Lipoprotein glomerulopathy with markedly increased arterial stiffness successfully treated with a combination of fenofibrate and losartan: a case report.

BACKGROUND: Lipoprotein glomerulopathy (LPG) is a apolipoprotein E (ApoE)-related glomerular disease and has been associated with type III hyperlipidemia. Without appropriate treatment, chronic kidney disease (CKD) caused by LPG progresses, and approximately half of the patients develop end-stage kidney disease within 1-27 years of disease onset. However, few studies have highlighted the clinical course of cardiovascular diseases (CVDs) in patients with LPG. Herein, we report the first case of LPG in which the CVD risk was assessed using arterial stiffness. CASE PRESENTATION: A 32-year-old Japanese man was referred to our hospital due to persistent proteinuria. Kidney biopsy showed markedly dilated capillary lumens containing pale-stained thrombi, which stained positively with Oil Red O. Electron microscopy revealed the presence of thrombi in the capillary lumen with low electron density and vacuoles of various sizes in part of the thrombi. Toluidine blue and Sudan IV stains were used to stain the thin sections of Epon-embedded tissue samples for electron microscopy. Sudan IV-positive droplets were observed in the capillary lumens, vascular walls, and cytoplasm of tubular cells. Increased serum ApoE concentration was observed. Liquid chromatography-tandem mass spectrometry of laser-microdissected glomeruli from paraffin sections revealed an increase in ApoE. Direct deoxyribonucleic acid sequencing of ApoE revealed a heterozygous ApoE Sendai mutation (Arg145Pro). The patient was finally diagnosed with LPG with heterozygosity for ApoE-Sendai mutation (Arg145Pro). Notably, at the time of diagnosis, he had markedly increased arterial stiffness for his age. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV), which was equivalent to that of a 56-year-old man. After three months of treatment with fenofibrate and losartan, a significant reduction in proteinuria was achieved along with an improvement in baPWV. Furthermore, these effects were maintained despite the lack of decrease in serum ApoE levels. CONCLUSION: Herein, we report the case of a patient with LPG with markedly increased arterial stiffness at the time of diagnosis, in whom combination therapy with fenofibrate and losartan successfully improved proteinuria and arterial stiffness. To the best of our knowledge, this is the first case report of LPG in which CVD risk was assessed using arterial stiffness.

Role of Fractalkine-CX3CR1 Axis in Acute Rejection of Mouse Heart Allografts Subjected to Ischemia Reperfusion Injury.

Transplantation outcomes are affected by the increase in rejection associated with ischemia reperfusion injury (IRI). Fractalkine (FKN), a chemokine for recruitment of CX3CR1+ leukocytes, contributes to the pathogenesis of various inflammatory diseases. Herein, we evaluated the importance of the FKN-CX3CR1 axis during IRI-related rejections using a mouse heterotopic heart transplantation model. FKN expression and graft survival was compared between wild-type C57BL/6 recipients transplanted with BALB/c hearts preserved for 8 (WT-IRI) and 0.5 h (WT-control) at 4°C. Graft survival of WT-IRI was shorter than that of WT-control. FKN was expressed on the vascular endothelium in WT-IRI allografts, but minimally in WT-control. The role of the FKN-CX3CR1 axis in IRI-related rejection was directly investigated using the transplant model with CX3CR1-deficient recipients (CX3CR1 KO-IRI) or treatment with anti-mouse FKN monoclonal antibodies. Graft survival of CX3CR1 KO-IRI was longer than that of WT-IRI; antibody treatment prolonged graft survival. The contribution of CX3CR1+ monocytes to IRI-related rejection was evaluated by adoptive transfer to CX3CR1 KO-IRI. Adoptive transfer of CX3CR1+ monocytes attenuated the effect of prolonged graft survival in CX3CR1 KO-IRI. Overall, the FKN-CX3CR1 axis plays a major role during IRI-related rejection; its blockade has the potential to improve the outcomes of deceased donor transplantation.

Evaluation of the impact of conventional immunosuppressant on the establishment of murine transplantation tolerance - an experimental study.

