Viral persistence in vivo through selection of neutralizing antibody-escape variants

Despite initial virus control by CD8(+) cytotoxic T lymphocytes (CTLs), noncytopathic or variably cytopathic viruses (e.g., hepatitis B and C viruses, HIV) are able to establish persistent infections. The role of neutralizing antibodies (nAbs) in controlling disease progression is unclear. Therefore, the phenomenon of viral evasion from the nAb response and its implications for virus persistence remain controversial. Here we demonstrate nAb-mediated viral clearance in CTL-deficient mice infected with the prototypic noncytopathic lymphocytic choriomeningitis virus (strain WE). During prolonged CTL absence, neutralization-resistant virus mutants were selected in individual mice within 70-90 days. In naive animals infected with these virus variants only low nAb responses were induced, resulting in an increased tendency of virus to persist.

Which subgroup of patients with rheumatoid arthritis benefits from switching to rituximab versus alternative anti-tumour necrosis factor (TNF) agents after previous failure of an anti-TNF agent?

BACKGROUND

Patients with rheumatoid arthritis (RA) with an inadequate response to TNF antagonists (aTNFs) may switch to an alternative aTNF or start treatment from a different class of drugs, such as rituximab (RTX). It remains unclear in which clinical settings these therapeutic strategies offer most benefit.

OBJECTIVE

To analyse the effectiveness of RTX versus alternative aTNFs on RA disease activity in different subgroups of patients.

METHODS

A prospective cohort study of patients with RA who discontinued at least one aTNF and subsequently received either RTX or an alternative aTNF, nested within the Swiss RA registry (SCQM-RA) was carried out. The primary outcome, longitudinal improvement in 28-joint count Disease Activity Score (DAS28), was analysed using multivariate regression models for longitudinal data and adjusted for potential confounders.

RESULTS

Of the 318 patients with RA included; 155 received RTX and 163 received an alternative aTNF. The relative benefit of RTX varied with the type of prior aTNF failure: when the motive for switching was ineffectiveness to previous aTNFs, the longitudinal improvement in DAS28 was significantly better with RTX than with an alternative aTNF (p = 0.03; at 6 months, -1.34 (95% CI -1.54 to -1.15) vs -0.93 (95% CI -1.28 to -0.59), respectively). When the motive for switching was other causes, the longitudinal improvement in DAS28 was similar for RTX and alternative aTNFs (p = 0.40). These results were not significantly modified by the number of previous aTNF failures, the type of aTNF switches, or the presence of co-treatment with a disease-modifying antirheumatic drug.

CONCLUSION

This observational study suggests that in patients with RA who have stopped a previous aTNF treatment because of ineffectiveness changing to RTX is more effective than switching to an alternative aTNF.

Persistence of lymphocytic choriomeningitis virus at very low levels in immune mice

Lymphocytic choriomeningitis virus (LCMV), strain WE, is a non-cytopathic RNA virus that is highly adapted to its natural host, the mouse. Acute infection of adult mice leads to generalized virus spread, followed by cytotoxic T lymphocyte-mediated virus clearance below the detection levels of conventional assays within 2-3 weeks. Indirect evidence had suggested that virus or viral antigen might persist in the immune mouse. Here we demonstrate LCMV-WE persistence at low levels after infection with 10(2) or 10(6) plaque-forming units, shown as viral genome, viral antigen, and replicative virus using sensitive in vitro and in vivo assays. The finding that LCMV-WE persists in the face of apparently intact immune responses resembles the situation in some viral (hepatitis B and C, HIV) and bacterial (tuberculosis, leprosy) infections in humans; the results are relevant to the understanding not only of other murine and human persistent viral infections but also of protective immunological memory by "infection immunity."

Impairment of CD4(+) T cell responses during chronic virus infection prevents neutralizing antibody responses against virus escape mutants

We have shown previously that neutralizing antibodies (nAbs) are important contributors to the long-term immune control of lymphocytic choriomeningitis virus infection, particularly if cytotoxic T cell responses are low or absent. Nevertheless, virus escape from the nAb response due to mutations within the surface glycoprotein gene may subsequently allow the virus to persist. Here we show that most of the antibody-escape viral mutants retain their immunogenicity. We present evidence that the failure of the infected host to mount effective humoral responses against emerging neutralization-escape mutants correlates with the rapid loss of CD4(+) T cell responsiveness during the establishment of viral persistence. Similar mechanisms may contribute to the persistence of some human pathogens such as hepatitis B and C viruses, and human immunodeficiency virus.

