T-independent responses to polysaccharides in humans mobilize marginal zone B cells prediversified against gut bacterial antigens.

Marginal zone (MZ) B cells are one of the main actors of T-independent (TI) responses in mice. To identify the B cell subset(s) involved in such responses in humans, we vaccinated healthy individuals with Pneumovax, a model TI vaccine. By high-throughput repertoire sequencing of plasma cells (PCs) isolated 7 days after vaccination and of different B cell subpopulations before and after vaccination, we show that the PC response mobilizes large clones systematically, including an immunoglobulin M component, whose diversification and amplification predated the pneumococcal vaccination. These clones could be mainly traced back to MZ B cells, together with clonally related IgA+ and, to a lesser extent, IgG+CD27+ B cells. Recombinant monoclonal antibodies isolated from large PC clones recognized a wide array of bacterial species from the gut flora, indicating that TI responses in humans largely mobilize MZ and switched B cells that most likely prediversified during mucosal immune responses against bacterial antigens and acquired pneumococcal cross-reactivity through somatic hypermutation.

High Frequency of Specific Polysaccharide Antibody Deficiency in Adults With Unexplained, Recurrent and/or Severe Infections With Encapsulated Bacteria.

BACKGROUND: Primary immunodeficiencies (PIDs) in adults are mainly revealed by recurrent and/or severe bacterial infections. The objective of this study was to evaluate a systematic research strategy of PIDs in adults with unexplained bacterial infections, with a special focus on specific polysaccharide antibody deficiency (SPAD). METHODS: In this prospective multicenter study, inclusion criteria were recurrent benign upper and lower respiratory tract infections (RTIs) for at least two years (group 1), at least one upper or lower RTI requiring hospitalization (group 2), and/or at least one invasive infection documented with encapsulated bacteria (group 3). Main exclusion criteria were all local and general conditions that could explain infections. If no PID diagnosis was made, response to polysaccharide antigens was assessed using a pneumococcal polysaccharide vaccine. RESULTS: From March 2015 to March 2020, 118 patients were included (37 males, median age of 41 years): 73, 17, and 28 in groups 1, 2, and 3, respectively. Forty-seven PIDs were diagnosed, giving an estimated frequency of 39.8% (95% confidence interval [CI] [30.4, 48.8]). SPAD was the most frequent diagnosis by far (n = 37/47, 78.7%), and was made in 23, 5, and 9 patients from groups 1 to 3, respectively. All SPAD patients received conjugate vaccines and, according to their infectious history, were on surveillance or treated with preventive antibiotics (n = 6) and/or with immunoglobulins replacement therapy (n = 10), the latter being dramatically efficient in all cases. CONCLUSIONS: Considering its high prevalence among adults with unexplained recurrent and/or severe bacterial infections, SPAD should be screened in those patients. CLINICAL TRIALS REGISTRATION: NCT02972281.

The 13-Valent Pneumococcal Conjugate Vaccine Elicits Serological Response and Lasting Protection in Selected Patients With Primary Humoral Immunodeficiency.

Background: Patients with primary humoral immunodeficiency are more prone to invasive as well as recurrent pneumococcal infections. Therefore, anti-pneumococcal vaccination including the 13-valent conjugate vaccine is recommended. Nevertheless, to date, no data is available on immunogenicity of this vaccine in this population. Objective: To assess the immunogenicity and the persistence of protection up to one year after a 13-valent pneumococcal conjugate vaccine in patients with primary humoral immunodeficiency. Methods: Twenty-nine patients with common variable immunodeficiency or IgG subclass deficiency were vaccinated. Immune response and immune protection at baseline as well as at one, six and twelve months after vaccination were evaluated by measuring specific IgG serum concentrations (ELISA), and opsonophagocytic activities directed against selected pneumococcal (MOPA). Results: By ELISA, half of the patients had protective IgG concentrations before vaccination, 35.7% showed an immune response one month after vaccination, 71.4%, 66.7% and 56.0% of the patients were protected at one, six and twelve months respectively. Conversely, by MOPA, 3.4% of the patients were protected at baseline, 10.7% showed an immune response and 28.6%, 48.2% and 33.3% were protected at one, six and twelve months respectively. IgG subclass deficiency, Ig replacement therapy and higher IgG2 concentrations at diagnosis were associated with long-term protection. Conclusion: Pneumococcal conjugate vaccine improves immune protection and antibodies' functionality in a subset of patients with primary immunodeficiency. Prime-boost vaccine strategy needs to be better and individually adapted.

