Amyloidosis of the Heart and Kidney.

Amyloidosis encompasses a collection of disorders of pathological protein folding. The extracellular location where these "amyloid fibril" proteins are deposited determines the clinical presentation of the disease. The abnormal architecture of these fibrils makes them insoluble and not easily removed, leading to disruption of normal tissue structure and interference with normal physiology. Amyloidosis of the heart and kidney can be inherited, secondary to unrelated diseases, or due to a plasma cell disorder. This review will focus on immunoglobulin light chain amyloidosis, which is life-threatening and must be diagnosed as early as possible by employing precise and accurate typing to ensure timely and frequently curative therapy.

Early humoral immune response to two doses of severe acute respiratory syndrome coronavirus 2 vaccine in a diverse group of solid organ transplant candidates and recipients.

Response to two doses of a nucleoside-modified messenger ribonucleic acid (mRNA) vaccine was evaluated in a large solid-organ transplant program. mRNA COVID-19 vaccine was administered to transplant candidates and recipients who met study inclusion criteria. Qualitative anti-SARS-CoV-2 Spike Total Immunoglobulin (Ig) and IgG-specific assays, and a semi-quantitative test for anti-SARS-CoV-2 Spike protein IgG were measured in 241 (17.2%) transplant candidates and 1163 (82.8%) transplant recipients; 55.2% of whom were non-Hispanic White and 44.8% identified as another race. Transplant recipients were a median (IQR) of 3.2 (1.1, 6.8) years from transplantation. Response differed by transplant status: 96.0% versus 43.2% by the anti-SARS-CoV-2 Total Ig (candidates vs. recipients, respectively), 93.5% versus 11.6% by the anti-SARS-CoV-2 IgG assay, and 91.9% versus 30.1% by anti-spike titers after two doses of vaccine. Multivariable analysis revealed candidates had higher likelihood of response versus recipients (odds ratio [OR], 14.6; 95 %CI 2.19, 98.11; P = .02). A slightly lower response was demonstrated in older patients (OR .96; 95 %CI .94, .99; P = .002), patients taking antimetabolites (OR, .21; 95% CI .08, .51; P = .001). Vaccination prior to transplantation should be encouraged.

Outcomes of Kidney Donors With Impaired Fasting Glucose.

BACKGROUND: Many kidney donor candidates with impaired fasting glucose (IFG) and all candidates with diabetes are currently excluded from kidney donation, fearing the development of an accelerated course of diabetic kidney disease in the remaining kidney. METHODS: We studied mortality, proteinuria, and end-stage kidney disease (ESKD) in 8280 donors who donated between 1963 and 2007 according to donation fasting plasma glucose (FPG): <100 mg/dL (n = 6204), 100-125 mg/dL (n = 1826), and ≥126 mg/dL (n = 250). RESULTS: Donors with IFG and those with FPG ≥126 mg/dL were older, less likely to be non-Hispanic White, had a higher body mass index, and were more likely to be related to their recipient. After 15.7 ± 10.5 y from donation to study close, 4.4% died, 29.4% developed hypertension, 13.8% developed proteinuria, and 41 (0.5%) developed ESKD. In both the logistic and Cox models, IFG was associated with a higher diabetes risk (adjusted hazard ratio [aHR], 1.65; 95% confidence interval [CI], 1.18-2.30) and hypertension (aHR, 1.35; 95% CI, 1.10-1.65; P = 0.003 for both), but not higher risk of proteinuria or ESKD. The multivariable risk of mortality in donors with ≥126 mg/dL was higher than the 2 other groups, but risks of proteinuria, cardiovascular disease, and reduced estimated glomerular filtration rate were similar to those with FPG <126 mg/dL. Three cases of ESKD developed in the 250 donors with FPG ≥126 mg/dL at 18.6 ± 10.3 y after donation (aHR, 5.36; 95% CI, 1.0-27.01; P = 0.04). CONCLUSIONS: Donors with IFG and the majority of donors with ≥126 mg/dL do well and perhaps should not be routinely excluded from donation.

Intermediate Renal Outcomes, Kidney Failure, and Mortality in Obese Kidney Donors.

