C3d-Targeted factor H inhibits tissue complement in disease models and reduces glomerular injury without affecting circulating complement.

Complement-mediated diseases can be treated using systemic inhibitors. However, complement components are abundant in circulation, affecting systemic inhibitors' exposure and efficacy. Furthermore, because of complement's essential role in immunity, systemic treatments raise infection risk in patients. To address these challenges, we developed antibody fusion proteins combining the alternative-pathway complement inhibitor factor H (fH1-5) with an anti-C3d monoclonal antibody (C3d-mAb-2fH). Because C3d is deposited at sites of complement activity, this molecule localizes to tissue complement while minimizing circulating complement engagement. These fusion proteins bind to deposited complement in diseased human skin sections and localize to activated complement in a primate skin injury model. We further explored the pharmacology of C3d-mAb-2fH proteins in rodent models with robust tissue complement activation. Doses of C3d-mAb-2fH >1 mg/kg achieved >75% tissue complement inhibition in mouse and rat injury models while avoiding circulating complement blockade. Glomerular-specific complement inhibition reduced proteinuria and preserved podocyte foot-process architecture in rat membranous nephropathy, indicating disease-modifying efficacy. These data indicate that targeting local tissue complement results in durable and efficacious complement blockade in skin and kidney while avoiding systemic inhibition, suggesting broad applicability of this approach in treating a range of complement-mediated diseases.

Diagnosis of autoimmune bullous dermatoses: Comparative analysis of immunohistochemical staining using C4d, C3d, IgG, and IgG4 in lesional tissues and perilesional frozen skin samples.

Immunohistochemical staining with immunoglobulins and complements may aid the diagnosis of patients whose clinical and histological findings are consistent with autoimmune bullous dermatoses (AIBD). We aimed to investigate the diagnostic value of immunohistochemical markers in lesional biopsy and perilesional frozen samples in AIBD. We included 136 cases from whom lesional biopsies and perilesional samples for direct immunofluorescence (DIF) examination were collected with a preliminary diagnosis of AIBD between January 2019 and January 2023. All diagnoses were reconfirmed by evaluating the clinical, histopathological, and serological findings and DIF results (C3, IgG, IgA, or IgM positivity compatible with the clinical diagnosis) altogether, although DIF results were considered a priority. After confirming the diagnoses, the samples were categorized as AIBD or the others. The perilesional tissues obtained for DIF simultaneously with skin biopsy and stored at -80 °C were thawed, and FFPE tissues were prepared. We performed immunohistochemical staining (C4d, C3d, IgG, and IgG4) on FFPE tissues of both lesional and perilesional samples. Strong, linear, or granular staining patterns at the dermoepidermal junction or the intraepidermal blistering space were considered positive in line with the diagnosis of the case. Cases other than AIBD were used as negative control tissues to assess the specificity of immunohistochemical markers. Of the 136 cases, 52 were diagnosed with AIBD. In lesional samples, the sensitivity of C4d, C3d, IgG, and IgG4 was 80.6 %, 69.4 %, 75 %, and 5.7 % with corresponding specificity of 100 %, 98.7 %, 89.6 %, and 97.4 %, respectively in pemphigoid diseases compared to a sensitivity of 18.2 %, 9.1 %, 70 %, and 9.1 % and specificity of 98.7 %, 100 %, 89.6 %, and 97.4 %, respectively in pemphigus diseases. In frozen samples, we detected expression in a limited number of cases. The sensitivity of C4d, C3d, IgG, and IgG4 was 8.7 %, 2.2 %, 19.4 %, and 2.2 %, with corresponding specificity of 100 %, 100 %, 98.5 %, and 98.6, respectively. There was a none to slight concordance rate between the IHC results of lesional tissues and perilesional frozen samples. Kappa coefficients for C4d, C3d, IgG, and IgG4 were 0.120 (P = 0.029), 0.111 (P = 0.050), 0.203 (P = 0.003), and - 0.15 (P = 0.846), respectively. Immunohistochemical staining with C4d, C3d, IgG, and IgG4 on biopsy samples collected from lesions may guide the diagnosis of AIBD, thereby eliminating the need for an additional biopsy and accelerating the diagnostic process.

