COSMC expression as a predictor of remission in IgA nephropathy

PURPOSE

The impact of core 1,3-galactosyltransferase-specific molecular chaperon (COSMC) gene expression and methylation profile on clinical progression of IgA nephropathy (IgAN) is unclear. The aim of this study was to determine the clinical significance and the relation of the COSMC gene expression and methylation pattern with the progression of IgAN.

METHODS

Thirty-nine biopsy-confirmed IgAN patients, 11 healthy relatives and 20 healthy controls were recruited. The COSMC mRNA levels and methylation profile of COSMC gene promoter were measured using the quantitative real-time PCR. The galactose-deficient IgA1 (Gd-IgA1) levels were measured using ELISA in serum and cell culture supernatant. The effect of IL-4 and AZA on COSMC expression and methylation and the correlation of COSMC gene expression and methylation levels with baseline kidney function tests, histology and long-term outcomes were examined.

RESULTS

The mean COSMC mRNA level was significantly lower, and serum Gd-IgA1 level was higher in IgAN patients compared with the control groups (p < 0.001, and p =  < 0.001, respectively). The COSMC mRNA levels were correlated with intensity of hematuria (r = - 0.41, p = 0.009), serum creatinine level (r = - 0.37, p = 0.002) and eGFR (r = 0.36, p = 0.002). The COSMC methylation levels were correlated with age (r = 0.25, p = 0.04) and baseline eGFR (r = - 0.326, p = 0.006). Twenty IgAN patients (51.3%) reached to complete (5, 12.8%) or partial remission (15, 38.5%) after a median of 34.5 months (IQR, 13.75-71). In multivariable Cox regression analysis, COSMC mRNA expression (adjusted HR (aHR) 1.871, 95% CI 1.287-2.722, p = 0.001) and Oxford T score (aHR 0.355, 95% CI 0.146-0.859, p = 0.022) predicted the remission.

CONCLUSION

COSMC mRNA level is a novel biomarker candidate to predict the remission in IgAN patients.

Recombination frequencies of human leukocyte antigen loci in hematological malignancies among Turkish population

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment option with growing performance for leukaemia, aplastic anaemia and genetic disorders. The frequency of MHC (Major Histocompatibility Complex) gene locus recombination is increased at loci close to the telomeres and in the female gender. The aim of the present study is to document the recombination events by pedigree diagrams with the primary goal to determine the frequency of recombination in a different ethnic population from mostly reported studies.

METHODS

Altogether 9545 allogeneic HSCT recipients and their family-based potential donors (n:36231) were included in this retrospective study.

RESULTS

Recombinations were determined in 118 (F/M:50/68) out of 9545 families enrolled on the study. These were present in 40 of the patients and 78 of healthy donors. The frequency of recombinations was 0.42% and 0.22%, in patients and donors, respectively. Of the 118 recombinations, 60 were detected in A locus (13 inpatients), 14 in B locus (3 inpatients) and 42 in DR locus (22 inpatients). In our study, due to recombinations in HLA (Human Leukocyte Antigen)-A,-B,-DR loci, we found that some patient-donor pairs became 6/5 matched instead of 6/6 (n:45), eliminating the allogeneic HSCT possibility for the patients from the full-matched siblings.

CONCLUSION

To our knowledge, this is the first study reporting the recombination frequencies in HLA loci among Turkish population and thus, providing informative data to the clinicians regarding the cross-over possibilities in Turkish patients with haematological malignancies.

Frequency of RHD variants in serologically weak D Turkish blood donors

BACKGROUND

RhD typing has remained of primary importance, as being the leading cause of hemolytic disease of the newborn. Among Rh system's 55 blood group antigens, RhD is the most immunogenic. We aimed with this study to determine weak D/partial D variant frequency in blood donors who were admitted to our blood center and have serologically designated blood group weak D.

MATERIALS AND METHODS

We screened blood donors who admitted between 2011 and 2017 to our blood center. Sixty-seven serologically weak D phenotyped donors have participated in the study. These donors' samples were studied further by Polymerase Chain Reaction Sequence- Specific Primers (PCR-SSP) for determining D variants.

RESULTS

Weak D phenotype was detected in 228(0.12 %) out of 177,554 donors. Sixty-seven of them agreed to take part in the study. The frequency of weak D and partial D was 68.7 % (n = 46), and 22.4 % (n = 15), in order. The most encountered weak D and partial D variant was type 15 and DFR type, respectively.

CONCLUSIONS

The prevalence of serologically weak D phenotypes varies by race and ethnicity. Turkey is a country covering a mixture of European and Asian DNA with different ethnic groups. Thus, our research as giving the overall distribution of RHD variants from the largest city of Turkey, which may reflect the general ethnic background of the country, would help to the establishment of a databank for blood banking. This paper is the first molecular study on RHD variants in Turkey. New molecular research would be more reliable and precise.