Neutralizing antiviral antibody responses

Neutralizing antibodies are evolutionarily important effectors of immunity against viruses. Their evaluation has revealed a number of basic insights into specificity, rules of reactivity (tolerance), and memory—namely, (1) Specificity of neutralizing antibodies is defined by their capacity to distinguish between virus serotypes; (2) B cell reactivity is determined by antigen structure, concentration, and time of availability in secondary lymphoid organs; and (3) B cell memory is provided by elevated protective antibody titers in serum that are depending on antigen stimulation. These perhaps slightly overstated rules are simple, correlate with in vivo evidence as well as clinical observations, and appear to largely demystify many speculations about antibodies and B cell physiology. The chapter also considers successful vaccines and compares them with those infectious diseases where efficient protective vaccines are lacking, it is striking to note that all successful vaccines induce high levels of neutralizing antibodies (nAbs) that are both necessary and sufficient to protect the host from disease. Successful vaccination against infectious diseases such as tuberculosis, leprosy, or HIV would require induction of additional long-lasting T cell responses to control infection.

Correlation of T cell independence of antibody responses with antigen dose reaching secondary lymphoid organs: implications for splenectomized patients and vaccine design

Many natural viral and bacterial pathogens activate B cells independently of Th cells (TI Ags). This study analyzed the characteristics of the activation of B cells after immunization with various forms of viral Ags using different immunization routes and found a decreasing dependence on T help with increasing amounts of Ag recruited to the spleen. Repetitive antigenic structure facilitated TI B cell responses if Ag was present in lymphoid organs. These results suggest that 1) Ag dose and localization in secondary lymphoid organs are the key for B cell activation in the absence of T help; 2) early TI Ab responses are crucial to protect against systemically spreading acute cytopathic infectious agents; and 3) there may be new rationales for improved vaccine design.

A comparison of T cell memory against the same antigen induced by virus versus intracellular bacteria

Cytotoxic T cell (CTL) memory was analyzed after infection with lymphocytic choriomeningitis virus (LCMV) and recombinant Listeria monocytogenes (rLM) expressing the complete nucleoprotein of LCMV (rLM-NP(actA)) or only the immunodominant epitope of H-2(d) mice (rLM-NP(118-126)). Immunization with LCMV and rLM induced a long-lived increased CTL precursor (CTLp) frequency specific for the viral (NP(118-126)) and for the bacterial (LLO(91-99)) epitope, respectively. However, after infection with rLM memory, CTLs were less protective against an intravenous LCMV challenge infection than a comparable number of LCMV-induced memory T cells. LCMV, but not recombinant Listeria-induced memory T cells were able to protect against lethal choriomeningitis by LCMV or a subsequent peripheral infection with recombinant vaccinia virus expressing LCMV-NP. The protective memory after viral and after rLM immunization was paralleled by evidence of LCMV but not rLM antigen persistence on day 15 and 30 after vaccination. These results document a striking difference in protective T cell memory between viral and bacterial vaccines and indicate that rapid T cell-dependent immune protection correlates with antigen persistence.

CD4+ T-cell-epitope escape mutant virus selected in vivo

Mutations in viral genomes that affect T-cell-receptor recognition by CD8+ cytotoxic T lymphocytes have been shown to allow viral evasion from immune surveillance during persistent viral infections. Although CD4+ T-helper cells are crucially involved in the maintenance of effective cytotoxic T-lymphocyte and neutralizing-antibody responses, their role in viral clearance and therefore in imposing similar selective pressures on the virus is unclear. We show here that transgenic virus-specific CD4+ Tcells, transferred into mice persistently infected with lymphocytic choriomeningitis virus, select for T-helper epitope mutant viruses that are not recognized. Together with the observed antigenic variation of the same T-helper epitope during polyclonal CD4+ T-cell responses in infected pore-forming protein-deficient C57BL/6 mice, this finding indicates that viral escape from CD4+ T lymphocytes is a possible mechanism of virus persistence.

Comparative effectiveness of antitumour necrosis factor agents, biologics with an alternative mode of action and tofacitinib in an observational cohort of patients with rheumatoid arthritis in Switzerland

Background

Multiple biologic and targeted synthetic disease-modifying rheumatic drugs (b/tsDMARDs) are approved for the management of rheumatoid arthritis (RA), including TNF inhibitors (TNFi), bDMARDs with other modes of action (bDMARD-OMA) and Janus kinase inhibitors (JAKi). Combination of b/tsDMARDs with conventional synthetic DMARDs (csDMARDs) is recommended, yet monotherapy is common in practice.

Objective

To compare drug maintenance and clinical effectiveness of three alternative treatment options for RA management.

