Outcomes of ABO-incompatible kidney transplantation in older patients: a national cohort study

BACKGROUND

Outcomes of ABO-incompatible living donor kidney transplantation (ABOi LDKT) in older individuals have not been established.

METHODS

This multicentric observational study, using data from the Korean Organ Transplantation Registry database, included 634 older patients (≥60 years) undergoing kidney transplantation. We compared clinical outcomes of ABOi LDKT (n = 80) with those of ABO-compatible LDKT (ABOc LDKT, n = 222) and deceased donor kidney transplantation (DDKT, n = 332) in older patients.

RESULTS

Death-censored graft survival was similar between the three groups (P = 0.141). Patient survival after ABOi LDKT was similar to that after ABOc LDKT (P = 0.489) but higher than that after DDKT (P = 0.038). In multivariable analysis, ABOi LDKT was not risk factor (hazard ratio [HR] 1.73, 95% confidence interval [CI] 0.29-10.38, P = 0.548), while DDKT was significant risk factor (HR 3.49, 95% CI 1.01-12.23, P = 0.049) for patient survival. Although ABOi LDKT showed higher biopsy-proven acute rejection than ABOc LDKT, the difference was not significant after adjustment with covariates. However, ABOi LDKT was significant risk factor for infection (HR 1.66, 95% CI 1.12-2.45, P = 0.012).

CONCLUSIONS

In older patients, ABOi LDKT was not inferior to ABOc LDKT and was superior to DDKT for patient survival. ABOi LDKT can be recommended for older patients, rather than waiting for DDKT.

Tacrolimus trough levels higher than 6 ng/mL might not be required after a year in stable kidney transplant recipients

Background

Little is known regarding optimal tacrolimus (TAC) trough levels after 1 year post-transplant in stable kidney transplant recipients (KTRs) who have not experienced renal or cardiovascular outcomes. This study aimed to investigate the effect of 1-year post-transplant TAC trough levels on long-term renal and cardiovascular outcomes and opportunistic infections in stable KTRs.

Methods

KTRs receiving TAC with mycophenolate-based immunosuppression who did not experience renal or cardiovascular outcomes within 1 year post-transplant were enrolled from a multicenter observational cohort study. Renal outcome was defined as a composite of biopsy-proven acute rejection, interstitial fibrosis and tubular atrophy, and death-censored graft loss. Cardiovascular outcome was defined as a composite of de novo cardiomegaly, left ventricular hypertrophy, and cardiovascular events. Opportunistic infections were defined as the occurrence of BK virus or cytomegalovirus infections.

Results

A total of 603 eligible KTRs were divided into the low-level TAC (LL-TAC) and high-level TAC (HL-TAC) groups based on a median TAC level of 5.9 ng/mL (range 1.3–14.3) at 1 year post-transplant. The HL-TAC group had significantly higher TAC trough levels at 2, 3, 4, and 5 years compared with the levels of the LL-TAC group. During the mean follow-up of 63.7 ± 13.0 months, there were 121 renal outcomes and 224 cardiovascular outcomes. In multivariate Cox regression analysis, LL-TAC and HL-TAC were not independent risk factors for renal and cardiovascular outcomes, respectively. No significant differences in the development of opportunistic infections and de novo donor-specific anti-human leukocyte antigen antibodies and renal allograft function were observed between the two groups.

Conclusions

TAC trough levels after 1 year post-transplant remained at a similar level until the fifth year after kidney transplantation and were not directly associated with long-term outcomes in stable Korean KTRs who did not experience renal or cardiovascular outcomes. Therefore, in Asian KTRs with a stable clinical course, TAC trough levels higher than approximately 6 ng/mL might not be required after a year of kidney transplantation.

Long-term compensation of renal function after donor nephrectomy

Background

Living donors are the major source of kidneys in countries with a shortage of deceased donors. Kidney donation after careful donor selection is generally accepted as a safe procedure, but the physiologic consequences after donor nephrectomy are not fully verified. In this study we retrospectively reviewed the renal function of the residual kidney in living donors.

Methods

Post-nephrectomy laboratory data of 1,175 living donors (60.7%) from 1,933 living donors who received uninephrectomy from January 1999 to December 2017 at Yonsei University, Severance Hospital, Korea were retrospectively collected. Post-nephrectomy renal function was monitored by the relative ratio of estimated glomerular filtration rate (e-GFR; pre-nephrectomy e-GFR ratio vs. post-nephrectomy e-GFR) that was calculated by the Modification of Diet in Renal Disease formula.

