Targeting CD38 with monoclonal antibodies disrupts key survival pathways in paediatric Burkitt's lymphoma malignant B cells.

Objectives: Paediatric Burkitt's lymphoma (pBL) is the most common childhood non-Hodgkin B-cell lymphoma. Despite the encouraging survival rates for most children, treating cases with relapse/resistance to current therapies remains challenging. CD38 is a transmembrane protein highly expressed in pBL. This study investigates the effectiveness of CD38-targeting monoclonal antibodies (mAbs), daratumumab and isatuximab, in impairing crucial cellular processes and survival pathways in pBL malignant cells. Methods: In silico analyses of patient samples, combined with in vitro experiments using the Ramos cell line, were conducted to assess the impact of daratumumab and isatuximab on cellular proliferation, apoptosis and the phosphoinositide 3-kinase (PI3K) pathway. Results: Isatuximab was found to be more effective than daratumumab in disrupting B-cell receptor signalling, reducing cellular proliferation and inducing apoptosis. Additionally, isatuximab caused a significant impairment of the PI3K pathway and induced metabolic reprogramming in pBL cells. The study also revealed a correlation between CD38 and MYC expression levels in pBL patient samples, suggesting CD38 involvement in key oncogenic processes. Conclusion: The study emphasises the therapeutic potential of CD38-targeting mAbs, particularly isatuximab, in pBL.

Surface antigen serocleared hepatitis B virus infection increases the risk of mixed cryoglobulinemia vasculitis in male patients with chronic hepatitis C.

Mixed cryoglobulinemia vasculitis (MCV) is caused in ~90% of cases by chronic hepatitis C virus (HCVposMCV) and more rarely by hepatitis B virus (HBV) infection, or apparently noninfectious. HCVposMCV develops in only ~5% of patients with chronic hepatitis C (CHC), but risk factors other than female gender have not been identified so far. We conducted a retrospective case control study investigating whether past active HBV infection, defined by hepatitis B surface antigen (HBsAg) seroclearance and anti-core antibody (HBcAb) positivity, could be a risk factor for developing HCVposMCV. The prevalence of HBsAg seroclearance was 48% within 123 HCVposMCV patients and 29% within 257 CHC patients (p=0.0003). Multiple logistic regression including as variables gender, birth year, age at HBV testing, cirrhosis, and hepatocellular carcinoma, confirmed an association of HBsAg seroclearance with HCVposMCV [adjusted odds ratio (OR) 2.82, 95% confidence interval (95% CI) 1.73-4.59, p<0.0001]. Stratification by gender, however, showed that HBsAg seroclearance was associated with HCVposMCV in male [OR 4.63, 95% CI 2.27-9.48, p<0.0001] and not in female patients [OR 1.85, 95% 95% CI 0.94-3.66, p=0.076]. HBsAg seroclearance, and more likely occult HBV infection, is an independent risk factor for HCVposMCV in male CHC patients.

Impact of COVID-19 and vaccination campaign on 1,755 systemic sclerosis patients during first three years of pandemic. Possible risks for individuals with impaired immunoreactivity to vaccine, ongoing immunomodulating treatments, and disease-related lung involvement during the next pandemic phase.

