Long-Term Success of Metal Endobronchial Stents in Lung Transplant Recipients.

BACKGROUND: Bronchial stenosis is a common complication following lung transplantation. We evaluated long-term associations of the use of self-expandable metal stents (SEMSs) with lung function tests, patient safety, and survival. METHODS: A retrospective chart review of 582 lung transplantations performed at our institution between January 2002 and January 2018. Fifty-four patients with SEMSs (intervention group) were matched one-to-one to patients without SEMSs (control group) using propensity score matching for age, sex, the year, and type of transplantation (unilateral/bilateral), and underlying disease. Data regarding long-term lung function and survival were compared between the groups. RESULTS: During a median follow-up of 54.8 months, the difference in survival between the study groups was not statistically significant (p = 0.2). Following 5, 7.5 and 10 years, values of mean forced expiratory volume in 1 second (FEV1) were comparable between patients with and without SEMSs as follows: 59.5 versus 62.6% (p = 0.2), 55.9 versus 55.0% (p = 0.4), and 63.5 versus 61.9% (p = 0.3), respectively. In the intervention group, a significant increase in the mean FEV1 was observed in 60 days after stent insertion (from 41.9 ± 12.8 to 49.5 ± 16.7% days, p < 0.001). Long-term complications following stent insertion included severe bleeding (1.8%), stent fractures (7.4%), stent stenosis (7.4%), stent collapse (3.7%), endobronchial pressure ulcer (1.9%), and stent migration (1.9%). CONCLUSION: SEMS insertion is associated with a positive sustained effect on lung function, without increasing long-term mortality. Thus, airway stenosis after lung transplantation can be safely and successfully treated using endobronchial metal stenting, with tight bronchoscopic follow-up and maintenance.

A null variant in the apolipoprotein L3 gene is associated with non-diabetic nephropathy.

Background: Inheritance of apolipoprotein L1 gene (APOL1) renal-risk variants in a recessive pattern strongly associates with non-diabetic end-stage kidney disease (ESKD). Further evidence supports risk modifiers in APOL1-associated nephropathy; some studies demonstrate that heterozygotes possess excess risk for ESKD or show earlier age at ESKD, relative to those with zero risk alleles. Nearby loci are also associated with ESKD in non-African Americans. Methods: We assessed the role of the APOL3 null allele rs11089781 on risk of non-diabetic ESKD. Four cohorts containing 2781 ESKD cases and 2474 controls were analyzed. Results: Stratifying by APOL1 risk genotype (recessive) and adjusting for African ancestry identified a significant additive association between rs11089781 and ESKD in each stratum and in a meta-analysis [meta-analysis P = 0.0070; odds ratio (OR) = 1.29]; ORs were consistent across APOL1 risk strata. The biological significance of this association is supported by the finding that the APOL3 gene is co-regulated with APOL1, and that APOL3 protein was able to bind to APOL1 protein. Conclusions: Taken together, the genetic and biological data support the concept that other APOL proteins besides APOL1 may also influence the risk of non-diabetic ESKD.

Emergence of an Israel faith-based community organization facilitating live donor kidney transplantation.

BACKGROUND: The 2014 Consensus Conference on Best Practices in Living Kidney Donations recognized live donor kidney transplantation as the best treatment for late-stage kidney disease, yielding superior graft and patient survival, improved quality of life, fewer requirements for dialysis and increased cost-effectiveness compared to deceased donor kidney transplantation. Yet in spite of the excellent results of living kidney donation, the annual number of living kidney donors is declining in many countries, including the United States. In Israel, a non-profit organization, Matnat Chaim ("Gift of Life" in Hebrew), a faith-based initiative, has emerged as a major force for arranging living donor kidney transplantation mainly by facilitating altruistic living unrelated donor transplantation. METHODS: A retrospective review of the records of live kidney donations facilitated by the Matnat Chaim organization and referred to Israel transplant centers, since the organization's inception in 2009, was performed and compared to published data from the Israel Ministry of Health. RESULTS: Matnat Chaim has facilitated 494 live kidney donations since its founding in February 2009 until the end of 2017. Of the 124 live kidney transplants performed in 2016, 111 (90%) were shown to be altruistic and unrelated. This large number of donations was associated with a doubling of the total number of kidney transplantations, performed in Israel (data published by the Israel Ministry of Health). CONCLUSIONS: The success of an Israel community organization in the promotion of kidney transplantation may serve as a model for other religious and non-religious communities worldwide.