Results

During 36.3±37.6 months of mean follow-up, two cases (0.17%, 2/1,175) of renal failure developed. The mean e-GFR decreased to 64.3±14.2 mL/min/1.73 m² immediately after nephrectomy from 99.2±19.9 mL/min/1.73 m² of the pre-nephrectomy e-GFR. Early decrement of e-GFR was prominent in male and obese donors (body mass index >25 kg/m², P<0.05). The e-GFR ratio increased according to post-nephrectomy duration, and the mean increment degree of e-GFR ratio after nephrectomy calculated by linear regression analysis was 1.94% per year. Unlike the early decrement of e-GFR ratio after nephrectomy, donor factors such as degree of obesity and donor sex did not affect the late increment of e-GFR ratio after nephrectomy (P>0.05).

Conclusions

Our data showed that long-term compensation of the renal function after nephrectomy occurs independently of preoperative donor characteristics.

Graft-versus-host disease after simultaneous pancreas-kidney transplantation

Graft-versus-host disease (GVHD) is rare complication after simultaneous pancreas-kidney transplantation (SPK). Here, we present a rare case of GVHD that developed in a SPK recipient. A 38-year-old female patient with end-stage renal disease due to type 1 diabetes mellitus underwent SPK from a deceased female donor. Four months after transplantation, she was readmitted with fever and abdominal pain and computed tomography revealed a retroperitoneal abscess. While being treated for the retroperitoneal abscess by percutaneous drainage and antibiotics, the patient developed skin rash and diarrhea. A skin biopsy performed at the time showed vacuolization and peri-venular lymphocytic infiltration compatible with GVHD. High-dose steroids resulted in complete remission of GVHD, and the patient was discharged after 2 weeks of treatment. This case demonstrates that early diagnosis of GVHD followed by timely treatment may led to a favorable outcome, and cautions that GVHD can occur in SPK patients.

Transplant outcomes in positive complement-dependent cytotoxicity- versus flow cytometry-crossmatch kidney transplant recipients after successful desensitization: a retrospective study

BACKGROUND

Despite the obvious survival benefit compared to that among waitlist patients, outcomes of positive crossmatch kidney transplantation (KT) are generally inferior to those of human leukocyte antigen (HLA)-compatible KT. This study aimed to compare the outcomes of positive complement-dependent cytotoxicity (CDC) crossmatch (CDC + FC+) and positive flow cytometric crossmatch (CDC-FC+) with those of HLA-compatible KT (CDC-FC-) after successful desensitization.

METHODS

We retrospectively analyzed 330 eligible patients who underwent KTs between June 2011 and August 2017: CDC-FC- (n = 274), CDC-FC+ (n = 39), and CDC + FC+ (n = 17). Desensitization protocol targeting donor-specific antibody (DSA) involved plasmapheresis, intravenous immunoglobulin (IVIG), and rituximab with/without bortezomib for positive-crossmatch KT.

RESULTS

Death-censored graft survival and patient survival were not different among the three groups. The median estimated glomerular filtration rate was significantly lower in the CDC + FC+ group than in the compatible group at 6 months (P < 0.001) and 2 years (P = 0.020). Biopsy-proven rejection within 1 year of CDC-FC-, CDC-FC+, and CDC + FC+ were 15.3, 28.2, and 47.0%, respectively. Urinary tract infections (P < 0.001), Pneumocystis jirovecii pneumonia (P < 0.001), and cytomegalovirus viremia (P < 0.001) were more frequent in CDC-FC+ and CDC + FC+ than in CDC-FC-.

CONCLUSIONS

This study showed that similar graft and patient survival was achieved in CDC-FC+ and CDC + FC+ KT compared with CDC-FC- through DSA-targeted desensitization despite the higher incidence of rejection and infection than that in compatible KT.