P1743IMPORTANCE OF KIDNEY ALLOGRAFT REJECTİON IN BK VIRUS NEPHROPATHY

Background and Aims

Allograft rejection following BK virus nephropathy (BKVN) is an important cause of allograft loss in kidney transplant recipients. However, the effect of rejection type on allograft survival in patients with BKVN has not been described previously. This study aimed to investigate the relationship between allograft rejection type and graft survival in patients with BKVN.

Method

We retrospectively analyzed the data of 159 kidney transplant recipients diagnosed BKVN and followed-up in our center between January 2009 and December 2019. BKVN was diagnosed by persistent viremia of more than 10000 copies/mL for four weeks or allograft biopsy. Vascular, obstructive or other non-parenchymal etiologies for allograft dysfunction were excluded. All patients were investigated for the presence of anti-HLA antibody at 6 and 12 months after BKVN diagnosis. Luminex solid-phase assay was used to investigate Class I and Class II PRA and MFI values greater than 1000 were accepted as positive. Allograft biopsy was performed in patients with progressive graft dysfunction or the presence of donor-specific antibodies (DSA) and analyzed according to the Banff Classification. The primary outcomes were defined as allograft loss or the allograft dysfunction which defined as was doubling serum creatinine levels.

Results

Patients were followed-up median 70 (IQR 13-198) months after kidney transplantation. Demographic data and clinical characteristics are provided in the table. 28 kidney transplant recipients suffered from allograft rejection after BKVN. Median rejection time to rejection after BKVN was 9 (IQR 5-164) months. 3 patients (18,8%) in the AMR group and 1 patient (8,3%) in the TCMR group experienced graft loss during follow-up. The mean serum creatinine levels at the last clinical visit were significantly higher in the AMR group compared to the TCMR group (1,9±0,8 vs 1,3±1,2 mg/dl; p=0,002). In multivariate analysis, AMR was an independent risk factor for allograft dysfunction (HR, 1,735; 95% CI 1,060 to 2,839; p=0,028).

Conclusion

The occurrence of AMR after BKVN is an important indicator of allograft dysfunction compared to TCMR. DSA screening should be routinely used in this group for early diagnosis and treatment of AMR.

EFI region 8 Balkan external proficiency testing for HLA typing: Results of 15 years

Istanbul Medical Faculty, Department of Medical Biology, as the first EFI-accredited HLA laboratory in Turkey since 1999 has been organizing both national and international quality control tests for HLA typing under the banner of the "Balkan external proficiency testing (BEPT)" encompassing countries from EFI regions 8. The first round of BEPT in 2004 was organized for low-resolution HLA-A,-B typing by molecular methods and 12 centres participated in the exercise. In 2005, low-resolution HLA-DR typing was added, and in 2007, low-resolution HLA-C and DQ typing were added to the exercise and 28 centres participated. In 2015, high-resolution (four digits or higher typing) HLA-A,-B,-C,-DR and -DQ typing added to the exercise and 40 centres participated. In the last 2 years, 2017 and 2018, the number of participating centres increased to 48 and 52, respectively. When the distribution of low-resolution typing methods applied in the exercises were investigated, it was found that 82% of the centres in the first round of BEPT in 2004 used PCR-SSP, whereas in the last round in 2018, 26% of the centres preferred SSP, while the rest used SSO (50%) or SSP and SSO (24%) methods. Methods for high-resolution typing were SBT (41%), NGS (18%), SSO (18%), SSP (6%), SBT + NGS (6%) and SBT + SSP (11%). In 15th trial for BEPT, nomenclature mistake rate was 12%, and erroneous result rate was 6% for HLA samples. The most common mistakes in the exercises were nomenclature mistakes. The EFI Standards Version 7.0 is stated "HLA type can be reported using a hyphen if homozygosity is not proven by family studies." In order to provide standard results among HLA laboratories and since accurate HLA typing leads to significant increase of graft and patient survival, quality control exercises should be performed in all HLA-based tests periodically.

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/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.

Immunosuppressive Treatment in C3 Glomerulopathy: Is it Really Effective?

BACKGROUND

C3 glomerulopathy (C3GP) is a recently identified and described disease that has a high risk of progressing into end-stage renal disease. We aimed to evaluate the effects of various immunosuppressive regimens on C3GP progression because there are conflicting data on the treatment modalities.

METHODS

In this retrospective study of 66 patients with C3GP, 27 patients received mycophenolate mofetil (MMF)-based treatment, 23 received non-MMF-based treatment (prednisolone or cyclophosphamide), and 16 received conservative care. The study groups were compared with each other with specific focus on primary outcomes defined as (1) kidney failure and (2) estimated glomerular filtration rate (eGFR) decline ≥50% from the baseline value.

