Two-component spike nanoparticle vaccine protects macaques from SARS-CoV-2 infection.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is continuing to disrupt personal lives, global healthcare systems, and economies. Hence, there is an urgent need for a vaccine that prevents viral infection, transmission, and disease. Here, we present a two-component protein-based nanoparticle vaccine that displays multiple copies of the SARS-CoV-2 spike protein. Immunization studies show that this vaccine induces potent neutralizing antibody responses in mice, rabbits, and cynomolgus macaques. The vaccine-induced immunity protects macaques against a high-dose challenge, resulting in strongly reduced viral infection and replication in the upper and lower airways. These nanoparticles are a promising vaccine candidate to curtail the SARS-CoV-2 pandemic.

Antigenic cartography using sera from sequence-confirmed SARS-CoV-2 variants of concern infections reveals antigenic divergence of Omicron.

Large-scale vaccination campaigns have prevented countless hospitalizations and deaths due to COVID-19. However, the emergence of SARS-CoV-2 variants that escape from immunity challenges the effectiveness of current vaccines. Given this continuing evolution, an important question is when and how to update SARS-CoV-2 vaccines to antigenically match circulating variants, similarly to seasonal influenza viruses where antigenic drift necessitates periodic vaccine updates. Here, we studied SARS-CoV-2 antigenic drift by assessing neutralizing activity against variants of concern (VOCs) in a set of sera from patients infected with viral sequence-confirmed VOCs. Infections with D614G or Alpha strains induced the broadest immunity, whereas individuals infected with other VOCs had more strain-specific responses. Omicron BA.1 and BA.2 were substantially resistant to neutralization by sera elicited by all other variants. Antigenic cartography revealed that Omicron BA.1 and BA.2 were antigenically most distinct from D614G, associated with immune escape, and possibly will require vaccine updates to ensure vaccine effectiveness.

Infection and transmission of SARS-CoV-2 depend on heparan sulfate proteoglycans.

The current pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and outbreaks of new variants highlight the need for preventive treatments. Here, we identified heparan sulfate proteoglycans as attachment receptors for SARS-CoV-2. Notably, neutralizing antibodies against SARS-CoV-2 isolated from COVID-19 patients interfered with SARS-CoV-2 binding to heparan sulfate proteoglycans, which might be an additional mechanism of antibodies to neutralize infection. SARS-CoV-2 binding to and infection of epithelial cells was blocked by low molecular weight heparins (LMWH). Although dendritic cells (DCs) and mucosal Langerhans cells (LCs) were not infected by SARS-CoV-2, both DC subsets efficiently captured SARS-CoV-2 via heparan sulfate proteoglycans and transmitted the virus to ACE2-positive cells. Notably, human primary nasal cells were infected by SARS-CoV-2, and infection was blocked by pre-treatment with LMWH. These data strongly suggest that heparan sulfate proteoglycans are important attachment receptors facilitating infection and transmission, and support the use of LMWH as prophylaxis against SARS-CoV-2 infection.

Aberrant neutrophil degranulation in hospitalized patients with COVID-19 partially remains for 6 months.

Neutrophils are important players in COVID-19, contributing to tissue damage by release of inflammatory mediators, including ROS and neutrophil elastase. Longitudinal studies on the effects of COVID-19 on neutrophil phenotype and function are scarce. Here, we longitudinally investigated the phenotype and degranulation of neutrophils in COVID-19 patients (28 nonhospitalized and 35 hospitalized patients) compared with 17 healthy donors (HDs). We assessed phenotype, degranulation, CXCL8 (IL-8) release, and ROS generation within 8 days, at one or 6 month(s) after COVID-19 diagnosis. For degranulation and ROS production, we stimulated neutrophils, either with ssRNA and TNF or granulocyte-macrophage colony-stimulating factor and N-Formylmethionyl-leucyl-phenylalanine. During active COVID-19, neutrophils from hospitalized patients were more immature than from HDs and were impaired in degranulation and ROS generation, while neutrophils from nonhospitalized patients only demonstrated reduced CD66b+ granule release and ROS production. Baseline CD63 expression, indicative of primary granule release, and CXCL8 production by neutrophils from hospitalized patients were elevated for up to 6 months. These findings show that patients hospitalized due to COVID-19, but not nonhospitalized patients, demonstrated an aberrant neutrophil phenotype, degranulation, CXCL8 release, and ROS generation that partially persists up to 6 months after infection.