BACKGROUND: Obesity is associated with the two archetypal kidney disease risk factors: hypertension and diabetes. Concerns that the effects of diabetes and hypertension in obese kidney donors might be magnified in their remaining kidney have led to the exclusion of many obese candidates from kidney donation. METHODS: We compared mortality, diabetes, hypertension, proteinuria, reduced eGFR and its trajectory, and the development of kidney failure in 8583 kidney donors, according to body mass index (BMI). The study included 6822 individuals with a BMI of <30 kg/m2, 1338 with a BMI of 30-34.9 kg/m2, and 423 with a BMI of ≥35 kg/m2. We used Cox regression models, adjusting for baseline covariates only, and models adjusting for postdonation diabetes, hypertension, and kidney failure as time-varying covariates. RESULTS: Obese donors were more likely than nonobese donors to develop diabetes, hypertension, and proteinuria. The increase in eGFR in obese versus nonobese donors was significantly higher in the first 10 years (3.5 ml/min per 1.73m2 per year versus 2.4 ml/min per 1.73m2 per year; P<0.001), but comparable thereafter. At a mean±SD follow-up of 19.3±10.3 years after donation, 31 (0.5%) nonobese and 12 (0.7%) obese donors developed ESKD. Of the 12 patients with ESKD in obese donors, 10 occurred in 1445 White donors who were related to the recipient (0.9%). Risk of death in obese donors was not significantly increased compared with nonobese donors. CONCLUSIONS: Obesity in kidney donors, as in nondonors, is associated with increased risk of developing diabetes and hypertension. The absolute risk of ESKD is small and the risk of death is comparable to that of nonobese donors.

Vancomycin-Associated Tubular Casts and Vancomycin Nephrotoxicity.

INTRODUCTION: Vancomycin nephrotoxicity is frequent and may be due to drug-induced acute tubular necrosis (ATN) or tubulointerstitial nephritis (TIN). Vancomycin-associated tubular cast (VTC) was recently described and may represent a novel cause of vancomycin nephrotoxicity. However, much is still unknown about VTC. MATERIALS AND METHODS: Thirty-seven kidney biopsy specimens from patients who were treated with vancomycin and developed acute kidney injury (AKI) were found among a total of 4673 biopsy samples between 2010 and 2019. These biopsy specimens were subjected to light microscopy, immunofluorescence, electron microscopy, and immunolocalization for vancomycin, uromodulin, myoglobin, tubular segment-specific markers, and examined for VTCs. The findings were correlated with the clinical course. RESULTS: VTCs displayed precipitated vancomycin casts in a background of uromodulin; the casts were limited to the distal tubules, and always associated with a background of more diffuse renal injury (ATN or TIN). The diagnosis of vancomycin nephrotoxicity was made in in 28 of 37 patients. VTC was noted in 25 of 28 biopsy samples from patients diagnosed with vancomycin nephrotoxicity and in one of nine biopsy samples from patients without this diagnosis. Vancomycin nephrotoxicity was diagnosed in 25 of 26 patients whose biopsy specimens showed VTC, but in only 3 of 11 patients without VTC in the biopsy samples. CONCLUSIONS: VTC displays a characteristic morphologic profile amenable to ready recognition in biopsy specimens. It results from coprecipitation of vancomycin and uromodulin. It facilitates the biopsy diagnosis of vancomycin nephrotoxicity. It may have a nephrotoxic effect superimposing on and independent from the ATN or interstitial nephritis in the pathogenesis of vancomycin nephrotoxicity.

Outcomes of Hypertensive Kidney Donors Using Current and Past Hypertension Definitions.

INTRODUCTION: As many as 50% of U.S. transplant centers do not accept kidney donor candidates with hypertension, citing the link between hypertension, kidney disease, and cardiovascular disease (CVD). METHODS: We ascertained mortality, CVD, proteinuria, estimated glomerular filtration rate (eGFR) trajectory, reduced eGFR, and end-stage kidney disease (ESKD) in 904 hypertensive donors (blood pressure [BP] ≥140/90 mm Hg or receiving treatment) versus 7817 donors with BP <140/90 mm Hg. RESULTS: Hypertensive donors were older, 58.1% were <50 years of age, and they had a lower eGFR. The majority were white and related to their recipient. At the end of follow-up, 14.3 ± 10.1 years (range 4-48 years) from donation, hypertensive and nonhypertensive donors had a similar prevalence of cardiovascular disease and renal outcomes. The multivariable risk of mortality, CVD, and proteinuria were also comparable in normotensive and hypertensive donors. eGFR slope over time was similar in hypertensive and nonhypertensive donors, and in total 5 hypertensive and 39 normotensive donors developed ESKD 19.2 ± 10.3 years after donation (adjusted hazard ratio 1.14 [95% confidence interval 0.62-2.12], P = 0.67). Sensitivity analysis using the new definition of hypertension (≥130/80 mm Hg or requiring treatment) yielded similar results for renal outcomes, but hypertensive donors were more likely to develop CVD and diabetes. CONCLUSIONS: Kidney donors with hypertension defined by past criteria do not appear to incur higher mortality, CVD, or ESKD. Donors with current definition of hypertension enjoyed similar renal outcomes but were more likely to develop CVD.