Rituximab protects against development of atherosclerotic cardiovascular disease after kidney transplantation: a propensity-matched study

Recent studies have implicated B cells in atherosclerosis and have verified the atheroprotective effect of rituximab. Rituximab is widely used for desensitization in ABO-incompatible or crossmatch-positive kidney transplantation (KT). Using a single-center KT database, we performed propensity-matched analysis to investigate the association between rituximab and posttransplant atherosclerotic cardiovascular disease (ASCVD). Among 1299 eligible patients, 239 given rituximab induction were matched with 401 controls in a 1:2 propensity score matching process. The cumulative rate of ASCVD during 8 years of follow-up was significantly lower in rituximab-treated patients, compared with matched controls (3.7% vs. 11.2%; P = 0.012). However, all-cause mortality did not differ by group (2.9% vs. 4%; P = 0.943). In multivariable Cox analysis, rituximab proved independently protective of ASCVD (hazard ratio = 0.34, 95% confidence interval: 0.14–0.83). The lower risk of ASCVD seen with rituximab induction reached significance only in patient subsets of diabetes mellitus, pretransplant dialysis, or older age (>50 years). Rituximab induction confers a lower risk of ASCVD during the posttransplant period. This atheroprotective effect appears particularly beneficial in patients whose risk of ASCVD is heightened.

Increase in 24-Hour Protein Excretion Immediately After Donation Is Associated With Decreased Functional Recovery in Living Kidney Donors

OBJECTIVES

In this study, we evaluated the occurrence of proteinuria in living kidney donors during the immediate postdonation period, aiming to determine its clinical significance in renal function recovery.

PATIENTS AND METHODS

We enrolled living kidney donors with predonation protein excretion rate (PER) < 150 mg/24 h. Participants were divided into 2 groups according to immediate postdonation PER (4 days after nephrectomy): non-microproteinuria (non-mPr; PER < 150 mg/24 h), n = 244; and immediate postdonation microproteinuria (ImPr; PER ≥ 150 mg/24 h), n = 605.

RESULTS

Estimated glomerular filtration rate (eGFR) did not differ significantly between groups immediately after nephrectomy but was consistently lower in the ImPr group 1 week to 1 year postdonation (1-year postdonation eGFR: ImPr group, 63.6 ± 12.1 mL/min/1.73 m²; non-mPr group, 68.6 ± 12.3 mL/min/1.73 m²; P = .001). Immediate postdonation microproteinuria was an independent predictor of eGFR at 1 year postdonation (β [standard error] = -2.68 [1.15], 95% confidence interval -4.94 to -0.42, P = .02), along with predonation eGFR, age, and sex. Immediate postdonation microproteinuria was more common in donors who were older or male and occurred in 71.3% of kidney donors, suggesting renal injury in this period.

CONCLUSIONS

Although proteinuria generally resolves, its impact persists and can impair renal function recovery. Donors who are older and male are more likely to undergo immediate hyperfiltration after donation.

Utilization of HbA1c in Screening Living Kidney Donors With Prediabetes

OBJECTIVES

To study the outcome of living kidney donors with prediabetes and to evaluate the utilization of baseline HbA1c to identify donors at high risk for developing diabetes during the postdonation follow-up period.

PATIENTS AND METHODS

Living kidney donors with prospectively collected preoperative fasting glucose and HbA1c results were included in the study. Donors were categorized to the high-risk group when both results were in the prediabetic range, the low-risk group when only 1 result was in the prediabetic range, and the control group when both results were normal.

RESULTS

Ninety-three donors were followed for 75.9 ± 23.3 months. A higher proportion of donors in the high-risk group progressed to diabetes compared with donors in the low-risk and control groups (31.3% vs 6.5% vs 0.0%, respectively; P < .001). Donors with prediabetes were not at a higher risk for new-onset hypertension (4.4% vs 10.0% vs 7.7%, in control, low-risk, and high-risk groups, respectively; P = .519) or microproteinuria (7.3% vs 10.3% vs 0.0%, in control, low-risk, and high-risk groups, respectively; P = .478) and exhibited equivalent postdonation renal function compared with donors with normal glucose metabolism.

CONCLUSIONS

HbA1c can identify donors with prediabetes who are at risk for progression to diabetes. Our results indicate that carefully accepted donors with prediabetes are not at increased risk of renal function deterioration in the immediate postdonation period.