Regulatory T cells (Tregs) play a significant role in immune tolerance. Since Treg function deeply depends on Interleukin-2 signaling, calcineurin inhibitors could affect their suppressive potentials, whereas mammalian target of rapamycin (mTOR) inhibitors may have less impact, as mTOR signaling is not fundamental to Treg proliferation. We previously reported a novel mixed hematopoietic chimerism induction regimen that promotes Treg proliferation by stimulating invariant natural killer T cells under CD40 blockade. Here, we use a mouse model to show the impact of tacrolimus (TAC) or everolimus (EVL) on the establishment of chimerism and Treg proliferation in the regimen. In the immunosuppressive drug-dosing phase, peripheral blood chimerism was comparably enhanced by both TAC and EVL. After dosing was discontinued, TAC-treated mice showed gradual graft rejection, whereas EVL-treated mice sustained long-term robust chimerism. Tregs of TAC-treated mice showed lower expression of both Ki67 and cytotoxic T lymphocyte antigen-4 (CTLA-4), and lower suppressive activity in vitro than those of EVL-treated mice, indicating that TAC negatively impacted the regimen by interfering with Treg proliferation and activation. Our results suggest that the usage of calcineurin inhibitors should be avoided if utilizing the regimen to induce Tregs in vivo for the establishment of mixed hematopoietic chimerism.

Clinicopathological study of de novo membranous nephropathy of 'stage 0' after kidney transplantation.

AIM: De novo membranous nephropathy (dnMN) contributes to graft failure, but the pathophysiology of the disease remains poorly understood. We defined cases exhibiting granular Immunoglobulin G (IgG) immunofluorescence staining but lacking dense deposits on electron microscopy as being of 'dnMN stage 0'; we studied the associated clinicopathological features. METHODS: We studied 4653 allograft biopsy specimens (from 1747 cases treated in the Department of Urology, Tokyo Women's Medical University) and found 42 cases of allograft membranous nephropathy, of which 28 (1.6%) were diagnosed as dnMN. Of these, five cases (0.06%) fulfilled the criteria for dnMN stage 0. RESULTS: All five cases were diagnosed based on biopsies indicating increased serum levels of creatinine. Proteinuria status varied from negative to 2+. The median period from transplantation to allograft biopsy was 4068 days. Four of the five cases exhibited suspicious antibody-mediated rejection together with dnMN. The glomerular capillaries of all cases were C4d-positive, as were the peritubular capillaries of three of the four ABO-compatible transplants. In terms of IgG subclass, IgG1 and IgG3 predominated in all cases, and phospholipase A2 receptor status (evaluated via immunoreactivity) was negative in all cases. We examined two cases by immunoelectron microscopy using anti-IgG and anti-C4d antibodies. We found subendothelial and intramembranous deposits expressing both IgG and C4d, corresponding to positivity in immunofluorescence analysis. CONCLUSION: We confirmed the existence of dnMN stage 0 by focusing on granular IgG immunofluorescence positivity.

Recurrence of native kidney disease after kidney transplantation.

The extent of recurrence of original kidney disease after kidney transplantation has been underestimated for several reasons. First, the duration of observation varies among studies. Second, the criteria used to schedule protocol and episode biopsies differ among institutions. And third, diagnostic modalities used for early detection of recurrent original kidney disease also vary. Thus, rates of graft loss attributable to a recurrence of original kidney disease vary among institutions and are often underestimated. However, the recurrence of original disease is often thought to be less important than chronic rejection followed by loss of a functioning allograft. It is important to note that recent data have shown that in patients with certain limited primary kidney diseases (e.g., membranous proliferative glomerulonephritis [MPGN], IgA nephritis [IgAN], focal segmental glomerulonephritis [FSGS], and membranous nephropathy [MN]), the predominant (60%) cause of graft loss is the recurrence of original kidney disease. In addition, the rate of 5-year graft survival in patients with recurrent original kidney disease averages 45%. Thus, research must address the recurrence of original kidney disease. Here we focus on this recurrence and discuss diagnoses, preventive strategies, treatments, and future research directions.

