Concurrent Cobalamin C and Plasminogen Deficiencies in a Patient with Chronic Thrombotic Microangiopathy.

BACKGROUND: Although most patients with atypical hemolytic uremic syndrome (aHUS) have variants in genes participating in alternative complement pathways, rare variants in non-complement pathway-related genes, including DGKE, INF2, MMACHC, PLG, and THBD, have also been described. CASE PRESENTATION: We report an 18-year-old male patient with renal biopsy-proven chronic thrombotic microangiopathy that raised suspicion of aHUS. Whole-exome sequencing revealed a novel pathogenic homozygous MMACHC c.484G>T (p.Gly162Trp) variant. Subsequently, clinical and laboratory findings confirmed cobalamin C (Cbl C) deficiency. Also, homozygous missense c.1112C>T PLG (p.Thr371Ile) variant was detected (it had been reported as a variant of unknown significance). However, the low serum plasminogen (PLG) activity proved the pathogenicity of c.1112C>T. Hence, the patient was diagnosed with concurrent Cbl C and PLG deficiencies. Segregation analysis revealed that the mother and father had the same heterozygous PLG and MMACHC variants. PLG variants have generally been described in aHUS patients concomitant with complement gene variants in the literature; therefore, the association between aHUS and PLG variants is controversial. The possible contribution of PLG deficiency to thrombotic microangiopathy was also discussed in this case. CONCLUSION: Non-complement-mediated aHUS is an exceptional disorder. A limited number of genes are involved in this entity. To our knowledge, this is the first aHUS patient diagnosed with both Cbl C and PLG deficiencies in the literature.

Spatial Distribution of Macrophage Subtypes Among Rejection Subtypes in Renal Transplant Biopsies by Dual Immunohistochemistry.

We performed dual immunohistochemistry for CD163/CD34 and CD68/CD34 in 108 renal transplant indication biopsies to investigate the presence and distribution of macrophages in various renal compartments. All Banff scores and diagnoses were revised according to the Banff 2019 classification. CD163 and CD68 positive cell counts (CD163pos and CD68pos) were evaluated in the interstitium, glomerular mesangium, and, within glomerular and peritubular capillaries. The diagnosis was antibody-mediated rejection (ABMR) in 38 (35.2%), T-cell mediated rejection (TCMR) in 24 (22.2%), mixed rejection in 30 (27.8%), and no rejection in 16 (14.8%). Banff lesion scores t , i , and ti were correlated with both CD163 and CD68 interstitial inflammation scores ( r > 0.30; P < 0.05). Glomerular total CD163pos was correlated to Banff lesion scores g and cg ( r > 0.30; P < 0.05). Glomerular total, mesangial, and intracapillary CD68pos were correlated with g ( r > 0.30; P < 0.05). Both glomerular total and peritubular capillary CD68pos were correlated with peritubular capillaritis ( r > 0.30; P < 0.05). Glomerular CD163pos were significantly higher in ABMR compared with no rejection, in mixed rejection compared with no rejection and TCMR. CD163pos in peritubular capillaries was significantly higher in mixed rejection compared with no rejection. Glomerular CD68pos was significantly higher in ABMR compared with no rejection. CD68pos per peritubular capillary was higher in mixed rejection, ABMR, and TCMR compared with no rejection. In conclusion, compared with CD68 positive macrophages, localization of CD163 positive macrophages in various renal compartments seems to be different among rejection subtypes and their glomerular infiltration seems to be more specific for the presence of ABMR component.

Efficacy and safety of interleukin-1 blockers in kidney transplant recipients with familial Mediterranean fever: a propensity score-matched cohort study.