Enhanced Vision-Based Taillight Signal Recognition for Analyzing Forward Vehicle Behavior.

This study develops a vision-based technique for enhancing taillight recognition in autonomous vehicles, aimed at improving real-time decision making by analyzing the driving behaviors of vehicles ahead. The approach utilizes a convolutional 3D neural network (C3D) with feature simplification to classify taillight images into eight distinct states, adapting to various environmental conditions. The problem addressed is the variability in environmental conditions that affect the performance of vision-based systems. Our objective is to improve the accuracy and generalizability of taillight signal recognition under different conditions. The methodology involves using a C3D model to analyze video sequences, capturing both spatial and temporal features. Experimental results demonstrate a significant improvement in the model's accuracy (85.19%) and generalizability, enabling precise interpretation of preceding vehicle maneuvers. The proposed technique effectively enhances autonomous vehicle navigation and safety by ensuring reliable taillight state recognition, with potential for further improvements under nighttime and adverse weather conditions. Additionally, the system reduces latency in signal processing, ensuring faster and more reliable decision making directly on the edge devices installed within the vehicles.

Research on Anomaly Detection of Surveillance Video Based on Branch-Fusion Net and CSAM.

As the monitor probes are used more and more widely these days, the task of detecting abnormal behaviors in surveillance videos has gained widespread attention. The generalization ability and parameter overhead of the model affect how accurate the detection result is. To deal with the poor generalization ability and high parameter overhead of the model in existing anomaly detection methods, we propose a three-dimensional multi-branch convolutional fusion network, named "Branch-Fusion Net". The network is designed with a multi-branch structure not only to significantly reduce parameter overhead but also to improve the generalization ability by understanding the input feature map from different perspectives. To ignore useless features during the model training, we propose a simple yet effective Channel Spatial Attention Module (CSAM), which sequentially focuses attention on key channels and spatial feature regions to suppress useless features and enhance important features. We combine the Branch-Fusion Net and the CSAM as a local feature extraction network and use the Bi-Directional Gated Recurrent Unit (Bi-GRU) to extract global feature information. The experiments are validated on a self-built Crimes-mini dataset, and the accuracy of anomaly detection in surveillance videos reaches 93.55% on the test set. The result shows that the model proposed in the paper significantly improves the accuracy of anomaly detection in surveillance videos with low parameter overhead.

Hypoxia-induced complement dysregulation is associated with microvascular impairments in mouse tracheal transplants.

BACKGROUND: Complement Regulatory Proteins (CRPs), especially CD55 primarily negate complement factor 3-mediated injuries and maintain tissue homeostasis during complement cascade activation. Complement activation and regulation during alloimmune inflammation contribute to allograft injury and therefore we proposed to investigate a crucial pathological link between vascular expression of CD55, active-C3, T cell immunity and associated microvascular tissue injuries during allograft rejection. METHODS: Balb/c→C57BL/6 allografts were examined for microvascular deposition of CD55, C3d, T cells, and associated tissue microvascular impairments during rejection in mouse orthotopic tracheal transplantation. RESULTS: Our findings demonstrated that hypoxia-induced early activation of HIF-1α favors a cell-mediated inflammation (CD4+, CD8+, and associated proinflammatory cytokines, IL-2 and TNF-α), which proportionally triggers the downregulation of CRP-CD55, and thereby augments the uncontrolled release of active-C3, and Caspase-3 deposition on CD31+ graft vascular endothelial cells. These molecular changes are pathologically associated with microvascular deterioration (low tissue O2 and Blood flow) and subsequent airway epithelial injuries of rejecting allografts as compared to non-rejecting syngrafts. CONCLUSION: Together, these findings establish a pathological correlation between complement dysregulation, T cell immunity, and microvascular associated injuries during alloimmune inflammation in transplantation.

C3d-positive donor-specific antibodies have a role in pretransplant risk stratification of cross-match-positive HLA-incompatible renal transplantation: United Kingdom multicentre study.