Introduction: The impact of COVID-19 pandemic represents a serious challenge for 'frail' patients' populations with inflammatory autoimmune systemic diseases such as systemic sclerosis (SSc). We investigated the prevalence and severity of COVID-19, as well the effects of COVID-19 vaccination campaign in a large series of SSc patients followed for the entire period (first 38 months) of pandemic. Patients and method: This prospective survey study included 1755 unselected SSc patients (186 M, 1,569F; mean age 58.7 ± 13.4SD years, mean disease duration 8.8 ± 7.3SD years) recruited in part by telephone survey at 37 referral centers from February 2020 to April 2023. The following parameters were carefully evaluated: i. demographic, clinical, serological, and therapeutical features; ii. prevalence and severity of COVID-19; and iii. safety, immunogenicity, and efficacy of COVID-19 vaccines. Results: The prevalence of COVID-19 recorded during the whole pandemic was significantly higher compared to Italian general population (47.3 % vs 43.3 %, p < 0.000), as well the COVID-19-related mortality (1.91 % vs 0.72 %, p < 0.001). As regards the putative prognostic factors of worse outcome, COVID-19 positive patients with SSc-related interstitial lung involvement showed significantly higher percentage of COVID-19-related hospitalization compared to those without (5.85 % vs 1.73 %; p < 0.0001), as well as of mortality rate (2.01 % vs 0.4 %; p = 0.002). Over half of patients (56.3 %) received the first two plus one booster dose of vaccine; while a fourth dose was administered to 35.6 %, and only few of them (1.99 %) had five or more doses of vaccine. Of note, an impaired seroconversion was recorded in 25.6 % of individuals after the first 2 doses of vaccine, and in 8.4 % of patients also after the booster dose. Furthermore, the absence of T-cell immunoreactivity was observed in 3/7 patients tested by QuantiFERON® SARSCoV-2 Starter Set (Qiagen). The efficacy of vaccines, evaluated by comparing the COVID-19-related death rate recorded during pre- and post-vaccination pandemic periods, revealed a quite stable outcome in SSc patients (death rate from 2.54 % to 1.76 %; p = ns), despite the significant drop of mortality observed in the Italian general population (from 2.95 % to 0.29 %; p < 0.0001). Conclusions: An increased COVID-19 prevalence and mortality rate was recorded in SSc patients; moreover, the efficacy of vaccines in term of improved outcomes was less evident in SSc compared to Italian general population. This discrepancy might be explained by concomitant adverse prognostic factors: increased rate of non-responders to vaccine in SSc series, low percentage of individuals with four or more doses of vaccine, ongoing immunomodulating treatments, disease-related interstitial lung disease, and/or reduced preventive measures in the second half of pandemic. A careful monitoring of response to COVID-19 vaccines together with adequate preventive/therapeutical strategies are highly recommendable in the near course of pandemic in this frail patients' population.

High prevalence of past hepatitis B virus infection in diffuse large B cell lymphoma: a retrospective study from Italy.

Studies from high endemic areas, mostly China, indicate that surface antigen positive (HBsAgpos) chronic hepatitis B virus (HBV) infection is associated with an increased risk of developing diffuse large B-cell lymphoma (DLBCL), whereas studies in low endemic areas have provided conflicting results. Past infection, serologically defined by negative HBsAg and positive anti-core antibody (HBsAgnegHBcAbpos), has also been suggested to increase the risk of B-cell non-Hodgkin's lymphoma (NHL) in high endemic areas. We retrospectively reviewed unselected clinical records of 253 patients with DLBCL (54% male, aged 60.3 ± 14.6 years at diagnosis) and 694 patients with different types of indolent B-cell NHL (46% male, aged 61.7 ± 12.8 years). Patients were seen at a single center in Italy between 2001 and 2022 and HBV serological status (HBsAg, HBsAb, HBcAb, HBeAg, HBeAb, and HBV DNA) was analyzed through enzyme-linked immunosorbent assays and molecular assays; patients infected with hepatitis C virus or human immunodeficiency virus were excluded. We used an unconditional multiple logistic regression model including as matching variables gender, age at diagnosis, immigrant status, and HBV serological status. Patients with DLBCL had, compared to indolent NHL, a higher prevalence of HBsAgpos active infection (odds ratio (OR) 2.8, 95% confidence interval (95% CI) 1.2-6.3, p = 0.014). Strikingly, patients with DLBCL had also a significantly higher prevalence of past infection (OR 2.4, 95% CI 1.5-4.0, p = 0.0006). Male gender was associated with increased risk of DLBCL independently of the HBV serological status. These findings suggest that both past and active HBV infection may increase the risk of DLBCL in a low endemic area. Our study needs confirmation by studies in areas or populations with different rates of chronic or past HBV infection.

Persistence of monoclonal B-cell expansion and intraclonal diversification despite virus eradication in patients affected by hepatitis C virus-associated lymphoproliferative disorders.

We investigated 23 hepatitis C virus (HCV)-infected patients with overt lymphoproliferative diseases (15 cases) or monoclonal B lymphocytosis (8 cases) treated with direct agent antiviral (DAAs) per clinical practice. DAA therapy yielded undetectable HCV-RNA, the complete response of cryoglobulinemia vasculitis and related signs, whilst the presence of B-cell clones (evaluated by flow cytometry, IGHV, and BCL2-IGH rearrangements), detected in 19/23 cases at baseline, was maintained (17/19). Similarly, IGHV intraclonal diversification, supporting an antigen-driven selection mechanism, was identified in B-cell clones at baseline and end of follow-up. DAA therapy alone, despite HCV eradication and good immunological responses, was less effective on the pathological B-cell clones.