Antibody-mediated rejection due to anti-HLA-DQ antibody after pregnancy and delivery in a female kidney transplant recipient.

Herein, we report a case of antibody-mediated rejection (ABMR) due to anti-HLA-DQ antibody after pregnancy and delivery in a female kidney transplant recipient. A 34-year-old female recipient was admitted at 2 years after delivery for an examination of an elevated serum creatinine (S-Cr) level. The patient had received a living kidney transplantation from her mother at 22 years of age, and her kidney graft function was almost stable. The episode biopsy showed peritubular capillaritis and transplant capillaropathy with C4d immunoreactivity in the peritubular capillaries. Additional examination revealed expression of a donor-specific antibody (DSA) against HLA-DQ5, leading to the diagnosis of chronic active ABMR. Intravenous immunoglobulin, plasma exchange, and rituximab were administered, and her S-Cr level was maintained stable. This case demonstrates a possible relationship between pregnancy/delivery and development of ABMR due to a de novo DSA in a female kidney transplant recipient.

Clinicopathological features and outcomes of kidney allografts in plasma cell-rich acute rejection: A case series.

Plasma cell-rich acute rejection (PCAR) is a rare type of acute rejection in renal transplantation. Despite aggressive immunotherapy, approximately 40-60% of patients develop graft loss within 1 year after an episode of PCAR. However, the reason for this outcome remains obscure. This study retrospectively identified six patients with PCAR diagnosed between 2009 and 2015 at a single university hospital. Clinicopathological data were collected. Five of the six patients were male, and mean age at the onset of PCAR was 49.0 ±14.5 years. None of the patients showed overall poor adherence to medication. Mean time to diagnosis was 302 ±234 days post-transplantation. All patients had preceding or concurrent viral infection. Four patients developed PCAR alone and two patients developed PCAR with antibody-mediated rejection. One of the six patients showed both severe tubulointerstitial and microvascular inflammation (total of Banff tubulitis 't' + interstitial inflammation 'i' + glomerulitis 'g' + peritubular capillaritis 'ptc' scores >10). This patient had progressive worsening of graft function and re-initiated dialysis at 74 months after a PCAR episode. In addition, three of the six patients had long-term recurrence of PCAR. With the recurrence of PCAR, patients with both moderate tubulointerstitial and microvascular inflammation (total of Banff 't' + 'i' + 'g' + 'ptc' scores >6) had progressive worsening of graft function. In summary, the present results suggest that concurrent moderate to severe tubulointerstitial and microvascular inflammation may lead to poor outcomes of graft function after a PCAR episode.

Long-term survival in Japanese renal transplant recipients with Alport syndrome: a retrospective study.

BACKGROUND: Patients with Alport syndrome (AS) develop progressive kidney dysfunction due to a hereditary type IV collagen deficiency. Survival of the kidney allograft in patients with AS is reportedly excellent because AS does not recur. However, several studies have implied that the type IV collagen in the GBM originates from podocytes recruited from the recipient's bone marrow-derived cells, suggesting the possibility of AS recurrence. Limited data are available regarding AS recurrence and graft survival in the Japanese population; the vast majority were obtained from living related kidney transplantation (LRKTx). METHODS: In this retrospective study, twenty-one patients with AS were compared with 41 matched patients without AS from 1984 to 2015 at two centers using propensity scores. Nineteen of the 21 patients with AS underwent LRKTx. The mean post-transplant follow-up period was 83 months in the AS group and 110 months in the control group. Histopathological AS recurrence was assessed by immunoreactivity of α5 (type IV collagen) antibody and electron microscopy. RESULTS: The graft survival rate was equivalent between patients with and without AS (86.7% vs. 77.1% and 69.3% vs. 64.2% at 5 and 10 years; p = 0.16, log-rank test). Immunoreactivity to α5 antibody showed strong linear positivity with no focal defect in six patients. Electron microscopy showed no GBM abnormalities in two patients who were exhibiting long-term kidney allograft survival. CONCLUSIONS: We confirmed that α5 and the GBM structure were histopathologically maintained in the long term after kidney transplantation. The patient and graft survival rates were equivalent between Japanese patients with and without AS.