APOL1-Mediated Cell Injury Involves Disruption of Conserved Trafficking Processes.

APOL1 harbors C-terminal sequence variants (G1 and G2), which account for much of the increased risk for kidney disease in sub-Saharan African ancestry populations. Expression of the risk variants has also been shown to cause injury to podocytes and other cell types, but the underlying mechanisms are not understood. We used Drosophila melanogaster and Saccharomyces cerevisiae to help clarify these mechanisms. Ubiquitous expression of the human APOL1 G1 and G2 disease risk alleles caused near-complete lethality in D. melanogaster, with no effect of the G0 nonrisk APOL1 allele, corresponding to the pattern of human disease risk. We also observed a congruent pattern of cellular damage with tissue-specific expression of APOL1. In particular, expression of APOL1 risk variants in D. melanogaster nephrocytes caused cell-autonomous accumulation of the endocytic tracer atrial natriuretic factor-red fluorescent protein at early stages and nephrocyte loss at later stages. We also observed differential toxicity of the APOL1 risk variants compared with the APOL1 nonrisk variants in S. cerevisiae, including impairment of vacuole acidification. Yeast strains defective in endosomal trafficking or organelle acidification but not those defective in autophagy displayed augmented APOL1 toxicity with all isoforms. This pattern of differential injury by the APOL1 risk alleles compared with the nonrisk alleles across evolutionarily divergent species is consistent with an impairment of conserved core intracellular endosomal trafficking processes. This finding should facilitate the identification of cell injury pathways and corresponding therapeutic targets of interest in these amenable experimental platforms.

APOL1 nephropathy: from gene to mechanisms of kidney injury.

The contribution of African ancestry to the risk of focal segmental glomerulosclerosis and chronic kidney disease has been partially explained by the recently described chromosome 22q variants in the gene apolipoprotein L1 (APOL1). The APOL1 variants appear at a high allele frequency in populations of West African ancestry as a result of apparent adaptive selection of the heterozygous state. Heterozygosity protects from infection with Trypanosoma brucei rhodesiense. This review will describe the role of the approaches in population genetics for the description of APOL1-associated nephropathies and draw inferences as to the biologic mechanisms from genetic epidemiology findings to date. Modifier loci can influence APOL1 risk for the development of kidney disease. 'Second hits', both viral and non-viral, may explain the discrepancy between the remarkably high odds ratios and the low lifetime risks of kidney disease in two allele carriers of APOL1 risk variants. Therapeutic strategies for APOL1-associated nephropathies will require the prevention and treatment of these 'second hits' and the development of drugs to protect the APOL1 downstream renal injury pathways.

Amlodipine treatment of hypertension associates with a decreased dementia risk.

Hypertension has been shown to be a risk factor for development of dementia. However, medical treatment of hypertension failed to reduce consistently the risk of dementia. Experimental study pointed to the possibility of difference between different calcium channel blockers (CCB) in their neuro-protective effect. The aim of our study was to evaluate the risk of dementia during treatment of hypertension with different CCBs. This is a retrospective cohort study based on electronic database of a large public health care organization. Study period was 11 years and it included patients aged 40-75 years old, having diagnosis of hypertension without diagnosis of dementia at the starting point, treated with either single specific CCB (study group) or with other than CCBs antihypertensive medications (control group) for at least 30 months during the study period. A total of 15,664 patients that satisfied these criteria were identified: 3,884 were treated with amlodipine, 2,062 were treated with nifedipine, 609 were treated with lercanidipine, and 9,109 never received CCBs. Dementia developed in 765 (4.9%) patients. Adjusted hazard ratio (HR) for dementia in patients treated with amlodipine, nifedipine, and lercanidipine was 0.60 (p < 0.001), 0.89 (NS), and 0.90 (NS). Decreased adjusted HR of dementia with amlodipine was demonstrated in the patients aged 60 or more (HR 0.61 [0.49-0.77], p < 0.001), but not in the patients aged less than 60 years old. This study shows that amlodipine therapy may be associated with a decreased dementia risk in hypertensive individuals older than 60 years, compared to those treated without CCBs.

