Experimental Identification of Cross-Reacting IgG Hotspots to Predict Existing Immunity Evasion of SARS-CoV-2 Variants by a New Biotechnological Application of Phage Display

Multiple pathogens are competing against the human immune response, leading to outbreaks that are increasingly difficult to control. For example, the SARS-CoV-2 virus continually evolves, giving rise to new variants. The ability to evade the immune system is a crucial factor contributing to the spread of these variants within the human population. With the continuous emergence of new variants, it is challenging to comprehend all the possible combinations of previous infections, various vaccination types, and potential exposure to new variants in an individual patient. Rather than conducting variant-to-variant comparisons, an efficient approach could involve identifying key protein regions associated with the immune evasion of existing immunity against the virus. In this study, we propose a new biotechnological application of bacteriophages, the phage display platform for experimental identification of regions (linear epitopes) that may function as cross-reacting IgG hotspots in SARS-CoV-2 structural proteins. A total of 34,949 epitopes derived from genomes of all SARS-CoV-2 variants deposited prior to our library design were tested in a single assay. Cross-reacting IgG hotspots are protein regions frequently recognized by cross-reacting antibodies in many variants. The assay facilitated the one-step identification of immunogenic regions of proteins that effectively induced specific IgG in SARS-CoV-2-infected patients. We identified four regions demonstrating both significant immunogenicity and the activity of a cross-reacting IgG hotspot in protein S (located at NTD, RBD, HR1, and HR2/TM domains) and two such regions in protein N (at 197-280 and 358-419 aa positions). This novel method for identifying cross-reacting IgG hotspots holds promise for informing vaccine design and serological diagnostics for COVID-19 and other infectious diseases.

Dynamics of anti-SARS-CoV-2 seroconversion in individual patients and at the population level

The immune response and specific antibody production in COVID-19 are among the key factors that determine both prognostics for individual patients and the global perspective for controlling the pandemics. So called “dark figure”, that is, a part of population that has been infected but not registered by the health care system, make it difficult to estimate herd immunity and to predict pandemic trajectories. Here we present a follow up study of population screening for hidden herd immunity to SARS-CoV-2 in individuals who had never been positively diagnosed against SARS-CoV-2; the first screening was in May 2021, and the follow up in December 2021. We found that specific antibodies targeting SARS-CoV-2 detected in May as the “dark figure” cannot be considered important 7 months later due to their significant drop. On the other hand, among participants who at the first screening were negative for anti-SARS-CoV-2 IgG, and who have never been diagnosed for SARS-CoV-2 infection nor vaccinated, 26% were found positive for anti-SARS-CoV-2 IgG. This can be attributed to of the “dark figure” of the recent, fourth wave of the pandemic that occurred in Poland shortly before the study in December. Participants who were vaccinated between May and December demonstrated however higher levels of antibodies, than those who undergone mild or asymptomatic (thus unregistered) infection. Only 7% of these vaccinated participants demonstrated antibodies that resulted from infection (anti-NCP). The highest levels of protection were observed in the group that had been infected with SARS-CoV-2 before May 2021 and also fully vaccinated between May and December. These observations demonstrate that the hidden fraction of herd immunity is considerable, however its potential to suppress the pandemics is limited, highlighting the key role of vaccinations.

Posterior interosseous nerve neuropathy in distal radius fracture

Background. The anatomy of the posterior interosseous nerve, which lies directly on the periostium of the distal epiphysis of the radius, may predispose to nerve migration between fragments after a fracture. This is especially like to be the case in a comminuted fracture of the distal radius, when the runs in the sagittal plane. Case histories. Based on 2 cases of patients treated for distal radius fracture immediately after trauma and 1 case of correction osteotomy, we describe entrapment of the articular branch of the posterior interosseous nerve was observed (DPIN). All these patients had pain syndrome in the narrow fourth compartment of the extensor, which included EIP and EDC. Our clinical observations are supported by cadaver studies and radiological imaging. Results. Good results were obtained after DPIN neurectomy or neurolysis.