Successful treatment of recurrent immunoglobulin a nephropathy using steroid pulse therapy plus tonsillectomy 10 years after kidney transplantation: a case presentation.

BACKGROUND: Both prevention and treatment of recurrent immunoglobulin A nephropathy (IgAN) in kidney transplant recipients are important since recurrent IgAN seems to affect long-term graft survival. We present here a case of recurrent IgAN that was successfully treated using steroid pulse therapy plus tonsillectomy 10 years after kidney transplantation. CASE PRESENTATION: A 46-year-old male was admitted for an episode biopsy with a serum creatinine level of 1.8 mg/dl and proteinuria (0.7 g/day). Histological features showed recurrent IgAN (only focal segmental mesangial proliferation) and severe arteriolar hyalinosis partly associated with calcineurin inhibitor toxicity, with limited interstitial fibrosis and tubular atrophy (5%) (IF/TA) 8 years after transplantation. Sodium restriction and conversion from cyclosporine to tacrolimus successfully reduced his proteinuria to the level of 0.15 g/day. However, 2 years later, his proteinuria increased again (1.0 g/day) and a second episode biopsy showed global mesangial proliferation with glomerular endocapillary and extracapillary proliferation accompanied by progressive IF/TA (20%). The steroid pulse therapy plus tonsillectomy successfully decreased his proteinuria and he achieved clinical remission 3 years after this treatment. CONCLUSION: This case, presented with a review of relevant literature, demonstrates the difficulty and importance of the treatment of recurrent IgAN and calcineurin inhibitor arteriolopathy, especially in long-term kidney allograft management.

Recurrence and graft loss after renal transplantation in adults with IgA vasculitis.

BACKGROUND: IgA vasculitis, a rare condition resulting in end-stage renal disease, is a small-vessel vasculitis that affects the kidney in 49-83 % of adults. The reported recurrence rate of IgA vasculitis in renal transplant recipients is 11.5-60 %, leading to graft loss in 0-50 % of these patients. However, limited data are available on recurrence and graft loss after renal transplantation. METHODS: We evaluated renal transplant recipients seen from 1987 to 2015 at the Jikei University School of Medicine and the Department of Urology, Tokyo Women's Medical University. Using a 1:2 match, 21 patients with IgA vasculitis and 42 controls were selected. The mean post-transplant follow-up was 121 ± 69 months for IgA vasculitis and 147 ± 66 months for the controls. RESULTS: The 15-year patient survival was 100 % in IgA vasculitis and 97.6 % in the controls (p = 0.22). The 5-, 10-, and 15-year graft survival rates were 95.2, 90.5, and 81 % in IgA vasculitis and 100, 90.5, and 88.1 % in the controls, respectively (p = 0.63). The recurrence rate was 28.6 % (6 of 21 cases) and half of them (3 of 6 cases) showed histological activity (ISKDC III). We treated them with methylprednisolone pulse therapy and/or tonsillectomy. None of the recurrence cases lost the allograft. CONCLUSION: The long-term patient and graft survival of IgA vasculitis in renal transplantation were comparable with the previous reports. The recurrence rate was 28.6 %, but none of the recurrent cases showed allograft loss in this study. We speculate that methylprednisolone pulse therapy and/or tonsillectomy prevent the progression of recurrent IgA vasculitis.

The prognostic values of caveolin-1 immunoreactivity in peritubular capillaries in patients with kidney transplantation.