Effect of Jewish-Arab Ancestry and Gender Matching on Clinical Outcome of Lung Transplantation in Israel.

BACKGROUND: Studies in lung transplantation demonstrate that the ancestry and gender dissimilarities of donor-recipients lead to a decrease in survival of the recipient. OBJECTIVES: To evaluate the survival of lung transplant recipients in Israel based on whether the donors and recipients are of Jewish or Arab ancestry as well as survival based on gender match or mismatch. METHODS: We performed a retrospective observational cohort study of 345 lung transplant recipients at the Rabin Medical Center, Petah Tikva, Israel between January 1997 and January 2013. We compared the survival of lung transplant recipients in two ancestry categories: ancestry matched (Jewish donors to Jewish recipients or Arab donors to Arab recipients) and ancestry mismatched (Jewish donors to Arab recipients and vice versa). We also compared the survival among the four gender donor and recipient combinations (male to male, female to female, male to female, and female to male). RESULTS: Survival analysis revealed no significant differences between the two ancestry groups (P = 0.51) and among the four gender combinations (P = 0.58). On Cox multivariate analysis, younger donor age was the only significant parameter for longer survival (hazards ratio 1.025, 95% confidence interval 1.012-1.037). CONCLUSIONS: Gender and ancestry mismatches in these two Israeli populations do not appear to alter the clinical outcomes following lung transplantation.

Hypertension-misattributed kidney disease in African Americans.

Lipkowitz et al. extend the African American Study of Kidney Disease and Hypertension to the level of genetic epidemiology, in a case-control study design. Analysis of genotypes at the APOL1 kidney disease risk region supports a paradigm shift in which genetic risk is proximate to both kidney disease and hypertension. The findings mandate urgency in clarifying mechanisms whereby APOL1 region risk variants interact with environmental triggers to cause progressive kidney disease accompanied by dangerous hypertension.

High population frequencies of APOL1 risk variants are associated with increased prevalence of non-diabetic chronic kidney disease in the Igbo people from south-eastern Nigeria.

BACKGROUND: Continental Africa is facing an epidemic of chronic kidney disease (CKD). APOL1 risk variants have been shown to be strongly associated with an increased risk for non-diabetic kidney disease including HIV nephropathy, primary non-monogenic focal and segmental glomerulosclerosis, and hypertension-attributed nephropathy among African ancestry populations in the USA. The world's highest frequencies of APOL1 risk alleles have been reported in West African nations, overlapping regions with a high incidence of CKD and hypertension. One such region is south-eastern Nigeria, and therefore we sought to quantify the association of APOL1 risk alleles with CKD in this region. METHODS: APOL1 risk variants were genotyped in a case-control sample set consisting of non-diabetic, CKD patients (n = 44) and control individuals (n = 43) from Enugu and Abakaliki, Nigeria. RESULTS: We found a high frequency of two APOL1 risk alleles in the general population of Igbo people of south-eastern Nigeria (23.3%). The two APOL1 risk allele frequency in the CKD patient group was 66%. Logistic regression analysis under a recessive inheritance model showed a strong and significant association of APOL1 two-risk alleles with CKD, yielding an odds ratio of 6.4 (unadjusted p = 1.2E-4); following correction for age, gender, HIV and BMI, the odds ratio was 4.8 (adjusted p = 5.1E-03). CONCLUSION: APOL1 risk variants are common in the Igbo population of south-eastern Nigeria, and are also highly associated with non-diabetic CKD in this area. APOL1 may explain the increased prevalence of CKD in this region.