Long-term outcomes of kidney donors with fibromuscular dysplasia.

BACKGROUND: Fibromuscular dysplasia (FMD) is a non-atherosclerotic systemic arterial disease that is not infrequently discovered during kidney donor evaluation. Current guidelines do not provide recommendations regarding the use of kidneys from donors with FMD and there is a paucity of data on the outcomes of these donors. METHODS: The Renal and Lung Living Donor Evaluation (RELIVE) study addressed long-term outcomes of 8922 kidney donors who donated between 1963 and 2007. We compared the development of hypertension, cardiovascular disease (CVD), proteinuria and reduced estimated glomerular filtration rate (eGFR) in 113 kidney donors with FMD discovered during donor evaluation versus 452 propensity score matched donors without FMD. Outcomes modeling with logistic and Cox regression analysis and Kaplan-Meier statistics were performed. RESULTS: Donors with FMD were older (51 versus 39 years), were more likely to be women (80% versus 56%) and had a higher systolic blood pressure at donation (124.7 versus 121.3 mmHg) (P < 0.05 for all). After a mean ± standard deviation follow-up of 15.5 ± 8.9 years, a similar proportion of donors with and without FMD were alive, and developed hypertension (22.2% versus 19.8%), proteinuria (20.6% versus 13.7%) and CVD (13.3% versus 13.5%). No donor with FMD developed an eGFR <30 mL/min/1.73 m2 or end-stage kidney disease. The multivariable risk of mortality, CVD and renal outcomes in donors with FMD was not elevated. CONCLUSIONS: Kidney donors with FMD appear to do well, do not appear to incur increased risks of hypertension, proteinuria, CVD or reduced eGFR, and perhaps carefully selected candidates with FMD can safely donate as long as involvement of other vascular beds is ruled out.

Outcomes of kidney donors with pre- and post-donation kidney stones.

Roughly 25% of US transplant centers exclude donor candidates with kidney stones fearing future obstructive consequences and the possible association between stones and CKD. We compared the development of hypertension, proteinuria, and reduced eGFR in 227 kidney donors with kidney stones to 908 propensity score-matched donor controls without kidney stones using data from The Renal and Lung Donor Evaluation (RELIVE) Study which studied intermediate and long-term outcomes of 8922 donors who donated between 1963 and 2007. 200 donors had kidney stones prior to donation, 21 had post-donation stones, and 6 had pre- and post-donation stones. Donors with stones were older, more likely to be Caucasian, less likely to be related to the recipient and had a higher fasting glucose. After 16.5 ± 10.9 years (range 0-44 years) from donation to study close, no ESKD occurred in donors with stones. The multivariable risks of hypertension, proteinuria, and reduced GFR were similar in donors with and without kidney stones. We could not demonstrate an association between stones and adverse renal outcomes in kidney donors, and the occurrence of post-donation stones was distinctly rare. These data may provide a rationale for possibly a wider acceptance of donor candidates with low kidney stones burden.

Delayed autologous stem cell transplantation following cardiac transplantation experience in patients with cardiac amyloidosis.

This study sought to retrospectively investigate the outcomes of patients with light-chain amyloidosis (AL) with advanced cardiac involvement who were treated with a strategy of heart transplantation (HT) followed by delayed autologous stem cell transplantation (ASCT) at 1-year posttransplant. Patients with AL amyloidosis with substantial cardiac involvement have traditionally had very poor survival (eg, several months). A few select centers have reported their outcomes for HT followed by a strategy of early ASCT (ie, 6 months) for CA. The outcomes of patients undergoing a delayed strategy have not been reported. All patients with AL amyloidosis at a single institution undergoing evaluation for HT from 2004-2018 were included. Retrospective analyses were performed. Sixteen patients underwent HT (including two combined heart-kidney transplant) for AL amyloidosis. ASCT was performed in a total of nine patients to date at a median 13.5 months (12.8-32.9 months) post-HT. Survival was 87.5% at 1 year and 76.6% at 5 years, comparable to institutional outcomes for nonamyloid HT recipients. In addition to these 16 patients, two patients underwent combined heart-lung transplantation. A strategy of delayed ASCT 1-year post-HT for patients with AL amyloidosis is feasible, safe, and associated with comparable outcomes to those undergoing an earlier ASCT strategy.

Initial survival data of kidney transplant patients with pre-transplant monoclonal gammopathy.