The low sensitivity of C4d immunoreactivity in peritubular capillaries (PTCs) hinders its use in the diagnosis of chronic active antibody-mediated rejection (CAAMR). C4d-negative CAAMR was defined in the 2013 Banff classification, which included the expression of endothelial-associated transcripts (ENDATs). We previously showed that the ENDAT caveolin-1 (CAV-1) is a distinct feature of CAAMR. In this study, we investigated the prognostic value of CAV-1 immunoreactivity in PTCs in kidney transplant patients. Ninety-eight kidney transplant recipients were included in this study. The prognostic value of CAV-1 immunoreactivity in PTCs was evaluated by double immunostaining for CAV-1 and pathologische Anatomie Leiden endothelium (PAL-E, a PTC marker) in the PTCs of kidney allograft biopsy samples. The patients were divided into two groups: CAV-1/PAL-E<50% and CAV-1/PAL-E≥50%. Kaplan-Meier curves showed that CAV-1/PAL-E≥50% patients had a significantly worse prognosis than that of CAV-1/PAL-E<50% patients (log-rank; P<.001). C4d staining of PTCs was not associated with the development of graft failure (log-rank; P=.345), whereas in a multivariate Cox regression analysis, CAV-1 immunoreactivity in PTCs was independently associated with graft failure (hazard ratio: 11.1; P=.0324). CAV-1 immunoreactivity in PTCs may serve as a prognostic marker for kidney allograft survival.

Successful treatment of recurrent Henoch-Schönlein purpura nephritis in a renal allograft with tonsillectomy and steroid pulse therapy.

We report a case of recurrent Henoch-Schönlein purpura nephritis (HSPN) treated successfully with a tonsillectomy and steroid pulse therapy in a kidney transplant patient. A 29-year-old woman was admitted to our hospital for an episode biopsy; she had a serum creatinine (S-Cr) of 1.0 mg/dL and 1.34 g/day proteinuria 26 months after kidney transplantation. Histological examination revealed increased amounts of mesangial matrix and mesangial hypercellularity with IgA deposition. Of note, one glomerulus showed focal endocapillary proliferation and tuft necrosis. We diagnosed active recurrent HSPN. Considering both the histological findings and refractory clinical course of the native kidney, she was treated for 3 consecutive days with steroid pulse therapy and a tonsillectomy. The patient's proteinuria decreased gradually to less than 150 mg/day 6 months later. A second biopsy 6 years after kidney transplantation showed an excellent response to treatment and revealed a marked reduction in both the mesangial matrix and mesangial hypercellularity, with trace IgA deposition. We conclude that a tonsillectomy and steroid pulse therapy appeared to be useful in this patient with active recurrent HSPN. This paper is the first to report a tonsillectomy and steroid pulse therapy as a therapeutic option for active recurrent HSPN. Further studies are needed to elucidate the efficacy and mechanisms of tonsillectomy with recurrent HSPN in kidney transplant patients.

Subclinical antibody-mediated rejection due to anti-human-leukocyte-antigen-DR53 antibody accompanied by plasma cell-rich acute rejection in a patient with cadaveric kidney transplantation.

A 56-year-old man who had undergone cadaveric kidney transplantation 21 months earlier was admitted to our hospital for a protocol biopsy; he had a serum creatinine level of 1.2 mg/dL and no proteinuria. Histological features showed two distinct entities: (i) inflammatory cell infiltration, in the glomerular and peritubular capillaries and (ii) focal, aggressive tubulointerstitial inflammatory cell infiltration, predominantly plasma cells, with mild tubulitis (Banff 13 classification: i2, t1, g2, ptc2, v0, ci1, ct1, cg0, cv0). Immunohistological studies showed mildly positive C4d immunoreactivity in the peritubular capillaries. The patient had donor specific antibody to human-leucocyte-antigen-DR53. We diagnosed him with subclinical antibody-mediated rejection accompanied by plasma cell-rich acute rejection. Both antibody-mediated rejection due to anti- human-leucocyte-antigen -DR53 antibodies and plasma cell-rich acute rejection are known to be refractory and have a poor prognosis. Thus, we started plasma exchange with intravenous immunoglobulin and rituximab for the former and 3 days of consecutive steroid pulse therapy for the latter. Three months after treatment, a follow-up allograft biopsy showed excellent responses to treatment for both histological features. This case report considers the importance of an early diagnosis and appropriate intervention for subclinical antibody-mediated rejection due to donor specific antibody to human-leucocyte-antigen-DR53 and plasma cell-rich acute rejection.

