Recent advances in the application of Mendelian randomization to chronic kidney disease.

OBJECTIVE: Chronic kidney disease (CKD) is a condition influenced by both genetic and environmental factors and has been a focus of extensive research. Utilizing Mendelian randomization, researchers have begun to untangle the complex causal relationships underlying CKD. This review delves into the advances and challenges in the application of MR in the field of nephrology, shifting from a mere summary of its principles and limitations to a more nuanced exploration of its contributions to our understanding of CKD. METHODS: Key findings from recent studies have been pivotal in reshaping our comprehension of CKD. Notably, evidence indicates that elevated testosterone levels may impair renal function, while higher sex hormone-binding globulin (SHBG) levels appear to be protective, predominantly in men. Surprisingly, variations in plasma glucose and glycated hemoglobin levels seem unaffected by genetically induced changes in the estimated glomerular filtration rate (eGFR), suggesting an independent pathway for renal function impairment. RESULTS: Furthermore, lifestyle factors such as physical activity and socioeconomic status emerge as significant influencers of CKD risk and kidney health. The relationship between sleep duration and CKD is nuanced; short sleep duration is linked to increased risk, while long sleep duration does not exhibit a clear causal effect. Additionally, lifestyle factors, including diet, exercise, and mental wellness activities, play a crucial role in kidney health. New insights also reveal a substantial causal connection between both central and general obesity and CKD onset, while no significant links were found between genetically modified LDL cholesterol or triglyceride levels and kidney function. CONCLUSION: This review not only presents the recent achievements of MR in CKD research but also illuminates the path forwards, underscoring critical unanswered questions and proposing future research directions in this dynamic field.

Current advances in the application of nanomedicine in bladder cancer.

Bladder cancer is the most common malignant tumor of the urinary system, however there are several shortcomings in current diagnostic and therapeutic measures. In terms of diagnosis, the diagnostic tools currently available are not sufficiently sensitive and specific, and imaging is poor, leading to misdiagnosis and missed diagnoses, which can delay treatment. In terms of treatment, current treatment options include surgery, chemotherapy, immunotherapy, gene therapy, and other emerging treatments, as well as combination therapies. However, the main reasons for poor efficacy and side effects during treatment are the lack of specificity and targeting, improper dose control of drugs and photosensitizers, damage to normal cells while attacking cancer cells, and difficulty in delivering siRNA to cancer cells. Nanomedicine is an emerging approach. Among the many nanotechnologies applied in the medical field, nanocarrier-assisted drug delivery systems have attracted extensive research interest due to their great translational value. Well-designed nanoparticles can deliver agents or drugs to specific cell types within target organs through active targeting or passive targeting (enhanced permeability and retention), which allows for imaging, diagnosis, as well as treatment of cancer. This paper reviews advances in the application of various nanocarriers and their advantages and drawbacks, with a focus on their use in the diagnosis and treatment of bladder cancer.

The association between cognitive impairment/dementia and albuminuria: a systematic review and meta-analysis.

BACKGROUND: To identify the association between albuminuria and dementia or cognitive impairment. METHODS: The literature search was performed to identify relevant scientific studies through August 2019, including PubMed/Medline and EMBASE. For inclusion, the studies had to fulfil the following criteria: population-based cohort, case-control or cross-sectional studies; quantifying an association of albuminuria with cognitive impairment or dementia; and reported odds ratio (OR), and the corresponding 95% confidential interval (95% CI). Random effects model was used to yield pooled estimates. RESULTS: A total of 16 studies (11 cohort studies and five cross-sectional studies) were included in the meta-analyses. Based on the fully adjusted estimates, albuminuria was associated with a significant higher risk of cognitive impairment or dementia. Furthermore, the same trend existed for cognitive impairment and dementia, respectively. In addition, both of Alzheimer's diseases (AD) and vascular dementia (VaD) were significantly associated with albuminuria. CONCLUSION: Albuminuria was significantly associated with cognitive impairment and dementia. Corresponding to an earlier subclinical time-point in kidney disease progress, albuminuria may be a potential factor predicting the future occurrence of dementia.