BACKGROUND: Data on use of interleukin (IL)-1 blockers in kidney transplant recipients (KTRs) with familial Mediterranean fever (FMF) are very limited. We aimed to evaluate the efficacy and safety of anakinra and canakinumab in the transplantation setting. METHODS: In this retrospective cohort study, we included KTRs who suffered from AA amyloidosis caused by FMF and treated with anakinra or canakinumab (study group, n = 36). Using propensity score matching, we selected 36 patients without FMF or amyloidosis from our database of 696 KTRs as the control group. Primary outcomes were patient and graft survival. Biopsy-confirmed graft rejection, changes in estimated glomerular filtration rate (eGFR), high-sensitivity CRP (hsCRP), erythrocyte sedimentation rate (ESR), proteinuria and number of monthly attacks were secondary outcomes. RESULTS: All KTRs with FMF began IL-1 blocker therapy with anakinra and nine (25%) were switched to canakinumab. Overall death was more frequent in the study group (19.4% vs 0%) (P = .005); however, overall graft loss was comparable between study (27.8%) and control groups (36.1%) (P = .448). Five- and 10-year graft survival rates were significantly higher in the study group (94.4% and 83.3%, respectively) than in the control group (77.8% and 63.9%, respectively) (P = .014 and P < .001, respectively). Rejections were numerically lower in study group (8.3% vs 25%), but it did not reach to statistical significance (P = .058). When compared with the pre-treatment period, with IL-1 blockers, the number of attacks per month (P < .001), and eGFR (P = .004), hsCRP (P < .001) and ESR (P = .026) levels were lower throughout the follow-up, whereas proteinuria levels were not. CONCLUSIONS: Anakinra and canakinumab are effective in KTRs suffering from FMF; however, the mortality rate may be of concern.

Diagnostic accuracy of core biopsies of renal masses: Experience in a real-life setting from a tertiary center.

OBJECTIVE: To document and analyze diagnostic accuracy of renal core biopsy (RCB), its diagnostic correlation with resection specimens, and to question the need for immunohistochemistry (IHC) in the preoperative diagnosis of renal masses. MATERIAL AND METHOD: RCBs performed at a reference center between 2007 and 2017 were included. Pathological, clinical, and radiological data were obtained from medical records. RESULTS: Among 302 biopsies included in this study, 274 (90.7%) were diagnostic. Two hundred sixty-six were neoplastic and 179 were of primary renal origin. The most common secondary neoplasms were hematolymphoid (n = 35) and metastatic (n = 17). Sixty-nine tumors were classified as small renal masses (SRMs) (≤4 cm in diameter) and 53 of them were malignant. Nephrectomy was performed in 58 patients. Overall diagnostic accuracy between resections and RCBs was 88.7%. IHC was performed in 160 (53%) cases. In 15 of those, a definite diagnosis could not be rendered. Renal cell origin and subtype were determined by histomorphology alone in 81 and 75 cases, respectively. Sixty primary neoplasms of renal cell origin required IHC for diagnosis. CONCLUSION: RCB is a safe and highly accurate method for the diagnosis of both primary and secondary renal neoplasms. IHC is mostly required for the diagnosis of secondary tumors. Histomorphology is still the primary diagnostic tool, highly dependent on the experience of the surgical pathologist.

Immunoexpression of SDHB, FH, and CK20 among eosinophilic renal tumors: A tissue microarray study.

BACKGROUND: Differential diagnosis can be a challenge for eosinophilic subtypes of renal cell tumors due to their overlapping histomorphological and immunohistochemical features. We aimed to investigate the frequency of rare variants of renal cell carcinomas (RCCs) such as succinate dehydrogenase-deficient RCC (SDDRCC), hereditary leiomyomatosis and RCC (HLRCC)-associated RCC, and eosinophilic, solid, and cystic RCC (ESCRCC) in our population. MATERIALS AND METHODS: Renal tumors which could be considered in the eosinophilic tumor category were included: 91 conventional clear cell RCCs with eosinophilic cytoplasm, 72 papillary RCCs, 74 chromophobe RCCs, 88 oncocytomas, and 37 other rare subtypes. Using the tissue microarray method, succinate dehydrogenase B (SDHB), fumarate hydratase (FH), and cytokeratin 20 (CK20) antibodies were performed by immunohistochemistry. Immunohistochemistry was repeated on whole block sections for selected cases. The utility of these antibodies in the differential diagnosis was also investigated. RESULTS: Loss of SDHB expression was detected in three tumors, two of which showed typical morphology for SDDRCC. In additional two tumors, SDHB showed weak cytoplasmic expression without a mitochondrial pattern (possible-SDHB deficient). None of the tumors showed loss of FH expression. Heterogeneous reactions were observed with SDHB and FH antibodies. Only one ESCRCC was detected with diffuse CK20 positivity. CONCLUSION: SDDRCCs, HLRCC-associated RCCs, and ESCRCCs are very rare tumors depending on the population. Possible weak staining and focal loss of SDHB and FH expression should be kept in mind and genetic testing must be included for equivocal results.

Clinical significance of glomerular C3 deposition in primary membranous nephropathy.

