Case report: Understanding the impact of persistent tissue-localization of SARS-CoV-2 on immune response activity via spatial transcriptomic analysis of two cancer patients with COVID-19 co-morbidity.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected half a billion people, including vulnerable populations such as cancer patients. While increasing evidence supports the persistence of SARS-CoV-2 months after a negative nasopharyngeal swab test, the effects on long-term immune memory and cancer treatment are unclear. In this report, we examined post-COVID-19 tissue-localized immune responses in a hepatocellular carcinoma (HCC) patient and a colorectal cancer (CRC) patient. Using spatial whole-transcriptomic analysis, we demonstrated spatial profiles consistent with a lymphocyte-associated SARS-CoV-2 response (based on two public COVID-19 gene sets) in the tumors and adjacent normal tissues, despite intra-tumor heterogeneity. The use of RNAscope and multiplex immunohistochemistry revealed that the spatial localization of B cells was significantly associated with lymphocyte-associated SARS-CoV-2 responses within the spatial transcriptomic (ST) niches showing the highest levels of virus. Furthermore, single-cell RNA sequencing data obtained from previous (CRC) or new (HCC) ex vivo stimulation experiments showed that patient-specific SARS-CoV-2 memory B cells were the main contributors to this positive association. Finally, we evaluated the spatial associations between SARS-CoV-2-induced immunological effects and immunotherapy-related anti-tumor immune responses. Immuno-predictive scores (IMPRES) revealed consistent positive spatial correlations between T cells/cytotoxic lymphocytes and the predicted immune checkpoint blockade (ICB) response, particularly in the HCC tissues. However, the positive spatial correlation between B cells and IMPRES score was restricted to the high-virus ST niche. In addition, tumor immune dysfunction and exclusion (TIDE) analysis revealed marked T cell dysfunction and inflammation, alongside low T cell exclusion and M2 tumor-associated macrophage infiltration. Our results provide in situ evidence of SARS-CoV-2-generated persistent immunological memory, which could not only provide tissue protection against reinfection but may also modulate the tumor microenvironment, favoring ICB responsiveness. As the number of cancer patients with COVID-19 comorbidity continues to rise, improved understanding of the long-term immune response induced by SARS-CoV-2 and its impact on cancer treatment is much needed.

Differential immunogenicity of homologous versus heterologous boost in Ad26.COV2.S vaccine recipients.

BACKGROUND: Protection offered by coronavirus disease 2019 (COVID-19) vaccines wanes over time, requiring an evaluation of different boosting strategies to revert such a trend and enhance the quantity and quality of Spike-specific humoral and cellular immune responses. These immunological parameters in homologous or heterologous vaccination boosts have thus far been studied for mRNA and ChAdOx1 nCoV-19 vaccines, but knowledge on individuals who received a single dose of Ad26.COV2.S is lacking. METHODS: We studied Spike-specific humoral and cellular immunity in Ad26.COV2.S-vaccinated individuals (n = 55) who were either primed with Ad26.COV2.S only (n = 13) or were boosted with a homologous (Ad26.COV2.S, n = 28) or heterologous (BNT162b2, n = 14) second dose. We compared our findings with the results found in individuals vaccinated with a single (n = 16) or double (n = 44) dose of BNT162b2. FINDINGS: We observed that a strategy of heterologous vaccination enhanced the quantity and breadth of both Spike-specific humoral and cellular immunity in Ad26.COV2.S-vaccinated individuals. In contrast, the impact of the homologous boost was quantitatively minimal in Ad26.COV2.S-vaccinated individuals, and Spike-specific antibodies and T cells were narrowly focused to the S1 region. CONCLUSIONS: Despite the small sample size of the study and the lack of well-defined correlates of protection against COVID-19, the immunological features detected support the utilization of a heterologous vaccine boost in individuals who received Ad26.COV2.S vaccination. FUNDING: This study is partially supported by the Singapore Ministry of Health's National Medical Research Council under its COVID-19 Research Fund (COVID19RF3-0060, COVID19RF-001, and COVID19RF-008), The Medical College St. Bartholomew's Hospital Trustees - Pump Priming Fund for SMD COVID-19 Research.

Monitoring for airborne respiratory viruses in a general pediatric ward in Singapore.