A Robust SARS-CoV-2-specific T and B Cell Response is Associated with Early Viral Clearance in SARS-CoV-2 Omicron-Infected Immunocompromised Individuals.

BACKGROUND: The immunological determinants of delayed viral clearance and intra-host viral evolution that drive the development of new pathogenic virus strains in immunocompromised individuals are unknown. Therefore, we longitudinally studied SARS-CoV-2-specific immune responses in relation to viral-clearance and evolution in immunocompromised individuals. METHODS: Among Omicron-infected immunocompromised individuals, we determined SARS-CoV-2-specific T- and B-cell responses, anti-spike IgG(3) titers, neutralization titers, and monoclonal antibody (mAb)-resistance-associated mutations. The 28-day post-enrollment nasopharyngeal specimen defined early (RT-PCR negative ≤28 days) or late (RT-PCR- positive >28 days) viral-clearance. RESULTS: Of 30 patients included (median age 61.9 years [IQR 47.4-72.3], 50% females), 20 (66.7%) received mAb-therapy. Thirteen (43.3%) demonstrated early and 17 (56.7%) late viral-clearance. Early viral-clearance patients and patients without resistance-associated mutations had significantly higher baseline IFN-γ release and early viral-clearance patients had a higher frequency of SARS-CoV-2-specific B-cells at baseline. In non-mAb-treated patients, day 7 IgG and neutralization titers were significantly higher in those with early versus late viral-clearance. CONCLUSION: An early robust adaptive immune response is vital for efficient viral-clearance and associated with less emergence of mAb-resistance-associated mutations in Omicron-infected immunocompromised patients. This emphasizes the importance of early SARS-CoV-2-specific T- and B-cell responses and thereby provides a rationale for development of novel therapeutic approaches.

Immune Responses 6 Months After mRNA-1273 COVID-19 Vaccination and the Effect of a Third Vaccination in Patients with Inborn Errors of Immunity.

PURPOSE: Patients with inborn errors of immunity (IEI) are at increased risk of severe coronavirus disease-2019 (COVID-19). Effective long-term protection against COVID-19 is therefore of great importance in these patients, but little is known about the decay of the immune response after primary vaccination. We studied the immune responses 6 months after two mRNA-1273 COVID-19 vaccines in 473 IEI patients and subsequently the response to a third mRNA COVID-19 vaccine in 50 patients with common variable immunodeficiency (CVID). METHODS: In a prospective multicenter study, 473 IEI patients (including X-linked agammaglobulinemia (XLA) (N = 18), combined immunodeficiency (CID) (N = 22), CVID (N = 203), isolated or undefined antibody deficiencies (N = 204), and phagocyte defects (N = 16)), and 179 controls were included and followed up to 6 months after two doses of the mRNA-1273 COVID-19 vaccine. Additionally, samples were collected from 50 CVID patients who received a third vaccine 6 months after primary vaccination through the national vaccination program. SARS-CoV-2-specific IgG titers, neutralizing antibodies, and T cell responses were assessed. RESULTS: At 6 months after vaccination, the geometric mean antibody titers (GMT) declined in both IEI patients and healthy controls, when compared to GMT 28 days after vaccination. The trajectory of this decline did not differ between controls and most IEI cohorts; however, antibody titers in CID, CVID, and isolated antibody deficiency patients more often dropped to below the responder cut-off compared to controls. Specific T cell responses were still detectable in 77% of controls and 68% of IEI patients at 6 months post vaccination. A third mRNA vaccine resulted in an antibody response in only two out of 30 CVID patients that did not seroconvert after two mRNA vaccines. CONCLUSION: A similar decline in IgG titers and T cell responses was observed in patients with IEI when compared to healthy controls 6 months after mRNA-1273 COVID-19 vaccination. The limited beneficial benefit of a third mRNA COVID-19 vaccine in previous non-responder CVID patients implicates that other protective strategies are needed for these vulnerable patients.

Immunogenicity of the mRNA-1273 COVID-19 vaccine in adult patients with inborn errors of immunity.