Prognostic Roles of Phosphofructokinase Platelet in Clear Cell Renal Cell Carcinoma and Correlation with Immune Infiltration.

BACKGROUND: Abnormal expression of phosphofructokinase platelet (PFKP) has been reported in various cancer types. However, the role of PFKP in clear cell renal cell carcinoma (ccRCC) remains unclear. METHODS: In this study, the PFKP expression levels in various cancers were systemically described by integrating multiple kinds of publicly available databases. The relationship between PFKP expression and clinical prognosis of ccRCC patients was analyzed based on the TCGA database. Furthermore, PFKP-related genes and the top 10 hub genes were identified. The enrichment analysis, PPI network, and the relationship between PFKP and tumor-infiltrating immune cells were conducted to explore why PFKP was associated with clinical outcomes in ccRCC patients. RESULTS: PFKP was significantly highly expressed in kidney cancer, especially in ccRCC. Moreover, patients with low expression of PFKP were correlated with poor 5-year and 10-year overall survival (OS) (P < 0.05). Low PFKP expression was a risk factor associated with decreased OS in subgroups including males, females, grade 3-4, and stage III-IV (all P < 0.05). GO and KEGG enrichment analyses showed that 10 hub genes were mainly enriched in the tumor immune response. Finally, PFKP expression level was highly correlated with the infiltration of B cell, CD8+ T cell, CD4+ T cell, macrophage, neutrophil, and dendritic cell. CONCLUSION: In short, our findings suggested that PFKP is highly expressed in ccRCC significantly and facilitated tumor immune response which in turn associated with a good prognosis.

Tunica vaginalis testis metastasis as the first clinical manifestation of pancreatic adenocarcinoma: A case report.

BACKGROUND: Metastases from pancreas or ampullary malignancies are common, but the spread to testicle and paratesticular tissue is exceedingly rare. To the best of our knowledge, fewer than 30 cases have been reported in the literature. More rarely, metastasis to tunica vaginalis testis occurs without involvement of the testes and epididymis. CASE SUMMARY: A 65-year-old male who complained of painless swelling of the left scrotum for over 1 wk was referred to the Department of Urology. Scrotal ultrasound showed left testicular hydrocele with paratesticular masses. Chest computed tomography revealed lung metastasis and enlarged left supraclavicular lymph node.The blood tumor markersalpha-fetoprotein, human chorionic gonadotropin, and serum lactate dehydrogenase were withinnormal limits.The preoperative diagnosis was left testicular tumor with lung metastasis. Then radical orchidectomy of the left testicle and high ligation of the spermatic cord were performed, and postoperative histopathology suggested metastatic tumors that was confirmed by an abdominal computed tomographic scan. The positive computed tomography findings, in conjunction with the expression of cytokeratin 7 (CK7), CK20, CK5/6, and absence of expression of Wilms' tumor suppressor gene 1, calretinin, melanocyte, prostate-specific antigen, thyroid transcription factor-1, GATA binding protein 3, caudal type homeobox 2, and napsinA supported the diagnosis of pancreatic adenocarcinoma. The outcome of this patient was unsatisfactory, and he died 3 mo later. CONCLUSION: This case suggests that pancreatic metastatic carcinoma must be considered in the differential diagnosis of scrotal enlargement. The advanced age of the patient wassuggestive of a secondary testicular tumor.In addition, careful physical examination and ultrasonography as well as radiological examination have become a standard modality.

Safety and Efficacy of Right Retroperitoneal Laparoscopic Live Donor Nephrectomy: A Retrospective Single-Center Study.