Investigation of Systolic Blood Pressure, Diastolic Blood Pressure, and Pulse Pressure in Living Kidney Donors After Donor Nephrectomy

Kidney transplants from living donors have increased, but few studies have examined the long-term risks of live donor nephrectomy. This is the first study to report the blood pressure (BP) changes associated with cardiovascular disease and linked to chronic kidney disease (CKD) 1 year after live donor nephrectomy. This study examined a prospective cohort of patients who underwent donor nephrectomy between March 1, 2006, and December 31, 2016, at the Severance Hospital, Seoul, South Korea. CKD was defined as a glomerular filtration rate (GFR) of < 60 mL/min/1.73m². Patients with a history of hypertension or CKD or an estimated GFR < 60 mL/min/1.73m² were excluded; those examined after 1 year post-nephrectomy were included in the study population. Among 420 patients who underwent donor nephrectomy, 137 (32.6%) developed a first-time onset of a GFR < 60 mL/min/1.73m² by the first year after surgery. After propensity score-matching the age, systolic BP (P < .001) and pulse pressure (P = .006) were significantly associated with the groups with newly developed CKD. Systolic BP and pulse pressure decreased significantly at 1 year after donor nephrectomy. These differences decreased after donor nephrectomy, possibly lowering the risk of cardiovascular disease.

Incidence of Post-transplantation Diabetes Mellitus Within 1 Year After Kidney Transplantation and Related Factors in Korean Cohort Study

BACKGROUND

Post-transplantation diabetes mellitus (PTDM) is associated with a higher risk of mortality and graft loss. The reported incidence of PTDM after kidney transplantation (KT) varies from 10% to 74% and varies by country and ethnicity. There are few reports of nationwide cohort studies on PTDM incidence and related factors in Korea. The purpose of this study was to evaluate incidence of PTDM and related factors within 1 year after KT in Korea.

METHODS

The KoreaN cohort study for Outcome in patients With Kidney Transplantation (KNOW-KT) enrolled 1080 recipients from July 2012 to August 2016. This study included 723 recipients, excluding 273 patients with pretransplant DM and 84 patients who were lost from follow-up within 1 year after KT.

RESULTS

Among 723 recipients, 85 (11.8%) recipients were diagnosed and treated with PTDM. Recipient age, HLA mismatches, hemoglobin A1c (HbA1c), waist-hip ratio (WHR), and use of prednisolone were significantly higher in PTDM group than the nondiabetic group. In the multivariable logistic regression analysis, independent risk factors for PTDM were older recipient age, higher WHR, and HbA1c before KT.

CONCLUSION

The incidence of PTDM was 11.8% in a nationwide Korean cohort study. The factors related to the development of PTDM within 1 year after KT were older recipient age and higher WHR, and HbA1c levels before KT. In recipients with high WHR, it is important to control pretransplant abdominal obesity to prevent PTDM after KT.

Clinical Significance of Revised Banff Criteria in the Diagnosis of Antibody-Mediated Rejection

BACKGROUND

The diagnostic criteria of antibody-mediated rejection (ABMR) has been significantly changed since Banff 2013. The most important revision was adopting microvascular inflammation (MVI) as immunopathologic evidence for ABMR even in C4d-negative cases. In this study, we retrospectively reviewed previous allograft biopsy results and evaluated the impact of this change.

METHODS

We reviewed results of 536 renal allograft biopsies at Severance Hospital during 2011 to 2013, which were diagnosed according to the Banff 2009 criteria. All biopsy results were reassessed according to the Banff 2017 criteria.

RESULTS

According to the Banff 2009 criteria, antibody-mediated changes were observed in 48 cases out of the 536 allograft biopsies (9.0%). According to the Banff 2017 criteria, 28 additional cases (5.2%) were reclassified as antibody-mediated changes. Twenty-six of these cases were C4d-negative ABMR. The most frequent diagnostic finding in these cases was MVI comprising glomerulitis and peritubular capillaritis. Donor-specific antibodies were investigated in 14 of these cases, which revealed positive results in 12 cases.

CONCLUSION

The incidence rate of ABMR has increased after the recent revision of the Banff criteria. The MVI in C4d-negative ABMR cases is the major cause for this increase.

