Mark Daniel Hicar

This retrospective observational cohort study evaluated acute illness predictors of pediatric Long coronavirus disease 2019 in Jamaica. Poisson regression modeling associated acute univariate symptoms of vomiting, abdominal pain, ageusia, anosmia, fatigue, confusion, brain fog, and multisystem inflammatory syndrome in children and multivariable composite predictors of multisystem inflammatory syndrome in children, vomiting and ageusia. The 47.3% incidence supports the need for improvements in similar resource-constrained settings.

Withdrawal statement: The authors have withdrawn their manuscript because it was posted without the consent of all individuals listed in the acknowledgements. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please refer to the resubmission of this article, or please contact the corresponding author.

Current HIV vaccine strategies are hampered by difficulty with recapitulating heavily mutated broadly neutralizing antibodies. We have previously isolated a highly mutated antibody termed “group C 76-Q13-6F5” (6F5) that uses immunoglobulin heavy chain variable region (VH)1-02. 6F5 targets a conformational epitope on HIV gp41 and mediates Ab-dependent cell cytotoxicity (ADCC). Reverting the group C 76 antibodies’ variable chain to VH1-02 germline in antibody 76Canc showed retained ADCC activity. A vaccine targeting an epitope functionally recognized by germline antibodies offers a distinct advantage. Due to the 76Canc germline antibody ability to retain anti-HIV function, we sought to identify a protein target that could form the basis of a vaccine. 76Canc specifically recognized a number of acidic peptides on a microarray containing 29,127 linear peptides. Meme analysis identified a peptide sequence similar to a non-structural protein of Hepacivirus previously implicated in Kawasaki disease (KD). Binding was confirmed to significant peptides, including the Hepacivirus -related and KD-related peptide. On serum competition studies using samples from children with KD compared to controls, targeting of this epitope showed no specific correlation to the clinical syndrome of KD. Yeast-displayed human protein microarray autoantigen screening was also reassuring. This study identifies a peptide that can mimic the gp41 epitope targeted by 76C group antibodies (i.e., a mimotope). We show little risk of autoimmune targeting inclusive of inflammation similar to KD, implying non-specific humoral immunity targeting of similar peptides during KD. Development of an HIV vaccine based on such peptides should proceed, but with continued caution. IMPORTANCE: The development of protective HIV vaccines continues to remain a significant challenge. Many of the broadly neutralizing antibodies require a significant number of mutations, suggesting that traditional vaccines will not be able to recapitulate these types of responses. We have discovered an antibody that has Ab dependent cell cytotoxicity (ADCC) activity against HIV even when mutating the heavy chain of that antibody to germline. As a potential target for vaccines, this offers a distinct advantage: a few immunizations should directly stimulate B cells harboring those specific germline variable chains for expansion. This study sought to identify potential peptide targets that could be formulated into such a vaccine. We identified a peptide that both germline and mature antibodies can recognize. Initial autoantigen screens and consideration of inflammatory disorders suggest this identified antigen is a feasible approach to move forward into pre-clinical models.

Rarely, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will lead to myocarditis associated with multisystem inflammatory syndrome in children (MIS-C). It remains unclear why MIS-C only targets specific children. To explore an association between coxsackievirus infections with MIS-C, we investigated the sero-epidemiology of CV in admitted pediatric patients in relation to the pandemic. This retrospective case–control study was performed by chart review of children (age ≤21 years) admitted to a tertiary care hospital with CV serological testing from January 2017 to August 2023. Clinical, laboratory, and imaging findings were used to classify patients as MIS-C and CV-unlikely or CV-possible for non-MIS-C patients. Out of 182 admissions (179 patients, median age, 6), CVB complement fixation (CF) assay on serotypes B1–B6 and CVA immunofluorescence assay IgG on serotypes A7, A9, A16, and A24 were positive in at least one serotype in 59.2% and 80.7% of cases, respectively. We observed a significant drop in CVB CF seropositivity during the peak of social distancing in 2020. The likelihood of elevated CVB CF titers was significantly higher in MIS-C than the CV-unlikely group (OR: 1.92, 95% CI: 1.02–3.63, P : 0.04) and showed a trend toward higher values in African Americans than Whites (OR: 1.57, 95% CI: 0.98–2.50, P : 0.057). The frequency of MIS-C was considerably higher in African Americans than Whites (18.1% versus 9%, P : 0.1). A higher likelihood of elevated CVB CF titers in patients with MIS-C compared with those unlikely to have acute CV infection along with a relatively higher frequency of MIS-C in African Americans warrants further investigation into the role of CVB infection in MIS-C development. IMPORTANCE: The emergence of multisystem inflammatory syndrome in children (MIS-C) during the SARS-CoV-2 pandemic raised major concerns in providers caring for children. This condition presents a hyper-inflammation state that can lead to severe complications, including myocarditis and cardiogenic shock. The pathogenesis of MIS-C has not been fully understood. Understanding the pathogenesis of this condition is not only important for developing effective treatments but also for applying preventive strategies. A two-hit hypothesis leading to MIS-C has been proposed. Coxsackievirus infections are prevalent during childhood and can also cause myocarditis, and coxsackievirus B specifically has been shown to cause persistent RNA presence in host cells, leading to continued inflammation. Herein, we show that elevated coxsackievirus B titers are associated with MIS-C cases, implying a role of successive infections with these viruses contributing to such a hyperinflammatory state. This study supports the need for larger investigations into this association.

