptor 1 Ratio in Cardiac Transplant Recipients With Acute Symptomatic Allograft Failure

Background Complement activation has been recognized as a contributing factor to cardiac allograft dysfunction. Combined measurement of erythrocyte C4d (E-C4d) and complement receptor 1 (E-CR1) are potential biomarkers to monitor complement activity in patients with autoimmune diseases. We conducted a prospective study using CR1-2B11 monoclonal antibody to detect the E-C4d to E-CR1 ratio among our cardiac transplant recipients with acute symptomatic allograft failure. Materials and methods Eight recipients with acute cardiac allograft failure and 72 healthy controls were included in this study. Levels of E-C4d and E-CR1 were measured by indirect immunofluorescence and flow cytometry. The results were utilized to determine the association between patient C4d staining, histological features, and clinical outcomes. Results Eight patients with nine episodes of sudden onset of graft failure and suspected antibody-mediated rejection (AMR) were included in this study. One patient who received emergent mechanical circulatory support was treated with plasmapheresis for his unstable hemodynamic status. The mean pretreatment left ventricular ejection fraction was 30.3%. No histological study demonstrated cellular rejection or AMR in any patient. There were two patients with positive C4d immunostaining. Three patients had four episodes of acute rejection with sudden death at home. The mean E-C4d/E-CR1 ratio in the study group ( n = 9) was 0.22 ± 0.07, and 0.12 ± 0.10 in the control group ( n = 72). As comparing both groups, we found the ratios were significant higher in the study group ( P = .0003). Conclusions Measurement of the E-C4d/E-CR1 ratio may be a noninvasive method for detecting acute rejection after cardiac transplantation.

Characterization of C4d Immunostaining Utilizing Paraffin-Embedded Tissue of Nonpresensitized Pediatric Heart Transplant Patients

Immunoperoxidase techniques for demonstration of complement split product C4d on paraffin-embedded endomyocardial biopsy samples have been used for the evaluation of humoral rejection mainly in adult heart transplantation. Interpretation of suspected humoral rejection in children requires knowledge of the pattern and frequency of C4d deposition in nonpresensitized pediatric heart transplantation patients. Paraffin-embedded endomyocardial biopsy samples of 65 patients with no rejection, acute cellular rejection (ACR), or early ischemic/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 ischemic/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 ischemic/reperfusion injury group. C4d immunostaining was negative in endomyocardial biopsy samples of the majority of our patients (91%). Endomyocardial biopsy samples with C4d+ did not show consistent ACR grade or time specificity. Contrary to previously reported data, none of the ischemic/reperfusion injury endomyocardial biopsy samples was C4d+, and histologic features alone were poor predictors of C4d+.

The role of C4d immunostaining in the evaluation of the causes of renal allograft dysfunction

Renal biopsy is the gold standard for diagnosis of acute rejection in renal transplant recipients. The Banff (1997) classification was revised in 2003 incorporating morphological criteria and C4d immunostaining for the diagnosis of acute antibody-mediated rejection. The aim of this study was to evaluate the role of histomorphology and C4d immunostaining in indicated renal allograft biopsies with a clinical follow-up for a minimum duration of 1 year. Histological analysis and C4d immunostaining were performed on 132 needle core biopsies and 2 nephrectomy specimens from 107 patients from July 2004 to June 2005. Histological analysis revealed 59 cases of acute rejection, 10 biopsies of acute tubular necrosis, 41 cases of chronic allograft nephropathy (CAN), either alone or in combination with other diseases, and 18 biopsies of normal morphology. There were four cases of BK nephropathy (BK N) and eight cases had miscellaneous diagnoses. C4d immunostaining was performed on 126 biopsies. Overall, the prevalence of C4d positivity was 45% (57 of 126). Fifty-five percent (28 of 51) of the cases of acute rejection showed C4d positivity including 81% of presumptive antibody-mediated rejection (P-AbAR), 20% acute cellular rejection and 58% acute cellular rejection + P-AbAR. Overall C4d positivity was 37% in chronic allograft nephropathy. Acute tubular necrosis and borderline rejection showed 25 and 50% C4d positivity, respectively. Amongst various histological features, capillary margination of polymorphs and dilatation of peritubular capillaries (PTC-D) showed significant association with C4d positivity (P < 0.005). In cases of CAN, transplant glomerulopathy had significant association with C4d positivity. C4d-positive cases had a higher mean value of serum creatinine at the time of biopsies. It is concluded that C4d staining is a useful adjunct marker of the humoral limb of rejection, both in early and late post-transplant periods.

