Diagnostic accuracy of 18F-PSMA-1007 PET/CT for prostate cancer in primary staging and biochemical recurrence with different serum PSA levels: A systematic review and meta-analysis

OBJECTIVE

We performed a systematic review and meta-analysis to evaluate the application value of fluorine-18-prostate specific membrane antigen (¹⁸F-PSMA-1007) positron emission tomography/computed tomography (PET/CT) in patients with different serum prostate specific antigen (PSA) levels and primary prostate cancer (PCa) or the biochemical recurrence of PCa.

METHODS

A comprehensive electronic literature search of the PubMed, Embase and Cochrane Library databases was conducted in accordance with the PRISMA statement. We calculated the pooled sensitivity and specificity of ¹⁸F-PSMA-1007 PET/CT in PCa. A summary receiver operator characteristic (SROC) curve and the area under the curve (AUC) were used to assess the accuracy of ¹⁸F-PSMA-1007 PET/CT for PCa.

RESULTS

The final analysis included 11 studies that described 799 patients and 4261 lesions with ¹⁸F-PSMA-1007 PET/CT in PCa. The pooled sensitivity and specificity of ¹⁸F-PSMA-1007 PET/CT in PCa were 0.836 and 0.946, respectively. The per-patient pooled sensitivity and specificity of ¹⁸F-PSMA-1007 PET/CT in PCa were 0.934 and 0.453, and the per-lesion values were 0.816 and 0.979, respectively. The pooled sensitivity and specificity of ¹⁸F-PSMA-1007 PET/CT in PCa with PSA>2ng/mL were 0.923 and 0.442 in a patient-based analysis and 0.799 and 0.961 in a lesion-based analysis, respectively. The pooled sensitivity and specificity of ¹⁸F-PSMA-1007 PET/CT in PCa with PSA≤2ng/mL were 0.832 and 0.277 in a patient-based analysis, respectively.

CONCLUSION

This meta-analysis showed that ¹⁸F-PSMA-1007 PET/CT has a higher diagnostic value for prostate cancer in the setting of primary PCa and biochemical recurrence. As serum PSA levels increase, the diagnostic accuracy of ¹⁸F-PSMA-1007 PET/CT also improves.

CT texture analysis-based nomogram for the preoperative prediction of visceral pleural invasion in cT1N0M0 lung adenocarcinoma: an external validation cohort study

AIM

To develop a nomogram based on computed tomography (CT) texture analysis for the preoperative prediction of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma.

MATERIALS AND METHODS

A dataset of chest CT containing lung nodules was collected from two institutions, and all surgically resected nodules were classified pathologically based on the presence of visceral pleural invasion. Each nodule on the CT image was segmented automatically by artificial-intelligence software and its CT texture features were extracted. The dataset was divided into training and external validation cohorts according to the institution, and a nomogram for predicting visceral pleural invasion was developed and validated.

RESULTS

Of a total of 313 patients enrolled from two independent institutions, 63 were diagnosed with visceral pleural invasion. Three-dimensional (3D) CT long diameter, skewness, and sphericity, and chronic obstructive pulmonary disease were identified as independent predictors for visceral pleural invasion by multivariable logistic regression. The nomogram based on multivariable logistic regression showed great discriminative ability, as indicated by a C-index of 0.890 (95% confidence interval [CI]: 0.867-0.914) and 0.864 (95% CI: 0.817-0.911) for the training and external validation cohorts, respectively. Additionally, calibration of the nomogram revealed good predictive ability, as indicated by the Brier score (0.108 and 0.100 for the training and external validation cohorts, respectively).

CONCLUSIONS

A nomogram was developed that could compute the probability of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma with good calibration and discrimination. The nomogram has potential as a reliable tool for clinical evaluation and decision-making.

An ensemble learning method based on ordinal regression for COVID-19 diagnosis from chest CT