Methods

This observational cohort study was nested within the Swiss RA Registry. TNFi, bDMARD-OMA (abatacept or anti-IL6 agents) or the JAKi tofacitinib (Tofa) initiated in adult RA patients were included. The primary outcome was overall drug retention. We further analysed secondary effectiveness outcomes and whether concomitant csDMARDs modified effectiveness, adjusting for potential confounding factors.

Results

4023 treatment courses of 2600 patients were included, 1862 on TNFi, 1355 on bDMARD-OMA and 806 on Tofa. TNFi was more frequently used as a first b/tsDMARDs, at a younger age and with shorter disease duration. Overall drug maintenance was significantly lower with TNFi compared with Tofa [HR 1.29 (95% CI 1.14 to 1.47)], but similar between bDMARD-OMA and Tofa [HR 1.09 (95% CI 0.96 to 1.24)]. TNFi maintenance was decreased when prescribed without concomitant csDMARDs [HR: 1.27 (95% CI 1.08 to 1.49)], while no difference was observed for bDMARD-OMA or Tofa maintenance with respect to concomitant csDMARDs.

Conclusion

Tofa drug maintenance was comparable with bDMARDs-OMA and somewhat higher than TNFi. Concomitant csDMARDs appear to be required for optimal effectiveness of TNFi, but not for bDMARD-OMA or Tofa.

Viral escape from the neutralizing antibody response: the lymphocytic choriomeningitis virus model

In addition to CD8+ cytotoxic T lymphocyte (CTL) responses, neutralizing antibodies contribute substantially to the long-term immune control of noncytopathic viruses, as demonstrated during infection with the lymphocytic choriomeningitis virus (LCMV). The high virus load during the initial phase of an infection and the ability of this RNA virus to spontaneously acquire mutations are important prerequisites for escaping an ongoing immune response. In this context, LCMV escape from the humoral response by single point mutations in neutralizing envelope protein determinants may occur, particularly during conditions of CTL deficiency, leading to virus persistence.

[Evidence-based therapy of Raynaud's syndrome]

Raynaud's syndrome has a prevalence of 3-5% in the general population. Despite its high frequency, the majority of available therapies have not been validated in randomized controlled trials. Effective therapies with a high level of evidence include the calcium channel blocker nifedipine. As analyzed by meta-analyses, nifedipine showed improvement of the peripheral circulation, as well as reduction of both the intensity and frequency of attacks in patients with primary and secondary Raynaud's syndrome as compared to placebo. Similar results in a metaanalysis were obtained for intravenous infusions of iloprost in patients with secondary Raynaud's phenomenon associated with systemic sclerosis. In addition, intravenous infusions of iloprost improved healing of fingertip ulcers in patients with systemic sclerosis. Therapies with significant effects in single randomized controlled trials include angiotensin II-receptor type 1 antagonists (losartan), the calcium channel blockers felodipine und amlodipine, serotonin-reuptake-inhibitors (fluoxetine) und phosphodiesterase-V-inhibitors (sildenafil, vardenafil). However, the results for these promising substances have to be confirmed in long-term trials with larger patient numbers.

Synthesis and anti-HIV activity of [d4U]-[trovirdine analogue] and [d4T]-[trovirdine analogue] heterodimers as inhibitors of HIV-1 reverse transcriptase

A series of eleven heterodimers containing both a nucleoside analogue (d4U, d4T) and a non-nucleoside type inhibitor (Trovirdine analogue) were synthesized and evaluated for their ability to inhibit HIV replication. Unfortunately, the (N-3)d4U-Trovirdine conjugates (9a-e) and (N-3)d4T-Trovirdine conjugates (10a-f) were found to be inactive suggesting that the two individual inhibitor compounds do not bind simultaneously in their respective sites.

Synthesis and antiviral activity of C-5 substituted analogues of d4T bearing methylamino- or methyldiamino-linker arms

A general strategy is reported for the preparation of C-5-methylamino- or methyldiamino-d4T analogues of "different sizes". Reactions of the 2',3'-didehydro-2',3'-dideoxy-C-5 hydroxymethyl precursor (7) with either polymethylene diamines (n = 6, 8, 10 and 12) or propargylamine proceed regioselectively via substitution reactions at the C-5 position of uracil. The compounds were evaluated for antiviral activity and cytotoxicity. No significant activity was observed for compounds 9, 11, and 13, but 10 and 12 exhibited a weak activity against HIV-1.