BACKGROUND: Patients with inborn errors of immunity (IEI) are at increased risk of severe coronavirus disease-2019 (COVID-19). Effective vaccination against COVID-19 is therefore of great importance in this group, but little is known about the immunogenicity of COVID-19 vaccines in these patients. OBJECTIVES: We sought to study humoral and cellular immune responses after mRNA-1273 COVID-19 vaccination in adult patients with IEI. METHODS: In a prospective, controlled, multicenter study, 505 patients with IEI (common variable immunodeficiency [CVID], isolated or undefined antibody deficiencies, X-linked agammaglobulinemia, combined B- and T-cell immunodeficiency, phagocyte defects) and 192 controls were included. All participants received 2 doses of the mRNA-1273 COVID-19 vaccine. Levels of severe acute respiratory syndrome coronavirus-2-specific binding antibodies, neutralizing antibodies, and T-cell responses were assessed at baseline, 28 days after first vaccination, and 28 days after second vaccination. RESULTS: Seroconversion rates in patients with clinically mild antibody deficiencies and phagocyte defects were similar to those in healthy controls, but seroconversion rates in patients with more severe IEI, such as CVID and combined B- and T-cell immunodeficiency, were lower. Binding antibody titers correlated well to the presence of neutralizing antibodies. T-cell responses were comparable to those in controls in all IEI cohorts, with the exception of patients with CVID. The presence of noninfectious complications and the use of immunosuppressive drugs in patients with CVID were negatively correlated with the antibody response. CONCLUSIONS: COVID-19 vaccination with mRNA-1273 was immunogenic in mild antibody deficiencies and phagocyte defects and in most patients with combined B- and T-cell immunodeficiency and CVID. Lowest response was detected in patients with X-linked agammaglobulinemia and in patients with CVID with noninfectious complications. The assessment of longevity of immune responses in these vulnerable patient groups will guide decision making for additional vaccinations.

Antibody responses against SARS-CoV-2 variants induced by four different SARS-CoV-2 vaccines in health care workers in the Netherlands: A prospective cohort study.

BACKGROUND: Emerging and future SARS-CoV-2 variants may jeopardize the effectiveness of vaccination campaigns. Therefore, it is important to know how the different vaccines perform against diverse SARS-CoV-2 variants. METHODS AND FINDINGS: In a prospective cohort of 165 SARS-CoV-2 naive health care workers in the Netherlands, vaccinated with either one of four vaccines (BNT162b2, mRNA-1273, AZD1222 or Ad26.COV2.S), we performed a head-to-head comparison of the ability of sera to recognize and neutralize SARS-CoV-2 variants of concern (VOCs; Alpha, Beta, Gamma, Delta and Omicron). Repeated serum sampling was performed 5 times during a year (from January 2021 till January 2022), including before and after booster vaccination with BNT162b2. Four weeks after completing the initial vaccination series, SARS-CoV-2 wild-type neutralizing antibody titers were highest in recipients of mRNA-1273, followed by recipients of BNT162b2 (geometric mean titers (GMT) of 358 [95% CI 231-556] and 214 [95% CI 153-299], respectively; p<0.05), and substantially lower in those vaccinated with the adenovirus vector-based vaccines AZD1222 and Ad26.COV2.S (GMT of 18 [95% CI 11-30] and 14 [95% CI 8-25] IU/ml, respectively; p<0.001). VOCs neutralization was reduced in all vaccine groups, with the greatest reduction in neutralization GMT observed against the Omicron variant (fold change 0.03 [95% CI 0.02-0.04], p<0.001). The booster BNT162b2 vaccination increased neutralizing antibody titers for all groups with substantial improvement against the VOCs including the Omicron variant. We used linear regression and linear mixed model analysis. All results were adjusted for possible confounding of age and sex. Study limitations include the lack of cellular immunity data. CONCLUSIONS: Overall, this study shows that the mRNA vaccines appear superior to adenovirus vector-based vaccines in inducing neutralizing antibodies against VOCs four weeks after initial vaccination and after booster vaccination, which implies the use of mRNA vaccines for both initial and booster vaccination.

Immunogenicity of a 5-dose pneumococcal vaccination schedule following allogeneic hematopoietic stem cell transplantation.