Nitric oxide has no beneficial effects on ion transport defects in cystic fibrosis human nasal epithelium

Nitric oxide (NO) has been reported to activate Cl- secretion via the cystic fibrosis transmembrane conductance regulator (CFTR) and inhibit epithelial Na+ absorption mediated by amiloride-sensitive epithelial Na+ channels (ENaC). These ion transport systems are defective in cystic fibrosis (CF): Cl- secretion by CFTR is impaired and Na+ absorption by ENaC is dramatically increased. By activating CFTR and depressing ENaC, NO is a potentially beneficial therapeutic agent for ion transport defects in human CF respiratory epithelia. To assess the effects of NO on human respiratory epithelial cells, the NO donors sodium nitroprusside (SNP) and spermine NONOate were applied to primary cultured nasal cells, surgically obtained from non-CF and CF patients. Measurements of transepithelial short-circuit current (ISC) showed that NO has no inhibitory potency against amiloride-sensitive nasal ENaC (nENaC) or amiloride-insensitive Na+-absorbing mechanisms in non-CF and CF epithelia. Furthermore, NO had no stimulatory effect on Cl- secretion by CFTR or any other Cl- conductance pathway in either tissue. Although NO elevated the intracellular Ca2+ concentration, we did not detect any activation of Ca2+-dependent Cl- channels. These results demonstrate that NO has no beneficial effect on CF epithelial cells of the upper airways.

[Pathophysiology, diagnosis and therapy of three congenital dacryocystoceles]

BACKGROUND

Congenital dacryocystocele has been rarely described in German literature. Congenital obstruction and distention of the lacrimal sac makes it necessary to differentiate for various causes.

PATIENTS AND METHODS

Three infants had congenital dacryocystocele. The diagnosis was made by sonography and was established by probing the lacrimal duct and nasal endoscopy that showed a white prominent tumor below the lowest conch.

RESULTS

Directly after endonasal and canalicular opening of the dacryocystocele clear liquid with white detritus drained, and the swelling decreased. No further procedure was needed.

CONCLUSION

The diagnosis of dacryocystocele can be made by inspection, probing the lacrimal duct, ultrasound and nasal endoscopy. If probing of the lacrimal duct could not easily open the Hasner's membrane, endonasal opening can be performed. The cooperation with an ear-nose-throat specialist could lead to the diagnosis of dacryocystocele and sufficient treatment without the need for any further radiological examinations.

[Snoring and postoperative pulmonary edema]

After uneventful ENT surgery, two male patients developed acute upper airway obstruction following extubation which progressed into negative pressure pulmonary edema (NPPE). One of these two patients suffered from known obstructive sleep apnoea syndrome, the other admitted to heavy snoring only after the incident. The pathophysiology of NPPE and the anaesthesiological implications of a patient's history of snoring are discussed.

Nicotine-induced endocytosis of amiloride-sensitive sodium channels in human nasal epithelium

In previous studies we developed and introduced a method to examine the transport mechanisms of ions in primary cell cultures of human nasal epithelium. In the current study, substances, especially nicotine, that influence these mechanisms are investigated. Specimens of nasal and paranasal epithelium of patients treated by endonasal surgery because of chronic sinusitis (n = 217) were used as primary cell cultures. Cell cultures of smokers (n = 83) and non-smokers (n = 134) were differentiated. Transepithelial Ussing chamber measurements were performed to examine sodium channel functions and to evaluate the influence of nicotine. These examinations were accompanied by simultaneous continuous capacitance measurements. Whereas transepithelial parameters, such as short-circuit current, (Isc), potential (Vt) and resistance (Rt), in tissues derived from smokers and non-smokers showed no difference, the transepithelial conductance was reduced immediately in cell cultures with apical application of nicotine (2 mM). This decrease was accompanied by a marked reduction of epithelial surface area. In the presence of nicotine, amiloride (100 microM) completely lost its inhibitory capacity. Amiloride-insensitive sodium channels were unaffected by nicotine, as proved by Na+ substitution. Furthermore, the Na+ channel blocker was accompanied by an increase in intracellular Ca2+. We conclude that the nicotine-induced increase in intracellular calcium (Ca2+) has stimulated Ca2+-dependent protein kinase (PKC). PKC promotes endocytosis removing amiloride-sensitive Na+ channels from the cell membrane into the cell by means of vesicular transport.