BACKGROUND: Monoclonal gammopathy of undetermined significance (MGUS) is the presence of a serum monoclonal protein at a concentration of <3 g/dL without evidence of lymphoproliferative disease or organ damage. The prevalence of MGUS in kidney transplantation (KT) candidates is unknown. The present is a retrospective report of patients who underwent evaluation for a KT and were found to have MGUS at our center. METHODS: All transplant candidates found to have MGUS between the years 2000 and 2007 were included. Variables were collected. Patients with MGUS that received a KT were compared with patients with MGUS that were not transplanted. RESULTS: Of a total of 1215 KT candidates, 34 were found to have MGUS during the KT evaluation. Nine patients with MGUS were transplanted. Myeloma or lymphoproliferative disease was not observed. Following transplantation, the MGUS group had a lower survival than the non-transplanted group. However, survival from the time of MGUS diagnosis was not different between the transplanted and non-transplanted MGUS groups. CONCLUSIONS: In this group, transplantation did not confer a survival benefit. It is our hope that these initial data will serve as a platform for future studies. We suggest MGUS screening in all patients older than 50 yr of age undergoing evaluation for transplantation.

Spontaneous recovery from early glomerular inflammation is associated with resistance to anti-GBM glomerulonephritis: tolerance and autoimmune tissue injury.

Different susceptibility to anti-GBM glomerulonephritis (GN) among animal strains has been reported. Using our rat model for T cell-mediated anti-GBM GN, this study initiated an investigation on the mechanism related with GN susceptibility. Anti-GBM GN was induced either through immunization with the nephritogenic T cell epitope pCol(28-40) from Col4alpha3NC1 or through the transfer of specific T cells. WKY rats were highly susceptible to GN while immuno-compatible LEW rats were GN-resistant. GN-resistance in LEW rats was not associated to the immune response to pCol(28-40). First, both strains mounted a Th1 T cell response to pCol(28-40) with identical specificities; transfer of T cells from LEW to WKY rats induced glomerular injury. Second, co-transfer of antibody from WKY to LEW failed to induce GN. Time-course studies revealed that LEW rats did develop T cell-mediated inflammation in glomeruli at early stages similar to WKY rats, as evidenced by histopathology, proteinuria, CD4(+) T cell infiltration in glomeruli, and glomerular expression of inflammatory molecules. However, glomerular inflammation in LEW rats was transient followed by a full recovery. Thus, GN-resistance in LEW rats was due to its ability to contain early T cell-mediated autoimmune glomerular damage. Our model may reveal a potential tolerance mechanism after autoimmune tissue damage has been initiated.

Acute antibody-mediated rejection of renal transplant: pathogenetic and diagnostic considerations.

CONTEXT: Acute antibody-mediated rejection (AMR) has emerged recently as an important cause of graft failure. OBJECTIVE: To review the pathogenetic, clinicopathologic, and diagnostic considerations of AMR. DATA SOURCES: Review of literature and the authors' experience. CONCLUSIONS: Acute antibody-mediated rejection is mediated by antibodies specific for donor antigens, which bind to target antigens and activate the complement system, culminating in tissue injury. The clinical manifestation of AMR is not specific, and transplant biopsy is needed for diagnosis. The glomeruli show thrombosis or neutrophils or mononuclear leukocytes in capillary lumens. The tubulointerstitial compartment shows edema, hemorrhage, necrosis, mild inflammation, and neutrophils or mononuclear leukocytes in the peritubular capillary lumens. The blood vessels show thrombosis, thrombotic microangiopathy, fibrinoid necrosis, or transmural vasculitis. Strong staining for C4d in the peritubular capillaries is characteristic. A definitive diagnosis of AMR requires (1) morphologic evidence of acute tissue injury, (2) immunopathologic evidence for antibody action, and (3) serologic evidence of circulating donor-specific antibodies. Acute antibody-mediated rejection should be suspected if some but not all 3 criteria are met. Since effective treatment is currently available, accurate and timely diagnosis of AMR is essential.

Coincident activation of Th2 T cells with onset of the disease and differential expression of GRO-gamma in peripheral blood leukocytes in minimal change disease.