The optimal schedule of pneumococcal vaccination after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains controversial. The objective of this study was to investigate the immunogenicity of a 5-dose pneumococcal vaccination schedule in adult allo-HSCT recipients with and without immunosuppressive therapy. In this prospective cohort study, allo-HSCT recipients received four doses of the 13-valent pneumococcal conjugate vaccine (PCV13) and one dose of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) starting 4-6 months after allo-HSCT. PCV13 was administered at T0, T1, T2, and T8 (T = months from enrollment) and PPSV23 at T10. Serum was collected at T0, T4, T8, T10, and T12, and IgG levels were measured for all 24 vaccine serotypes by immunoassay. The primary outcome was overall seroprotection at T12 defined as an IgG concentration ≥1.3 µg/ml for 17/24 vaccine serotypes in allo-HCST recipients with and without immunosuppressive therapy at baseline. Secondary outcomes were serotype-specific seroprotection and dynamics of IgG levels. We included 89 allo-HSCT recipients in the final analysis. Overall seroprotection was 47% (15/32) for patients without immunosuppressive therapy at baseline versus 24% (11/46) for patients with immunosuppressive therapy (p = .03). Seroprotection was higher for PCV13 serotypes (78% and 54% respectively; p = .03) and lower for PPSV23-unique serotypes (28% and 13% respectively; p = .1). IgG concentrations increased significantly over time for all 24 serotypes. Concluding, although immunogenicity of PCV13 serotypes was reasonable, the poor response to PPSV23 serotypes resulted in an insufficient overall response to pneumococcal vaccination for allo-HSCT recipients. Research into vaccination strategies with higher-valent T-cell-dependent pneumococcal vaccines is needed.

Decreased Time to Viral Suppression After Implementation of Targeted Testing and Immediate Initiation of Treatment of Acute Human Immunodeficiency Virus Infection Among Men Who Have Sex With Men in Amsterdam.

BACKGROUND: Men who have sex with men (MSM) with acute human immunodeficiency virus (HIV) infection (AHI) are a key source of new infections. To curb transmission, we implemented a strategy for rapid AHI diagnosis and immediate initiation of combination antiretroviral therapy (cART) in Amsterdam MSM. We assessed its effectiveness in diagnosing AHI and decreasing the time to viral suppression. METHODS: We included 63 278 HIV testing visits in 2008-2017, during which 1013 MSM were diagnosed. Standard of care (SOC) included HIV diagnosis confirmation in < 1 week and cART initiation in < 1 month. The AHI strategy comprised same-visit diagnosis confirmation and immediate cART. Time from diagnosis to viral suppression was assessed for 3 cART initiation periods: (1) 2008-2011: cART initiation if CD4 < 500 cells/µL (SOC); (2) January 2012-July 2015: cART initiation if CD4 < 500 cells/µL, or if AHI or early HIV infection (SOC); and (3a) August 2015-June 2017: universal cART initiation (SOC) or (3b) August 2015-June 2017 (the AHI strategy). RESULTS: Before implementation of the AHI strategy, the proportion of AHI among HIV diagnoses was 0.6% (5/876); after implementation this was 11.0% (15/137). Median time (in days) to viral suppression during periods 1, 2, 3a, and 3b was 584 (interquartile range [IQR], 267-1065), 230 (IQR, 132-480), 95 (IQR, 63-136), and 55 (IQR, 31-72), respectively (P < .001). CONCLUSIONS: Implementing the AHI strategy was successful in diagnosing AHI and significantly decreasing the time between HIV diagnosis and viral suppression.

Nailfold capillary abnormalities in childhood-onset systemic lupus erythematosus: a cross-sectional study compared with healthy controls.