Single-Dose 13-Valent Conjugate Pneumococcal Vaccine in People Living With HIV - Immunological Response and Protection.

Background: Patients living with HIV (PLHIV) are prone to invasive pneumococcal disease. The 13-valent conjugated pneumococcal vaccine (PCV13) is currently recommended for all PLHIV, followed in most guidelines by a 23-valent polysaccharide pneumococcal vaccine. Data are scarce concerning the immunological efficacy of PCV13 among PLHIV. Objective: To assess the immunological response at one month, and the immunological protection at 1-, 6-, and 12 months in PLHIV with a CD4 cell count above 200 cells/µl after a single dose of PCV13, as measured by both ELISA and opsonophagocytic assay (OPA). Methods: PLHIV with CD4 cell count >200 cells/µl were included. Specific IgG serum concentrations for eight serotypes by ELISA and seven serotypes by OPA were measured at baseline, 1-, 6-, and 12 months after the PCV13 vaccination. Global response was defined as a two-fold increase from baseline of specific IgG antibody levels (µg/ml) assayed by ELISA or as a four-fold increase in OPA titer from baseline, for at least five serotypes targeted by PCV13. Global protection was defined as an IgG-concentration ≥1 µg/ml by ELISA or as an opsonization titer ≥LLOQ by OPA for at least five tested serotypes targeted by PCV13. Factors associated with global response and global protection were assessed using logistic regression. Results: Of the 38 PLHIV included, 57.9% and 63.2% were global responders, 92.1% and 78.9% were globally protected at one month, and 64.7% and 55.9% were still protected at 12 months, by ELISA and OPA respectively. A CD4/CD8 ratio of >0.8 was significantly associated with a better global response by OPA (OR=6.11, p=0.02), and a CD4 nadir <200 was significantly associated with a poorer global response by ELISA (OR=0.22, p=0.04). A CD4 cell count nadir <200 and age over 50 years were associated with poorer global protection by OPA at M1 (OR=0.18, p=0.04) and M12 (OR= 0.15, p=0.02), respectively. Plasma HIV RNA viral load <40 copies/ml was significantly associated with a better global protection at M1 by ELISA and OPA (OR=21.33, p=0.025 and OR=8.40, p=0.04). Conclusion: Vaccination with PCV13 in these patients induced immunological response and protection at one month. At one year, more than half of patients were still immunologically protected.

Serum IgG2 levels predict long-term protection following pneumococcal vaccination in systemic lupus erythematosus (SLE).

Systemic lupus erythematosus (SLE) patients are at risk for pneumococcal infection. Twenty-one consecutive SLE patients (40[25-75] years) received the sequential PCV13/PPSV23 vaccine and factors associated with long-term protection were analyzed. Immune protection, defined by an antigen-specific IgG concentration ≥1.3 µg/mL for at least 70% of 7 pneumococcal serotypes was assessed at baseline, 2, 6, 12 and 36 months defining long-term protection. Only 10 patients showed pneumococcal immune protection 36 months after vaccination. Eleven (52.4%) patients had no long-term protection with a seroconversion that never or only transiently occurred. SLE disease features, treatment received and immunological characteristics did not differ between protected and unprotected patients except for the pre-vaccination IgG2 serum levels. Serum IgG2 level >2.125 µg/ml showed a sensitivity of 100% and a specificity of 90.9% for long-term protection. Sequential pneumococcal vaccination conferred poor immune protection in SLE. Baseline IgG2 serum level identified patients able to benefit from pneumococcal vaccination.

