Non-invasive molecular imaging of immune cell dynamics for vaccine research

Activated Natural Killer Cell Inoculation Alleviates Fibrotic Liver Pathology in a Carbon Tetrachloride-Induced Liver Cirrhosis Mouse Model

Activated hepatic stellate cells (HSCs) play a detrimental role in liver fibrosis progression. Natural killer (NK) cells are known to selectively recognize abnormal or transformed cells via their receptor activation and induce target cell apoptosis and, therefore, can be used as a potential therapeutic strategy for liver cirrhosis. In this study, we examined the therapeutic effects of NK cells in the carbon tetrachloride (CCl₄)-induced liver cirrhosis mouse model. NK cells were isolated from the mouse spleen and expanded in the cytokine-stimulated culture medium. Natural killer group 2, member D (NKG2D)-positive NK cells were significantly increased after a week of expansion in culture. The intravenous injection of NK cells significantly alleviated liver cirrhosis by reducing collagen deposition, HSC marker activation, and macrophage infiltration. For in vivo imaging, NK cells were isolated from codon-optimized luciferase-expressing transgenic mice. Luciferase-expressing NK cells were expanded, activated and administrated to the mouse model to track them. Bioluminescence images showed increased accumulation of the intravenously inoculated NK cells in the cirrhotic liver of the recipient mouse. In addition, we conducted QuantSeq 3' mRNA sequencing-based transcriptomic analysis. From the transcriptomic analysis, 33 downregulated genes in the extracellular matrix (ECM) and 41 downregulated genes involved in the inflammatory response were observed in the NK cell-treated cirrhotic liver tissues from the 1532 differentially expressed genes (DEGs). This result indicated that the repetitive administration of NK cells alleviated the pathology of liver fibrosis in the CCl₄-induced liver cirrhosis mouse model via anti-fibrotic and anti-inflammatory mechanisms. Taken together, our research demonstrated that NK cells could have therapeutic effects in a CCl₄-induced liver cirrhosis mouse model. In particular, it was elucidated that extracellular matrix genes and inflammatory response genes, which were mainly affected after NK cell treatment, could be potential targets.

Immune Response Related to Lymphadenopathy Post COVID-19 Vaccination

Mass vaccination against coronavirus disease 2019 (COVID-19) is a global health strategy to control the COVID-19 pandemic. With the increasing number of vaccinations, COVID-19 vaccine-associated lymphadenopathy (C19-VAL) has been frequently reported. Current findings emphasize the characteristics of C19-VAL. The mechanism of C19-VAL is complicated to explore. Accumulated reports separately show that C19-VAL incidence is associated with receiver age and gender, reactive change within lymph nodes (LN), etc. We constructed a systematic review to evaluate the associated elements of C19-VAL and provide the mechanism of C19-VAL. Articles were searched from PubMed, Web of Science and EMBASE by using the processing of PRISMA. The search terms included combinations of the COVID-19 vaccine, COVID-19 vaccination and lymphadenopathy. Finally, sixty-two articles have been included in this study. Our results show that days post-vaccination and B cell germinal center response are negatively correlated with C19-VAL incidence. The reactive change within LN is highly related to C19-VAL development. The study results suggested that strong vaccine immune response may contribute to the C19-VAL development and perhaps through the B cell germinal center response post vaccination. From the perspective of imaging interpretation, it is important to carefully distinguish reactive lymph nodes from metastatic lymph node enlargement through medical history collection or evaluation, especially in patients with underlying malignancy.

Effects of nonsteroidal anti-inflammatory drugs on ultrasound findings of mRNA COVID-19 vaccine-related lymphadenopathy

BACKGROUND

Previous studies reported axillary lymphadenopathy (LAP) as a side effect of the anti-COVID-19 vaccine. However, the effects of nonsteroidal anti-inflammatory drug (NSAID)s on mRNA COVID-19 vaccine-related LAP have not been investigated.

PURPOSE

We aimed to investigate the effects of NSAIDs on temporal changes in sonographic findings of COVID-19 vaccine-associated LAP.

METHODS

Our single-center retrospective cohort study was conducted between October 2021 and April 2022. We included patients (aged ≥ 18 years) who applied with complaints of swelling in the ipsilateral axillary region after the COVID-19 vaccine and had axillary region ultrasound (US) scans in electronic medical records within 30 days pre-vaccination. The serial US was performed on the third, 10th, and 30th days post-vaccination.