Rare case of nephrocalcinosis in the distal tubules caused by hereditary renal hypouricaemia 3 months after kidney transplantation.

We report a rare case of nephrocalcinosis caused by hereditary renal hypouricaemia 3 months after kidney transplantation. A 41-year-old man who underwent living-related kidney transplantation from his father was admitted to our hospital for a protocol biopsy; he had a serum creatinine (S-Cr) of 1.37 mg/dL and no proteinuria. Histologically, there was no evidence of rejection or calcineurin inhibitor toxicity, although scattered nephrocalcinosis was observed in the distal tubules. Perioperatively, the patient had a serum uric acid (S-UA) of 1.9 mg/dL with a fractional excretion of uric acid (FEUA) of 29% (normal, <10%) and UA clearance of 26.8 mL/min (normal, 7.3-14.7 mL/min) 3 days after kidney transplantation. The donor also had a relatively low S-UA of 2.4 mg/dL and high FEUA of 10.3%. Subsequent DNA direct sequencing followed by restriction fragment length polymorphism revealed that both the recipient's and donor's urate transporter 1 (URAT1) gene had a heterozygous nonsense mutation in exon 5 (C889T). Further, the immunoreactivity of antibodies for the C terminus of URAT1 revealed a partial deletion. De Galantha and von Kossa staining revealed that the nephrocalcinosis was due to urate crystals and calcium stones. Therefore, we diagnosed hereditary renal hypouricaemia. We directed the patient to avoid hard exercise, drink plenty of water, and alkalize the urine. The 1-year follow-up allograft biopsy showed no evidence of nephrocalcinosis in the distal tubules. This is the first report of nephrocalcinosis in the distal tubules as a diagnostic clue to hereditary renal hypouricaemia. We also review the related literature.

Change in glomerular volume and its clinicopathological impact after kidney transplantation.

BACKGROUND: Both immunological and non-immunological etiologies affect graft function after kidney transplantation, including acute rejection, calcineurin inhibitor toxicity, and a recurrence of glomerulonephritis. Glomerular enlargement or glomerular sclerosis due to glomerular hyperfiltration related to increased renal blood flow is another cause. Although the glomerular volume in baseline biopsies predicts late allograft function, the relationship between allograft function and the annual changes in glomerular volume after kidney transplantation are unclear. AIM: We investigated changes in glomerular volume after kidney transplantation and their clinicopathological relationship. METHODS: We enrolled 23 patients with stable kidney function without an episode of rejection or any complication resulting in a functional decrease in the graft. We measured glomerular volume (GV) using the Weibel-Gomez method and glomerular density (GD) using 0,1 h biopsy samples as baseline controls and 1 yr biopsy samples and investigated the association between the changes in them and clinical parameters, including graft function, proteinuria, and renal hemodynamic markers, including effective renal plasma flow (ERPF) and filtration fraction (FF). The ERPF was calculated from a 99mTc-mercaptoacetyltriglycine (MAG3) renogram. RESULTS: The GV and ERPF increased significantly 1 yr after kidney transplantation. In contrast, proteinuria decreased significantly and Δproteinuria (1 yr - 1 month after transplantation) was correlated with ΔGV (P < 0.05, rs = -0.467). CONCLUSION: Glomerular enlargement 1 yr after transplantation may be related to improved proteinuria. It is possible that glomerular enlargement serves as a renal adaptation after kidney transplantation.

Clinical and pathological features of donor/recipient body weight mismatch after kidney transplantation.