PRIMVAC vaccine adjuvanted with Alhydrogel or GLA-SE to prevent placental malaria: a first-in-human, randomised, double-blind, placebo-controlled study.

BACKGROUND: PRIMVAC is a VAR2CSA-derived placental malaria vaccine candidate aiming to prevent serious clinical outcomes of Plasmodium falciparum infection during pregnancy. We assessed the safety and immunogenicity of PRIMVAC adjuvanted with Alhydrogel or glucopyranosyl lipid adjuvant in stable emulsion (GLA-SE) in French and Burkinabe women who were not pregnant. METHODS: This first-in-human, randomised, double-blind, placebo-controlled, dose escalation trial was done in two staggered phases, a phase 1A trial in 18-35-year-old women who were malaria naive in a hospital in France and a subsequent phase 1B trial in women who were naturally exposed to P falciparum and nulligravid in the clinical site of a research centre in Burkina Faso. Volunteers were recruited into four sequential cohorts receiving PRIMVAC intramuscularly at day 0, 28, and 56: two cohorts in France receiving 20 µg or 50 µg of PRIMVAC and then two in Burkina Faso receiving 50 µg or 100 µg of PRIMVAC. Volunteers were randomly assigned (1:1) to two groups (PRIMVAC adjuvanted with either Alhydrogel or GLA-SE) in France and randomly assigned (2:2:1) to three groups (PRIMVAC adjuvanted with either Alhydrogel, GLA-SE, or placebo) in Burkina Faso. Randomisation was centralised, using stratification by cohort and blocks of variable size, and syringes were masked by opaque labels. The primary endpoint was the proportion of participants with any grade 3 or higher adverse reaction to vaccination up until day 35. Safety at later time points as well as humoral and cellular immunogenicity were assessed in secondary endpoints. This trial is registered with ClinicalTrials.gov, NCT02658253. FINDINGS: Between April 19, 2016, and July 13, 2017, 68 women (18 in France, 50 in Burkina Faso) of 101 assessed for eligibility were included. No serious adverse event related to the vaccine occurred. PRIMVAC antibody titres increased with each dose and seroconversion was observed in all women vaccinated with PRIMVAC (n=57). PRIMVAC antibody titres reached a peak (geometric mean 11 843·0, optical density [OD] 1·0, 95% CI 7559·8-18 552·9 with 100 µg dose and GLA-SE) 1 week after the third vaccination (day 63). Compared with Alhydrogel, GLA-SE tended to improve the PRIMVAC antibody response (geometric mean 2163·5, OD 1·0, 95% CI 1315·7-3557·7 with 100 µg dose and Alhydrogel at day 63). 1 year after the last vaccination, 20 (71%) of 28 women who were vaccinated with PRIMVAC/Alhydrogel and 26 (93%) of 28 women who were vaccinated with PRIMVAC/GLA-SE still had anti-PRIMVAC antibodies, although antibody magnitude was markedly lower (452·4, OD 1·0, 95% CI 321·8-636·1 with 100 µg dose and GLA-SE). These antibodies reacted with native homologous VAR2CSA expressed by NF54-CSA infected erythrocytes (fold change from baseline at day 63 with 100 µg dose and GLA-SE: 10·74, 95% CI 8·36-13·79). Limited cross-recognition, restricted to sera collected from women that received the 100 µg PRIMVAC dose, was observed against heterologous VAR2CSA variants expressed by FCR3-CSA (fold change from baseline at day 63: 1·49, 95% CI 1·19-1·88) and 7G8-CSA infected erythrocytes (1·2, 1·08-1·34). INTERPRETATION: PRIMVAC adjuvanted with Alhydrogel or GLA-SE had an acceptable safety profile, was immunogenic, and induced functional antibodies reacting with the homologous VAR2CSA variant expressed by NF54-CSA infected erythrocytes. Cross-reactivity against heterologous VAR2CSA variants was limited and only observed in the higher dose group. An alternate schedule of immunisation, antigen dose, and combinations with other VAR2CSA-based vaccines are envisaged to improve the cross-reactivity against heterologous VAR2CSA variants. FUNDING: Bundesministerium für Bildung und Forschung, through Kreditanstalt für Wiederaufbau, Germany; Inserm, and Institut National de Transfusion Sanguine, France; Irish Aid, Department of Foreign Affairs and Trade, Ireland.