Anti-HLA-antibody characteristics aid to risk-stratify patients and improve long-term renal graft outcomes. Complement activation by donor-specific antibody (DSA) is an important characteristic that may determine renal allograft outcome. There is heterogeneity in graft outcomes within the moderate to high immunological risk cases (cross-match-positive). We explored the role of C3d-positive DSAs in sub-stratification of cross-match-positive cases and relate to the graft outcomes. We investigated 139 cross-match-positive living-donor renal transplant recipients from four transplant centres in the United Kingdom. C3d assay was performed on serum samples obtained at pretreatment (predesensitization) and Day 14 post-transplant. C3d-positive DSAs were found in 52 (37%) patients at pretreatment and in 37 (27%) patients at Day 14 post-transplant. Median follow-up of patients was 48 months (IQR 20.47-77.57). In the multivariable analysis, pretreatment C3d-positive DSA was independently associated with reduced overall graft survival, the hazard ratio of 3.29 (95% CI 1.37-7.86). The relative risk of death-censored five-year graft failure was 2.83 (95% CI 1.56-5.13). Patients with both pretreatment and Day 14 C3d-positive DSAs had the worst five-year graft survival at 45.5% compared with 87.2% in both pretreatment and Day 14 C3d-negative DSA patients with the relative risk of death-censored five-year graft failure was 4.26 (95% CI 1.79, 10.09). In this multicentre study, we have demonstrated for the first time the utility of C3d analysis as a distinctive biomarker to sub-stratify the risk of poor graft outcome in cross-match-positive living-donor renal transplantation.

Comparison of C3d immunohistochemical staining to enzyme-linked immunosorbent assay and immunofluorescence for diagnosis of bullous pemphigoid.

BACKGROUND: Bullous pemphigoid (BP), the most common autoimmune blistering disease, may be diagnostically challenging. Direct immunofluorescence (DIF), indirect immunofluorescence (IIF), enzyme-linked immunosorbent assay (ELISA), and recently, C3d immunohistochemistry (IHC), are used as adjuncts to diagnosis. OBJECTIVE: To compare C3d IHC to DIF, IIF, and ELISA testing in BP diagnosis. METHODS: C3d IHC was performed on skin biopsy specimens from 51 patients (27 with BP and 24 with other blistering diseases) and compared to DIF and IIF, with anti-BP180 or anti-BP230 ELISA results used as the gold standard. RESULTS: We found C3d IHC, DIF, and IIF had similar sensitivity (74.1%, 63.1%, and 70.4%), specificity (95.8%, 100%, and 100%), positive predictive value (95.2%, 100%, and 100%), and negative predictive value (76.7%, 70.6%, and 75%) for BP. Cases with positive C3d IHC, DIF, and IIF had significantly higher anti-BP180 and anti-BP230 by ELISA than cases with negative testing (P < .0001). False-negative IIF results were associated with lower BP230 compared with true-positive results (P = .03). LIMITATIONS: This was a single-center, retrospective study. CONCLUSION: Our study compared C3d IHC to DIF and IIF in BP diagnosis, demonstrating C3d IHC on fixed tissue provides similar diagnostic utility to immunofluorescence and ELISA.

Radiotherapy for the treatment of pituitary adenomas: A dosimetric comparison of three planning techniques.