RESULTS

Our study included 38 patients with a median age of 36 (IQR, 32-43) years. In 18 (47.4%) patients used NSAIDs in the early post-vaccination period. Measurements of LAPs on ultrasound scans increased at day 3 post-vaccination compared with pre-vaccination both in NSAID users and non-users. On the 10th day, a statistically insignificant decrease in LAP diameters and cortical thickness was observed in NSAID users compared to non-users. On the post-vaccination 30th day, axillary LAPs regressed similarly in both groups.

CONCLUSION

In our study, post-vaccine NSAID use had no statistically significant effect on the course of axillary LAPs.

Lymphadenopathy subsequent to Covishield (ChAdOx1 nCoV-19) Corona virus vaccine: ultrasound findings and clinical implications

Introduction

Post anti-COVID-19 vaccine lymphadenopathies have been recently described in literature, from different parts of the world. Although there have been studies on lymphadenopathy following mRNA vaccines, there is a paucity of studies on lymphadenopathy following inactivated viral vaccines, such as Covishield.

Aim

In this study, we explored lymphadenopathy subsequent to Covishield vaccine in terms of its various ultrasound parameters in the Indian population.

Methods

This hospital-based longitudinal study was conducted among 50 adult beneficiaries of Covishield vaccine. Sociodemographic details and relevant clinical history were recorded using a semi-structured performa. Detailed ultrasound (USG) examination of the bilateral axillae was done on the day of vaccination and after 6-12 days post vaccination. Vaccine beneficiaries were evaluated for the presence of any vaccine-associated lymphadenopathy and described the presence, number, size, morphology, cortical thickness, and presence or absence of echogenic hilum.

Results

Out of total (63) lymph nodes evaluated sonologically, majority (80.9%) of lymph nodes showed the features of benign lymphadenopathy. However, 12.6% (8/63) lymph nodes showed diffusely thickened cortex with preserved central echogenic hilum, 4.76% (3/63) lymph nodes showed eccentric cortical thickness with preserved hilar pattern, while only one lymph node showed diffuse cortical thickening with loss of central echogenic hilum.

Conclusion

With an increase in vaccination coverage, clinicians are likely to confront increasing cases of vaccine-associated axillary lymphadenopathy. Therefore, they should exercise care, that contemporary anti-COVID-19 vaccination can present an aetiology of axillary lymph nodes with suspicious USG features.

Lymphadenopathy in the era of COVID-19 vaccination - an oncological dilemma in diagnostic imaging

Initial clinical experience with COVID-19 vaccination suggests that approved COVID-19 mRNA vaccines induce a strong immune response and thus cause a significantly higher incidence of axillary lymphadenopathy compared with other vaccines. It can therefore be expected to complicate the diagnosis of patients with overt or suspected mali-gnancy, in whom it may be indistinguishable from malignant node involvement. There is a need for guidelines on the appropriate management of unilateral axillary lymph node enlargement. This article studies the available reports on vaccine-associated lymphadenopathy. It also presents a basic strategy for the assessment of axillary lymphadenopathy based on preliminary recommendations and an algorithm. According to these recommendations, screening should be scheduled before or at least 4-6 weeks after the last dose of the vaccine. This will allow reactive adenopathy to resolve and avoid unnecessary and costly axillary lymph node biopsy. Clear and effective communication between patients, radiologists, referring physician teams, and the general public is the way forward in the management of adenopathy following COVID-19 vaccination.

Herein we present 5 cases of lymph node enlargement after mRNA vaccine administration from different authors. Their initial radiological diagnosis raised concerns that they might be metastases. Therefore, radiologists need to include COVID-19 vaccination in the differential diagnosis of patients with unilateral axillary adenopathy. Short-term follow-up of unilateral axillary adenopathy with recent COVID-19 vaccination is an appropriate recommendation.

Axillary Lymphadenopathy on Ultrasound after COVID-19 Vaccination and Its Influencing Factors: A Single-Center Study

PURPOSE

This study aimed to assess the incidence of axillary lymphadenopathy on ultrasound after COVID-19 vaccination and to investigate the factors affecting lymphadenopathy.