Antipneumococcal Seroprotection Years After Vaccination in Allogeneic Hematopoietic Cell Transplant Recipients.

BACKGROUND: International guidelines recommend vaccinating allogeneic hematopoietic cell transplant (HCT) recipients at 3 months after transplant, giving 3 doses of pneumococcal conjugate vaccine (PCV) followed by either a dose of 23-valent pneumococcal polysaccharide vaccine (PSV23) or a fourth PCV dose in the case of graft-versus-host disease (GvHD). However, the long-term immunity after this regimen is unknown, and there is no recommendation from 24 months after transplant regarding boosts. Our objective was to assess the antipneumococcal antibody titers and seroprotection rates of allogeneic HCT recipients years after different schedules of vaccination. METHODS: We assessed 100 adult HCT recipients a median of 9.3 years (range: 1.7-40) after transplant. All patients had received at least one dose of PCV and were assessed for antipneumococcal immunoglobulin G (IgG) antibody titers against the 7 serotypes shared by PCV7, PCV13, and PSV23. Sixty-six percent of the patients had been vaccinated according to the current guidelines. RESULTS: Considering an IgG titer ≥ 0.35 µg/mL as protective for each serotype, the seroprotection rate was 50% for 7/7 serotypes and 70% for 5/7 serotypes, with no differences between the different vaccination schedules. The lack of seroprotection was associated with a transplant performed not in complete remission or from a cord-blood unit, a relapse after transplant, or chronic GvHD at assessment. CONCLUSION: Because only half of the vaccinated patients had long-term protection, pending prospective studies defining the best boost program after the initial one, we recommend the assessment of specific IgG titers starting from 24 months to decide for further doses.

Immunogenicity and persistence of a prime-boost re-vaccination strategy for pneumococcal vaccines in patients with rheumatoid arthritis.

OBJECTIVES: Patients with rheumatoid arthritis (RA) are at an increased risk of Pneumococcal infections. Immunogenicity and persistence of a prime-boost revaccination strategy using 13-valent/23-valent anti-pneumococcal vaccines was evaluated in patients with RA treated by Methotrexate (MTX) and anti-TNF. METHOD: Twenty-four patients with RA received one dose of PCV13 (Prevenar13®; Pfizer) followed two months later by one dose of PPV23 (Pneumovax®, Merck). Concentrations of IgG specific for 7 serotypes common to both vaccines and 3 uncommon serotypes, included only in the PPV23 were measured by ELISA and Opsonophagocytic Assay (OPA) at baseline and after 4, 12 and 24 months post-vaccine. RESULTS: Similar percentages of protection were found at 4 months (63% vs. 55%), 12 months (54% vs. 50%) and 24 months (52% vs. 55%) for the 7 common and 3 uncommon serotypes when antibody titers were assayed by ELISA. Based on functional antibody measurements by OPA, a decrease of protected patients was observed 24 months after vaccine with only 19% of patients protected compared to 29% at baseline. CONCLUSION: Although the combined pneumococcal revaccination strategy induces good protection in the short term in RA patients, this protection does not persist beyond two years with levels of functional antibody decreasing below pre-vaccine levels. We did not observe a higher efficacy of the conjugate vaccine compared to the polysaccharide vaccine. Our results clearly question the advantage of the prime-boost strategy as it highlight the possible hyporesponse induced by PPV23 against the immune response elicited by the primo-injection of the PCV13 vaccine.