There is an increasing body of evidence suggesting that transmission of respiratory viruses occurs through the inhalation of virus-laden particles. Our study describes the use of an aerosol sampling system to monitor the prevalence of airborne viruses in a hospital setting. Using SKC AirCheck Touch pumps, with National Institute for Occupational Safety and Health (NIOSH) bioaerosol samplers and SKC filter cassette blanks, 28 aerosol samples were collected in a hospital ward in Singapore. Following DNA/RNA extraction, real-time RT-PCR/PCR was used for the detection of influenza A, B and D viruses, coronaviruses, enteroviruses, and adenoviruses. Airborne virus was detected in nine (32%) of 28 samples. Among the nine positive samples, eight were PCR-positive for adenovirus and one for influenza A virus. Our data suggest that bioaerosol sampling could be valuable in monitoring for airborne respiratory viruses in clinical environments to better understand the risk of infection during a hospital visit.

Mycobacterium abscessus Infection During Ustekinumab Treatment in Crohn's Disease: A Case Report and Review of the Literature.

The introduction of ustekinumab, an interleukin [IL]12/23 p40 inhibitor, to the therapeutic armamentarium of Crohn's disease has provided a much needed treatment option for patients who have failed conventional biologics with anti-tumour necrosis factor [TNF] and anti-integrin agents. Despite targeting two major cytokine pathways, the side effect profile of ustekinumab appears to be favourable in clinical trials. In particular, the risk of tuberculosis infection was observed to be lower than in patients who have received anti-TNF agents. The risk of non-tuberculosis mycobacterium infection, however, remains unknown. Here, we report the first case of a patient with Crohn's disease who developed Mycobacterium abscessus infection while on ustekinumab treatment.

A case report of invasive candidiasis and fungal osteomyelitis mimicking oropharyngeal carcinoma recurrence in an immunocompetent patient following transoral robotic surgery.

INTRODUCTION: Transoral robotic surgery(TORS) for the excision of oropharyngeal tumour is increasingly considered for its lower rates of postoperative complications and better functional outcomes. However, we report a case of invasive candidiasis in an immunocompetent patient with previous radiation therapy years ago who underwent TORS recently. CASE PRESENTATION: A 55year old Chinese female with previous radiation therapy for nasopharyngeal carcinoma diagnosed in 1986 underwent wide excision of a newly diagnosed oropharyngeal carcinoma with TORS. From 4 to 8 weeks post-op, an enlarging exophytic lesion at the surgical excision site was noted. Initial biopsy did not show malignancy or fungal organisms. A repeat biopsy under anaesthesia was done as CT imaging showed suspicion of either infective or tumour recurrence. The patient was treated with long term antifungals as final culture results showed invasive candidiasis. The surgical site showed no further lesions 6 months post-op. DISCUSSION: Previous radiation therapy to the oropharyngeal area predisposes a patient to colonization of fungal organisms. Despite TORS showing lower rates of infection, patients who have had previous radiotherapy may be more susceptible to infections as the dissection involves down to the pre-vertebral fascia. Hence, it is appropriate for such patients to have microbiological and fungal cultures performed for a lesion such as this and be treated according to the results of the culture. CONCLUSION: This case serves as a reminder of the risk of invasive candidiasis requiring early investigation and treatment in an immunocompetent patient with prior history of both radiation therapy and recent TORS.

Galactomannan-guided preemptive vs. empirical antifungals in the persistently febrile neutropenic patient: a prospective randomized study.

BACKGROUND: Patients with neutropenic fever after 4-7 days of broad-spectrum antibiotics are given antifungals empirically. This strategy may lead to over-treatment. METHODS: Patients with hematological malignancies undergoing intensive chemotherapy or hematopoietic stem cell transplantation were randomized to two arms. Patients in the 'preemptive' arm had regular galactomannan (GM) assays, and received caspofungin, amphotericin or voriconazole (CAV) for persistent febrile neutropenia if they had two positive GM results, or a positive GM result and a computed tomography (CT) of the thorax suggestive of invasive pulmonary aspergillosis (IPA). Patients in the 'empirical' arm received CAV in accordance with established guidelines. RESULTS: Of 27 episodes in the preemptive arm, two cases of IPA were picked up by monitoring. In six episodes, CAV was started despite persistently negative GM readings. One additional patient received CAV for a false-positive GM. Of 25 episodes in the empirical arm, CAV was started empirically in 10, one of whom had CT features of IPA. By intent-to-treat and evaluable-episode analyses, respectively, the preemptive approach saved 11% and 14% of patients from empirical antifungals. Twelve-week survival was 85.2% in the preemptive arm and 84% in the empirical arm. CONCLUSIONS: A preemptive approach may reduce empirical antifungal use without compromising survival in persistently febrile neutropenic patients.