Inflammatory rheumatic diseases with onset after SARS-CoV-2 infection or COVID-19 vaccination: a report of 267 cases from the COVID-19 and ASD group.

OBJECTIVES: To better define the spectrum of new-onset post-COVID-19 and post-COVID-19 vaccine inflammatory rheumatic diseases (IRD) from a large multicentric observational study. METHODS: Consecutive cases of IRD encountered during a 12-month period and satisfying one of the following inclusion criteria: (a) onset of the rheumatic manifestations within 4 weeks from SARS-CoV-2 infection or (b) onset of the rheumatic manifestations within 4 weeks from the administration of one of the COVID-19 vaccines ws recruited. RESULTS: The final analysis cohort comprised 267 patients, of which 122 (45.2%) in the post-COVID-19 and 145 (54.8%) in the postvaccine cohort. Distribution of IRD categories differed between the two cohorts: the post-COVID-19 cohort had a higher percentage of patients classified as having inflammatory joint diseases (IJD, 52.5% vs 37.2%, p=0.013) while the post-vaccine cohort had a higher prevalence of patients classified as polymyalgia rheumatica (PMR, 33.1% vs 21.3%, p=0.032). No differences were detected in the percentage of patients diagnosed with connective tissue diseases (CTD 19.7% vs 20.7%, p=0.837) or vasculitis (6.6% vs 9.0%, p=0.467). Despite the short follow-up period, IJD and PMR patients' response to first-line therapy was favourable, with both groups achieving a drop in baseline disease activity scores of ~30% and ~70% respectively. CONCLUSION: Our article reports the largest cohort published to date of new-onset IRD following SARS-CoV-2 infection or COVID-19 vaccines. Although causality cannot be ascertained, the spectrum of possible clinical manifestations is broad and includes IJD, PMR, CTD and vasculitis.

Distinct platelet crosstalk with adaptive and innate immune cells after adenoviral and mRNA vaccination against SARS-CoV-2.

BACKGROUND: Genetic-based COVID-19 vaccines have proved to be highly effective in reducing the risk of hospitalization and death. Because they were first distributed in a large-scale population, the adenoviral-based vaccines were linked to a very rare thrombosis with thrombocytopenia syndrome, and the interplay between platelets and vaccinations increasingly gained attention. OBJECTIVES: The objective of this article was to study the crosstalk between platelets and the vaccine-induced immune response. METHODS: We prospectively enrolled young healthy volunteers who received the mRNA-based vaccine, BNT162b2 (n = 15), or the adenovirus-based vaccine, AZD1222 (n = 25) and studied their short-term platelet and immune response before and after vaccine injections. In a separate cohort, we retrospectively analyzed the effect of aspirin on the antibody response 1 and 5 months after BNT162b2 vaccination. RESULTS: Here, we show that a faster antibody response to either vaccine is associated with the formation of platelet aggregates with marginal zone-like B cells, a subset geared to bridge the temporal gap between innate and adaptive immunities. However, although the mRNA-based vaccine is associated with a more gradual and tolerogenic response that fosters the crosstalk between platelets and adaptive immunity, the adenovirus-based vaccine, the less immunogenic of the 2, evokes an antiviral-like response during which the platelets are cleared and less likely to cooperate with B cells. Moreover, subjects taking aspirin (n = 56) display lower antibody levels after BNT162b2 vaccination compared with matched individuals. CONCLUSION: Platelets are a component of the innate immune pathways that promote the B-cell response after vaccination. Future studies on the platelet-immune crosstalk post-immunization will improve the safety, efficacy, and strategic administration of next-generation vaccines.

Opposite Effects of mRNA-Based and Adenovirus-Vectored SARS-CoV-2 Vaccines on Regulatory T Cells: A Pilot Study.

New-generation mRNA and adenovirus vectored vaccines against SARS-CoV-2 spike protein are endowed with immunogenic, inflammatory and immunomodulatory properties. Recently, BioNTech developed a noninflammatory tolerogenic mRNA vaccine (MOGm1Ψ) that induces in mice robust expansion of antigen-specific regulatory T (Treg) cells. The Pfizer/BioNTech BNT162b2 mRNA vaccine against SARS-CoV-2 is identical to MOGm1Ψ except for the lipid carrier, which differs for containing lipid nanoparticles rather than lipoplex. Here we report that vaccination with BNT162b2 led to an increase in the frequency and absolute count of CD4posCD25highCD127low putative Treg cells; in sharp contrast, vaccination with the adenovirus-vectored ChAdOx1 nCoV-19 vaccine led to a significant decrease of CD4posCD25high cells. This pilot study is very preliminary, suffers from important limitations and, frustratingly, very hardly can be refined in Italy because of the >90% vaccination coverage. Thus, the provocative perspective that BNT162b2 and MOGm1Ψ may share the capacity to promote expansion of Treg cells deserves confirmatory studies in other settings.