RESULTS

Overall, 17 (25.8%) patients reached the primary outcome after a median period of 28 months. The number of patients who reached the primary outcome were similar among the study groups (MMF-based: 8/27 [29.6%], non-MMF-based: 4/23 [17.4%], and conservative care: 5/16 [31.3%], p = 0.520). In the Cox regression analysis, age (HR 0.912, p = 0.006), eGFR (HR 0.945, p = 0.001), and proteinuria levels (HR 1.418, p = 0.015) at the time of biopsy, percentage of crescentic (HR 1.035, p = 0.001) and sclerotic glomeruli (HR 1.041, p = 0.006), severity of interstitial fibrosis (HR 1.981, p = 0.048), as well as no remission of proteinuria (HR 2.418, p = 0.002) predicted the primary outcome.

CONCLUSION

Although patients receiving immunosuppressive treatments had higher proteinuria and lower serum albumin at baseline, there were no differences between these patients and those receiving conservative care alone in proteinuria remission or in the decline of renal function. Younger age, higher proteinuria, lower eGFR, and the presence of crescentic and sclerotic glomeruli, severity of interstitial fibrosis, and no remission of proteinuria predicted the progression of kidney disease.

A Novel Biomarker for Post-Transplant Recurrent IgA Nephropathy

BACKGROUND

The serum levels of galactose-deficient immunoglobulin (Ig)A1 (Gd-IgA1) represent the most promising candidate biomarker for IgA nephropathy (IgAN). The aim of this study was to evaluate the serum levels of Gd-IgA1 as a novel noninvasive biomarker for post-transplant IgAN recurrence.

METHODS

Serum Gd-IgA1 levels of 18 patients with recurrent IgAN were compared with control renal transplant recipients (n = 23) with non-recurrent IgAN and control non-transplant IgAN patients (n = 44) and healthy relatives (n = 11). Serum Gd-IgA1 levels of patients were measured with the use of KM55 enzyme-linked immunosorbent assay (ELISA). The effects of serum Gd-IgA1 concentrations on IgAN recurrence, post-transplant events, and graft survival were evaluated.

RESULTS

All recurrent IgAN patients presented with renal dysfunction (mean serum creatinine, 1.62 ± 0.39 mg/dL) and detectable proteinuria at the time of diagnosis. Serum Gd-IgA1 levels of recurrent IgAN patients (8735 ± 10854 ng/mL [log10: 3.71 ± 0.45]) were significantly higher than those of non-recurrent IgAN patients (4790 ± 6089 ng/μL [log10: 3.31 ± 0.64]) (P = .027). Serum Gd-IgA1 levels of non-transplant IgAN patients were significantly higher (8791 ± 8700 ng/μL [log10: 3.79 ± 0.36]) than those of non-recurrent IgAN patients (4790 ± 6089 ng/μL [log10: 3.31 ± 0.64]) and healthy relatives (2615 ± 1611 ng/μL [log10: 3.34 ± 0.27]) (P < .001 and P = .021, respectively). Receiver-operating characteristic curve analysis revealed that the area under the curve for recurrence of IgAN was 0.69 (0.53-0.85) for serum Gd-IgA1 (P = .038). Biopsy-confirmed allograft rejection rates were similar in the recurrent IgAN group [3 (17%)] compared with the non-recurrent IgAN [6 (26%)] group (P = .47). Graft failure rate was not also significantly different in the recurrent IgAN group [4 (22.2%)] compared with the non-recurrent IgAN group [2 (8.7%)] (P = .224).

CONCLUSIONS

This novel lectin-independent Gd-IgA1 ELISA that can detect serum Gd-IgA1 in patients with recurrent IgAN can be used as a biomarker for diagnosis and activity assessment of post-transplant recurrent IgAN.

Association Between HLA Antibodies and Different Sensitization Events in Renal Transplant Candidates

BACKGROUND

Human leukocyte antigen (HLA) allo-immunization is caused by various events such as blood transfusions, pregnancies, or organ transplantations, which can lead to sensitization. In this retrospective study, we evaluated different sensitization models and their effects on panel-reactive antibody (PRA) profiles of renal transplantation candidates.

METHODS

Anti-HLA class I/II antibody screening tests were performed in 906 renal transplantation candidates with the use of a microbead-based assay (Luminex).

RESULTS

Two hundred ninety-seven (32.8%) of the patients were determined as positive in terms of PRA, and 609 (67.2%) were negative. Sensitized and non-sensitized patients were compared separately in terms of each sensitization type. The anti-HLA class I, II, and I+II positivity rates in patients sensitized only by blood transfusion were 13.1%, 6.3%, and 14.1%, the rates with pregnancy sensitization were 35.5%, 29%, and 45.2%, and rates with previous transplantation sensitization were 15.6%, 34.4%, and 38.9%, respectively. Prevalence of PRA positivity was significantly higher in patients with previous pregnancy than with transplantation and transfusion (odds ratio, 1.003; 95% confidence interval, 0.441-2.281; P = .031). The risk of developing HLA class I antibodies was higher in pregnancies (P < .001), and the risk of developing anti-HLA class II antibodies was higher in patients who had undergone a previous transplantation (P < .001). The rate of developing HLA-B antibodies in patients sensitized by pregnancy were significantly higher compared with sensitization after transfusion (P = .015), as was the rate of developing HLA-DQ antibodies in patients sensitized by previous transplantation compared with sensitization through pregnancy (P = .042).