APOL1 risk variants predict histopathology and progression to ESRD in HIV-related kidney disease.

With earlier institution of antiretroviral therapy, kidney diseases other than HIV-associated nephropathy (HIVAN) predominate in HIV-infected persons. Outcomes for these diseases are typically worse among those infected with HIV, but the reasons for this are not clear. Here, we examined the role of APOL1 risk variants in predicting renal histopathology and progression to ESRD in 98 HIV-infected African Americans with non-HIVAN kidney disease on biopsy. We used survival analysis to determine time to ESRD associated with APOL1 genotype. Among the 29 patients with two APOL1 risk alleles, the majority (76%) had FSGS and 10% had hypertensive nephrosclerosis. In contrast, among the 54 patients with one APOL1 risk allele, 47% had immune-complex GN as the predominant lesion and only 23% had FSGS. Among the 25 patients with no APOL1 risk allele, 40% had immune-complex GN and 12% had FSGS. In 310 person-years of observation, 29 patients progressed to ESRD. In adjusted analyses, individuals with two APOL1 risk alleles had a nearly three-fold higher risk for ESRD compared with those with one or zero risk alleles (P=0.03). In summary, these data demonstrate an association between APOL1 variants and renal outcomes in non-HIVAN kidney disease, suggesting a possible use for APOL1 genotyping to help guide the care of HIV-infected patients.

African ancestry allelic variation at the MYH9 gene contributes to increased susceptibility to non-diabetic end-stage kidney disease in Hispanic Americans.

Recent studies identified MYH9 as a major susceptibility gene for common forms of non-diabetic end-stage kidney disease (ESKD). A set of African ancestry DNA sequence variants comprising the E-1 haplotype, was significantly associated with ESKD. In order to determine whether African ancestry variants are also associated with disease susceptibility in admixed populations with differing genomic backgrounds, we genotyped a total of 1425 African and Hispanic American subjects comprising dialysis patients with diabetic and non-diabetic ESKD and controls, using 42 single nucleotide polymorphisms (SNPs) within the MYH9 gene and 40 genome-wide and 38 chromosome 22 ancestry informative markers. Following ancestry correction, logistic regression demonstrated that three of the E-1 SNPs are also associated with non-diabetic ESKD in the new sample sets of both African and Hispanic Americans, with a stronger association in Hispanic Americans. We also identified MYH9 SNPs that are even more powerfully associated with the disease phenotype than the E-1 SNPs. These newly associated SNPs, could be divided into those comprising a haplotype termed S-1 whose association was significant under a recessive or additive inheritance mode (rs5750248, OR 4.21, P < 0.01, Hispanic Americans, recessive), and those comprising a haplotype termed F-1 whose association was significant under a dominant or additive inheritance mode (rs11912763, OR 4.59, P < 0.01, Hispanic Americans, dominant). These findings strengthen the contention that a sequence variant of MYH9, common in populations with varying degrees of African ancestry admixture, and in strong linkage disequilibrium with the associated SNPs and haplotypes reported herein, strongly predisposes to non-diabetic ESKD.

APOL1 allelic variants are associated with lower age of dialysis initiation and thereby increased dialysis vintage in African and Hispanic Americans with non-diabetic end-stage kidney disease.