Inverted papilloma of the nasal cavity and paranasal sinuses: clinical data, surgical strategy and recurrence rates

BACKGROUND

In the last decade inverted papillomas of the nasal cavity and paranasal sinuses have been observed in increasing numbers, and treatment modalities have ranged from extensive open radical procedures to microinvasive endonasal surgical excision.

OBJECTIVE

To establish criteria for selecting patients for open osteoplastic or endonasal surgery according to clearly defined pathological and clinical data.

MATERIAL AND METHOD

In a retrospective study, clinical data of 55 patients treated surgically in the University ENT Clinic Giessen from 1991 to 1998 were analysed. In 33 patients (60%) endonasal excision of the papillomas was carried out and in 22 (40%) osteoplastic lateral rhinotomy or maxillotomy were performed. All histological specimens were revised. Patients were followed up and endoscopically examined until 31 March 1999.

RESULTS

In 22 patients, tumours involving the frontal sinus, maxillary sinus, parts of the frontal skull base and anterior ethmoid, and the orbit were operated on using open osteoplastic procedures, with 4 (18%) recurrences observed. Tumours excised endonasally showed the same recurrence rate: 6 out of 33 (18%). These tumours were smaller in size and localized in the nasal cavity, the middle and posterior parts of the ethmoid involving the sphenoid, and the medio-posterior wall of the maxillary sinus. The functional outcome was excellent for all patients; two patients developed a mucocele. Cancerization was observed in three cases.

CONCLUSIONS

In select cases the endonasal microsurgical approach to inverted papillomas has the same good results concerning function and tumour control as osteoplastic open rhinotomy. This method should still be preferred in tumours localized in the frontal sinus, anterior ethmoid. anterior. caudal and lateral parts of the maxillary sinus and beyond the sinuses.

[Ion transport in nasal and paranasal sinus mucosa in mucoviscidosis and chronic sinusitis]

Cystic fibrosis (CF) is the most commonly inherited disease in Caucasians and is caused by a mutation in the gene encoding a membrane transport protein. This cystic fibrosis transmembrane conductance regulator (CFTR) is thought to be an apical Cl- channel activated by intracellular cAMP. Most recent findings suggest that CFTR is more than a pure Cl- channel and might be involved in the regulation of other transport systems. In the present study we show that CFTR as a Cl- channel plays only a minor role in primary cultured human nasal epithelium derived from non-CF and CF patients. These findings are especially of interest for non-CF human nasal epithelia in which CFTR is correctly inserted. In both tissues Cl- secretion is negligible as compared with Na+ absorption. We confirm and expand our previous observations that Na+ absorption in human nasal epithelium is the dominant ion transport process and that Cl- secretion is detectable in both CF and non-CF tissue. Moreover, we show that cAMP and ATP were not able to stimulate any silent Cl- channels in CF or non-CF human nasal epithelial cells. We further give evidence that in human nasal CF and non-CF epithelium Na+ absorption is mediated by epithelial Na+ channels (ENaC) that are either different from those of other epithelia or which exhibit altered regulation. These differences between Na+ channels of human nasal epithelium and "classical" epithelial Na+ channels include lack of activation by the intracellular second messenger cAMP and the steroid hormone aldosterone. We show further that human nasal Na+ channels are inhibited by Cl- channel blockers and exhibit a different pharmacology towards common Na+ channel blockers.

Histomorphological characteristics of non-metastatic lymph nodes in patients with head and neck cancer according to their site in the neck

The prognostic relevance of histomorphologically defined reaction patterns of lymph nodes was demonstrated in head and neck cancer. Till today the lymph node site in the neck has not been taken into account. Therefore histomorphologically defined reaction patterns of non-metastatic lymph nodes in the neck were examined according to their site in the neck. A total of 1188 dissected neck lymph nodes of 32 previously untreated patients with carcinoma of the head and neck region were examined histologically by serial sections and classified into 6 different lymph node levels and 6 histomorphological types. The objectivity of the morphological examinations could be evaluated morphometrically by means of an interactive image analysis system (IBAS) and a more precise definition of the lymph node reaction types could be established. The results of the morphological and morphometrical classifications show a statistically highly significant relationship (p < 0.0001) between the reaction types of lymph nodes and their site in the neck. These findings allow a division of the neck in an upper anterior half with immunologically active lymph nodes and a lower caudal-dorsal half, which contains essentially less immunologically active lymph nodes.