Hepatitis B virus-infection related cryoglobulinemic vasculitis. Clinical manifestations and the effect of antiviral therapy: A review of the literature.

Objective: Hepatitis B virus (HBV) infection causes chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Furthermore, about 20% of the patients develop extrahepatic manifestations such as cryoglobulinemic vasculitis (CV), polyarteritis nodosa, non-rheumatoid arthritis, glomerulonephritis and non-Hodgkin lymphoma. This review analyzed literature data on clinical manifestations of HBV-related CV and the impact of antiviral therapy with analoques nucleotide. Methods: A PubMed search was performed to select eligible studies in the literature, up to July 2022. Results: Some studies have analyzed clinical manifestations in HBV-related CV and have investigated the role of antiviral therapy with nucleotides analogues (NAs). Clinical manifestations of CV vary from mild to moderate (purpura, asthenia and arthralgias) to severe (leg ulcers, peripheral neuropathy, glomerulonephritis, and non-Hodking lymphoma). NAs therapy leads to suppression of HBV-DNA; therefore, it is capable of producing clinical response in the majority of patients with mild to moderate symptoms. Conclusion: Antiviral therapy with NAs is the first choice for HBV suppression and control of mild to moderate disease. In severe vasculitis (glomerulonephritis, progressive peripheral neuropathy and leg ulcers), rituximab alone or with plasma-exchange is always indicated in combination with antiviral therapy.

Dual stimulation by autoantigen and CpG fosters the proliferation of exhausted rheumatoid factor-specific CD21low B cells in hepatitis C virus-cured mixed cryoglobulinemia.

Introduction: Hepatitis C virus (HCV) causes mixed cryoglobulinemia (MC) by driving clonal expansion of B cells expressing B cell receptors (BCRs), often encoded by the VH1-69 variable gene, endowed with both rheumatoid factor (RF) and anti-HCV specificity. These cells display an atypical CD21low phenotype and functional exhaustion evidenced by unresponsiveness to BCR and Toll-like receptor 9 (TLR9) stimuli. Although antiviral therapy is effective on MC vasculitis, pathogenic B cell clones persist long thereafter and can cause virus-independent disease relapses. Methods: Clonal B cells from patients with HCV-associated type 2 MC or healthy donors were stimulated with CpG or heath-aggregated IgG (as surrogate immune complexes) alone or in combination; proliferation and differentiation were then evaluated by flow cytometry. Phosphorylation of AKT and of the p65 NF-kB subunit were measured by flow cytometry. TLR9 was quantified by qPCR and by intracellular flow cytometry, and MyD88 isoforms were analyzed using RT-PCR. Discussion: We found that dual triggering with autoantigen and CpG restored the capacity of exhausted VH1-69pos B cells to proliferate. The signaling mechanism for this BCR/TLR9 crosstalk remains elusive, since TLR9 mRNA and protein as well as MyD88 mRNA were normally expressed and CpG-induced phosphorylation of p65 NF-kB was intact in MC clonal B cells, whereas BCR-induced p65 NF-kB phosphorylation was impaired and PI3K/Akt signaling was intact. Our findings indicate that autoantigen and CpG of microbial or cellular origin may unite to foster persistence of pathogenic RF B cells in HCV-cured MC patients. BCR/TLR9 crosstalk might represent a more general mechanism enhancing systemic autoimmunity by the rescue of exhausted autoreactive CD21low B cells.

COVID-19 and Mixed Cryoglobulinemia Syndrome: Long-Term Survey Study on the Prevalence and Outcome, Vaccine Safety, and Immunogenicity.