BACKGROUND: The APOL1 G1 and G2 genetic variants make a major contribution to the African ancestry risk for a number of common forms of non-diabetic end-stage kidney disease (ESKD). We sought to clarify the relationship of APOL1 variants with age of dialysis initiation and dialysis vintage (defined by the time between dialysis initiation and sample collection) in African and Hispanic Americans, diabetic and non-diabetic ESKD. METHODS: We examined APOL1 genotypes in 995 African and Hispanic American dialysis patients with diabetic and non-diabetic ESKD. RESULTS: The mean age of dialysis initiation for non-diabetic African-American patients with two APOL1 risk alleles was 48.1 years, >9 years earlier than those without APOL1 risk alleles (t-test, P=0.0003). Similar results were found in the non-diabetic Hispanic American cohort, but not in the diabetic cohorts. G1 heterozygotes showed a 5.3-year lower mean age of dialysis initiation (t-test, P=0.0452), but G2 heterozygotes did not show such an effect. At the age of 70, 92% of individuals with two APOL1 risk alleles had already initiated dialysis, compared with 76% of the patients without APOL1 risk alleles. Although two APOL1 risk alleles are also associated with ∼2 years increased in dialysis vintage, further analysis showed that this increase is fully explained by earlier age of dialysis initiation. CONCLUSIONS: Two APOL1 risk alleles significantly predict lower age of dialysis initiation and thereby increased dialysis vintage in non-diabetic ESKD African and Hispanic Americans, but not in diabetic ESKD. A single APOL1 G1, but not G2, risk allele also lowers the age of dialysis initiation, apparently consistent with gain of injury or loss of function mechanisms. Hence, APOL1 mutations produce a distinct category of kidney disease that manifests at younger ages in African ancestry populations.

Linkage disequilibrium analysis reveals an albuminuria risk haplotype containing three missense mutations in the cubilin gene with striking differences among European and African ancestry populations.

BACKGROUND: A recent meta-analysis described a variant (p.Ile2984Val) in the cubilin gene (CUBN) that is associated with levels of albuminuria in the general population and in diabetics. METHODS: We implemented a Linkage Disequilibrium (LD) search with data from the 1000 Genomes Project, on African and European population genomic sequences. RESULTS: We found that the p.Ile2984Val variation is part of a larger haplotype in European populations and it is almost absent in west Africans. This haplotype contains 19 single nucleotide polymorphisms (SNPs) in very high LD, three of which are missense mutations (p.Leu2153Phe, p.Ile2984Val, p.Glu3002Gly), and two have not been previously reported. Notably, this European haplotype is absent in west African populations, and the frequency of each individual polymorphism differs significantly in Africans. CONCLUSIONS: Genotyping of these variants in existing African origin sample sets coupled to measurements of urine albumin excretion levels should reveal which is the most likely functional candidate for albuminuria risk. The unique haplotypic structure of CUBN in different populations may leverage the effort to identify the functional variant and to shed light on evolution of the CUBN gene locus.

Absence of APOL1 risk variants protects against HIV-associated nephropathy in the Ethiopian population.

BACKGROUND: Susceptibility to end-stage kidney disease (ESKD) among HIV-infected Americans of African ancestral heritage has been attributed to APOL1 genetic variation. We determined the frequency of the APOL1 G1 and G2 risk variants together with the prevalence of HIV-associated nephropathy (HIVAN) among individuals of Ethiopian ancestry to determine whether the kidney disease genetic risk is PanAfrican or restricted to West Africa, and can explain the previously reported low risk of HIVAN among Ethiopians. METHODS: We studied a cohort of 338 HIV-infected individuals of Ethiopian ancestry treated in one Israeli and one Ethiopian center. We sought clinical evidence for HIVAN (serum creatinine >1.4 mg/dl or proteinuria >30 mg/dl in a spot urine sample). Genetic analyses included the genotyping of the APOL1 G1 and G2 variants, and a panel of 33 genomic ancestry-informative markers. Statistical analysis compared clinical and genetic indices for HIV-infected individuals of Ethiopian ancestry and overall Ethiopians to those reported for HIV-infected African-Americans, overall African-Americans, West Africans and non-Africans. FINDINGS: Three (0.8%) of 338 HIV-infected patients of Ethiopian ancestry showed clinical criteria compatible with renal impairment. Two of these 3 patients also have severe poorly controlled diabetes mellitus. The third nondiabetic patient underwent renal biopsy which ruled out HIVAN. This absence of clinically apparent HIVAN was significantly different from that reported for African-Americans. The APOL1 G1 and G2 risk variants were found, respectively, in 0 and 2 (heterozygote state) of the 338 HIV-infected individuals. Global ancestry and the frequencies of the APOL1 G1 and G2 variants are not statistically different from their frequencies in the general Ethiopian population, but are significantly and dramatically lower than those observed among HIV-infected African-Americans, African-Americans and West Africans. INTERPRETATION: The coinciding absence of HIVAN and the APOL1 risk variants among HIV-infected individuals of Ethiopian ancestry support a Western rather than Pan-African ancestry risk for ESKD, and can readily explain the lack of HIVAN among individuals of Ethiopian ancestry.