Early hospital readmissions after ABO- or HLA- incompatible living donor kidney transplantation

Early hospital readmission (EHR) after kidney transplantation (KT) is associated with adverse outcomes and significant healthcare costs. Despite survival benefits, ABO- and HLA-incompatible (ABOi and HLAi) KTs require desensitization and potent immunosuppression that increase risk of EHR. However, little data exist regarding EHR after incompatible KT. We defined EHR as admission for any reason within 30 days of discharge from the index hospitalization. Patients who underwent living donor KT from 2010–2017 were classified into one of three groups (control, ABOi KT, or HLAi KT). Our study included 732 patients, 96 (13.1%) of who experienced EHR. HLAi KT patients had a significantly higher incidence of EHR than other groups (26.6%; P < 0.001). In addition, HLAi KT (HR, 2.26; 95% CI, 1.35–3.77; P = 0.002) and advanced age (≥60 years) (HR, 1.93; 95% CI, 1.20–3.12; P = 0.007) were independent risk factors for EHR. Patients with EHR showed 1.5 times and 3 times greater risk of late hospital readmission and death-censored graft loss, respectively, and consistently exhibited inferior renal function compared to those without EHR, regardless of immunologic incompatibilities. We recommend that KT recipients experiencing EHR or its risk factors be managed with extreme care due to their increased susceptibility to adverse outcomes.

The Impact of Perioperative Factors on Changes in Diastolic Function after Kidney Transplantation: A Retrospective Analysis

PURPOSE

Cardiac changes in end-stage renal disease are the most common causes of death after kidney transplantation (KT). Chronic kidney disease presents a major risk factor for the development and progression of diastolic dysfunction. The purpose of this study was to identify the association between changes in left ventricular (LV) diastolic function and perioperative clinical factors in patients with preserved ejection fraction following KT.

MATERIALS AND METHODS

We reviewed 115 patients who underwent KT between January 2011 and December 2015 with both preand post-transplant echocardiograms; patients with LV systolic dysfunction were excluded. LV diastolic function was measured using the ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e').

RESULTS

Patients with normal pre-operative LV systolic function (n=97) showed improvement in E/e' after KT (11.9±4.4 to 10.5±3.8, p=0.023). Additionally, post-KT estimated glomerular filtration ratio was associated with changes in E/e' (odds ratio, -0.056; 95% confidence interval, -0.014 to -0.007; p=0.026). Among patients with preexisting diastolic dysfunction (20/97 patients), the amount of intraoperative fluid administration was related to E/e' changes (odds ratio, 0.003; 95% confidence interval, 0.000 to 0.005; p=0.029).

CONCLUSION

KT is associated with improved diastolic function. Post-KT renal function was significantly related to changes in LV diastolic function. The amount of intraoperative fluid was a risk factor for worsening diastolic function after KT in patients with preexisting diastolic dysfunction.

Clinical significance of donor-specific anti-HLA-DR51/52/53 antibodies for antibody-mediated rejection in kidney transplant recipients

Background

The presence of donor-specific antibodies (DSAs) to human leukocyte antigen (HLA) increases the risk of antibody-mediated rejection (ABMR) after kidney transplantation (KT). However, the clinical relevance of anti-HLA-DR51/52/53 antibodies remains unclear because of their weak antigen expression. This study evaluated the association between anti-HLA-DR51/52/53 DSAs and ABMR.

Methods

We retrospectively reviewed the single-antigen-bead panel reactive antibody (single PRA) results of 130 patients tested between August 1, 2009 and March 6, 2015, based on clinical necessity after allograft KT. Single PRA analysis was performed using Luminex assay kits (Lifecodes LSA class I and II). We reviewed the clinical course and biopsy results of patients with anti-HLA-DR51/52/53 DSAs.

Results

Post-KT DSAs were identified in 89 of the 130 patients (68.5%), with 26 of 32 class I DSAs and 63 of 66 class II DSAs being immunodominant DSAs. Thirteen patients had anti-HLA-DR51/52/53 DSAs. Three patients with anti-HLA-DR51/52/53 immunodominant DSAs alone were diagnosed with biopsy-proven ABMR. One patient who developed anti-HLA-DR DSA 13 days after KT showed a rapid increase in anti-HLA-DR51 DSA and had biopsy-proven ABMR.

Conclusions

Although the expression of the HLA-DR51/52/53 antigen was weak, anti-HLA-DR51/52/53 DSAs might be correlated with biopsy-proven ABMR. Therefore, anti-HLA-DR51/52/53 DSAs must be evaluated as a cause of ABMR after transplantation.

Association between post-transplant serum uric acid levels and kidney transplantation outcomes

Background

Serum uric acid (UA) level has been reported to be associated with chronic allograft nephropathy and graft failure in patients who undergo kidney transplantation (KT). However, the role of serum UA level in renal graft survival remains controversial.