BACKGROUND The aim of this study was to investigate the efficacy and safety of right retroperitoneal laparoscopic live donor nephrectomy (LDN) in 81 cases of living-related renal transplant. MATERIAL AND METHODS We retrospectively reviewed all living-related donors who underwent right retroperitoneoscopic living donor nephrectomy between June 2010 and December 2017 at the First Hospital of Jilin University and their corresponding recipients. Demographic and clinical data were collected from the hospital's electronic clinical data system. Data on preoperative renal retention parameters, operative time, and donor kidney warm ischemia time, the trimmed length of the renal artery and vein of donor kidney, and the time to extubation were recorded. Complications in both donors and recipients were recorded. RESULTS We included 81 donors who underwent successful right-sided retroperitoneoscopic LDN, with 31 males and 50 females and a mean age of 47.1 years (range 21-63 years). There was no intraoperative conversion to open donor nephrectomy. The mean operative time was 120.68±29.8 min. The mean warm ischemic time was 49.26±3.86 s. The estimate blood loss was 54.32 mL (range 50-400 mL). The median length of hospital stay was 7 days (range 4-13 days). There was neither intraoperative complication such as hemorrhage or lymph fistula nor kidney graft injury. There was no graft renal vein thrombosis and ureteral stricture or other complications. No graft rejection occurred. CONCLUSIONS Right retroperitoneal laparoscopic live donor nephrectomy is safe and effective for renal transplant in living-related renal transplant by laparoscopic excision and extraction of the right kidney with vena cava flap.

Peptidyl Arginine Deiminase, Type II (PADI2) Is Involved in Urothelial Bladder Cancer.

Peptidyl arginine deiminase, type II (PADI2) expression has been shown to potentiate multiple different carcinogenesis pathway including breast carcinoma and spontaneous skin neoplasia. The objective of this study was to examine the role of PADI2 in urothelial bladder cancer which has not been evaluated previously. Analysis of mutation and genome amplification of bladder cancer within The Cancer Genome Atlas (TCGA) showed that PADI2 is both mutated and amplified in a cohort of bladder cancer patients, with the largest number of mutations detected in urothelial bladder cancer. Even though PADI2 expression was not significantly correlated to survival in bladder cancer patients, it was significantly overexpressed at the mRNA and protein levels, as revealed by TCGA data and immunohistochemistry analysis, respectively. PADI2 showed wide expression pattern in bladder cancer tissues but was hardly detected in tumor adjacent normal tissue. RNAi mediated silencing of PADI2 in the bladder cancer cell line T24 did not result in a change of proliferation. Interestingly knockdown of PADI2 expression did not affect Snail1 protein, which is associated with metastatic progression, in these cells. However, PADI2 silencing remarkably attenuated both in vitro migration and invasion- in T24 cells indicating a Snail1-independent effect of PADI2 on invasive potential of urothelial bladder cancer. This was further corroborated by in vivo xenograft assays where PADI2 shRNA harboring T24 cells did not have detectable tumors by week 4 as compared to robust tumors in the control Luciferase shRNA harboring cells. PADI2 silencing did not affect proliferation rates and hence this would suggest that PADI2 knockdown is perhaps causing increased apoptosis as well as transition through the cell cycle, which needs to be confirmed in future studies. Our results reveal a yet undefined role of PADI2 as an oncogene in urothelial bladder cancer.

B cell clonal expansion within immune infiltrates in human cardiac allograft vasculopathy.

Cardiac allograft vasculopathy (CAV) is associated with intragraft B cell infiltrates. Here, we studied the clonal composition of B cell infiltrates using 4 graft specimens with CAV. Using deep sequencing, we analyzed the immunoglobulin heavy chain variable region repertoire in both graft and blood. Results showed robust B cell clonal expansion in the graft but not in the blood for all cases. Several expanded B cell clones, characterized by their uniquely rearranged complementarity-determining region 3, were detected in different locations in the graft. Sequences from intragraft B cells also showed elevated levels of mutated rearrangements in the graft compared to blood B cells. The number of somatic mutations per rearrangement was also higher in the graft than in the blood, suggesting that B cells continued maturing in situ. Overall, our studies demonstrated B cell clonal expansion in human cardiac allografts with CAV. This local B cell response may contribute to the pathophysiology of CAV through a mechanism that needs to be identified.

Role of regulatory T cells in CD47/donor-specific transfusion-induced immune tolerance in skin-heart transplantation mice.