Long-term outcomes of metallic endobronchial stents in lung transplant recipients are not affected by bacterial colonization.

OBJECTIVES: We evaluated associations of endobronchial stenting with airway bacterial colonization, the antimicrobial resistance profile, hospitalizations for pneumonia and survival in lung transplant recipients. METHODS: This is a retrospective single-centre study of 582 recipients of lung transplant during 2002-2018. We compared outcomes of 57 patients (9.7%) who received endobronchial stents (intervention group) to a control group of 57 patients without stents who were matched one to one for age, sex, year of transplantation, unilateral/bilateral transplantation and underlying disease. RESULTS: For the intervention compared to the control group, airway colonization was more common for Pseudomonas (86% vs 35%, P < 0.001), Acinetobacter (21% vs 7%, P = 0.05), Klebsiella (21% vs 5%, P = 0.02) and Staphylococcus species (11% vs 0%, P = 0.02). The respective proportions of patients with positive bronchoalveolar lavage cultures on the third post-transplantation day, the day of stent insertion and 6-month post-stent insertion were 47.4%, 50.9% and 65.4% for Pseudomonas sp.; 15.8%, 12.3% and 3.8% for Klebsiella sp.; and 8.8%, 5.3% and 5.8% for Acinetobacter sp. The mean number of hospitalizations for pneumonia per patient was higher, without statistical significance, in the intervention than the control group (1.5 ± 1.7 vs 0.9 ± 1.5, P = 0.1). Kaplan-Meier survival curves did not show a statistically significant difference between the intervention group and the entire group without endobronchial stents (n = 525) (P = 0.4). CONCLUSIONS: Lung transplant recipients with endobronchial stents were more likely to be colonized with pathologic bacteria and having pneumonia; however, stent placement was not associated with increased long-term mortality with appropriate stent maintenance.

Missense mutations in the APOL1 gene are highly associated with end stage kidney disease risk previously attributed to the MYH9 gene.

MYH9 has been proposed as a major genetic risk locus for a spectrum of nondiabetic end stage kidney disease (ESKD). We use recently released sequences from the 1000 Genomes Project to identify two western African-specific missense mutations (S342G and I384M) in the neighboring APOL1 gene, and demonstrate that these are more strongly associated with ESKD than previously reported MYH9 variants. The APOL1 gene product, apolipoprotein L-1, has been studied for its roles in trypanosomal lysis, autophagic cell death, lipid metabolism, as well as vascular and other biological activities. We also show that the distribution of these newly identified APOL1 risk variants in African populations is consistent with the pattern of African ancestry ESKD risk previously attributed to MYH9.Mapping by admixture linkage disequilibrium (MALD) localized an interval on chromosome 22, in a region that includes the MYH9 gene, which was shown to contain African ancestry risk variants associated with certain forms of ESKD (Kao et al. 2008; Kopp et al. 2008). MYH9 encodes nonmuscle myosin heavy chain IIa, a major cytoskeletal nanomotor protein expressed in many cell types, including podocyte cells of the renal glomerulus. Moreover, 39 different coding region mutations in MYH9 have been identified in patients with a group of rare syndromes, collectively termed the Giant Platelet Syndromes, with clear autosomal dominant inheritance, and various clinical manifestations, sometimes also including glomerular pathology and chronic kidney disease (Kopp 2010; Sekine et al. 2010). Accordingly, MYH9 was further explored in these studies as the leading candidate gene responsible for the MALD signal. Dense mapping of MYH9 identified individual single nucleotide polymorphisms (SNPs) and sets of such SNPs grouped as haplotypes that were found to be highly associated with a large and important group of ESKD risk phenotypes, which as a consequence were designated as MYH9-associated nephropathies (Bostrom and Freedman 2010). These included HIV-associated nephropathy (HIVAN), primary nonmonogenic forms of focal segmental glomerulosclerosis, and hypertension affiliated chronic kidney disease not attributed to other etiologies (Bostrom and Freedman 2010). The MYH9 SNP and haplotype associations observed with these forms of ESKD yielded the largest odds ratios (OR) reported to date for the association of common variants with common disease risk (Winkler et al. 2010). Two specific MYH9 variants (rs5750250 of S-haplotype and rs11912763 of F-haplotype) were designated as most strongly predictive on the basis of Receiver Operating Characteristic analysis (Nelson et al. 2010). These MYH9 association studies were then also extended to earlier stage and related kidney disease phenotypes and to population groups with varying degrees of recent African ancestry admixture (Behar et al. 2010; Freedman et al. 2009a, b; Nelson et al. 2010), and led to the expectation of finding a functional African ancestry causative variant within MYH9. However, despite intensive efforts including re-sequencing of the MYH9 gene no suggested functional mutation has been identified (Nelson et al. 2010; Winkler et al. 2010). This led us to re-examine the interval surrounding MYH9 and to the detection of novel missense mutations with predicted functional effects in the neighboring APOL1 gene, which are significantly more associated with ESKD than all previously reported SNPs in MYH9.