OBJECTIVES: For selection of high-risk systemic lupus erythematosus (SLE) patients it is necessary to obtain indicators of disease severity that predict disease damage. As in systemic sclerosis, nailfold capillary abnormalities could be such a biomarker in SLE. The primary objective of this cross-sectional study is to describe capillary abnormalities in childhood-onset SLE (cSLE) cohort (onset < 18 years) and compare them with matched healthy controls. The secondary objective is to correlate the observed capillary abnormalities with demographical variables in both cohorts and with disease-specific variables in cSLE patients. METHODS: Healthy controls were matched for ethnic background, age and gender. Videocapillaroscopy was performed in eight fingers with 2-4 images per finger. Quantitative and qualitative assessments of nailfold capillaroscopy images were performed according to the definitions of the EULAR study group on microcirculation in Rheumatic Diseases. RESULTS: Both groups (n = 41 cSLE-patients and n = 41 healthy controls) were comparable for ethnic background (p = 0.317). Counted per mm, cSLE-patients showed significantly more 'giants' (p = 0.032), 'abnormal capillary shapes' (p = 0.003), 'large capillary hemorrhages' (p < 0.001) and 'pericapillary extravasations' (p < 0.001). Combined 'abnormal capillary shapes and pericapillary extravasations' (in the same finger) were detected in 78% (32/41 patients). By qualitative analysis, 'microangiopathy' was detected in 68.3% (28/41) and a 'scleroderma pattern' in 17.1% (7/41) of the cSLE-patients (without scleroderma symptoms). The difference of percentage positive anti-RNP antibodies in the group with or without a scleroderma pattern was not significant (p = 0.089). The number of 'abnormal capillary shapes per mm' was significantly correlated with treatment-naivety. The number of 'large pathological hemorrhages per mm' was significantly correlated with SLEDAI score and presence of nephritis. Compared to healthy controls, 'pericapillary extravasations' were found in significantly higher numbers per mm (p < 0.001) as well as in percentage of patients (p < 0.001). CONCLUSIONS: Our observations confirm that giants, abnormal capillary morphology and capillary hemorrhages are also observed in cSLE, as was already known for adults with SLE. Number of capillary hemorrhages in cSLE was significantly correlated with disease activity. A high frequency and total amount of "pericapillary extravasations" was observed in cSLE patients, possibly revealing a new subtype of capillary hemorrhage that might reflect endothelial damage in these pediatric patients.

Promoting HIV indicator condition-guided testing in hospital settings (PROTEST 2.0): study protocol for a multicentre interventional study.

BACKGROUND: Late presentation remains a key barrier towards controlling the HIV epidemic. Indicator conditions (ICs) are those that are AIDS-defining, associated with a prevalence of undiagnosed HIV > 0.1%, or whose clinical management would be impeded if an HIV infection were undiagnosed. IC-guided HIV testing is an effective strategy in identifying undiagnosed HIV, but opportunities for earlier HIV diagnosis through IC-guided testing are being missed. We present a protocol for an interventional study to improve awareness of IC-guided testing and increase HIV testing in patients presenting with ICs in a hospital setting. METHODS: We designed a multicentre interventional study to be implemented at five hospitals in the region of Amsterdam, the Netherlands. Seven ICs were selected for which HIV test ratios (proportion of patients with an IC tested for HIV) will be measured: tuberculosis, cervical/vulvar cancer or high-grade cervical/vulvar dysplasia, malignant lymphoma, hepatitis B and C, and peripheral neuropathy. Prior to the intervention, a baseline assessment of HIV test ratios across ICs will be performed in eligible patients (IC diagnosed January 2015 through May 2020, ≥18 years, not known HIV positive) and an assessment of barriers and facilitators for HIV testing amongst relevant specialties will be conducted using qualitative (interviews) and quantitative methods (questionnaires). The intervention phase will consist of an educational intervention, including presentation of baseline results as competitive graphical audit and feedback combined with discussion on implementation and opportunities for improvement. The effect of the intervention will be assessed by comparing HIV test ratios of the pre-intervention and post-intervention periods. The primary endpoint is the HIV test ratio within ±3 months of IC diagnosis. Secondary endpoints are the HIV test ratio within ±6 months of diagnosis, ratio ever tested for HIV, HIV positivity percentage, proportion of late presenters and proportion with known HIV status prior to initiating treatment for their IC. DISCUSSION: This protocol presents a strategy aimed at increasing awareness of the benefits of IC-guided testing and increasing HIV testing in patients presenting with ICs in hospital settings to identify undiagnosed HIV in Amsterdam, the Netherlands. TRIAL REGISTRATION: Dutch trial registry: NL7521 . Registered 14 February 2019.