Synthesis of 5-alkenylated D4T analogues via the Pd-catalyzed cross-coupling reaction

The target compounds 5-[N-(6-amino-hexyl)-acrylamide]-2',3'-didehydro-2',3'-dideoxy-uridine (12) and 5-[N-[5-(methoxycarbonyl)-pentyl]-acrylamide]-2',3'-didehydro-2',3'- dideoxy-uridine (15) were prepared by the palladium acetate-triphenylphosphine-catalyzed reaction of the 5'-O-acetyl-5-iodo-d4T analogue (3). These compounds 12 and 15 can be used to prepare nucleotide probes carrying fluorescent labels and were nevertheless screened for their anti-HIV activity. The biological data demonstrated that none of them were active against HIV-1.

Long-term immunogenicity after yellow fever vaccination in immunosuppressed and healthy individuals

BACKGROUND

The live-attenuated yellow fever vaccine (YFV) is generally contraindicated in immunosuppressed patients. Our aim was to investigate if immunosuppressive therapy impairs the long-term protection against yellow fever virus in patients who had received YFV prior to the start of their immunosuppressive therapy.

METHODS

Our study examined 35 healthy individuals and 40 immunosuppressed patients with autoimmune diseases or organ transplants. All individuals had received YFV prior to the onset of their immunosuppression. We analysed the long-term influence of the immunosuppressive therapy on the YFV protective immunity by measuring neutralising antibodies (NA) with the Plaque Reduction Neutralisation Test (PRNT). We assessed risk factors for a negative PRNT result (titre below 1: 10) and their influence on the magnitude of the NA.

RESULTS

A median time interval of 21.1 years (interquartile range 14.4-31.3 years) after the YFV in all patients, a total of 35 immunosuppressed patients (88%) were seropositive (PRNT ≥ 1:10) compared to 31 patients (89%) in the control group. The geometric mean titres of NA did not differ between the groups. The duration of an underlying rheumatic disease was the only risk factor found for a lower magnitude of NA. An insufficient level of NA was found in nine subjects (12%) who had received a single dose of YFV (in one subject, the number of YFV doses was unknown).

CONCLUSION

The use of an immunosuppressive drug started after the administration of the YFV did not affect long-term persistence of NA. A second dose of YFV may be necessary to secure long-term immunity.

Relationship between preterm birth and post-partum periodontal maternal status: a hospital-based Romanian study

PURPOSE

This cross-sectional case-control study of post-partum women aimed to estimate whether maternal periodontitis was a predictive contributor to preterm birth and to identify other risk factors associated with preterm birth in our target population.

METHODS

The case group included women who delivered preterm (74 cases) and the control group included women who had a normal term delivery (120 controls). Medical records, a 16-item questionnaire, and a full-mouth periodontal examination were used to collect information about socio-demographic characteristics, general health problems, birth-related information, behavioral factors and periodontal status. Logistic regression analysis was used to estimate the strength of the relationship between predictors and the categorical outcome variable, preterm birth.

RESULTS

The bivariate analysis revealed the significant associations between preterm birth and socio-demographic factors (educational level, p = 0.003), antepartum smoking habit (p = 0.001) and birth weight lower than 2500 g (p < 0.001). The multivariate analysis highlighted that the presence of post-partum maternal periodontitis and its severity remained independent risk factors of preterm birth in the presence of antepartum smoking habit and route of delivery [adjusted OR 2.26, 95% CI (1.06; 4.82), respectively, OR 3.46, 95% CI (1.08; 11.15)].

CONCLUSION

Post-partum maternal periodontal disease and its severity might, in part, be considered as contributor to preterm deliveries before 37 weeks of gestation.

Synthesis and antiviral activity of C-5 substituted beta-D- and beta-L-D4T analogues

A series of beta-D-2',3'-didehydro-2',3'-dideoxy-nucleosides bearing a tether attached at the C-5 position and their beta-L-counterparts was synthesized. Their inhibitory activities against human immunodeficiency virus (HIV) were investigated and compared to establish relationship(s) between compound structure and their antiviral activity. No significant activity was observed for beta-D- and beta-L-modified nucleosides respectively 7a-c and 14a-c, but 7d and 14d exhibited a weak activity against HIV-1.

Synthesis of 5-alkynylated d4T Analogues as Potential HIV-1 Reverse Transcriptase Inhibitors

A series of 2',3'-didehydro-2',3'-dideoxynucleosides substituted with an alkynylhydroxy- (6, 7, 12 and 13) and alkynylamino- (20) groups at the C-5 position were synthesized. All these five target modified nucleosides were tested for anti-human immunodeficiency virus type 1 activity in CEM-SS and MT-4 cells and unfortunately displayed no improvement in antiviral activity.

