The KANNO blood group system

The KANNO blood group system (International Society of Blood Transfusion [ISBT] 037) includes one high-prevalence antigen, KANNO1, across ethnic groups. Sporadic KANNO1- cases among East and South Asians are theoretically estimated by the DNA database library. Anti-KANNO1 has been found most often among Japanese women with current or prior pregnancy. Thus far, there are no reported cases of hemolytic transfusion reaction or hemolytic disease of the fetus and newborn due to anti-KANNO1.

Quantitative estimation of pulmonary artery wedge pressure from chest radiographs by a regression convolutional neural network

Introduction

Recent studies reported that a convolutional neural network (CNN; a deep learning model) can detect elevated pulmonary artery wedge pressure (PAWP) from chest radiographs, the diagnostic images most commonly used for assessing pulmonary congestion in heart failure. However, no method has been published for quantitatively estimating PAWP from such radiographs. We hypothesized that a regression CNN, an alternative type of deep learning, could be a useful tool for quantitatively estimating PAWP from chest radiographs in cardiovascular diseases.

Methods

We retrospectively enrolled 936 patients with cardiovascular diseases who had undergone right heart catheterization (RHC) and chest radiography and estimated PAWP by constructing a regression CNN based on the VGG16 model. We randomly categorized 80% of the data as training data (training group, n=748) and 20% as test data (test group, n=188). Moreover, we tuned the learning rate–one of the model parameters–by 5-hold cross-validation of the training group. Correlations between PAWP measured by RHC (ground truth [GT] PAWP) and PAWP derived from the regression CNN (estimated PAWP) were tested. To visualize how the regression CNN assessed the images, we created a regression activation map (RAM), a visualization technique for regression CNN.

Results

Estimated PAWP correlated significantly with GT PAWP in both the training (r=0.76, P<0.001) and test group (r=0.62, P<0.001). Bland-Altman plots found a mean (SEM) difference between GT and estimated PAWP of −0.23 (0.16) mm Hg in the training and −0.05 (0.41) mm Hg in the test group. The RAM showed that our regression CNN model estimated high PAWP by focusing on the cardiomegaly and pulmonary congestion. In the test group, the area under the curve (AUC) for detecting elevated PAWP (≥18 mm Hg) produced by the regression CNN model was similar to the AUC of an experienced cardiologist (0.86 vs 0.83, respectively; P=0.24).

Conclusion

This proof-of-concept study shows that regression CNN can quantitatively estimate PAWP from standard chest radiographs in cardiovascular diseases.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The Bayer Academic Support

O-301 Genome-wide association study identified meiotic variant associated with aneuploid pregnancy loss

Study question

Which single nucleotide variant (SNVs) are associated with aneuploid pregnancy loss?

Summary answer

We identified a SNV on MEIG1 gene, which are associated with meiosis/spermiogenesis.

What is known already

Recurrent pregnancy loss (RPL) refers to the loss of two or more pregnancies, with a frequency of 5%. Chromosomal abnormalities in embryos are found in 80% of first trimester miscarriages, 86% of which are aneuploid. Recently, embryonic aneuploidy was found to be the most common cause of RPL, with a frequency of 40-50%. Most trisomy miscarriages are of maternal origin, with errors occurring during meiosis of the oocyte. Chromosome segregation abnormalities in oocytes are thought to be an event associated with increasing maternal age, but in addition, maternal genetic causes are thought to contribute.

Study design, size, duration

A Genome wide association study (GWAS) was performed on a clinically well characterized cohort of 189 women with RPL whose previous aborted conceptus was ascertained to be an aneuploid embryo. Samples were mainly collected from 2007 to 2018 mainly at Nagoya City University Hospital. For control samples, we used 1157 samples from the population-based prospective cohorts that included fertile women.

Participants/materials, setting, methods

All patients underwent a systematic examination. Patients with antiphospholipid syndrome, an abnormal chromosome in either partner, or uterine anomaly were excluded. Patients whose previously miscarried POC exhibited triploidy or 45, X were excluded. DNA was isolated from stored EDTA-blood samples and genotyped by Axiom Japonica-array v2659,503 SNVs). For the GWAS, a chi-squared test was applied to a two-by-two contingency table in allele frequency model.

Main results and the role of chance

The mean (SD) ages and number of previous miscarriages of the patients were 36.8 (4.3) and 3.09 (1.13). GWAS data revealed 5 SNVs with suggestive significance (p < 9.46e-06). The SNVs that showed the most significant associations (P = 1.06E-06, OR = 1.72) was located on meiosis/spermiogenesis associated 1 (MEIG1) gene under an allelic model after Bonferroni correction considering the number of analyzed SNVs. The SNV rs7908491 was reported as a splicing QTL in the MEIG1 gene, which is a meiosis/meiosis-associated factor and is plausibly associated with chromosome aneuploidy. This is the first GWAS in patients with RPL caused by aneuploidy.

Limitations, reasons for caution

Since this study was conducted in a single center and had a small sample size, it needs to be replicated in different centers with more subjects and on an international scale. Whole genome imputation analysis will be performed to detect SNVs with more significant associations.

Wider implications of the findings

Our findings demonstrate that a specific genotype of MEIG1 gene can be a risk factor for aneuploid pregnancy loss. The establishment of clinically applicable maternal germ cell markers could identify groups for whom PGT would be more useful or provide patients with counseling that provides prognostic information about pregnancy.

Trial registration number

not applicable

Impact of psm-mec in the mobile genetic element on the clinical characteristics and outcome of SCCmec-II methicillin-resistant Staphylococcus aureus bacteraemia in Japan

Over-expression of alpha-phenol-soluble modulins (PSMs) results in high virulence of community-associated methicillin-resistant Staphylococcus aureus (MRSA). The psm-mec gene, located in the mobile genetic element SCCmec-II, suppresses PSMαs production. Fifty-two patients with MRSA bacteraemia were enrolled. MRSA isolates were evaluated with regard to the psm-mec gene sequence, bacterial virulence, and the minimum inhibitory concentration (MIC) of vancomycin and teicoplanin. Fifty-one MRSA isolates were classified as SCCmec-II, and 10 had one point mutation in the psm-mec promoter. We compared clinical characteristics and outcomes between mutant MRSA and wild-type MRSA. Production of PSMα3 in mutant MRSA was significantly increased, but biofilm formation was suppressed. Wild-type MRSA caused more catheter-related bloodstream infections (30/41 vs. 3/10, p 0.0028), whereas mutant MRSA formed more deep abscesses (4/10 vs. 3/41, p 0.035). Bacteraemia caused by mutant MRSA was associated with reduced 30-day mortality (1/10 vs. 13/41, p 0.25), although this difference was not significant. The MIC90 of teicoplanin was higher for wild-type MRSA (1.5 mg/L vs. 1 mg/L), but the MIC of vancomycin was not different between the two groups. The 30-day mortality of MRSA with a high MIC of teicoplanin (≥1.5 mg/L) was higher than that of strains with a lower MIC (≤0.75 mg/L) (6/10 vs. 6/33, p 0.017). Mutation of the psm-mec promoter contributes to virulence of SCCmec-II MRSA, and the product of psm-mec may determine the clinical characteristics of bacteraemia caused by SCCmec-II MRSA, but it does not affect mortality.