CONCLUSIONS

In patients who are waiting for kidney transplantation, sensitization by pregnancy and transplantation have a significant impact on development of HLA class I and class II antibodies.

Relationship between clinical findings and genetic mutations in patients with familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is one of the most frequent genetic diseases encountered in the Mediterranean region. We aimed to investigate the correlation between genetic mutations and the clinical findings in 562 patients with FMF.

METHODS

In this retrospective cross-sectional study conducted with patients' files between 2006, and 2013, reverse hybridization assay for MEFV gene mutations was used and the 12 most frequent mutations were screened. Mutation types and clinical findings were compared with variance analysis.

RESULTS

The mean age was 6.9 ± 3.4 years (range, 1.8-11.6 years). The most common symptom was fever (97.3%). Thirty-four of the patients (6.04%) were admitted with periodic fever only. Of these patients, M694V was the most common mutation type (73.5%). The percentage of the patients predominantly presenting with recurrent abdominal pain was 77.78% and the most frequent mutations were M694V and E148Q. The rate of arthritis and arthralgia was significantly higher in patients with M694V and E148Q mutations. Chest pain was reported more often in patients homozygous for M694V (61.4%). Pericardial effusion was documented in the echocardiography of 10.9% of the 229 children with chest pain. Some patients had both FMF and Henoch Schönlein purpura (HSP), and were more likely to harbor either homozygote M694V or E148Q mutations. The frequency of episodes was higher in patients with homozygous M694V mutations (number of attacks = 4.4 ± 1.6/month). Proteinuria was detected in 106 patients of cases (29.2%), at an average of 854 ± 145 mg/L. Most of the patients with proteinuria and elevated serum amyloid-A had homozygous M694V mutation.

CONCLUSION

The most common mutation in children in Turkey with FMF is the M694V mutation. Recurrent abdominal pain, arthritis or arthralgia, chest pain, and pericarditis were commonly seen in patients with M694V and E148Q mutations.

Evaluation of Alpha-Thalassemia Mutations in Cases with Hypochromic Microcytic Anemia: The İstanbul Perspective

Objective:

Alpha thalassemia syndromes are caused by mutations on one or more of the four α-globin genes. Mutations could be either more commonly deletional or non-deletional. As some deletions (3.7 and 4.2) cause α+-thalassemia, some cause (-20.5, MED, THAI, FIL) α0 -thalassemia. The aim of this study was to determine alpha thalassemia mutations in patients with unsolved hypochromic microcytic anemia and to evaluate types of mutations.

Material and Methods:

Two hundred six patients with hypochromic microcytic anemia were evaluated for alpha thalassemia. A venous blood sample of 2 mL was drawn from each patient for DNA isolation. The samples were investigated for α-thalassemia mutations by using the Vienna Lab α-Globlin StripAssay TM commercial kit.

Results:

Fourteen different mutations were determined in 95 (46.1%) patients. The most common mutation was the 3.7 single gene deletion and was found in 37 patients (n=37/95, 39%). Others common mutations were the 20.5 kb double gene deletion (n=20 patients, 21%), MED double gene deletion (n=17 patients, 17.9%), α2 IVS1 (n=10 patients, 10.5%), α2 cd142 Hb Koya Dora (n=6 patients, 6.3%), α2 polyA1 (Saudi type) (n=6 patients, 6.3%), 4.2 single gene deletion (n=4 patients, 4.2%), α1 cd14 (n=2 patients, 2.1%), and -FIL mutation (n=2 patients 2.1%), respectively. Hb Adana, Hb Icaria, α2 init cd and α2 polyA2 (Turkish type) were found in 1% of the patients (n=1). Seven patients (7.4%) had α-thalassemia triplication. In our study, three mutations (Hb Icaria, α1 cd14, α2 init.cd) were determined firstly in Turkey. Seven mutations (-SEA, -THAI, Hb Constant Spring, α2 cd19, α2 cd59, α2 cd125, Hb Paksé) were not determined in this study.

Conclusion:

Alpha thalassemia should be considered in the differential diagnosis of hypochromic microcytic anemia especially in cases without iron deficiency and b-thalassemia carrier state. Genetic testing should be performed for the suspicious cases. We also recommend that a national database with all mutations in Turkey should be created to screen the alpha thalassemia cost-effectively.