Antibody-Mediated Rejection of the Kidney after Simultaneous Pancreas-Kidney Transplantation

The prevalence, risk factors, and outcome of antibody-mediated rejection (AMR) of the kidney after simultaneous pancreas-kidney transplantation are unknown. In 136 simultaneous pancreas-kidney recipients who were followed for an average of 3.1 yr, 21 episodes of AMR of the kidney allograft were identified. Eight episodes occurred early (</=90 d) after transplantation, and 13 occurred later. Histologic evidence of concomitant acute cellular rejection was noted in 12 cases; the other nine had evidence only of humoral rejection. In 13 cases, clinical rejection of the pancreas was diagnosed simultaneously, and two of these were biopsy proven and were positive for C4d immunostaining. Multivariate analysis identified only one significant risk factor: Female patients were three times more likely to experience AMR. Nearly all early episodes resolved with treatment and did not predict graft loss, but multivariate Cox models revealed that late AMR episodes more than tripled the risk for kidney and pancreas graft loss; therefore, new strategies are needed to prevent and to treat late AMR in simultaneous pancreas-kidney transplant recipients.

Renal allograft biopsies in the era of C4d staining: the need for change in the Banff classification system

C4d immunostaining in the peritubular capillaries (PTC) is a marker of antibody-mediated rejection (AMR). We evaluated the histopathologic diagnoses of 388 renal transplant biopsies since the implementation of routine C4d immunostaining at our center. Of these, 155 (40%) biopsies had evidence of acute cellular rejection (ACR), out of which 119 (77%) had pure ACR, 31 (20%) had ACR with concomitant features of AMR, and five (3%) had ACR with focal C4d staining. Sixty-four (16%) biopsies exhibited features of AMR [33 (52%) pure AMR, and 31(48%) concomitant AMR and ACR]. One hundred and fifty-five (40%) biopsies had features of interstitial fibrosis and tubular atrophy (IFTA). Of these, 20 (13%) had concomitant AMR [13 (8.5%) had pure AMR and seven (4.5%) had concomitant ACR and AMR]. Creatinine at the time of biopsy was higher in patients with mixed ACR and AMR and the clinical behavior of mixed lesions is more aggressive over time. Despite having a lower serum creatinine at the time of biopsy, patients with IFTA experienced gradual decline in graft function over time. The pathologic findings in renal allograft biopsies are often mixed and mixed lesions appear to have more aggressive clinical behavior. These findings suggest the need for change in the Banff classification system to better capture the complexity of renal allograft pathologies.

Antibody-mediated rejection following renal transplantation

Antibody-mediated rejection (AMR) accounts for 20 – 30% of all acute rejection episodes following renal transplantation. AMR is generally less responsive to conventional anti-rejection therapy, resulting in poor allograft survival. Introduction of C4d immunostaining of renal allograft biopsies and the demonstration of donor-specific antibodies in the recipients have increased our ability to diagnose AMR. Therapeutic options are evolving and include plasmapheresis, intravenous immunoglobulin, immunoadsorption and rituximab, together with intensification of immunosuppression with a tacrolimus/mycophenolate mofetil combination. Future studies might further define optimal therapeutic approach in renal transplant recipients presenting with AMR.

Correlation of conventional histology, clinical outcomes, and C4d immunostaining in ABO-incompatible liver transplantation

In ABO blood type-incompatible liver transplantation (ABO-I LT), acute humoral rejection triggered by antibodies against donor-type isoagglutinins is the most serious form of rejection and often associated with graft loss. Typical histology of humoral rejection is recognized by biopsies taken at the onset of elevation of alloantibody titers; such biopsies reveal marked portal edema with or without hemorrhagic necrosis. Edema disappears several days after the onset of humoral rejection, and follow-up biopsies reveal relatively nonspecific findings such as hepatocyte necrosis or cholangitis-like portal fibrosis. In our series enrolled between 1995 and 2004, hemorrhagic portal edema was recognized in 17 of 114 (15%) patients who underwent primary ABO-I LT. All 17 patients showed elevation of anti-donor A/B IgM antibody titers (1:64 or higher), and 6-month graft survival was 59%. Deposition of C4d in portal stroma was demonstrated in 11 of 12 (92%) patients with hemorrhagic portal edema and some patients with other histology showing high postoperative alloantibody titers. Although more study is needed, these results suggest that C4d immunostaining can be a useful marker to demonstrate humoral rejection in ABO-I LT.