Immunogenicity and persistence of the 13-valent Pneumococcal Conjugate Vaccine (PCV13) in patients with untreated Smoldering Multiple Myeloma (SMM): A pilot study.

Smoldering multiple myeloma (SMM) is an asymptomatic clonal plasma cell disorder that frequently progress to multiple myeloma (MM), a disease at high risk of pneumococcal infections. Moreover, if the polysaccharide vaccine is poorly immunogenic in MM, the 13-valent conjugated vaccine has never been tested in clonal plasma cell disorders. We evaluated its immunogenicity for 7 serotypes in 20 patients ≥ 50 years of age with smoldering multiple myeloma (SMM) pre and post routine-vaccination with PCV13. Concentrations of IgG specific for 7 serotypes were measured at baseline, 1, 6, and 12 months after vaccination by standardized ELISA and an Opsonophagocytic Assay (OPA). The primary endpoint was the proportion of patients responding to at least 5 of the 7 serotypes by ELISA at one month. At 1 month post vaccination, 12 patients (60%) were responders by ELISA, among whom 8 were also responders by OPA. At 6 months, 6 (30% of total) of the 12 responders had persistent immunity, and only 2 (10% of total) at 12 months. These results suggested a partial response in this population and a rapid decrease in antibody levels in the first months of vaccination. Although one injection of the 13-valent pneumococcal conjugate vaccine is immunogenic in some patients with SMM, the response is transient. Repeated injections are likely to be needed for effective and sustained protection.

Pneumococcal vaccination in patients with systemic lupus erythematosus: A multicenter placebo-controlled randomized double-blind study.

BACKGROUND: Invasive pneumococcal disease and respiratory tract infections are both frequent and severe in patients with systemic lupus erythematosus (SLE). This study aimed to compare the immunological efficacy and safety of pneumococcal vaccination with the 23-valent polysaccharide (PPS) vaccine alone to a sequential immunization with the 7-valent pneumococcal conjugate (PnCj) vaccine followed by PPS in patients with SLE and stable diseaase. METHODS: Multicenter randomized placebo-controlled double-blind trial: PPS vaccine alone (placebo-PPS group) or PnCj vaccine followed by PPS vaccine (PnCj-PPS group) 24weeks later. The primary endpoint was the rate of responders at week 28 to at least 5 of the 7 serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) shared by both PPS and PnCj. Pneumococcal IgG antibodies' opsonophagocytic activity (OPA) were also assessed. RESULTS: Twenty-five patients in the placebo-PPS group and 17 in the PnCj-PPS group were included in a modified intention-to-treat analysis. The primary endpoint was reached in 72% (18/25) in the placebo-PPS and 76% (13/17) in the PnCj-PPS group (p=0.75). There was no difference in the rates of responders with OPA. At week 52, 13/18 (72%) patients in the placebo-PPS group and 10/13 (77%) patients in the PnCj-PPS group (p=0.77) that met the primary endpoint at week 28 were still responders to ≥5/7 serotypes shared by both PPS and PnCj vaccines. Nine SLE flares were reported in 6 patients (4 in the placebo-PPS and 2 in the PnCj-PPS groups respectively, p=0.70). CONCLUSION: Sequential administration of PnCj vaccine followed by PPS vaccine is safe and shows short-term immunological efficacy in patients with SLE but was not superior to the PPS vaccine alone. TRIAL REGISTRATION: www.clinicaltrials.gov, NCT NCT00611663.

Specific Polysaccharide Antibody Deficiency Revealed by Severe Bacterial Infections in Adulthood: A Report on 11 Cases.