Coronavirus disease 2019 (COVID-19) has brought huge losses to the world, and it remains a great threat to public health. X-ray computed tomography (CT) plays a central role in the management of COVID-19. Traditional diagnosis with pulmonary CT images is time-consuming and error-prone, which could not meet the need for precise and rapid COVID-19 screening. Nowadays, deep learning (DL) has been successfully applied to CT image analysis, which assists radiologists in workflow scheduling and treatment planning for patients with COVID-19. Traditional methods use cross-entropy as the loss function with a Softmax classifier following a fully-connected layer. Most DL-based classification methods target intraclass relationships in a certain class (early, progressive, severe, or dissipative phases), ignoring the natural order of different phases of the disease progression,i.e.,from an early stage and progress to a late stage. To learn both intraclass and interclass relationships among different stages and improve the accuracy of classification, this paper proposes an ensemble learning method based on ordinal regression, which leverages the ordinal information on COVID-19 phases. The proposed method uses multi-binary, neuron stick-breaking (NSB), and soft labels (SL) techniques, and ensembles the ordinal outputs through a median selection. To evaluate our method, we collected 172 confirmed cases. In a 2-fold cross-validation experiment, the accuracy is increased by 22% compared with traditional methods when we use modified ResNet-18 as the backbone. And precision, recall, andF1-score are also improved. The experimental results show that our proposed method achieves a better classification performance than the traditional methods, which helps establish guidelines for the classification of COVID-19 chest CT images.

Elaboration of a Radiomics Strategy for the Prediction of the Re-positive Cases in the Discharged Patients With COVID-19

Objective: A considerable part of COVID-19 patients were found to be re-positive in the SARS-CoV-2 RT-PCR test after discharge. Early prediction of re-positive COVID-19 cases is of critical importance in determining the isolation period and developing clinical protocols. Materials and Methods: Ninety-one patients discharged from Wanzhou Three Gorges Central Hospital, Chongqing, China, from February 10, 2020 to March 3, 2020 were administered nasopharyngeal swab SARS-CoV-2 tests within 12-14 days, and 50 eligible patients (32 male and 18 female) with completed data were enrolled. Average age was 48 ± 11.5 years. All patients underwent non-enhanced chest CT on admission. A total of 568 radiomics features were extracted from the CT images, and 17 clinical factors were collected based on the medical record. Student's t-test and support vector machine-based recursive feature elimination (SVM-RFE) method were used to determine an optimal subset of features for the discriminative model development. Results: After Student's t-test, 62 radiomics features showed significant inter-group differences (p < 0.05) between the re-positive and negative cases, and none of the clinical features showed significant differences. These significant features were further selected by SVM-RFE algorithm, and a more compact feature subset containing only two radiomics features was finally determined, achieving the best predictive performance with the accuracy and area under the curve of 72.6% and 0.773 for the identification of the re-positive case. Conclusion: The proposed radiomics method has preliminarily shown potential in identifying the re-positive cases among the recovered COVID-19 patients after discharge. More strategies are to be integrated into the current pipeline to improve its precision, and a larger database with multi-clinical enrollment is required to extensively verify its performance.

MRI and 18F-FDG PET/CT findings of a giant cell tumor of the tendon sheath of the knee joint (pigmented villonodular synovitis): A case report and literature review

We present a case of a 33-year-old female hospitalized with a 3-month history of right knee pain when squatting. Her physical examination showed no resting pain or local skin fever. Magnetic resonance imaging (MRI) showed multiple nodular long T1 and short T2 abnormal signal shadows in the popliteal fossa region. A patchy T2 high signal shadow was found in the soft tissue around the right knee.Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) revealed multiple soft tissue density nodules around and within the right knee joint (largest 20x13mm) with a maximum standardized uptake value (SUVmax) of 10.5 and a delayed SUVmax of 12.0. The subsequent histopathologic examination confirmed the diagnosis of a diffuse giant cell tumor of the tendon sheath (GCTTS) and pigmented villonodular synovitis(PVNS).

Hippocampal subfields atrophy contribute more to cognitive impairment in middle-aged patients with type 2 diabetes rather than microvascular lesions

AIMS

Neurodegeneration and microvascular lesions are related to cognitive impairment in type 2 diabetes mellitus (T2DM). We aimed to use the volume of hippocampal subfields and the burden of white matter hyperintensities (WMH) as neurodegeneration and microangiopathy markers, respectively, to investigate their potential associations with cognitive impairment in T2DM patients.

METHODS

A total of 76 T2DM patients and 45 neurologically unimpaired normal controls were enrolled between February 2016 to August 2018. All participants underwent structural magnetic resonance imaging (MRI) and Montreal Cognitive Assessment (MoCA). The T2DM patients were divided into the T2DM without mild cognitive impairment (T2noMCI) group (n = 44) and the T2DM with mild cognitive impairment (T2MCI) group (n = 32) according to MoCA scores. We used automatic brain segmentation and quantitative technique to assess the volume of twelve hippocampal subfields and WMH on MRI. We used age, sex, education, and total intracranial volume as our covariates and the Bonferroni method for multiple comparison correction.