Treatment overview of axial spondyloarthritis in 2023

The treatment of patients with axial spondyloarthritis (axSpA) is characterized by non-pharmacological and pharmacological treatment options. It may depend on the type and extent of musculoskeletal and extramusculoskeletal manifestations. Recent data on non-pharmacological treatment options, such as physical activity, physiotherapy, and modification of lifestyle factors, are summarized in this review. Moreover, we have provided an overview on non-steroidal anti-inflammatory drugs and the ever-expanding number of biological and targeted synthetic disease-modifying antirheumatic drugs (bDMARDs and tsDMARDs, respectively). In addition to data on efficacy and safety, the review also encompasses data on switching/cycling, tapering, and treatment selection for specific patient subgroups to optimize treatment outcomes.

Self-reported and clinical periodontal conditions in a group of Eastern European postpartum women

Periodontitis is a highly prevalent condition leading to a continuous destruction of tooth-supporting tissues. It increases the risk for various systemic diseases and adverse pregnancy outcomes. Therefore, screening for periodontitis is important. Screening measures can range from self-reported symptoms to clinical full-mouth periodontal examination. The hypothesis of our study was that self-reported parameters and clinical definition perform equally well in identifying periodontitis patients. The aim of this study was to develop, validate its internal consistency, and evaluate a self-reported instrument against periodontal clinical evaluation for diagnosis of periodontitis in a group of postpartum women, as well as to describe their periodontal status and the risk factors associated with periodontal disease. A cross-sectional study on postpartum women was conducted in a tertiary university hospital, from April 2018 to March 2019. Sociodemographic and behavioral data, periodontal clinical parameters, and self-reported periodontal perception were collected. A 16-item questionnaire was developed to obtain information about perceived periodontal alterations and oral hygiene habits. The utility of the questionnaire was tested against a periodontal diagnosis based on a full-mouth periodontal examination. The questionnaire was applied in 215 postpartum women aged 29.16±5.54 years (mean age (y) ± standard deviation) having the following periodontal status: 16 individuals without periodontal disease (7.44%), 32 individuals with gingivitis (14.88%), 19 individuals with mild periodontitis (8.84%), 132 individuals with moderate periodontitis (61.39%), and 16 individuals with severe periodontitis (7.44%). A significant association was observed between oral hygiene score, smoking status, and periodontal conditions (p<0.05). A significant association between the self-reported items related to “gum swelling”, “halitosis”, “previous periodontal diagnosis” and “previous periodontal treatment” with clinical periodontitis have been identified (p<0.05). Using self-reported questionnaires for detection of periodontal disease was ineffective in our studied population, since self-reported parameters and clinical definition do not appear to perform equally in identifying periodontitis cases. Clinical periodontal examination remains the gold standard for screening. Periodontitis was frequent in our group and the severity was significantly associated with the oral hygiene score and smoking. These results underline the necessity for periodontal clinical examination during pregnancy.

Synthesis of novel C-5 substituted d4T analogues bearing linker arms as potential anti-HIV agents

This work reports the synthesis of 2',3'-didehydro-2',3'-dideoxy-thymidine analogues bearing several kinds of amino-linker arms at the C-5 position of the pyrimidine moiety. C-5 is an attractive position since a flexible chain may permit the triphosphates to be generated. The beta-D- and beta-L-d4T analogues were synthesized following a multi-step reaction from D-ribose and D-xylose, from D- and L-arabinose (towards an oxazoline ring) or from uridine and then were reacted with alkylene diamines.

A Local Desiccant Antimicrobial Agent as an Alternative to Adjunctive Antibiotics in the Treatment of Periodontitis: A Narrative Review

Periodontitis is one of the most common oral polymicrobial infectious diseases induced by the complex interplay between the altered subgingival microbiota and the host’s dysregulated immune-inflammatory response, leading to the initiation of progressive and irreversible destruction of the periodontal tissues and eventually to tooth loss. The main goal of cause-related periodontal therapy is to eliminate the dysbiotic subgingival biofilm in order to arrest local inflammation and further periodontal tissue breakdown. Because, in some cases, subgingival mechanical instrumentation has limited efficiency in achieving those goals, various adjunctive therapies, mainly systemic and locally delivered antimicrobials, have been proposed to augment its effectiveness. However, most adjunctive antimicrobials carry side effects; therefore, their administration should be precociously considered. HybenX® (HY) is a commercial therapeutical agent with decontamination properties, which has been studied for its effects in treating various oral pathological conditions, including periodontitis. This review covers the current evidence regarding the treatment outcomes and limitations of conventional periodontal therapies and provides information based on the available experimental and clinical studies related to the HY mechanism of action and effects following its use associated with subgingival instrumentation and other types of dental treatments.