The Etiology and Prognosis of Delayed Postoperative Leukocytosis in Lung Transplant Recipients.

BACKGROUND: Leukocytosis (white blood cell count >12 000/µL) in the delayed postoperative period (4-7 days) after lung transplantation is due to diverse etiologies. We aimed to describe the etiologies of delayed postoperative leukocytosis in lung transplant recipients and to evaluate the association of leukocytosis causes with short-term survival. METHODS: A retrospective chart review of 274 lung transplantations performed in our institution during 2006 to 2013. RESULTS: Delayed postoperative leukocytosis was seen in 159 (58.0%) of lung transplant recipients. In 57 (35.8%) of them, the etiology of the leukocytosis was not identified. The etiologies of leukocytosis that were identified were infection (n = 39), second surgery, acute rejection (n = 12), primary graft dysfunction (n = 3), multiple etiologies (n = 17), and other causes (n = 10). On multivariate analysis, delayed postoperative leukocytosis was one of the variables that most significantly associated with decreased survival in the entire sample (hazard ratio [HR] = 1.52, 95% confidence interval [CI]: 1.01-2.29, P = .040). On additional analysis for mortality assessing each leukocytosis subgroup, the data were acute graft rejection (HR = 8.21, 95% CI: 4.09-16.49, P < .001), second surgery (HR = 2.05, 95% CI: 1.08-3.90, P = .020), primary graft dysfunction (HR = 2.72, 95% CI: 0.65-11.33, P = .169), other causes (HR = 1.30, 95% CI: 0.47-3.62, P = .620), and unknown etiology (HR = 0.94, 95% CI: 0.54-1.62, P = .800). CONCLUSIONS: Delayed post-lung transplant leukocytosis is a poor prognostic sign, especially when attributed to acute graft rejection, infection, and multiple etiologies. In the absence of an identifiable etiology, it can be attributed to postoperative reactive stress, is not associated with increased mortality, and likely does not warrant further diagnostic investigation.

Serum Chromium Levels Are Higher in Peritoneal Dialysis than in Hemodialysis Patients.