RESULTS

Both the T2MCI group and T2noMCI group showed significant hippocampal subfields atrophy compared to the controls, which were mainly in the left hippocampal tail, left CA1, bilateral molecular layer, bilateral dentate gyrus, and bilateral CA4 (all p < 0.0042). No significant differences in the volume of total WMH, deep-WMH, and periventricular-WMH were found among the three groups. The HbA1c levels were significantly negatively correlated with hippocampal atrophy, and the MoCA scores were positively correlated with bilateral hippocampal volume in T2DM patients and all samples. Mediation analyses demonstrated that the association of HbA1c levels with cognitive function was mediated by hippocampal subfields volume.

CONCLUSION

Widespread hippocampal atrophies across the subfields have been found in middle-aged T2DM patients, which was positively correlated with the MoCA scores and negatively correlated with the HbA1c levels. The association of HbA1c levels with cognitive function was mediated by some crucial hippocampal subfields volume. In middle-aged patients with T2DM, the neurodegeneration is more strongly associated with cognitive impairment than microvascular lesions. Trail Registeration This study was registered on Clinical-Trails.gov (NCT02738671).

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

MiR-137 affects bone mineral density in osteoporosis rats through regulating RUNX2

OBJECTIVE

To study the influence of micro ribonucleic acid (miR)-137 on osteoporosis rats by regulating runt-related transcription factor 2 (RUNX2).

MATERIALS AND METHODS

A total of 36 Sprague-Dawley rats were randomly assigned to the normal group (n=12), model group (n=12), and inhibitor group (n=12). No treatment was performed in the normal group. The osteoporosis model in rats was prepared in the model group, and miR-137 inhibitor was administered in osteoporosis rats of inhibitor group. Following 12 weeks of intervention, sampling was conducted. The expression of RUNX2 was detected via immunohistochemistry, and its protein expression level was determined via Western blotting. Quantitative Polymerase Chain Reaction (qPCR) was carried out to detect the mRNA level of miR-137. The contents of serum bone Gla protein (BGP) and total alkaline phosphatase (TALP) were measured using enzyme-linked immunosorbent assay (ELISA). Finally, bone mineral density was determined with a dual-energy X-ray absorptiometry instrument.

RESULTS

According to the immunohistochemistry detection, the rats in model group and inhibitor group had a notably lower positive expression level of RUNX2 than normal group (p<0.05), and its expression level in the inhibitor group was substantially higher than that in the model group (p<0.05). Western blotting results showed that compared with that in the normal group, the protein expression level of RUNX2 was notably lowered in the model and inhibitor group (p<0.05), which was markedly higher in the inhibitor group than that in the model group (p<0.05). It was found through the qPCR that the expression level of miR-137 was remarkably raised in both model group and inhibitor group compared with that in the normal group, showing statistically significant differences (p<0.05). The rats in the inhibitor group had a remarkably lower expression level of miR-137 than the model group (p<0.05). ELISA results revealed that the model group and inhibitor group had substantially lower contents of serum BGP and TALP than the normal group (p<0.05), and that their contents rose dramatically in the inhibitor group compared with that in the model group (p<0.05). Additionally, based on the measurement of bone mineral density, compared with that in the normal group, bone mineral density declined considerably in the model group and inhibitor group (p<0.05). It was markedly elevated in inhibitor group in comparison with that in the model group (p<0.05).

CONCLUSIONS

MiR-137 regulates RUNX2 to affect the bone mineral density of osteoporosis model rats.

Opsin 5 is a key regulator of ultraviolet radiation-induced melanogenesis in human epidermal melanocytes

Background

Human skin, which is constantly exposed to solar ultraviolet radiation (UVR), has a unique ability to respond by increasing its pigmentation in a protective process driven by melanogenesis in human epidermal melanocytes (HEMs). However, the molecular mechanisms used by HEMs to detect and respond to UVR remain unclear.

Objectives

To investigate the function and potential mechanism of opsin 5 (OPN5), a photoreceptor responsive to UVR wavelengths, in melanogenesis in HEMs.

Methods

Melanin content in HEMs was determined using the NaOH method, and activity of tyrosinase (TYR) (a key enzyme in melanin synthesis) was determined by the l‐DOPA method. OPN5 expression in UVR‐treated vs. untreated HEMs and explant tissues was detected by reverse‐transcription quantitative polymerase chain reaction (RT‐qPCR), Western blotting and immunofluorescence. Short interfering RNA‐mediated OPN5 knockdown and a lentivirus OPN5 overexpression model were used to examine their respective effects on TYR, tyrosinase‐related protein 1 (TRP1), TRP2 and microphthalmia‐associated transcription factor (MITF) expression, under UVR. Changes in expression of TYR, TRP1 and TRP2 caused by changes in OPN5 expression level were detected by RT‐qPCR and Western blot. Furthermore, changes in signalling pathway proteins were assayed.