PURPOSE: Mixed cryoglobulinemia syndrome (MCs) is a rare immunoproliferative systemic disorder with cutaneous and multiple organ involvement. Our multicenter survey study aimed to investigate the prevalence and outcome of COVID-19 and the safety and immunogenicity of COVID-19 vaccines in a large MCs series. METHODS: The survey included 430 unselected MCs patients (130 M, 300 F; mean age 70 ± 10.96 years) consecutively collected at 11 Italian referral centers. Disease classification, clinico-serological assessment, COVID-19 tests, and vaccination immunogenicity were carried out according to current methodologies. RESULTS: A significantly higher prevalence of COVID-19 was found in MCs patients compared to Italian general population (11.9% vs 8.0%, p < 0.005), and the use of immunomodulators was associated to a higher risk to get infected (p = 0.0166). Moreover, higher mortality rate was recorded in MCs with COVID-19 compared to those without (p < 0.01). Patients' older age (≥ 60 years) correlated with worse COVID-19 outcomes. The 87% of patients underwent vaccination and 50% a booster dose. Of note, vaccine-related disease flares/worsening were significantly less frequent than those associated to COVID-19 (p = 0.0012). Impaired vaccination immunogenicity was observed in MCs patients compared to controls either after the first vaccination (p = 0.0039) and also after the booster dose (p = 0.05). Finally, some immunomodulators, namely, rituximab and glucocorticoids, hampered the vaccine-induced immunogenicity (p = 0.029). CONCLUSIONS: The present survey revealed an increased prevalence and morbidity of COVID-19 in MCs patients, as well an impaired immunogenicity even after booster vaccination with high rate of no response. Therefore, MCs can be included among frail populations at high risk of infection and severe COVID-19 manifestations, suggesting the need of a close monitoring and specific preventive/therapeutical measures during the ongoing pandemic.

COVID-19 vaccination rate and safety profile in a multicentre Italian population affected by mixed cryoglobulinaemic vasculitis.

OBJECTIVES: Mixed cryoglobulinaemic vasculitis (MCV) is an immune-complex-mediated systemic vasculitis characterised by heterogeneous clinical manifestations mainly involving lymphatic system, skin, kidney and peripheral nervous system. Although MCV patients have been included in priority programs for vaccination against SARS-CoV-2 in Italy, limited information is available for these patients. The aims of this multicentre Italian study were to investigate SARS-CoV-2 vaccination rate in MCV patients and its safety profile. METHODS: All MCV patients referring to participating centres were assessed with an interview-based survey about vaccination, reasons for not getting vaccinated, adverse events (AE), and disease flares within a month after vaccination. RESULTS: A total of 416 patients were included in the study. Among participants, 7.7% did not get vaccinated, mainly for fear related to vaccine side-effects (50%) or medical decision (18.8%). They were more frequently treated with chronic glucocorticoids or rituximab (p=0.049 and p=0.043, respectively). Mild and self-limiting AE were recorded in 31.7% of cases, while post-vaccination vasculitis flares were observed in 5.3% of subjects. Disease relapses were mainly observed in patients with peripheral neuropathy or skin vasculitis (40% and 25%, respectively). CONCLUSIONS: Vaccination against SARS-CoV-2 has been performed in a high percentage of MCV patients with encouraging safety profile. Vasculitis flares rate was in line with that observed for other autoimmune diseases, despite patients with purpura or peripheral neuropathy seem to be at risk for symptoms' exacerbation. Patients' hesitancy, rituximab and glucocorticoids treatment were the main reasons for delaying vaccination.

Management of mixed cryoglobulinemia with rituximab: evidence and consensus-based recommendations from the Italian Study Group of Cryoglobulinemia (GISC).

Cryoglobulinemic vasculitis (CV) or mixed cryoglobulinemic syndrome (MCS) is a systemic small-vessel vasculitis characterized by the proliferation of B-cell clones producing pathogenic immune complexes, called cryoglobulins. It is often secondary to hepatitis C virus (HCV), autoimmune diseases, and hematological malignancies. CV usually has a mild benign clinical course, but severe organ damage and life-threatening manifestations can occur. Recently, evidence in favor of rituximab (RTX), an anti-CD 20 monoclonal antibody, is emerging in CV: nevertheless, questions upon the safety of this therapeutic approach, especially in HCV patients, are still being issued and universally accepted recommendations that can help physicians in MCS treatment are lacking. A Consensus Committee provided a prioritized list of research questions to perform a systematic literature review (SLR). A search was made in Medline, Embase, and Cochrane library, updated to August 2021. Of 1227 article abstracts evaluated, 27 studies were included in the SLR, of which one SLR, 4 RCTs, and 22 observational studies. Seventeen recommendations for the management of mixed cryoglobulinemia with rituximab from the Italian Study Group of Cryoglobulinemia (GISC) were developed to give a valuable tool to the physician approaching RTX treatment in CV.