We report on 11 cases of specific polysaccharide antibody deficiency (SPAD) revealed in adulthood by severe infections with encapsulated bacteria. Given that immunoglobulin replacement therapy can effectively prevent the recurrence of bacterial infections in this context, SPAD should be considered once other antibody deficiencies have been ruled out.

Dimethyl Fumarate Controls the NRF2/DJ-1 Axis in Cancer Cells: Therapeutic Applications.

The transcription factor NRF2 (NFE2L2), regulates important antioxidant and cytoprotective genes. It enhances cancer cell proliferation and promotes chemoresistance in several cancers. Dimethyl fumarate (DMF) is known to promote NRF2 activity in noncancer models. We combined in vitro and in vivo methods to examine the effect of DMF on cancer cell death and the activation of the NRF2 antioxidant pathway. We demonstrated that at lower concentrations (<25 µmol/L), DMF has a cytoprotective role through activation of the NRF2 antioxidant pathway. At higher concentrations, however (>25 µmol/L), DMF caused oxidative stress and subsequently cytotoxicity in several cancer cell lines. High DMF concentration decreases nuclear translocation of NRF2 and production of its downstream targets. The pro-oxidative and cytotoxic effects of high concentration of DMF were abrogated by overexpression of NRF2 in OVCAR3 cells, suggesting that DMF cytotoxicity is dependent of NRF2 depletion. High concentrations of DMF decreased the expression of DJ-1, a NRF2 protein stabilizer. Using DJ-1 siRNA and expression vector, we observed that the expression level of DJ-1 controls NRF2 activation, antioxidant defenses, and cell death in OVCAR3 cells. Finally, antitumoral effect of daily DMF (20 mg/kg) was also observed in vivo in two mice models of colon cancer. Taken together, these findings implicate the effect of DJ-1 on NRF2 in cancer development and identify DMF as a dose-dependent modulator of both NRF2 and DJ-1, which may be useful in exploiting the therapeutic potential of these endogenous antioxidants. Mol Cancer Ther; 16(3); 529-39. ©2017 AACR.

Value of the Overall Pneumococcal Polysaccharide Response in the Diagnosis of Primary Humoral Immunodeficiencies.

BACKGROUND: An overall response assay [OVA, based on a 23-valent pneumococcal polysaccharide vaccine (PPV23)] is widely used to screen for anti-pneumococcal antibodies. Given the heterogeneity of response from one polysaccharide (PS) to another, a World Health Organization-standardized serotype-specific enzyme-linked immunosorbent assay (SSA) is considered to be the only reliable method for testing anti-PS antibody responses in individuals with suspected primary immunodeficiencies (PIDs). OBJECTIVE: To evaluate the OVA relative to the reference SSA. METHODS: Serum samples of adult patients referred for a suspected PID were collected before and then 4-8 weeks after immunization with PPV23. The anti-pneumococcal response was systematically assessed with an SSA (7-16 serotypes) and interpreted according to the American Academy of Asthma, Allergy and Immunology's current guidelines. We used receiver operating characteristic curves and agreement indices to assess the OVA's diagnostic value in a first cohort. In order to validate these findings, a second (validation) cohort was then prospectively included. RESULTS: Sixty-two adult patients were included, and 42 (67.7%) were defined as poor responders according to the SSA. Only the post-immunization titer in the OVA was able to correctly identify poor responders; a titer below 110 mg/L gave a positive predictive value of 100% [identifying 24 (57.1%) of the 42 poor responders], and similar levels of diagnostic performance were observed in the validation cohort. The pre-vaccination antibody titer, the post/pre-vaccination antibody titer ratio and a post-vaccination titer above 110 mg/L in the OVA were not predictive of the response in the SSA. CONCLUSION: A post-vaccination antibody titer below 110 mg/L in the OVA was constantly associated with a poor PPV23 response using the SSA. In all other cases, SSA is the only reliable method for assessing diagnostic vaccination with PPV23.