Objective

This study aimed to investigate the effect of mean serum UA level during two different post-KT periods on long-term renal graft outcomes in a large population cohort in which living donor KT prevails.

Material and methods

A retrospective cohort study was performed using KT data prospectively collected at a single institution. Patients (n = 2,993) were divided into low-, normal-, and high-UA groups according to the mean serum UA level within the first year (1-YR) and 1–5 years (5-YR) after transplantation.

Results

In the 1-YR Cox proportional hazards analysis, the low- and high-UA groups had a significantly decreased and increased risk, respectively, for overall graft failure (OGF), death-censored graft failure (DCGF), and composite event (return to dialysis, retransplantation, death from graft dysfunction, and 40% decline in estimated glomerular filtration rate) compared with the normal-UA group. Similarly, in the 5-YR analysis, the low-UA group had a significantly reduced risk of DCGF compared with the normal-UA group, whereas the high-UA group had a significantly increased risk of all three graft outcomes. In a marginal structural model, hyperuricemia had a significant causal effect on worsening graft outcomes, with consideration of all confounding variables (OGF: hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.33–3.78; DCGF: HR 2.38, 95% CI 1.09–4.9; composite event: HR 3.05, 95% CI 1.64–5.49).

Conclusions

A low-to-normal serum UA level within the first year and 1–5 years after KT is an independent factor for better renal allograft outcomes in the long-term follow-up period rather than high serum UA level.

Effects of rituximab dose on hepatitis B reactivation in patients with resolved infection undergoing immunologic incompatible kidney transplantation

Sensitized patients received desensitization therapy with rituximab for kidney transplantation. However, the impact of rituximab dose on hepatitis B virus (HBV) reactivation is unknown. Patients who underwent living donor kidney transplantation between 2008 and 2016 were grouped according to rituximab dose (control vs. standard-dose rituximab [375 mg/m²] vs. reduced-dose rituximab [200 mg/body]) for comparison of HBV reactivation. A total of 336 hepatitis B surface antigen (HBsAg)-negative/antibody to hepatitis B core antigen (anti-HBc)-positive patients underwent kidney transplantation, of whom 91 (27.1%) received rituximab for desensitization (57 standard-dose and 34 reduced-dose rituximab). During the study period, eight patients experienced HBV reactivation (three in the control group, five in the standard-dose group). In the standard-dose group, four patients experienced hepatitis flare, and one patient died due to hepatic failure. No HBV reactivation occurred in the reduced-dose group. Standard-dose rituximab significantly decreased hepatitis B surface antigen antibody titer (anti-HBs; −99.8 IU/L) at 12 months, compared with reduced-dose rituximab (−20.1 IU/L) and control (−39.1 IU/L, P = 0.017). Standard-dose rituximab (HR, 10.60; 95% CI, 2.52–44.60; P = 0.001) and anti-HBs < 100 IU/L at transplantation (HR, 9.06; 95% CI, 1.11–74.30; P = 0.04) were independent risk factors for HBV reactivation. Standard-dose rituximab significantly increased HBV reactivation risk for HBsAg-negative/anti-HBc-positive kidney transplant patients.

Impact of Cigarette Smoking on Living Kidney Donors

BACKGROUND

Smoking is known to result in a decline in renal allograft function and survival of recipients; however, the effect of smoking on living kidney donors remains unknown. In this study we evaluated the impact of cigarette smoking on renal function of kidney donors.

METHODS

Among 1056 donors who underwent nephrectomy, 612 completed the 6-month follow-up protocol and were enrolled in the study. The association of smoking status, including pack-years smoking history, and postoperative renal function was evaluated.

RESULTS

Among donors, 68.1% had never smoked, 8% were former smokers, and 23.9% were current smokers. Donors who never smoked were older than former and current smokers (42.3 ± 11.8, 41.9 ± 11.1, and 38.3 ± 10.9 years, respectively; P < .001). There was no difference in preoperative renal function between groups; however, postoperative estimated glomerular filtration rate (eGFR) was lower in former and current smokers than in those who never smoked (64.6 ± 13.8, 64.7 ± 12.3, and 67.8 ± 13.1 mL/min/1.73 m², respectively; P = .023). In former and current smokers, pack-years smoking history was negatively associated with pre- and postoperative eGFR (r = -0.305 and -0.435, P < .001), and correlated with postoperative percent eGFR decline (r = 0.248, P < .001). Smoking history was associated with postoperative development of chronic kidney disease (CKD). Especially in former smokers, a smoking history of more than 12 pack-years was strongly associated with development of CKD (odds ratio = 7.5, P = .003).

