Potential Antigenic Cross-reactivity Between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Dengue Viruses.

BACKGROUND: Coronavirus disease 2019 (COVID-19) and dengue fever are difficult to distinguish given shared clinical and laboratory features. Failing to consider COVID-19 due to false-positive dengue serology can have serious implications. We aimed to assess this possible cross-reactivity. METHODS: We analyzed clinical data and serum samples from 55 individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To assess dengue serology status, we used dengue-specific antibodies by means of lateral-flow rapid test, as well as enzyme-linked immunosorbent assay (ELISA). Additionally, we tested SARS-CoV-2 serology status in patients with dengue and performed in-silico protein structural analysis to identify epitope similarities. RESULTS: Using the dengue lateral-flow rapid test we detected 12 positive cases out of the 55 (21.8%) COVID-19 patients versus zero positive cases in a control group of 70 healthy individuals (P = 2.5E-5). This includes 9 cases of positive immunoglobulin M (IgM), 2 cases of positive immunoglobulin G (IgG), and 1 case of positive IgM as well as IgG antibodies. ELISA testing for dengue was positive in 2 additional subjects using envelope protein directed antibodies. Out of 95 samples obtained from patients diagnosed with dengue before September 2019, SARS-CoV-2 serology targeting the S protein was positive/equivocal in 21 (22%) (16 IgA, 5 IgG) versus 4 positives/equivocal in 102 controls (4%) (P = 1.6E-4). Subsequent in-silico analysis revealed possible similarities between SARS-CoV-2 epitopes in the HR2 domain of the spike protein and the dengue envelope protein. CONCLUSIONS: Our findings support possible cross-reactivity between dengue virus and SARS-CoV-2, which can lead to false-positive dengue serology among COVID-19 patients and vice versa. This can have serious consequences for both patient care and public health.

Clinical efficacy of CFTR modulator therapy in people with cystic fibrosis carrying the I1234V mutation.

BACKGROUND: The cystic fibrosis transmembrane conductance regulator (CFTR) mutation I1234V (I1234V, p.Ile1234Val, c.3700A>G), is a missense-mutation that creates a cryptic splice site, with the formation of a protein lacking 6 amino acids, that is misfolded and misprocessed. The in vitro effects of CFTR modulator (CFTRm) therapies on human bronchial cell models and intestinal organoids carrying this mutation are conflicting. The aim of this study was therefore to explore the clinical efficacy of CFTRm in people with cystic fibrosis (pwCF) carrying this mutation. METHODS: This was a retrospective descriptive study of the clinical records of homozygous and compound heterozygous (none F508del) pwCF, for the I1234V mutation, that received CFTRm. Parameters explored were body mass index (BMI), forced expiratory volume in one second percent predicted (FEV1%), lung clearance index (LCI) and quantitative sweat chloride measurements. RESULTS: Mean age was 38.6 ± 14 years (range 21-60). Two subjects were homozygous and five compound heterozygous, with minimal function mutations. Four were pancreatic insufficient and three pancreatic sufficient. The two homozygous subjects received Tezacaftor/Ivacaftor, the remaining Elexacaftor/Tezacaftor/Ivacaftor (ETI); treatment ranged from 6 to 12 months. Mean BMI score increased from 21.7 ± 1.3 to 23.6 ± 2.1 kg/m2 (p = 0.04); FEV1(%pred) increased by 20.14±10.2while mean change in FEV1 in the year prior to CFTRm initiation was -0.14±1.18 (p = 0.0001). Additionally, LCI 2.5% decreased from 18.7 to 14.5 (p = 0.07); sweat chloride decreased from 116±10 to 90±17 mEq/L (p = 0.017) and chronic pseudomonas airway infection was eradicated in one subject. CONCLUSIONS: This study supports a clinical benefit for CFTRm therapy in pwCF carrying the I1234V mutation.

Phenotypic and molecular characteristics of CF patients carrying the I1234V mutation.

BACKGROUND: The Mutation I1234V is a CF causing mutation; however the mechanisms leading to loss of function are not fully understood. In this study, we aimed to characterize phenotypically individuals with the I1234V variant, and to gain a structural point of view of the mutant CFTR using computational studies. METHODS: We conducted a retrospective descriptive study, reviewing the clinical records of 9 Israeli patients. The study was designed to include patients either homozygous or compound heterozygous for the I1234V mutation. For a comparison we analyzed clinical data of 12 patients homozygous for the F508del mutation. Computer models were constructed for I1234V, 1234-1239del and wild type CFTR. RESULTS: Mean FEV1 was 73.8 ± 21% predicted with an average annual rate of decline of 1%. When compared to patients homozygous for F508del the mean annual values of FEV1% predicted during the 6 years of data collection ranged from 51 to 58 ± 22-30 in the F508del group versus 76-82 ± 14-19 in the I1234V group (p < 0.05). Structural models did not demonstrate noticeable differences between the three simulated constructs. Although the mutation resides in the NBD2, no interference with ATP binding was detected. DISCUSSION: This study describes phenotypically patients carrying the I1234V mutation. Compared to patients homozygous for F508del, these patients present with more favorable outcome. Structural models show high similarity between the static and dynamics pictures obtained for both the mutated and the WT-CFTR; however this model does not explore the folding process and therefore may strengthen the notion of a misfolding mutation.