AIM: Our goal was to compare conformal 3D (C3D) radiotherapy (RT), modulated intensity RT (IMRT), and volumetric modulated arc therapy (VMAT) planning techniques in treating pituitary adenomas. BACKGROUND: RT is important for managing pituitary adenomas. Treatment planning advances allow for higher radiation dosing with less risk of affecting organs at risk (OAR). MATERIALS AND METHODS: We conducted a 5-year retrospective review of patients with pituitary adenoma treated with external beam radiation therapy (C3D with flattening filter, flattening filter-free [FFF], IMRT, and VMAT). We compared dose-volume histogram data. For OARs, we recorded D2%, maximum, and mean doses. For planning target volume (PTV), we registered V95%, V107%, D95%, D98%, D50%, D2%, minimum dose, conformity index (CI), and homogeneity index (HI). RESULTS: Fifty-eight patients with pituitary adenoma were included. Target-volume coverage was acceptable for all techniques. The HI values were 0.06, IMRT; 0.07, VMAT; 0.08, C3D; and 0.09, C3D FFF (p < 0.0001). VMAT and IMRT provided the best target volume conformity (CI, 0.64 and 0.74, respectively; p < 0.0001). VMAT yielded the lowest doses to the optic pathway, lens, and cochlea. The position of the neck in extreme flexion showed that it helps in planning mainly with VMAT by allowing only one arc to be used and achieving the desired conformity, decreasing the treatment time, while allowing greater protection to the organs of risk using C3D, C3DFFF. CONCLUSIONS: Our results confirmed that EBRT in pituitary adenomas using IMRT, VMAT, C3D, C3FFF provide adequate coverage to the target. VMAT with a single arc or incomplete arc had a better compliance with desired dosimetric goals, such as target coverage and normal structures dose constraints, as well as shorter treatment time. Neck extreme flexion may have benefits in treatment planning for better preservation of organs at risk. C3D with extreme neck flexion is an appropriate treatment option when other treatment techniques are not available.

Pelvic radiation therapy with volumetric modulated arc therapy and intensity-modulated radiotherapy after renal transplant: A report of 3 cases.

AIM: Describe characteristics and outcomes of three patients treated with pelvic radiation therapy after kidney transplant. BACKGROUND: The incidence of pelvic cancers in kidney transplant (KT) recipients is rising. Currently it is the leading cause of death. Moreover, treatment is challenging because anatomical variants, comorbidities, and associated treatments, which raises the concern of using radiotherapy (RT). RT has been discouraged due to the increased risk of urethral/ureteral stricture and KT dysfunction. MATERIALS AND METHODS: We reviewed the electronic health records and digital planning system of patients treated with pelvic RT between December 2013 and December 2018 to identify patients with previous KT. CASES DESCRIPTION: We describe three successful cases of KT patients in which modern techniques allowed full standard RT for pelvic malignances (2 prostate and 1 vaginal cancer) with or without elective pelvic nodal RT, without allograft toxicity at short and long follow-up (up to 60 months). CONCLUSION: When needed, RT modern techniques remain a valid option with excellent oncologic results and acceptable toxicity. Physicians should give special considerations to accomplish all OAR dose constraints in the patient's specific setting. Recent publications recommend KT mean dose <4 Gy, but graft proximity to CTV makes this unfeasible. We present 2 cases where dose constraint was not achieved, and to a short follow-up of 20 months renal toxicity has not been documented. We recommend the lowest possible mean dose to the KT, but never compromising the CTV coverage, since morbimortality from recurrent or progressive cancer disease outweighs the risk of graft injury.

Structure of the UspA1 protein fragment from Moraxella catarrhalis responsible for C3d binding.

The gram-negative bacterium Moraxella catarrhalis infects humans exclusively, causing various respiratory tract diseases, including acute otitis media in children, septicaemia or meningitis in adults, and pneumonia in the elderly. To do so, M. catarrhalis expresses virulence factors facilitating its entry and survival in the host. Among them are the ubiquitous surface proteins (Usps): A1, A2, and A2H, which all belong to the trimeric autotransporter adhesin family. They bind extracellular matrix molecules and inhibit the classical and alternative pathways of the complement cascade by recruiting complement regulators C3d and C4b binding protein. Here, we report the 2.5 Šresolution X-ray structure of UspA1299-452, which previous work had suggested contained the canonical C3d binding site found in both UspA1 and UspA2. We show that this fragment of the passenger domain contains part of the long neck domain (residues 299-336) and a fragment of the stalk (residues 337-452). The coiled-coil stalk is left-handed, with 7 polar residues from each chain facing the core and coordinating chloride ions or water molecules. Despite the previous reports of tight binding in serum-based assays, we were not able to demonstrate binding between C3d and UspA1299-452 using ELISA or biolayer interferometry, and the two proteins run separately on size-exclusion chromatography. Microscale thermophoresis suggested that the dissociation constant was 140.5 ±â€¯8.4 µM. We therefore suggest that full-length proteins or other additional factors are important in UspA1-C3d interactions. Other molecules on the bacterial surface or present in serum may enhance binding of those two molecules.