BACKGROUND: Previous studies have shown that a donor/recipient body weight mismatch affects long-term graft survival and graft function after kidney transplantation. However, the mechanisms are not fully understood. AIM: To address the mechanisms, we compared the pathological and physiological features between patients with a donor/recipient body weight mismatch and those without a mismatch 1 yr after kidney transplantation. Furthermore, we investigated the correlation with the donor/recipient body weight ratio. METHODS: We examined allograft biopsy specimens from 10 recipients with stable kidney function, with body weight mismatch (donor/recipient body weight ratio [D/R BWR] < 0.9), and compared them with samples from 13 patients without mismatch. We measured glomerular volume (GV) using the Weibel-Gomez method and glomerular density (GD) defined by nonsclerotic glomerular number/renal cortical area as pathological findings. The physiological parameters included estimated glomerular filtration rate and proteinuria (mg/day). These data were evaluated to identify a correlation with D/R BWR. RESULTS: The pathological features showed that GV and GD were identical in the two groups. However, when glomerular enlargement was defined by ΔGV (GV at the 1-yr biopsy minus GV at baseline biopsy), ΔGV was higher in mismatch cases compared with that in cases without a mismatch (10.6 ± 4.6 vs. 5.5 ± 7.1 × 10(5) µm(3) ; P = 0.049). Furthermore, D/R BWR was significantly correlated with ΔGV (P = 0.03, r = -0.436). eGFR values were physiologically identical between the two groups, but the mismatch cases had significantly higher proteinuria levels than that of the cases without a mismatch at 1 yr after kidney transplantation. CONCLUSION: A donor/recipient body weight mismatch could affect glomerular enlargement and increased proteinuria 1 yr after kidney transplantation. How these two features affect long-term graft survival and function must be addressed in the future.

Probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies.

We report a case of probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies. A 44 year-old male was admitted to our hospital for a kidney transplant. The donor, his wife, was an ABO minor mismatch (blood type O to A) and had Gitelman syndrome. Graft function was delayed; his serum creatinine level was 10.1 mg/dL at 3 days after transplantation. Open biopsy was performed immediately; no venous thrombosis was observed during surgery. Histology revealed moderate peritubular capillaritis and mild glomerulitis without C4d immunoreactivity. Flow cytometric crossmatching was positive, but no panel-reactive antibodies against HLA or donor-specific antibodies (DSAbs) to major histocompatibility complex class I-related chain A (MICA) were detected. Taken together, we diagnosed him with probable C4d-negative accelerated antibody-mediated rejection due to non-HLA, non-MICA antibodies, the patient was treated with steroid pulse therapy (methylprednisolone 500 mg/day for 3 days), plasma exchange, intravenous immunoglobulin (40 g/body), and rituximab (200 mg/body) were performed. Biopsy at 58 days after transplantation, at which time S-Cr levels were 1.56 mg/dL, found no evidence of rejection. This case, presented with a review of relevant literature, demonstrates that probable C4d-negative accelerated acute AMR can result from non-HLA antibodies.

Acute T cell-mediated rejection accompanied by C4d-negative acute antibody-mediated rejection and cell debris in tubulus: A case report.

Herein, we report a complicated case of acute T-cell-mediated rejection (ACR) accompanied by C4d-negative acute antibody-mediated rejection (AMR) and cell debris in tubulus. A 32 year-old male was admitted for an episode biopsy with a serum creatinine (S-Cr) level of 1.83 mg/dL and pyuria (20-29 white blood cells per high power field) 49 days following kidney transplantation. Histological features included three distinct entities, mainly, in one of the three specimens: 1) focal aggressive tubulointerstitial inflammatory cell infiltration with moderate tubulitis, 2) inflammatory cell infiltration in peritubular capillaries (including neutrophils) and glomerular capillaries, and 3) cell debris consisting mainly of neutrophils in tubulus. Laboratory examination revealed evidence of non-human leukocyte antigen donor-specific antibodies. However, urinary culture and gram staining were negative. Considering both the histological and laboratory findings, the patient was diagnosed with ACR accompanied by C4d-negative AMR and suspicion of a urinary tract infection (UTI). The patient was treated for three consecutive days with steroid pulse therapy. The patient's S-Cr level decreased to ~1.5 mg/dL following treatment and did not increase thereafter. A second biopsy 133 days following kidney transplantation showed an excellent response to treatment and revealed no evidence of rejection. This case report demonstrates the difficulty in the diagnosis of, and therapy for, the complicated pathological findings of ACR, AMR and suspicion of a UTI.