Breakthrough infections after COVID-19 vaccinations do not elicit platelet hyperactivation and are associated with high platelet-lymphocyte and low platelet-neutrophil aggregates.

Background: Severe COVID-19 is associated with an excessive immunothrombotic response and thromboinflammatory complications. Vaccinations effectively reduce the risk of severe clinical outcomes in patients with COVID-19, but their impact on platelet activation and immunothrombosis during breakthrough infections is not known. Objectives: To investigate how preemptive vaccinations modify the platelet-immune crosstalk during COVID-19 infections. Methods: Cross-sectional flow cytometry study of the phenotype and interactions of platelets circulating in vaccinated (n = 21) and unvaccinated patients with COVID-19, either admitted to the intensive care unit (ICU, n = 36) or not (non-ICU, n = 38), in comparison to matched SARS-CoV-2-negative patients (n = 48), was performed. Results: In the circulation of unvaccinated non-ICU patients with COVID-19, we detected hyperactive and hyperresponsive platelets and platelet aggregates with adaptive and innate immune cells. In unvaccinated ICU patients with COVID-19, most of whom had severe acute respiratory distress syndrome, platelets had high P-selectin and phosphatidylserine exposure but low capacity to activate integrin αIIbß3, dysfunctional mitochondria, and reduced surface glycoproteins. In addition, in the circulation of ICU patients, we detected microthrombi and platelet aggregates with innate, but not with adaptive, immune cells. In vaccinated patients with COVID-19, who had no acute respiratory distress syndrome, platelets had surface receptor levels comparable to those in controls and did not form microthrombi or platelet-granulocyte aggregates but aggregated avidly with adaptive immune cells. Conclusion: Our study provides evidence that vaccinated patients with COVID-19 are not associated with platelet hyperactivation and are characterized by platelet-leukocyte aggregates that foster immune protection but not excessive immunothrombosis. These findings advocate for the importance of vaccination in preventing severe COVID-19.

COVID-19 vaccine immunogenicity in 16 patients with autoimmune systemic diseases. Lack of both humoral and cellular response to booster dose and ongoing disease modifying therapies.

Background: Patients with autoimmune systemic diseases (ASDs) represent a frail population during the ongoing COVID-19 pandemic. The vaccination is the major preventive measure; however, a significant number of ASD patients show an impaired production of anti-COVID-19 neutralizing antibodies (NAb), possibly counterbalanced by adequate T-cell response. The present study aimed at evaluating both humoral and cellular response to COVID-19 vaccine booster dose in this particular setting. Patients and methods: Serum NAb titer and T-cell response (measuring interferon gamma -IFN-γ- release) were evaluated 3 weeks after the COVID-19 vaccine booster dose, in 17 patients (12 F, mean age 68.8 ± 15.3 SD yrs) with different ASDs, compared to 17 healthy controls (HCs). Results: The analysis excluded one patient reporting symptoms of COVID-19 only after the immunogenicity tests had been performed.The NAb levels were significantly lower in ASD compared to HCs (p < 0.0001); moreover, patients showed a higher percentage of negative/sub-optimal humoral response (31% vs 0% of HCs; p = 0.0184).The study of cellular response showed lower levels of IFN-γ for both Ag1 (p = 0.0032) and Ag2 (p = 0.0136) in ASD patients compared to HCs, as well lower rate of adequate T-cell response compared to HCs (50% vs 94%; p = 0.0066).Disease modifying therapies (DMT) were administered in all patients with deficient NAb production (5/5, 100%), but in only 3/11 (27%) of responders (p = 0.025).Worthy to note, 3/16 (19%) ASD patients developed neither humoral nor cellular responses, all treated with DMT. Conclusions: The impaired immunogenicity to COVID-19 vaccine booster and even more the concomitant lack of both humoral and cellular response might represent a high risk for severe COVID-19, particularly in ASD patients undergoing DMT.These frail subjects should be tightly monitored for their immune protection and prioritized for the fourth dose of COVID-19 vaccine. Moreover, in the occurrence of SARS-CoV2 infection, treatments with specific monoclonal antibodies and/or antivirals may be highly recommendable.

The Effect of SARS-CoV-2 Vaccination on B-Cell Phenotype in Systemic Sclerosis Patients.