OBJECTIVES: To explore the role of regulatory T (Treg ) cells in the establishment of immune tolerance induced by donor-specific transfusion (DST) in mice with skin-heart transplantation. METHODS: C57BL/6 mice received DST of splenocytes from CD47+/+ or CD47-/- H-2bm1 mice or no DST 7 days before skin-heart transplantation from major histocompatibility complex class I-mismatched H-2bm1 donors. The number and proportion of Treg cells in graft and lymphoid organs were measured by flow cytometry (FACS) and immunohistochemistry (IHC). The inhibitory function of Treg cells and anti-donor T-cell responses were assessed by mixed lymphocyte reaction. RESULTS: We observed that mean survival time (MST) of skin or heart graft was significantly longer in C57BL/6 mice which received DST from CD47+/+ H-2bm1 mice than from CD47-/- H-2bm1 mice. By FACS, we found that the number of Treg cells in spleen was increased significantly in mice which received CD47-/- DST compared to mice which received CD47+/+ DST. However, the percentages of Treg cells in total splenocytes and lymph node cells were significantly higher in mice that received CD47+/+ DST than mice which received CD47-/- DST. Immunohistochemistry showed an increased heart grafts infiltration of Treg cells in the recipients with CD47-/- DST, but not CD47+/+ DST. Supporting this, we found that donor T-cell proliferation was significantly suppressed in mice which received CD47+/+ DST compared to mice which received CD47-/- DST. There was no difference of inhibitory function of Treg cells between these two groups. CONCLUSION: Our results indicated that CD47 expression on DST cells plays an important role in the induction of immune tolerance in mice with skin-heart transplantation. Increased percentage of Treg cells may contribute to immune tolerance induced by CD47+/+ DST.

Post-Transplant Natural Antibodies Associate with Kidney Allograft Injury and Reduced Long-Term Survival.

Background The development of antibodies specific to HLA expressed on donor tissue (donor-specific antibodies [DSAs]) is a prominent risk factor for kidney graft loss. Non-HLA antibodies with pathogenic potential have also been described, including natural antibodies (Nabs). These IgG Nabs bind to immunogenic self-determinants, including oxidation-related antigens.Methods To examine the relationship of Nabs with graft outcomes, we assessed Nabs in blinded serum specimens collected from a retrospective cohort of 635 patients who received a transplant between 2005 and 2010 at Necker Hospital in Paris, France. Serum samples were obtained immediately before transplant and at the time of biopsy-proven rejection within the first year or 1 year after transplant. Nabs were detected by ELISA through reactivity to the generic oxidized epitope malondialdehyde.Results Univariate Cox regression analysis identified the development of post-transplant Nabs (defined as 50% increase in reactivity to malondialdehyde) as a significant risk factor for graft loss (hazard ratio, 2.68; 95% confidence interval, 1.49 to 4.82; P=0.001). Post-transplant Nabs also correlated with increased mean Banff scores for histologic signs of graft injury in post-transplant biopsy specimens. Multivariable Cox analyses confirmed Nabs development as a risk factor independent from anti-HLA DSAs (hazard ratio, 2.07; 95% confidence interval, 1.03 to 4.17; P=0.04). Moreover, patients with Nabs and DSAs had a further increased risk of kidney graft loss.Conclusions These findings reveal an association between Nabs, kidney graft injury, and eventual graft failure, suggesting the involvement of Nabs in immune mechanisms of rejection.

Recurrent primary hyperoxaluria type 2 leads to early post-transplant renal function loss: A case report.

Primary hyperoxaluria type 2 is a rare autosomal recessive disorder caused by glyoxylate reductase/hydroxypyruvate reductase deficiency and characterized by recurrent episodes of nephrolithiasis and nephrocalcinosis. Herein, we describe a case of primary hyperoxaluria type 2 in a 33-year-old man who failed to respond to conventional therapies; thus renal transplantation was performed. This case demonstrated that, although primary hyperoxaluria type 2 is rare, hyperoxaluria should be suspected and blood oxalate and stone component be examined in patients with recurrent episodes of nephrolithiasis, particularly in those who are unresponsive to conventional therapies. Combined liver-kidney transplant may be required as kidney transplant alone is not likely to be successful.