A candidate DNA vaccine encoding a fusion protein of porcine complement C3d-P28 and ORF2 of porcine circovirus type 2 induces cross-protective immunity against PCV2b and PCV2d in pigs.

BACKGROUND: Porcine circovirus type 2 (PCV2) is an economically important viral pathogen for swine industry worldwide. However, current PCV2 vaccines provide incomplete protection against the PCV2d, which has recently emerged as the predominant pathogenic form of PCV2. METHODS: To develop a novel DNA vaccine with high efficacy against PCV2d virus, we fused the ORF2 of PCV2d to three copies of the minimum-binding domain of the complement C3 cascade terminal component, C3d-P28. Expression of ORF2 alone (pVO) or fused C3d-P28 (pVOC3) were verified by immunofluorescent assay. Vaccine efficacy was tested by measured the DNA copy and T and B cell immune response. RESULTS: Vaccination with pVOC3 reduced the levels of PCV2 genomic DNA after pigs were infected with either PCV2b or PCV2d genotypes, produced potent antibodies against PCV2, and stimulated PCV2-specific interferon-γ secreting cells. CONCLUSION: Results suggested pVOC3 would be a safe and effective DNA vaccine to confer cross-protection against both PCV2b and PCV2d genotypes in pigs.

Is Early Complement Activation in Renal Transplantation Associated with Later Graft Outcome?

BACKGROUND/AIMS: Complement activation is important in post-transplantation renal injury, but data on its role as predictor of transplant outcome/complications when assessed in donor kidneys are lacking. METHODS: In human renal transplant biopsies with delayed graft function (DGF, n=12), antibody mediated rejection (ABMR, n=8), T-cell mediated rejection (TCMR, n=11), 1 year protocol biopsies (control, n=10) and corresponding zero-biopsies we performed immunohistochemical analyses of 6 complement factors using FFPE sections and correlated the findings with kidney function, as assessed by serum creatinine, and morphological changes including interstitial fibrosis and tubular atrophy (IF/TA). RESULTS: In DGF, TCMR and ABMR significant complement deposition was observed, which was less pronounced in corresponding zero-biopsies. Zero-biopsies with subsequent ABMR showed glomerular complement factor D and C3c expression. Moreover, glomerular C3c and C9 and tubular MASP-2 and Collectin-11 expression in zero-biopsies significantly correlated with serum creatinine at diagnosis of DGF, TCMR or ABMR. Glomerular C1q was significantly increased in ABMR, but not in DGF and TCMR. In contrast, peritubular C1q was significantly enhanced in DGF and TCMR compared to zero-biopsies. Using C3d as a surrogate marker for complement activity we could confirm that stained complement factors are frequently associated with complement activity. CONCLUSION: Complement deposition strongly correlated with histopathological changes observed in renal transplants. All 3 complement pathways were operational in biopsies with DGF, TCMR and ABMR albeit with differential abundance and localization. Since complement deposition in zero-biopsies correlated with graft function and morphological changes, early specific complement inhibition in renal transplantation may be a new therapeutic option to prevent graft loss.

The solvent at antigen-binding site regulated C3d-CR2 interactions through the C-terminal tail of C3d at different ion strengths: insights from molecular dynamics simulation.

BACKGROUND: The interactions of complement receptor 2 (CR2) and the degradation fragment C3d of complement component C3 play important links between the innate and adaptive immune systems. Due to the importance of C3d-CR2 interaction in the design of vaccines and inhibitors, a number of studies have been performed to investigate C3d-CR2 interaction. Many studies have indicated C3d-CR2 interactions are ionic strength-dependent. METHODS: To investigate the molecular mechanism of C3d-CR2 interaction and the origin of effects of ionic strength, molecular dynamics simulations for C3d-CR2 complex together with the energetic and structural analysis were performed. RESULTS: Our results revealed the increased interactions between charged protein and ions weaken C3d-CR2 association, as ionic strengths increase. Moreover, ion strengths have similar effects on antigen-binding site and CR2 binding site. Meanwhile, Ala17 and Gln20 will transform between the activated and non-activated states mediated by His133 and Glu135 at different ion strengths. CONCLUSIONS: Our results reveal the origins of the effects of ionic strengths on C3d-CR2 interactions are due to the changes of water, ion occupancies and distributions. GENERAL SIGNIFICANCE: This study uncovers the origin of the effect of ionic strength on C3d-CR2 interaction and deepens the understanding of the molecular mechanism of their interaction, which is valuable for the design of vaccines and small molecule inhibitors.