Autoimmune pediatric neurologic diseases have variable phenotypes and presentations, making diagnosis challenging. The pathologic mechanisms are also distinct, including cell-mediated and Ab-mediated autoimmunity, paraneoplastic syndromes, and postinfectious processes. In recent years a number of studies have described the characteristics of the autoantibodies involved in a number of these diseases. Some of the described Abs use a restricted set of variable gene segments. We sought to compare the Ab characteristics of autoantibodies related to some of the more common disorders to discover whether specific Ab signatures are universally associated with neuroautoimmune diseases. We initially performed a literature review to summarize the Ab characteristics of autoantibodies related to some of the more common disorders, including N-methyl-d-aspartate receptor (NMDAR) and leucine-rich, glioma-inactivated 1 (LGI-1). Next, we performed data analysis from selected studies that sequenced Ig genes to further characterize NMDAR and LGI-1 autoantibodies including CDR3 length distribution, variable gene sequence usage, and isotype use. We found that CDR3 length of NMDAR autoantibodies was normally distributed whereas the CDR3 length distribution of LGI-1 autoantibodies was skewed, suggesting that there is no global structural restriction on types of autoantibodies that can cause encephalitis. We also found that IgG1–IgG3 were the main NMDAR autoantibody isotypes detected, while IgG4 was the major isotype used in autoantibodies from LGI-1 encephalitis. These findings are useful for our understanding of autoimmune encephalitis and will help facilitate better diagnosis and treatment of these conditions in the future.

Background: We have previously isolated a highly mutated VH1-02 antibody termed group C 76-Q13-6F5 (6F5) that targets a conformational epitope on gp41. 6F5 has the capacity to mediate Ab dependent cell cytotoxicity (ADCC). When the VH1-02 group C 76 antibodies variable chain sequence was reverted to germline (76Canc), this still retained ADCC activity. Due to this ability for the 76Canc germline antibody to functionally target this epitope, we sought to identify a protein target for vaccine development. Methods: Initially, we interrogated peptide targeting by screening a microarray containing 29,127 linear peptides. Western blot and ELISAs were used to confirm binding and explore human serum targeting. Autoimmune targeting was further interrogated on a yeast-displayed human protein microarray. Results: 76Canc specifically recognized a number of acidic peptides. Meme analysis identified a peptide sequence similar to a non-structural protein of Hepacivirus previously implicated in Kawasaki disease (KD). Binding was confirmed to top peptides, including the Hepacivirus -related and KD-related peptide. On serum competitions studies using samples from children with KD compared to controls, targeting of this epitope showed no specific correlation to having KD. Human protein autoantigen screening was also reassuring. Conclusions: This study identifies a peptide that can mimic the gp41 epitope targeted by 76C group antibodies ( i.e. a mimotope). We show little risk of autoimmune targeting including any inflammation similar to KD, implying non-specific targeting of this peptide during KD. Development of such peptides as the basis for vaccination should proceed cautiously.

Coxsackieviruses (CVs) are common causes of infections and can be life-threatening. Unfortunately, rigorous studies guiding the clinician in interpreting CV serum antibody titer testing is lacking. To explore the epidemiology of circulating CVs and the serological test utility in aiding diagnosis of CV infections in our community, we obtained results of CV immunologic diagnostic tests between 2018 and 2022 from a regional healthcare database. For CV type A, rare individuals had positive CF (complement fixation) tests whereas all 16 individuals with IFA testing showed at least one positive serotype. For CV type B CF testing, 52.2% of 222 patients had at least one serotype positive, with B5 being most common and also the most common with higher titers (14.8% with ≥1:32). We found a significant reduction in seropositivity rate during the pandemic in 2020 compared to 2018, which continued through 2022 (OR: 0.2, 95% CI: 0.08–0.49, p-value < 0.001). During the pandemic, the seasonal pattern of positive tests varied from the pre-pandemic pattern. Testing for CVs was increased after the first year of the pandemic. Overall, the variability by month and seasonal change in our data support that CF testing can be used to identify recent CVB infection.

We have previously isolated a highly mutated (83% homologous to predicted heavy chain germline) antibody (Ab) termed C group 76-Q13-6F5 (6F5) that targets a conformational epitope on gp41. 6F5, though non-neutralizing, has the capacity to mediate Ab dependent cell cytotoxicity (ADCC). When the variable chain (predicted to be VH1-02 derived) was mutated to germline (termed C group 76 ancestor, or 76Canc), surprisingly this Ab still exhibited significant ADCC activity. Many HIV vaccine strategies are focused on raising highly mutated Abs. We propose that there would be an advantage to developing vaccines related to epitopes that permit functional targeting by Abs using germline variable gene sequences. To explore potential protein targets for vaccination strategies to raise and develop such Abs, we interrogated a peptide array of 29,127 linear peptides using PEPperCHIP® Human Epitome Microarray. We then confirmed peptide binding by Western blot and ELISAs. We also assessed binding to CDI laboratories HuProt protein microarray, containing > 21,000 human proteins. HIV-1 gp41 antibodies recognize peptides similar to peptide implicated in Kawasaki Disease This study reveals acidic motif targeting by specific anti-gp41 Abs and the derived germline Ab, but no evidence that these Abs are related to inflammation similar to KD. Cautious development of targeting such Abs by vaccination is warranted. Future structural comparison of these peptides with native proteins and binding competition studies are needed to confirm mimotope binding. Mark D. Hicar, MD/PhD, Pfizer: site investigator for 2 trial