BACKGROUND: Involvement of Th2 T cells/NFkappaB in minimal change disease (MCD) has been postulated. A promising but unconfirmed glomerular permeability factor (GPF) from MCD T cells has been described. We explored whether GPF was the consequence of Th2 cell activation. METHODS: Peripheral blood leukocytes (PBL) from 16 MCD patients and 7 normal controls were analyzed and the results were statistically compared. RESULTS: Flow cytometry demonstrated a significant expansion of CD4+ T cell population and dramatically increased CD69+ cells among CD4+ T cells in MCD, suggesting coincident activation of T cells with onset of the disease. RT-PCR on RNA from either freshly isolated PBL or post in vitroactivation showed high-level expression of the Th2 cytokine interleukin-4 in all MCD patients. Importantly, both antibody microarray assay on sera and RT-PCR on mRNA of PBL revealed expression of a CXC chemokine GRO-gamma (growth-related oncogene) in all MCD patients as compared with one of 7 controls. CONCLUSIONS: Our results reveal an association between onset of MCD and activation of Th2 cells. The GRO family has been implicated in the function of endothelial cells, and its expression is under NFkappaB regulation. Thus, GRO-gamma is a promising candidate for Th2-associated GPF in MCD.

Do inherited hypercoagulable states play a role in thrombotic events affecting kidney/pancreas transplant recipients?

BACKGROUND: Pancreas graft thrombosis remains the leading non-immunologic cause of graft loss after pancreas transplantation. We studied the role of hypercoagulable states (HCS) in pancreas graft thrombosis (pthx). METHODS: Between January 1, 1994, and January 1, 2003, 131 pancreas transplant recipients experienced a pthx (n = 67) or other thrombotic events. Fifty-six recipients consented to have their blood drawn and tested for the HCS. These results were compared with a control group of pancreas transplant recipients who did not experience a thrombotic event. Fisher's exact test was used to compare the groups. RESULTS: We found 18% of the recipients with pancreas thrombosis to have a HCS. Factor V Leiden (FVL) was found in 15% vs. 4% in the control group (p = ns) vs. 3-5% in the general white population. We found 3% of the pancreas thrombosis patients to have a prothrombin gene mutation (PGM) vs. 0% in the control group (p = ns) vs. 1-2% in the general white population. CONCLUSIONS: Of pancreas transplant recipients with thrombosis, 18% had one or more of the most common factors associated with a HCS (FVL or PGM). This can be compared with 4% in a control group and 4-7% in the general white population, respectively. Although the differences are not statistically significant due to small numbers, we feel that the findings may be clinically relevant. While this is only a pilot study, it may be reasonable to screen select pancreas transplant candidates for HCS, especially FVL and PGM, until more data become available.

Immunoglobulin therapy for plasma cell-rich rejection in the renal allograft.

Plasma cell-rich acute rejection (PCAR) is associated with poor allograft outcome in renal transplantation. Previous studies report a graft half-life of six months after a single PCAR episode. However, the management of this condition is unclear. Intravenous immunoglobulin (IVIG) therapy, by virtue of its immunomodulating properties, and its influence on B-cell maturation into plasma cells, may be a good candidate for reversing this type of rejection. We report four episodes of PCAR in two patients who responded well to IVIG with improvement in renal function.

Granulomatous pyelitis associated with urinary obstruction: a comprehensive clinicopathologic study.

Urinary obstruction is rarely associated with a distinct granulomatous inflammation, which involves the pyelocalyceal system and closely simulates infectious conditions including tuberculosis. Its clinicopathologic features, however, have not been adequately studied since there are only seven isolated reported cases. In a comprehensive study of 112 kidney specimens with urinary obstruction, we identified five cases of granulomatous pyelitis. The features of these cases were detailed and compared with the previously reported cases. Among the five identified subjects, three patients had history of urolithiasis and two had ureteral stenosis and all had stent placement 7 weeks to 12 years before nephrectomy for relief of the unilateral urinary obstruction. The age distribution was between 38 and 81 years. Two had end-stage renal disease or chronic renal failure. The pyelocaliceal system showed frank hydronephrosis (1 case) or partial dilatation (4 cases) and contained cheesy and gritty material in its lumen. Each case showed severe granulomatous inflammation, which was limited to the pelvic wall and closely associated with calcified debris, necrotic inflammatory cells, and material consistent with Tamm-Horsfall protein. The kidney showed chronic tubulointerstitial nephritis but without granulomas. Cultures of urine, blood, and the renal pelvic content, and special stains of tissue sections did not show fungi or mycobacteria in any case. Many of these features were also observed in previously reported cases. Granulomatous pyelitis is a rare but distinct cliniocopathologic entity characterized by severe noninfectious granulomatous inflammation limited to the renal pelvis, which is uniformely asociated with urinary obstruction and pyelocalyceal dilatation and may develop in response to accumulated calcified material in the renal pelvis. Awareness of this entity and its characteristic clinicopathologic features also helps eliminate an infectious etiology with obvious treatment and prognostic implications.