[Expression of C3d in normal human liver tissues with non-immunologic osmostic mechanism].

Objective: To observe the deposition of complement C3d at different development stages in human normal organs and tissues, and investigate the significance of its deposition. Methods: Using immunohistochemical methods, the deposition of C3d was detected at different development stages of 60 normal human organs and tissue specimens and double staining was performed in some specimens. Ninty-five cases of other organs or tissues were collected as control group. Results: In 50 of 60 livers, it was observed the deposition of C3d in Glisson's capsule and periportal sheath, with irregular linear network-like disposition surrounding the portal sheath. In different age groups, the expression of C3d was more beyond the 20 year-old group than 3 to 20 year-old group. There wasn't any expression of C3d under 3-year-old group. Under the immuning electron micrograph, C3d depositing at the Glisson's capsule was observed, without immuning compounding. Thirty in 40 spleens, deposition of C3d in capsules, arteries of lymphatic sheath, follicles in the spleen was observed. Conclusions: The deposition of C3d in Glisson's capsule, splenic trabeculae, fibrous sheath, endarterium of liver and spleen arterioles, within normal human tissues from patients elder than 3 years, are osmosis/immunogenic deposition. The deposition of C3d is a normal physiological phenomenon, and treatment of the deposition of C3d should be avoided, as it is an immune complex or immuning reaction phenomenon.

Clinically and/or Serologically Misleading Findings Surrounding Immune Haemolytic Anaemias.

Autoimmune haemolytic anaemias (AIHAs) are well-characterized disorders. They can be differentiated from one another and from other non-immune haemolytic anaemias by clinical, laboratory and serological testing. However, several misleading clinical presentations and/or serological findings may result in misinterpretation, delay and/or misdiagnosis. Such failures are avoidable by adequate clinical and serological experience of the responsible physicians and serologists or, at least, by an optimised bidirectional communication. As long as this has not been achieved, unpleasant failures are to be expected. A true diagnosis of AIHA can neither be verified by clinical nor serological findings alone. Thus, a collective clinical and serological picture remains obligatory for fulfilling the criteria of optimal diagnosis and therapy. Ultimately, the majority of pioneer scientific and practical work in this field stems from scientists who were simultaneously involved in both the clinic and serology.

Reduction of fertility in male mice immunised with pSG.SS.C3d3.YL.Bin1b recombinant vaccine.

OBJECTIVES: To study the anti-fertility effect of a DNA vaccine using Bin1b as the target antigen in male mice. METHODS: A novel recombinant eukaryotic vector containing a fusion gene sequence of mouse Bin1b in tandem with three copies of C3d fragment (C3d3) was used to construct pSG.SS.C3d3.YL.Bin1b. The correct expression of the Bin1b-C3d3 protein was confirmed in transfected HEK293 cells by indirect immunofluorescence and western blot analysis. The fertility of immunised mice was determined by a mating experiment and sperm motility test. Anti-Bin1b antibody titres in sera were examined by ELISA assays. Binding activity of C3d3 fragment of the fusion protein was verified in C3d receptor-expressing Raji cells and flow cytometric analysis. RESULTS: Immunisation of pSG.SS.C3d3.YL.Bin1b recombinant DNA vaccine significantly decreased sperm motility and compromised fertility in male mice. ELISA results showed that the titres of anti-Bin1b IgG in sera of immunised mice increased markedly with the immunisation process. Further, the anti-fertility effect of pSG.SS.C3d3.YL.Bin1b was significantly better than that of pSG.SS.YL.Bin1b DNA vaccine and generated higher titres of anti-Bin1b antibody. CONCLUSIONS: Our results show that recombinant DNA vaccine targeting Bin1b can markedly reduce fertility in male mice, providing an alternative approach for birth control.