Acute humoral rejection and C4d immunostaining in ABO blood type-incompatible liver transplantation

Complement C4d deposition in graft capillaries has been reported to be associated with antibody-mediated rejection in kidney and other solid organ transplantation. The correlation of C4d deposits and humoral rejection in liver transplants, however, is not well understood. We investigated the C4d immunostaining pattern in 34 patients whose liver biopsy was taken within the first 3 postoperative weeks for suspected acute rejection after ABO blood type-incompatible liver transplantation. The staining pattern was classified as positive (portal stromal staining), indeterminate (endothelial staining only), and negative (no staining). Positive C4d immunostaining was seen in 17 (50%) patients and was significantly associated with high (x64 or more) postoperative antidonor A/B antibody (immunoglobulin M (IgM)) titers (88 vs. 35%, P = 0.002) and poorer overall survival rate (41 vs. 88%, P = 0.007). Ten of 11 (91%) cases with histological acute humoral rejection (periportal edema and necrosis (PEN) or portal hemorrhagic edema) were positive for C4d, all of which showed high postoperative antibody titers. The other histologies associated with C4d positivity was purulent cholangitis (n = 4), coagulative hepatocyte necrosis (n = 1), acute cellular rejection (n = 1), and hepatocanalicular cholestasis (n = 1). Full clinical recovery was observed in only 6 of 17 (35%) C4d-positive patients, and tended to be associated with a lower rejection activity index (RAI). In conclusion, our study indicates that C4d deposits in the portal stroma can be a hallmark of acute humoral rejection in ABO-incompatible liver transplantation, and allograft damage can be reversible in a minority of cases.

C4d immunostaining in acute humoral rejection after ABO blood group-incompatible liver transplantation

C4d immunostaining in acute humoral rejection after ABO blood group-incompatible liver transplantation

Characterization of C4d immunostaining utilizing paraffin-embedded tissue of non-presensitized pediatric heart transplant patients

Characterization of C4d immunostaining utilizing paraffin-embedded tissue of non-presensitized pediatric heart transplant patients

Histologic Findings of Antibody-Mediated Rejection in ABO Blood-Group-Incompatible Living-Donor Kidney Transplantation

The purpose of this study was to characterize the histology of antibody-mediated rejection (AMR) in ABO blood-group-incompatible (ABOI) kidney transplants as well as on protocol biopsies performed at the time of stable allograft function. Between 5/99 and 1/02, we performed 32 ABOI kidney transplants (13 A2, 19 non-A2 blood-group living donors). Nineteen biopsies were performed for allograft dysfunction, and 127 protocol biopsies were performed 0, 3, 7, 14, 28 days and 3 and 12 months post transplant. Twenty-five of 32 patients have functioning allografts (mean 585 days post transplant). Nine of 32 (28%) developed clinical AMR. Biopsy revealed glomerular thrombi (78%), mesangiolysis (78%), peritubular capillary C4d staining (56%) and neutrophil infiltration (67%), interstitial hemorrhage and necrosis (56%) and arteriolar thrombi (33%). Subclinical AMR was diagnosed by protocol biopsies in four patients. Findings consisted of glomerular thrombi (100%), mesangiolysis (25%), and C4d staining (100%). In late protocol biopsies performed 214–420 days post transplant, mild mesangiolysis was seen in 2/17 (11.7%), and C4d immunostaining was detected in 3/12 (25%). AMR is characterized by glomerular thrombi, mesangiolysis, peritubular capillary neutrophil infiltration interstitial hemorrhage, necrosis, and C4d deposition. Glomerular thrombi appear early in AMR and may appear prior to graft dysfunction.

Acute humoral rejection and C4d immunostaining: emerging new concepts in renal transplant pathology

Acute humoral rejection and C4d immunostaining: emerging new concepts in renal transplant pathology