Background:An elevation in serum chromium levels in individuals treated with renal replacement therapy has been previously described, but chromium levels have not been systematically studied in patients treated with different dialysis modalities. The aim of this study was to compare serum chromium levels in patients treated with chronic peritoneal dialysis (PD) and hemodialysis (HD).Methods:We studied 169 chronic dialysis patients in a single medical center, of which 148 were treated with HD and 21 with PD. Serum chromium levels were measured by atomic absorption spectrometry.Residual renal function was accessed using a timed urine collection for the measurement of urine output and calculation of glomerular filtration rate (GFR).Results:The median (interquartile range) serum chromium level was significantly higher in patients treated with PD than in patients treated with HD: 5.00 (3.24 - 6.15) vs 1.83 (1.29 - 2.45) mcg/L, p < 0.001. In a univariate analysis, serum chromium level was associated with PD modality: Exp (B) 7.46 (95% confidence interval [CI] 2.1 - 26.4), p = 0.002. The association of PD modality with serum chromium level was even more significant using a multivariate logistic regression model: odds ratio (OR) 11.87 (95% CI 2.85 - 49.52), p = 0.001 after adjustment for age, gender, diabetes, smoking, dialysis vintage, use of diuretics, and residual renal function.Conclusions:In patients treated with chronic dialysis, serum chromium levels are higher in patients treated with PD than in those treated with HD.

G1 is the major APOL1 risk allele for hypertension-attributed nephropathy in Central Africa.

BACKGROUND: Sub-Saharan Africans exhibit a higher frequency of chronic kidney disease (CKD) than other populations. In this study, we sought to determine the frequency of apolipoprotein L1 (APOL1) genotypes in hypertension-attributed CKD in Kinshasa, Democratic Republic of the Congo. METHODS: We performed a case-control study identifying 162 subjects: 79 with hypertension-attributed CKD and 83 controls living in Kinshasa who were genotyped for APOL1 risk variants between July 2013 and November 2016. We selected control subjects from the general population and matched them with the cases according to age. Logistic regression analysis was used to examine the relationship between APOL1 high-risk genotypes and CKD. RESULTS: The frequencies of the APOL1 G1 and G2 alleles were 19.1 and 7.1%, respectively. The number of individuals with the G1 and G2 risk alleles was significantly higher in the CKD group (12.7%) than in the control group (2.4%), particularly in individuals with end-stage kidney disease (14.3%). Subjects carrying two risk alleles was strongly and independently associated with hypertension-attributed nephropathy, with an adjusted odds ratio of 7.7 (95% confidence interval 1.5-39.7; P = 0.014). The high-risk APOL1 genotypes were G1/G1 and G1/G2, whereas G2/G2 was not found in the study population. CONCLUSIONS: The results of this study demonstrate the association of high-risk APOL1 genotypes with kidney disease in Kinshasa. The absence of G2/G2 may be consistent with powerful selective sweeps induced by Trypanosoma brucei gambiense infection. In contrast, the presence of APOL1 G2/G2 among individuals of African ancestry in the USA may indicate relaxation of natural selection in a trypanosome-free environment.

APOL1 Nephropathy: A Population Genetics and Evolutionary Medicine Detective Story.

Common DNA sequence variants rarely have a high-risk association with a common disease. When such associations do occur, evolutionary forces must be sought, such as in the association of apolipoprotein L1 (APOL1) gene risk variants with nondiabetic kidney diseases in populations of African ancestry. The variants originated in West Africa and provided pathogenic resistance in the heterozygous state that led to high allele frequencies owing to an adaptive evolutionary selective sweep. However, the homozygous state is disadvantageous and is associated with a markedly increased risk of a spectrum of kidney diseases encompassing hypertension-attributed kidney disease, focal segmental glomerulosclerosis, human immunodeficiency virus nephropathy, sickle cell nephropathy, and progressive lupus nephritis. This scientific success story emerged with the help of the tools developed over the past 2 decades in human genome sequencing and population genomic databases. In this introductory article to a timely issue dedicated to illuminating progress in this area, we describe this unique population genetics and evolutionary medicine detective story. We emphasize the paradox of the inheritance mode, the missing heritability, and unresolved associations, including cardiovascular risk and diabetic nephropathy. We also highlight how genetic epidemiology elucidates mechanisms and how the principles of evolution can be used to unravel conserved pathways affected by APOL1 that may lead to novel therapies. The APOL1 gene provides a compelling example of a common variant association with common forms of nondiabetic kidney disease occurring in a continental population isolate with subsequent global admixture. Scientific collaboration using multiple experimental model systems and approaches should further clarify pathomechanisms further, leading to novel therapies.