Results

We found that OPN5 is the key sensor in HEMs responsible for UVR‐induced melanogenesis. OPN5‐induced melanogenesis required Ca²⁺‐dependent G protein‐coupled receptor‐ and protein kinase C signal transduction, thus contributing to the UVR‐induced MITF response to mediate downstream cellular effects, and providing evidence of OPN5 function in mammalian phototransduction. Remarkably, OPN5 activation was necessary for UVR‐induced increase in cellular melanin and has an inherent function in melanocyte melanogenesis.

Conclusions

Our results provide insight into the molecular mechanisms of UVR sensing and phototransduction in melanocytes, and may reveal molecular targets for preventing pigmentation or pigment diseases.

What is already known about this topic?

Ultraviolet radiation (UVR) induces a protective response to DNA damage mediated by melanin synthesis in human epidermal melanocytes (HEMs).

Tyrosinase (TYR), with tyrosinase‐related proteins (TRP1, TRP2), are the key enzymes for melanin synthesis.

Microphthalmia‐associated transcription factor regulates key genes for melanocyte development and differentiation, and can stimulate melanogenesis by activating transcription of TYR and other pigmentation genes, including TRP1.

Opsin 5 (OPN5) is known to function as a photoreceptor responsive to wavelengths in the near UV spectrum.

What does this study add?

UVR induces melanogenesis in HEMs via OPN5.

OPN5 regulates expression of TYR, TRP1 and TRP2 through the calcium‐dependent G protein‐coupled and protein kinase C signalling pathways.

OPN5 has an inherent role in HEMs in mediating melanogenesis.

What is the translational message?

OPN5 was discovered as a key sensor for UVR‐induced melanogenesis in human skin melanocytes.

It could be a target for early treatment of pigmentation or pigment diseases, to provide a more personalized and economically feasible method.

Linked Comment: L.V.M. de Assis and A.M. de Lauro Castrucci. Br J Dermatol 2021; 185:249–250.

Plain language summary available online

CT imaging features of different clinical types of COVID-19 calculated by AI system: a Chinese multicenter study

Background

The study is designed to explore the chest CT features of different clinical types of coronavirus disease 2019 (COVID-19) pneumonia based on a Chinese multicenter dataset using an artificial intelligence (AI) system.

Methods

A total of 164 patients confirmed COVID-19 were retrospectively enrolled from 6 hospitals. All patients were divided into the mild type (136 cases) and the severe type (28 cases) according to their clinical manifestations. The total CT severity score and quantitative CT features were calculated by AI pneumonia detection and evaluation system with correction by radiologists. The clinical and CT imaging features of different types were analyzed.

Results

It was observed that patients in the severe type group were older than the mild type group. Round lesions, Fan-shaped lesions, crazy-paving pattern, fibrosis, “white lung”, pleural thickening, pleural indentation, mediastinal lymphadenectasis were more common in the CT images of severe patients than in the mild ones. A higher total lung severity score and scores of each lobe were observed in the severe group, with higher scores in bilateral lower lobes of both groups. Further analysis showed that the volume and number of pneumonia lesions and consolidation lesions in overall lung were higher in the severe group, and showed a wider distribution in the lower lobes of bilateral lung in both groups.

Conclusions

Chest CT of patients with severe COVID-19 pneumonia showed more consolidative and progressive lesions. With the assistance of AI, CT could evaluate the clinical severity of COVID-19 pneumonia more precisely and help the early diagnosis and surveillance of the patients.

LncRNA LINC00707 promotes osteogenic differentiation of hBMSCs through the Wnt/β-catenin pathway activated by LINC00707/miR-145/LRP5 axis

OBJECTIVE

Human bone marrow mesenchymal stem cells (hBMSCs) have a strong self-renewal potential and osteogenic differentiation ability, thus providing a new method for bone defect repair research. LncRNA LINC00707 participates in the regulation of osteogenic differentiation of hBMSCs and our aim was to explore the potential regulatory mechanism.