BACKGROUND: We aimed to investigate the effects of glomerular C3 deposition on clinical, histopathological features, and outcomes of patients with primary membranous nephropathy (MN). METHODS: A total of 261 patients with biopsy-proven primary MN, who were on follow up for at least 6 months, were included in the study. The patients were grouped according to their C3 immunostaining in kidney biopsy samples at the time of diagnosis: Low intensity [LI; (C3 1 +)] and high intensity [HI; (C3 2 + or C3 3 +)]. The primary outcome was the development of kidney failure. Complete (CR) or partial remission (PR) was defined as secondary outcome. RESULTS: Sixteen patients reached the primary outcome after a median follow-up of 33.8 months. Patients in the high intensity group (119 cases) had lower eGFR and higher proteinuria at admission and last follow-up compared to patients in the low intensity group (142 cases). Also, more patients in the high intensity group reached the primary outcome compared to patients in the low intensity group: twelve patients (10.1%) in the high intensity group and four patients (2.8%) in the low intensity group reached the primary outcome (p = 0.015). Kaplan-Meier analysis demonstrated that patients in the high intensity group had a higher risk for kidney failure (p = 0.02). In multivariate logistic regression analysis, high intensity C3 deposition and initial estimated glomerular filtration rate (eGFR) indepenently predicted primary outcome. CONCLUSION: Extensive glomerular C3 deposition is a predictor of kidney failure in patients with MN.

Amyloid A Amyloidosis After Renal Transplantation: An Important Cause of Mortality.

BACKGROUND: There are limited data on the outcome of transplant recipients with familial Mediterranean fever (FMF)-associated AA amyloidosis. The aim of the present study is to evaluate demographic, clinical, laboratory, and prognostic characteristics and outcome measures of these patients. METHODS: Eighty-one renal transplant recipients with FMF-associated AA amyloidosis (group 1) and propensity score-matched transplant recipients (group 2, n = 81) with nonamyloidosis etiologies were evaluated in this retrospective, multicenter study. Recurrence of AA amyloidosis was diagnosed in 21 patients (group 1a), and their features were compared with 21 propensity score-matched recipients with FMF amyloidosis with no laboratory signs of recurrence (group 1b). RESULTS: The risk of overall allograft loss was higher in group 1 compared with group 2 (25 [30.9%] versus 12 [14.8%]; P = 0.015 [hazard ratio, 2.083; 95% confidence interval, 1.126-3.856]). Patients in group 1 were characterized by an increased risk of mortality compared with group 2 (11 [13.6%] versus 0%; P = 0.001 [hazard ratio, 1.136; 95% confidence interval, 1.058-1.207]). Kaplan-Meier analysis revealed that 5- and 10-year patient survival rates in group 1 (92.5% and 70.4%) were significantly lower than in group 2 (100% and 100%; P = 0.026 and P = 0.023, respectively). Although not reaching significance, overall, 5- and 10-year graft survival rates (57.1%, 94.7%, and 53.8%, respectively) in group 1a were worse than in group 1b (76.2%, 95%, and 77.8%, respectively; P = 0.19, P = 0.95, and P = 0.27, respectively). CONCLUSIONS: AA amyloidosis is associated with higher risk of mortality after kidney transplantation. Inflammatory indicators should be monitored closely, and persistent high levels of acute-phase reactants should raise concerns about amyloid recurrence in allograft.

Co-Deposition of IgM and C3 May Indicate Unfavorable Renal Outcomes in Adult Patients with Primary Focal Segmental Glomerulosclerosis.