Rationale, design and initial results of an educational intervention to improve provider-initiated HIV testing in primary care.

OBJECTIVES: In the Netherlands, general practitioners (GPs) perform two-thirds of sexually transmitted infection (STI) consultations and diagnose one-third of HIV infections. GPs are, therefore, a key group to target to improve provider-initiated HIV testing. We describe the design and implementation of an educational intervention to improve HIV testing by Amsterdam GPs and explore trends in GPs' testing behaviour. METHODS: Interactive sessions on HIV and STI using graphical audit and feedback started in 2015. Participating GPs developed improvement plans that were evaluated in follow-up sessions. Laboratory data on STI testing by Amsterdam GPs from 2011 to 2017 were collected for graphical audit and feedback and effect evaluation. The primary outcome was the HIV testing rate: number of HIV tests per 10 000 person-years (PY). Secondary endpoints were chlamydia and gonorrhoea testing rates and HIV positivity ratios. RESULTS: Since 2015, 41% of GPs participated. HIV testing rate declined from 2011 to 2014 (from 175 to 116 per 10 000 PY), more in women than men (176 to 101 versus 173 to 132), and stabilized from 2015 to 2017. The HIV positivity ratio declined from 0.8% in 2011 to 0.5% in 2017. From 2011 to 2017, chlamydia and gonorrhoea testing rates declined in women (from 618 to 477 per 10 000 PY) but remained stable in men (from 270 to 278). CONCLUSIONS: The stabilization of the downward trend in HIV testing coincided with this educational intervention. Follow-up data are needed to formally assess the intervention's impact on GP testing behaviour whilst considering contextual factors and secular trends.

Validation of the San Diego Early Test Score for Early Human Immunodeficiency Virus Infection Among Amsterdam Men Who Have Sex With Men.

The San Diego Early Test score is a simple risk-assessment tool for acute, and early human immunodeficiency virus (HIV) infection. Validation in a prospective cohort of Amsterdam men who have sex with men showed fair prediction of HIV seroconversion (AUC, 0.701). This score can help prioritize and target HIV-prevention strategies.

Allogeneic hematopoietic cell transplantation in the management of GATA2 deficiency and pulmonary alveolar proteinosis.

Human hematopoiesis is critically dependent on the transcription factor GATA2. Patients with GATA2 deficiency typically present with myelodysplastic syndrome, reduced numbers of monocytes, NK cells and B cells, and/or opportunistic infections. Here, we present two families that harbor distinct GATA2 mutations with highly variable onset and course of disease. We discuss the use of allogeneic hematopoietic cell transplantation in these patients, especially as treatment for pulmonary alveolar proteinosis.

Pathogenic NFKB2 variant in the ankyrin repeat domain (R635X) causes a variable antibody deficiency.

Genetic studies are identifying an increasing number of monogenic causes of Common Variable Immunodeficiency (CVID). Pathogenic variants in the C-terminus of NFKB2 have been identified in the subset of CVID patients whose immunodeficiency is associated with ectodermal dysplasia and central adrenal insufficiency. We describe 2 unrelated CVID pedigrees with 4 cases of pathogenic stop gain variants (c.1903C > T) in the ankyrin repeat domain (ARD) of NF-κB2, leading to a premature truncation of the protein at p.Arg635Term (R635X). By immunophenotyping and functional ex vivo B- and T-cell experiments we characterized the variant by reduced class-switched memory B-cell counts and immature plasmablasts, unable to produce IgG and IgA. Features of a poor proliferative T-cell response and reduced expansion of CD4+CXCR5+ T cells was only observed in the two clinically affected index cases without any clear clinical correlate. In conclusion, pathogenic stop variants in the ARD of NFKB2 can cause 'infection-only' CVID with an abnormal B-cell phenotype and a variable clinical penetrance.

Loss-of-function nuclear factor κB subunit 1 (NFKB1) variants are the most common monogenic cause of common variable immunodeficiency in Europeans.