Fenofibrate inhibits mTOR-p70S6K signaling and simultaneously induces cell death in human prostate cancer cells.

Fenofibrate is the most widely used lipid-lowering drug, but it seems to have anti-tumor effects in several tumor cell lines. However, there are only a few reports on its effects on human prostate cancer cells. Thus, we investigated the anti-proliferative effects of fenofibrate on human prostate cancer cells and potential mechanisms. The methods used include cell viability analysis with an MTT assay, as well as apoptosis and related signaling pathway analyses with flow cytometry and Western blotting. Fenofibrate inhibited PC-3 cell growth in dose- and time-dependent manners. The fenofibrate-induced cell death is predominantly apoptotic death that is mediated by both the caspase-3 activation and apoptosis-inducing factor (AIF) signaling pathways. Fenofibrate also increased the expression of Bad and decreased the expression of Bcl-2 and Survivin. Mechanistically, fenofibrate-induced cell death was associated with decreased p-p70S6K and the mammalian target of rapamycin (mTOR) phosphorylation levels. When further exploring the upstream mediators of mTOR/p70S6K, we found that fenofibrate increased p38 MAPK and AMPK phosphorylation but did not significantly change the phosphorylation levels of PI3K, AKT, and JNK. However, the inhibition of either p38 MAPK or AMPK with their specific inhibitor did not change the effect of fenofibrate-induced cell death. These findings suggested that fenofibrate indeed significantly inhibited the proliferation of PC-3 cells via apoptotic action, which is associated with the inactivation of the mTOR/p70S6K-dependent cell survival pathway. Although the mechanisms by which fenofibrate inactivates this pathway remains unclear, this study reveals great potential for its use for the clinical treatment of prostate cancers.

Diabetes Mellitus induces alterations in metallothionein protein expression and metal levels in the testis and liver.

Objective To investigate the effect of diabetes with and without vitamin E treatment on testicular metallothionein (MT) and metal (zinc, copper and iron) changes. Methods Diabetes was induced with a single intraperitoneal injection (i.p.) of streptozotocin in rats, and diabetic rats were given Vitamin E by i.p. every other day for 4 weeks. MT protein was measured by the cadmium-haeme assay and metal levels were detected by an atomic absorption spectrophotometer. Results Diabetes did not change testicular MT protein, but significantly increased hepatic MT protein. Diabetes significantly decreased testicular copper, but not hepatic copper. Zinc and iron levels were unchanged in both diabetic testis and liver. Vitamin E significantly enhanced both testicular and hepatic MT, and zinc levels in diabetic rats. Vitamin E slightly decreased the copper levels, but did not change the testicular and hepatic iron in diabetic rats. Conclusions Testicular MT protein expression was not increased, even though hepatic MT significantly increased independent of metal changes, in diabetic rats. Vitamin E enhanced testicular and hepatic MT, which correlated with increased zinc levels.

Prevalence of polyreactive innate clones among graft--infiltrating B cells in human cardiac allograft vasculopathy.

BACKGROUND: Cardiac allograft vasculopathy (CAV) has been associated with graft-infiltrating B cells, although their characteristics are still unclear. In this study we examined the frequency, localization and reactivity profile of graft-infiltrating B cells to determine their contribution to the pathophysiology of CAV. METHODS: B cells, plasma cells and macrophages were examined by immunohistochemistry in 56 allografts with CAV, 49 native failed hearts and 25 autopsy specimens. A total of 102 B-cell clones were immortalized directly from the infiltrates of 3 fresh cardiac samples with CAV. Their secreted antibodies were assessed using enzyme-linked immunoassay and flow cytometry. RESULTS: B-cell infiltration was observed around coronary arteries in 93% of allograft explants with CAV. Comparatively, intragraft B cells were less frequent and less dense in the intraventricular myocardium from where routine biopsies are obtained. Plasma cells and macrophages were also detected in 85% and 95% of explants, respectively. Remarkably, B-cell infiltrates were not associated with circulating donor-specific antibodies (DSA) or prior episodes of antibody-mediated rejection (AMR). Among all B-cell clones generated from 3 explants with CAV, a majority secreted natural antibodies reactive to multiple autoantigens and apoptotic cells, a characteristic of innate B cells. CONCLUSIONS: Our study reveals a high frequency of infiltrating B cells around the coronary arteries of allografts with CAV, independent of DSA or AMR. These cells are enriched for innate B cells with a polyreactive profile. The findings shift the focus from conventional DSA-producing B cells to the potentially pathogenic polyreactive B cells in the development of clinical CAV.