OBJECTIVE: to assess the influence of SARS-CoV-2 mRNA vaccine on B-cell phenotypes in systemic sclerosis (SSc). METHODS: peripheral blood B-cell subpopulations were evaluated before (t1) and 3 months (t3) after the second dose of vaccine in 28 SSc patients. Peripheral blood B-cell subpopulations were evaluated in 21 healthy controls (HCs) only at t1. Anti-spike IgG levels were evaluated at t3 in both cohorts. RESULTS: SSc patients presented higher naive, double-negative, and CD21low B cells compared to HCs. IgM-memory and switched-memory B cells were lower in SSc patients than HCs. No differences in anti-spike IgG levels after vaccination were observed between SSc patients and HCs. Anti-spike IgG levels after vaccination were lower in SSc patients with increased CD21low B cells at baseline compared to SSc patients with normal CD21low B cells. A positive correlation was found between IgG levels and naive B cells. A negative linear correlation was shown between IgG levels and IgM-memory, switched-memory, double-negative, and CD21low B cells. CONCLUSIONS: SARS-CoV-2 mRNA vaccine response is normal in SSc patients not undergoing immunosuppressive therapy. The normal number of naive B cells is a positive marker of antibody response. The increased percentage of CD21low B cells represents a negative marker of antibody response.

Human CD38 regulates B cell antigen receptor dynamic organization in normal and malignant B cells.

CD38 is a multifunctional protein expressed on the surface of B cells in healthy individuals but also in B cell malignancies. Previous studies have suggested a connection between CD38 and components of the IgM class B cell antigen receptor (IgM-BCR) and its coreceptor complex. Here, we provide evidence that CD38 is closely associated with CD19 in resting B cells and with the IgM-BCR upon engagement. We show that targeting CD38 with an antibody, or removing this molecule with CRISPR/Cas9, inhibits the association of CD19 with the IgM-BCR, impairing BCR signaling in normal and malignant B cells. Together, our data suggest that CD38 is a new member of the BCR coreceptor complex, where it exerts a modulatory effect on B cell activation upon antigen recognition by regulating CD19. Our study also reveals a new mechanism where α-CD38 antibodies could be a valuable option in therapeutic approaches to B cell malignancies driven by aberrant BCR signaling.

Absent or suboptimal response to booster dose of COVID-19 vaccine in patients with autoimmune systemic diseases.

Autoimmune systemic diseases (ASD) show impaired immunogenicity to COVID-19 vaccines. Our prospective observational multicenter study aimed at evaluating the seroconversion elicited by COVID-19 vaccine over the entire vaccination cycle including the booster dose. Among 478 unselected ASD patients originally evaluated at the end of the first vaccination cycle (time 1), 344 individuals were re-evaluated after a 6-month period (time 2), and 244 after the booster vaccine dose (time 3). The immunogenicity of mRNA COVID-19 vaccines (BNT162b2 and mRNA-1273) was assessed by measuring serum IgG-neutralizing antibody (NAb) on samples obtained at the three time points in both patients and 502 age-matched controls. In the 244 ASD group that received booster vaccine and monitored over the entire follow-up, the mean serum NAb levels (time 1, 2, and 3: 696.8 ± 52.68, 370.8 ± 41.92, and 1527 ± 74.16SD BAU/mL, respectively; p < 0.0001) were constantly lower compared to controls (p < 0.0001), but they significantly increased after the booster dose compared to the first two measurements (p < 0.0001). The percentage of patients with absent/suboptimal response to vaccine significantly decreased after the booster dose compared to the first and second evaluations (time 1, 2, and 3: from 28.2% to 46.3%, and to 7.8%, respectively; p < 0.0001). Of note, the percentage of patients with absent/suboptimal response after the booster dose was significantly higher compared to controls (19/244, 7.8% vs 1/502, 0.2%; p < 0.0001). Similarly, treatment with immune-modifiers increased the percentage of patients exhibiting absent/suboptimal response (16/122, 13.1% vs 3/122, 2.46%; p = 0.0031). Overall, the above findings indicate the usefulness of booster vaccine administration in ASD patients. Moreover, the persistence of a significantly higher percentage of individuals without effective seroconversion (7.8%), even after the booster dose, warrants for careful monitoring of NAb levels in all ASD patients to identify those with increased risk of infection. In this particularly frail patients' setting, tailored vaccination and/or therapeutic strategy are highly advisable.