BACKGROUND: The genetic cause of primary immunodeficiency disease (PID) carries prognostic information. OBJECTIVE: We conducted a whole-genome sequencing study assessing a large proportion of the NIHR BioResource-Rare Diseases cohort. METHODS: In the predominantly European study population of principally sporadic unrelated PID cases (n = 846), a novel Bayesian method identified nuclear factor κB subunit 1 (NFKB1) as one of the genes most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense, and gene deletion variants. This accounted for 4% of common variable immunodeficiency (CVID) cases (n = 390) in the cohort. Amino acid substitutions predicted to be pathogenic were assessed by means of analysis of structural protein data. Immunophenotyping, immunoblotting, and ex vivo stimulation of lymphocytes determined the functional effects of these variants. Detailed clinical and pedigree information was collected for genotype-phenotype cosegregation analyses. RESULTS: Both sporadic and familial cases demonstrated evidence of the noninfective complications of CVID, including massive lymphadenopathy (24%), unexplained splenomegaly (48%), and autoimmune disease (48%), features prior studies correlated with worse clinical prognosis. Although partial penetrance of clinical symptoms was noted in certain pedigrees, all carriers have a deficiency in B-lymphocyte differentiation. Detailed assessment of B-lymphocyte numbers, phenotype, and function identifies the presence of an increased CD21low B-cell population. Combined with identification of the disease-causing variant, this distinguishes between healthy subjects, asymptomatic carriers, and clinically affected cases. CONCLUSION: We show that heterozygous loss-of-function variants in NFKB1 are the most common known monogenic cause of CVID, which results in a temporally progressive defect in the formation of immunoglobulin-producing B cells.

Development and validation of a risk score to assist screening for acute HIV-1 infection among men who have sex with men.

BACKGROUND: Early treatment of acute HIV-1 infection (AHI) is beneficial for patients and could reduce onward transmission. However, guidelines on whom to test for AHI with HIV-1 RNA testing are lacking. METHODS: A risk score for possible AHI based on literature and expert opinion - including symptoms associated with AHI and early HIV-1 - was evaluated using data from the Amsterdam Cohort Studies among men who have sex with men (MSM). Subsequently, we optimized the risk score by constructing two multivariable logistic regression models: one including only symptoms and one combining symptoms with known risk factors for HIV-1 seroconversion, using generalized estimating equations. Several risk scores were generated from these models and the optimal risk score was validated using data from the Multicenter AIDS Cohort Study. RESULTS: Using data from 1562 MSM with 175 HIV-1 seroconversion visits and 17,271 seronegative visits in the Amsterdam Cohort Studies, the optimal risk score included four symptoms (oral thrush, fever, lymphadenopathy, weight loss) and three risk factors (self-reported gonorrhea, receptive condomless anal intercourse, more than five sexual partners, all in the preceding six months) and yielded an AUC of 0.82. Sensitivity was 76.3% and specificity 76.3%. Validation in the Multicenter AIDS Cohort Study resulted in an AUC of 0.78, sensitivity of 56.2% and specificity of 88.8%. CONCLUSIONS: The optimal risk score had good overall performance in the Amsterdam Cohort Studies and performed comparable (but showed lower sensitivity) in the validation study. Screening for AHI with four symptoms and three risk factors would increase the efficiency of AHI testing and potentially enhance early diagnosis and immediate treatment.

B cells in HIV pathogenesis.

PURPOSE OF REVIEW: The induction of a virus-clearing humoral immune response in natural HIV infection is impaired. Insights into early events in HIV infection that affect B-cell responses and antibody development are addressed and related to strategies for the design of an HIV vaccine. RECENT FINDINGS: Broadly neutralizing antibody responses do not develop early in HIV-1 infection, and recent reports highlight the role of preexisting suboptimal B-cell populations that can dominate the early antibody response. Furthermore, from the earliest phases of infection, virus replication is a driving force behind alterations in the B cell and T-follicular helper cell (TFH) compartments. Paradoxically, the factors that drive these abnormalities, such as high virus load, duration of infection, and increased viral diversity, are likely necessary for the development of both TFH and broadly neutralizing antibodies. SUMMARY: These data provide new insights into prerequisites for an effective HIV vaccine. First, a vaccine should induce specific B-cell lineages so that preexisting cross-reactivity is avoided and, additionally, it must mimic high levels of diverse antigen in the absence of chronic virus replication within immune cells to activate high levels of quality of TFH and stimulate antibody maturation.