BACKGROUND/AIMS: We aimed to investigate the effects of glomerular IgM and C3 deposition on outcomes of adult patients with primary focal segmental glomerulosclerosis (FSGS). METHODS: In this retrospective analysis, 86 consecutive adult patients with biopsy-proven primary FSGS were stratified into 3 groups according to their histopathological features: IgM- C3-, IgM+ C3-, and IgM+ C3+. Primary outcome was defined as at least a 50% reduction in baseline estimated glomerular filtration rate (eGFR) or development of kidney failure, while complete or partial remission rates were secondary outcomes. RESULTS: Glomerular IgM deposits were found in 44 (51.1%) patients, 22 (25.5%) of which presented with accompanying C3 deposition. Patients in IgM+ C3+ group had higher level of proteinuria (5.6 g/24 h [3.77-8.5], p = 0.073), higher percentage of segmental glomerulosclerosis (20% [12.3-27.2], p = 0.001), and lower levels of eGFR (69 ± 37.2 mL/min/1.73 m2, p = 0.029) and serum albumin (2.71 ± 0.85 g/dL, p = 0.045) at the time of diagnosis. Despite 86.3% of patients in IgM+ C3+ group (19/22) received immunosuppressive treatment, the primary outcome was more common in patients in the IgM+ C3+ group compared with patients in IgM+ C3- and IgM- C3- groups (11 [50%] vs. 2 [9%] and 11 [26.1%] respectively [p = 0.010]). Complete or partial remission rates were lower in patients in the IgM+ C3+ group (5/22, 22.7%), as well (p = 0.043). Multivariate Cox regression analysis revealed that IgM and C3 co-deposition was an independent risk factor associated with primary outcome (hazard ratio 3.355, 95% CI 1.349-8.344, p = 0.009). CONCLUSIONS: Glomerular IgM and C3 co-deposition is a predictor of unfavorable renal outcomes in adult patients with primary FSGS.

The pathological upgrading after radical prostatectomy in low-risk prostate cancer patients who are eligible for active surveillance: How safe is it to depend on bioptic pathology?

BACKGROUND: Active surveillance (AS) is one of the treatment alternatives in low-risk prostate cancer (PCa). The pathological upgrading after radical prostatectomy (RP) were investigated in patients who were eligible for AS in the present study. METHODS: Between August 2006 and July 2017, 627 patients underwent RP in our institution. One hundred and thirty-six patients who were eligible for AS at the time of RP were included in this study. The previously defined AS criteria Gleason 3 + 3=6 adenocarcinoma at maximum two biopsy cores, prostate-specific antigen (PSA) < 10 ng/mL and clinical T stage ≤ 2a were used in the study. The demographics, clinical, and histopathological outcomes were retrospectively compared between two groups, which were divided in accordance with the upgrading status at final pathology as Group 1 (n = 67, upgrading) and Group 2 (n = 69, nonupgrading). RESULTS: Gleason upgrading (GU) was found in 67 (49.3%) patients, and 17 patients (12.5%) were upstaged to pT3a. The upgrading to Gleason 3 + 4 was reported in 38.7% of patients, however, 7.4%, and 3.7% of the patients were upgraded to Gleason 4 + 3, and Gleason 4 + 4, respectively. The 10.3% of the patients had extraprostatic involvement, and the rate (19.4% vs 1.4%, P = .002) was significantly higher in Group 1. PSA density (P = .001), tumor size (P < .001), tumor percentage (P < .001), apical involvement (P = .013), and perineural invasion (P < .001) in RP specimen were higher in Group 1. Multivariate analysis showed that perineural invasion (OR = 4.26; 95%CI: 1.76-10.33; P = .001) and pathologic T stage (OR = 5.45; 95%CI: 1.08-27.4; P = .04) were independently associated with GU. CONCLUSIONS: Since 12.5% of the patients upstaged to pT3a disease, and there is a possible risk of Gleason 4 pattern, upgrading of the tumor should carefully be kept in mind before offering AS to low-risk patients with PCa.

Infectious Complications of Induction Therapies in Kidney Transplantation.

BACKGROUND Cytomegalovirus (CMV) and BK virus (BKV) are post-transplant opportunistic viral infections that affect patient and graft survival. This study was designed to evaluate the risk of BKV nephropathy and CMV disease in kidney transplant recipients who received induction therapy with ATG or basiliximab. MATERIAL AND METHODS We retrospectively analyzed information on 257 adult patients who underwent kidney transplantation between January 2007 and 2017. Patients were categorized into 3 groups according to the induction therapies. The primary endpoint was the onset of CMV disease or biopsy-confirmed BKV nephropathy. The secondary endpoints were biopsy-proven rejection episodes, graft loss, loss to follow-up, and death. RESULTS We followed 257 patients for a median of 55.5 months. The incidence of CMV disease was significantly higher in the only ATG group compared to the group without induction treatment (p<0.001). There was no significant difference in the incidence of BKV nephropathy among groups (p>0.05). The dosage of ATG (OR, 10.685; 95% CI, 1.343 5 to 85.009; P=0.025) was independent risk factor for death. CONCLUSIONS This study demonstrated that a higher dosage of ATG in high-risk patients is associated with an increased risk of CMV disease and patient death, also, reducing the dosage may be a rational strategy for increasing graft and patient's survival.