CONCLUSION

Even if they no longer smoke, donors with a smoking history require close observation due to increased risk of CKD development after kidney donation. A detailed pack-years smoking history should be obtained, and smoking cessation strategies should be implemented in kidney donors.

Clinical Significance of Macrophage Polarization in Antibody-Mediated Rejection of Renal Allograft

BACKGROUND

The significance of proinflammatory M1 (classically activated) and profibrotic M2 (alternatively activated) macrophages in antibody-mediated rejection (ABMR) after kidney transplantation has not been investigated.

METHODS

Fifty-five biopsy-confirmed ABMR samples were stained with MRP 8/14 (a marker of M1 macrophages) and CD163 (a marker of M2 macrophages), and positive cells were counted in glomeruli and the tubulointerstitium, respectively. Patients were classified into M1 and M2 polarization groups according to the glomerular and tubulointerstitial M1:M2 ratio, and the results were compared with Banff scores, serum creatinine level, estimated glomerular filtration rate (eGFR), and graft survival.

RESULTS

The glomerular M2 polarization group showed significantly higher chronic glomerulopathy scores, serum creatinine levels, and lower eGFR at the time of biopsy (P = .019 and P = .015, respectively) and 3-month postbiopsy (P = .016 and P = .032, respectively) than the M1 polarization group. The tubulointerstitial M2 polarization group had significantly lower glomerulitis, arteritis, peritubular capillaritis, and glomerulitis + peritubular capillaritis scores than the M1 polarization group, but there was no significant difference in renal function. Long-term graft survival was not associated with macrophage polarization.

CONCLUSION

Glomerular M2 polarization in ABMR biopsy samples is associated with chronic glomerular injury and poorer graft function, but without graft survival.

Long-term Follow-up of Living Kidney Donors With Chronic Kidney Disease at 1 Year After Nephrectomy

BACKGROUND

Although renal function recovery of living kidney donors has been reported in a number of studies, many patients show poor recovery, and the long-term prognosis of these patients has not been well studied. In this investigation we explored the long-term prognosis of renal function in patients with chronic kidney disease (CKD) at 1 year after nephrectomy.

METHODS

Patients who underwent donor nephrectomy during the period from March 2006 to April 2014, with a follow-up creatinine study at 1 year postoperatively and more than 3 years of follow-up, were included in the study. Creatinine and estimated glomerular filtration rate (eGFR, using the Modification of Diet in Renal Disease formula) before and after surgery were studied. Age, sex, history of hypertension or diabetes, body mass index, blood pressure, complete blood count, preoperative routine serum chemistry, and urine study results were reviewed.

RESULTS

Among 841 patients who had donor nephrectomy, 362 were included in the study. There were 111 patients (30.6%) with eGFR <60 mL/min/1.73 m² at 1 year postsurgery, and the median follow-up period was 62.8 months (interquartile range [IQR] 42.0-86.3 months). The maximum eGFR after 3-year follow-up was studied, and 48 patients (43.2%) never recovered eGFR to >60 mL/min/1.73 m². Age, history of hypertension, preoperative eGFR, and eGFR at 1 year were predictive factors at univariate analysis. Multivariate analysis of these factors was studied, and age (52.5 [IQR 47-55.7] vs 47 [IQR 7-53] years, odds ratio [OR] 1.1, 95% confidence interval [CI] 1.02-1.15, P = .007), history of hypertension (16.7% vs 1.6%, OR 10.0, 95% CI 1.09-92.49, P = .042), and eGFR at 1 year (53.9 [IQR 50.3-56.0] vs 57.0 [IQR 54.2-58.4] mL/min/1.73 m², OR 0.8, 95% CI 0.72-0.92, P = .002) remained as significant risk factors.

CONCLUSION

Of all living donors, 15.7% had CKD after >3 years of follow-up. Close observation is warranted when donors have CKD after 1 year follow-up, as 43.2% fail to recover renal function. Patients who are older, have a history of hypertension, and have low eGFR at 1-year follow-up are especially at risk.