METHODS

We evaluated patients who had received a COVID-19 vaccination within 12 weeks before an ultrasound examination between August and October 2021. The incidence of vaccine-related ipsilateral axillary lymphadenopathy was evaluated using ultrasound. Age, sex, presence of axillary symptoms, injection site, vaccine type, interval from vaccination, and dose were compared between the groups with and without axillary lymphadenopathy.

RESULTS

We included 413 patients, 202 (49%) of whom showed axillary lymphadenopathy on ultrasound after COVID-19 vaccination. Age, interval from vaccine, vaccine brand, vaccine type, dose, and symptom were significantly different between the lymphadenopathy and non-lymphadenopathy groups (p < 0.001), while the injection site and sex were not. Receiving an mRNA vaccine was the most important factor for axillary lymphadenopathy (p < 0.001), followed by intervals of 1-14 (p < 0.001) and 15-28 days (p < 0.001), younger age (p = 0.006), and first dose (p = 0.045).

CONCLUSION

COVID-19 vaccine-related axillary lymphadenopathy on ultrasound is common. mRNA type, an interval of 4 weeks, younger age, and first dose were the important factors. Breast clinicians should be well aware of these side effects when performing imaging examinations and provide accurate information to patients.

Multidisciplinary Recommendations Regarding Post-Vaccine Adenopathy and Radiologic Imaging: Radiology Scientific Expert Panel

Vaccination-associated adenopathy is a frequent imaging finding after administration of COVID-19 vaccines that may lead to a diagnostic conundrum in patients with manifest or suspected cancer, in whom it may be indistinguishable from malignant nodal involvement. To help the medical community address this concern in the absence of studies and evidence-based guidelines, this special report offers recommendations developed by a multidisciplinary panel of experts from three of the leading tertiary care cancer centers in the United States. According to these recommendations, some routine imaging examinations, such as those for screening, should be scheduled before or at least 6 weeks after the final vaccination dose to allow for any reactive adenopathy to resolve. However, there should be no delay of other clinically indicated imaging (eg, for acute symptoms, short-interval treatment monitoring, urgent treatment planning or complications) due to prior vaccination. The vaccine should be administered on the side contralateral to the primary or suspected cancer, and both doses should be administered in the same arm. Vaccination information-date(s) administered, injection site(s), laterality, and type of vaccine-should be included in every preimaging patient questionnaire, and this information should be made readily available to interpreting radiologists. Clear and effective communication between patients, radiologists, referring physician teams, and the general public should be considered of the highest priority when managing adenopathy in the setting of COVID-19 vaccination.

COVID-19 vaccine-related lymph node activation - patterns of uptake on PET-CT

In a bid to end the current COVID-19 crisis, many countries including UK have begun a mass immunization programme. Immunization can cause transient inflammation thereby causing increased metabolic activity at injection site and hypermetabolic lymph nodes. Various vaccinations and local injections have been known to cause diagnostic dilemma due to false-positive uptake on FDG PET-CT.

In this pictorial case review, we present five cases demonstrating various patterns of uptake including an ipsilateral deltoid muscle, axillary, supraclavicular, and subpectoral lymph nodes post COVID-19 vaccination.

A careful history of COVID-19 vaccination and normal size and morphology of lymph node on unenhanced low-dose CT will aid the diagnosis. All patients undergoing FDG PET-CT will require detailed documentation of the vaccination history including the time interval since vaccination.

Knowledge about these patterns of uptake on PET-CT will ensure accurate interpretation by Nuclear Medicine physicians and radiologists during the current vaccination drive.

COVID-19 vaccine is here: practical considerations for clinical imaging applications

Imaging tools are potentially able to provide valuable data regarding the development of an efficient vaccine against viral diseases. Tracking immune cells in vivo by imaging modalities can help us understand the intrinsic behaviors of immune cells in response to vaccine components. Imaging patterns at the vaccination site and draining lymph nodes might provide useful information about the vaccine potency. Besides, serial lung CT imaging has been purposed to evaluate vaccine efficiency regarding its protection against typical lung lesions of viral pneumonias. On the other hand, vaccination causes various confusing radiologic patterns that pose diagnostic challenges for clinicians and pitfalls for reading radiologists. This manuscript reviews potential applications of imaging modalities in the process of vaccine development and also goes over some of the imaging findings/pitfalls following vaccination.