Dynamics of B Cell Recovery In Kidney/Bone Marrow Transplant Recipients.

BACKGROUND: Previous studies identified B cell gene signatures and predominance of specific B cell subsets as a marker of operational tolerance after kidney transplantation. These findings suggested a role for B cells in the establishment or maintenance of tolerance. Here we analyzed B cell recovery in 4 subjects, 3 of whom achieved tolerance after combined kidney/bone marrow transplantation. METHODS: Peripheral B cell subsets were examined longitudinally by flow cytometry. Immunoglobulin heavy chain repertoire analysis was performed using next-generation sequencing. Lastly, the patients' serum reactivity to HLA was assessed by Luminex. RESULTS: B cell counts recovered approximately 1 year posttransplant except for 1 subject who experienced delayed reconstitution. This subject resumed immunosuppression for acute rejection at 10 months posttransplant and underwent preemptive retransplantation at 3 years for chronic rejection. B cell recovery was accompanied by a high frequency of CD20 + CD24CD38 transitional B cells and a diversified clonal repertoire. However, all 4 subjects showed prevalence of CD20 + CD27+ memory B cells around 6 months posttransplant when B cell counts were still low and the clonal B cell repertoire very limited. The predominance of memory B cells was also associated with high levels of somatically mutated immunoglobulin heavy chain variable sequences and transient serum reactivity to HLA. CONCLUSIONS: Our observations reveal the presence of memory B cells early posttransplant that likely escaped the preparative regimen at a time consistent with the establishment of tolerance. Further studies are warranted to characterize the functional properties of these persisting memory cells and evaluate their potential contribution to tolerance induction.

Cell Cycle Arrest as a Therapeutic Target of Acute Kidney Injury.

The current lack of complete understanding of the pathogenesis of acute kidney injury (AKI) is a significant barrier to its early diagnosis and treatment. Cell cycle arrest plays an important role in the protection of renal tubular epithelial cells and maladaptive repair following AKI. G1 phase cell arrest serves as a protective mechanism following AKI, avoiding replication of damaged DNA. Insulinlike growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinase-2 (TIMP-2) are closely associated with G1 cell cycle arrest during the very early phase of cellular damage and can serve as an ideal biomarker to predict AKI. However, sustained cell cycle arrest after severe AKI may result in cell senescence and maladaptive repair, with typical characteristics of the development of cell cycle arrest in the gap 2 (G2) or mitotic (M) phase. Markers of cell cycle arrest signal and spread the "alarm" from the site of injury to adjacent cells in an autocrine or paracrine manner, giving rise to abnormal amplification and release of profibrogenic factors, activation of pericytes/perivascular fibroblasts, and eventually fibrosis. Therefore, cell cycle regulation has become a potentially new target for the prevention and treatment of AKI. In this review, we summarize the characteristics of the cell cycle following AKI and the markers of cell cycle arrest that enable the early detection of AKI. We also discuss how to prevent the progression of chronic kidney disease (CKD) by regulating cell cycle arrest.

[Clinical analysis of microsurgical treatment of giant intracranial arteriovenous malformations].