Storage of RBCs results in an increased susceptibility for complement-mediated degradation.

OBJECTIVE: The objective of this study was to elucidate whether complement activation occurs during the storage of RBCs in newly formulated PAGGS-M storage medium. BACKGROUND: The reason for red blood cell (RBC) storage lesions is not yet fully understood. The contribution of complement to RBC storage lesion has not been extensively characterised. STUDY DESIGN AND METHODS: We investigated the surface expression of CD35, CD55, CD59 and CD47, as well as deposition of C3d, using flow cytometry over a storage period of up to 42 days on a weekly basis. C3d and the immunoglobulins IgG, IgM and IgA were additionally investigated via the direct antiglobulin test (DAT). The effect of contact with homologous serum for 30 min at 37 °C was also performed for C3d and CD35 and is subsequently termed as a 'transfusion simulation (TS)'. RESULTS: A weak but significant increase of C3d was observed prior to TS (anova P = 0.0103), whereas a stronger increase from 74.0 ± 12.4 to 101.2 ± 9.7 was observed post-TS (anova; P < 0.0001). These findings were confirmed by the DAT. CD35, CD55 and CD47 demonstrated a decrease in their expression over storage time (anova; P < 0.0001 each). The majority of changes occurred following 14 days. There was neither a decrease of CD59 observed nor an increase of IgG, IgM and IgA. CONCLUSION: RBCs are becoming increasingly susceptible to spontaneous complement deposition following TS, which might be associated with the decrease of C35 and CD55 by proteolytic cleavage and vesiculation during storage. As the impact of storage lesions is rather controversial, institutions involved in blood collection and administration of blood products should focus on carrying out research on the prevention of storage lesions.

C3d deposition in the media of renal arterioles is a useful marker for arteriolosclerosis in IgA nephropathy.

C3d deposition in peritubular capillaries has been demonstrated to indicate antibody-mediated alloresponse during renal transplantation. C3d deposition in renal arterioles in IgA nephropathy (IgAN), however, is poorly documented. Especially, its significance to the pathology of primary glomerulonephritis remains unclear. This retrospective study included 340 patients with IgAN who underwent renal biopsy at our center. C3d strongly positive deposition in arterioles was observed in 123 (36.2%) of the 340 cases, and weakly positive deposition of C3d was observed in 217 cases (63.8%). In the weakly positive group, C3d mainly deposited in the intima of arterioles. In the strongly positive group, C3d deposited in the intima and the media of arterioles, presenting as the medial thickening and sclerosis of varying severities. The prognosis was worse in the C3d strongly positive group than in the weakly positive group during a 2-year follow-up (P = .027). The predictive value of C3d deposition in the media of arterioles in patients with IgAN may be a useful marker for arteriolosclerosis indicating unfavorable clinical outcomes.

Defective C3d caused by C3 p.W1034R in inherited atypical hemolytic uremic syndrome.

INTRODUCTION: Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy. Personal genome analyses have revealed numerous aHUS-causing variants, mainly complement-related genes. However, not all aHUS-causing variants have been functionally validated. METHODS: An exome sequence analysis of a Japanese multiplex family composed of three patients diagnosed with aHUS in infancy and showing frequent relapses clustered in a dominant transmission mode was performed. Protein interaction between the C3d and C-terminal domains of factor H was analyzed using a quartz crystal microbalance. RESULTS: Following filtering by heterozygous variants, amino acid substitutions, and allele frequency, the analysis revealed eight rare variants shared by the affected individuals. Variant prioritization listed C3 p.W1034R as the most likely candidate gene mutation in the affected individuals, despite being classified as a variant of uncertain significance. Binding of recombinant C3d harboring 1034R to recombinant short consensus repeats 15 to 20 of factor H was significantly suppressed compared with that of C3 with 1034W. CONCLUSION: C3 p.W1034R results in an inherited form of aHUS that often presents with recurrent episodes, possibly because of impaired interactions between the C3d and C-terminal domains of factor H. Following comprehensive genomic analysis, functional validation of C3 p.W1034R strengthens the molecular basis for aHUS pathophysiology.