MATERIALS AND METHODS

Firstly, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression levels of LINC00707, miR-145, the low-density lipoprotein receptor-related protein 5 (LRP5) and osteogenesis-related genes. Next, alkaline phosphatase (ALP) activity assay was used to measure the relative activity of ALP in hBMSCs. The protein levels of LRP5 and osteogenesis-related genes were detected by Western blot. Finally, the relationship among LINC00707, miR-145 and LRP5 were predicted by online software and verified by Dual-Luciferase reporter assay, RNA pull-down and RNA immunoprecipitation (RIP).

RESULTS

LINC00707 and osteogenesis-related genes were gradually upregulated during osteogenesis of hBMSCs. Meanwhile, overexpression of LINC00707 promoted osteogenic differentiation of hBMSCs. Interestingly, we found that LINC00707 negatively regulated the miR-145 expression and osteogenic differentiation functions by directly interacting with miR-145, and LINC00707 affected the functions of LRP5 by sponging miR-145 in hBMSCs. Moreover, LINC00707 promoted the Wnt/β-catenin pathway through the LINC00707/miR-145/LRP5 axis.

CONCLUSIONS

LncRNA LINC00707 promoted osteogenic differentiation of hBMSCs by targeting LRP5 mediated by miR-145 through the activation of the Wnt/β-catenin pathway.

Effects of the prebiotic inulin-type fructans on post-antibiotic reconstitution of the gut microbiome

AIMS

Interventions using prebiotic inulin-type fructans (ITFs) are widely prescribed to modulate the gut microbiota composition and activity to promote health. However, the impacts of ITFs on post-antibiotic reconstitution of the gut microbiome remain incompletely understood. The aim of the present study was to investigate the effects of ITFs supplementation on intestinal inflammation, the composition of the intestinal microbiota and the colonic transcriptome after antibiotic treatment.

METHODS AND RESULTS

Male BALB/c mice were subjected to an antibiotic cocktail (ABx) treatment for 7 days, and their microbiomes were then reconstituted either spontaneously or with ITFs supplementation (5%) for 14 days. Our data showed that ITFs supplementation delayed the recovery of antibiotic-induced colitis compared with the spontaneous recovery. Neither ITFs supplementation nor spontaneous recovery could restore the microbial community composition at the genus level back to its initial composition. ITFs supplementation increased the relative abundance of some beneficial bacteria and butyrate levels, but resulted in selective blooms of some opportunistic pathogens and elevated the pathways associated with diseases linked to gut microbiota function. Both ITFs supplementation and spontaneous recovery could restore the colonic transcriptome nearly to the initial profile to a certain extent; however, ITFs supplementation delayed the restoration of the immunoglobulin genes compared to spontaneous recovery.

CONCLUSION

These data showed that post-antibiotic ITFs consumption did not always lead to beneficial effects but might lead to potential adverse effects in the context of dysbiosis.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings highlighted that caution is required when supplementing ITFs to restore intestinal homeostasis in the context of dysbiosis resulting from broad-spectrum antibiotics.

Clinical and immunologic features among COVID-19-affected mother-infant pairs: antibodies to SARS-CoV-2 detected in breast milk

The coronavirus disease 2019 (COVID-19) pandemic remains threatening to women and children, but clinical evidence regarding women during pregnancy, puerperium and lactation is limited. We assessed clinical and immunologic features of and breastfeeding advice provided to mother–infant pairs. This observational analysis was conducted in a tertiary-care centre in Wuhan, China. Pregnant patients with laboratory-confirmed COVID-19 who delivered during hospitalization were enrolled. Clinical characteristics and serial specimens of the mother–infant pairs were examined, supplemented with follow-ups regarding recovery and breastfeeding. Fourteen pregnant patients had live births and recovered well; four patients continued breastfeeding while taking precautions. No neonatal infections were observed. No infants developed COVID-19 during breastfeeding. Common maternal symptoms were fever (11/14, 78.1%) and cough (6/14, 42.9%). A pregnancy-specific symptom was abnormal foetal movement, which was noticed by three patients (21.4%). The mean virus shedding time was 9 days (standard deviation, 6 days; range, 1–22 days). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome was not detected in breast milk or maternal vaginal secretions. Immunologic assay revealed seroconversion of IgM on day 8 after onset and IgG on day 28. Both IgM and IgG antibodies to SARS-CoV-2 were detected in breast milk, cord blood and neonatal serum. The study results suggest that passive acquisition of antibodies against SARS-CoV-2 is available by ingesting breast milk. Breastfeeding has a low risk of transmitting SARS-CoV-2 or escalating maternal disease, so continuing breastfeeding with prudent precautions is encouraged.