OBJECTIVE: To explore the clinical features and microsurgical treatment strategies of giant intracranial arteriovenous malformations (AVM). METHODS: A total of 15 cases of giant intracranial AVM treated with microsurgery were analyzed retrospectively. According to the Spetzler-Martin grade, there were 4 cases of grade Ⅳ, 11 cases of grade Ⅴ. Pre-operative endovascular embolizations were carried out in 3 AVMs. RESULTS: All the included patients were confirmed as giant intracranial AVM by magnetic resonance angiography (MRA), digital subtraction angiography (DSA), 3-dimensional CT angiography (3D-CTA) before surgery. All the resected tissues were sent for pathological examination, and the diagnoses were confirmed as AVM. The average operation time of the 15 patients was 10.3 ±6.9 hours. After 1-3 months, all the patients were rechecked by DSA, the large vascular malformations in 12 cases were completely resected, 3 cases had a small amount of residual further treated with gamma knife treatment. Magnetic resonance imaging (MRI) and MRA examination indicated that the residual AVM was occluded after 12 months. Patients were followed up at 6, 12 and 24 months after operation, and assessed by Glasgow outcome scale (GOS) score: 13 cases good, 1 cases mild disability, 1 cases severe disability; the good rate was 86.6%, with no dead case. CONCLUSION: Sufficiently preoperative preparation, appropriate operative methods and skills are necessary to treat giant intracranial arteriovenous malformation.

Evidence to Support a Contribution of Polyreactive Antibodies to HLA Serum Reactivity.

BACKGROUND: Assessing the serum reactivity to HLA is essential for the evaluation of transplant candidates and the follow-up of allograft recipients. In this study, we look for evidence at the clonal level that polyreactive antibodies cross-reactive to apoptotic cells and multiple autoantigens can also react to HLA and contribute to the overall serum reactivity. METHODS: We immortalized B cell clones from the blood of 2 kidney transplant recipients and characterized their reactivity to self-antigens, apoptotic cells as well as native, denatured, and cryptic HLA determinants using enzyme-linked immunosorbent assay (ELISA), immunofluorescence, flow cytometry and Luminex assays. We also assessed the reactivity of 300 pretransplant serum specimens to HLA and apoptotic cells. RESULTS: We report here 4 distinct B cell clones cross-reactive to self and HLA class I. All 4 clones reacted to numerous HLA class I alleles but did not appear to target canonical "shared" epitopes. In parallel experiments, we observed a strong correlation between IgG reactivity to HLA and apoptotic cells in pretransplant serum samples collected from 300 kidney transplant recipients. Further analysis revealed that samples with higher reactivity to apoptotic cells displayed significantly higher class I percent panel-reactive antibodies compared to samples with low reactivity to apoptotic cells. CONCLUSIONS: We provide here (1) proof of principle at the clonal level that human polyreactive antibodies can cross-react to HLA, multiple self-antigens and apoptotic cells and (2) supportive evidence that polyreactive antibodies contribute to overall HLA reactivity in the serum of patients awaiting kidney transplant.

The human thymus perivascular space is a functional niche for viral-specific plasma cells.

The human thymus is susceptible to viral infections that can severely alter thymopoiesis and compromise the mechanisms of acquired tolerance to self-antigens. In humans, plasma cells residing primarily in the bone marrow confer long-lasting protection to common viruses by secreting antigen-specific antibodies. Since the thymus also houses B cells, we examined the phenotypic complexity of these thymic resident cells and their possible protective role against viral infections. Using tissue specimens collected from subjects ranging in age from 5 days to 71 years, we found that starting during the first year of life, CD138+ plasma cells (PC) begin accumulating in the thymic perivascular space (PVS) where they constitutively produce IgG without the need for additional stimulation. These, thymic PC secrete almost exclusively IgG1 and IgG3, the two main complement-fixing effector IgG subclasses. Moreover, using antigen-specific ELISpot assays, we demonstrated that thymic PC include a high frequency of cells reactive to common viral proteins. Our study reveals an unrecognized role of the PVS as a functional niche for viral-specific PCs. The PVS is located between the thymic epithelial areas and the circulation. PCs located in this compartment may therefore provide internal protection against pathogen infections and preserve the integrity and function of the organ.