Peripheral Blood Absolute Lymphocyte Count as a Predictor of Cytomegalovirus Infection in Kidney Transplant Recipients.

BACKGROUND: Cytomegalovirus viremia and infection have been reported to increase the risks for acute graft rejection and mortality in kidney transplant recipients. Previous studies demonstrated that a lower absolute lymphocyte count in peripheral blood is associated with cytomegalovirus infection. The aim of this study was to investigate whether absolute lymphocyte count could predict cytomegalovirus infection in kidney transplant recipients. METHODS: From January 2010 to October 2021, 48 living kidney transplant recipients in whom both donor and recipient were positive for immunoglobulin G of cytomegalovirus were included in this retrospective study. The primary outcome was defined as cytomegalovirus infection occurring ≥28 days after kidney transplantation. All recipients were followed for 1 year after kidney transplantation. The diagnostic accuracy of absolute lymphocyte count on day 28 post-transplantation for cytomegalovirus infection was analyzed using receiver operating characteristic curves. A Cox proportional hazards model was used to calculate hazard ratios for the incidence of cytomegalovirus infection. RESULTS: There were 13 patients (27%) with cytomegalovirus infection. The sensitivity and specificity for cytomegalovirus infection were 62% and 71%, respectively; the negative predictive value was 83% when an absolute lymphocyte count of 1100 cells/µL on day 28 post-transplantation was used as the cutoff. The incidence of cytomegalovirus infection was significantly higher when the absolute lymphocyte count was <1100 cells/µL on day 28 post-transplantation (hazard ratio, 3.32; 95% CI, 1.08-10.2). CONCLUSION: Absolute lymphocyte count is an inexpensive and easy test that can effectively predict cytomegalovirus infection. Further validation is needed to confirm its utility.

Long-Term Humoral Response After a Second Dose of SARS-CoV-2 mRNA Vaccine in Japanese Kidney Transplant Recipients.

Background: The mortality rate due to COVID-19 in kidney transplant recipients (KTRs) is 16.8 to 32%. Vaccination against COVID-19 is expected to contribute to the prevention of infection, severe disease, and mortality; however, it has been reported that the humoral response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine in KTRs is poor. Vaccination strategies against COVID-19 vary from country to country, and in Japan, the third dose is given 6 months after the second dose. Few studies have evaluated long-term humoral responses after the second dose of SARS-CoV-2 mRNA vaccine. In addition, the superiority of BNT162b2 vaccine and mRNA-1,273 vaccine in KTRs regarding humoral response is controversial. Methods: Ninety-four KTRs were administered a second dose of the BNT162b2 or mRNA-1,273 vaccines, and anti-spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 antibody levels were measured 5 months (149.2 ± 45.5 days) later. The cutoff value of anti-S antibodies was defined ≥50 AU/ml and 1.4 Index for anti-N antibodies. The primary outcome was the rate of seropositivity, and factors associated with an appropriate humoral response were assessed by univariate and multivariate analysis. Results: Of 94 KTRs, only 45 (47.9%) patients were positive for anti-S antibodies. The median anti-S SARS-CoV-2 IgG antibody titers was 35.3 (Interquartile range 3.8 to 159.7). Anti-N SARS-CoV-2 IgG antibodies in all patients were < 1.4 Index. Response to SARS-CoV-2 mRNA vaccines were 43.2 and 65% for BNT162b2 and mRNA-1,273, respectively (p = 0.152). In comparison with high-dose, low-dose of mycophenolic acid was a robust factor associated with an adequate humoral response. Conclusion: The long-term humoral response after a second dose of SARS-CoV-2 mRNA vaccine in Japanese KTRs was poor. In comparison with high-dose, low-dose mycophenolic acid was related to an appropriate humoral response. Five months is too long to wait for a 3rd dose after 2nd dose of SARS-CoV-2 vaccine in KTRs. In this cohort, there was no statistical difference in humoral response to the BNT162b2 and mRNA-1,273 vaccines. Additional large observational studies and meta-analyses are needed to clarify the factors related to an appropriate humoral immune response to COVID-19 vaccination.