Blog

Biology (Basel). 2024 Mar 23;13(4):207. doi: 10.3390/biology13040207.

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect human cells by first attaching to the ACE-2 receptor via its receptor-binding domain (RBD) in the spike protein. Here, we report the influence of N-glycosylation sites of the RBD and the membrane (M) protein on IgG antibody binding in serum samples from patients infected with the original SARS-CoV-2 strain in Germany. The RBDs of the wildtype, alpha, beta, gamma, and kappa variants expressed in HEK293S GnTI- cells were all N-glycosylated at Asn331, Asn334, Asn343, and Asn360 or Asn370, whereas the M-protein was glycosylated at Asn5. An ELISA using a coated RBD and probed with anti-RBD IgG antibodies gave a sensitivity of 96.3% and a specificity of 100% for the wildtype RBD, while the sensitivity decreased by 5% to 10% for the variants of concern, essentially in the order of appearance. Deglycosylation of the wildtype RBD strongly reduced antibody recognition by ~20%, considering the mean of the absorbances recorded for the ELISA. This effect was even stronger for the unglycosylated RBD expressed in Escherichia coli, suggesting structural changes affecting epitope recognition. Interestingly, the N-glycosylated M-protein expressed in HEK293S GnTI- cells gave good sensitivity (95%), which also decreased to 65% after deglycosylation, and selectivity (100%). In conclusion, N-glycosylation of the M-protein, the RBD, and most likely the spike protein are important for proper antibody binding and immunological assays, whereas the type of N-glycosylation is less relevant.

PMID:38666819 | DOI:10.3390/biology13040207

Hematol Transfus Cell Ther. 2024 Apr 17:S2531-1379(24)00074-9. doi: 10.1016/j.htct.2024.02.026. Online ahead of print.

ABSTRACT

BACKGROUND/AIM: There are several complications of hematopoietic stem cell transplantation. Without any doubt, most important of these is aGvHD that increases transplant-related mortality. The aim of this study is to investigate whether ST-2 and Reg3α levels measured at an early stage in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation can be individual biomarkers identifying future GvHD and predicting treatment response.

MATERIALS AND METHODS: From January 2019 to January 2021, 27 patients undergoing hematopoietic stem cell transplantation for primary immunodeficiency or hematopoietic diseases formed the study group. During their follow-up, the patients were classified into two groups as those developing and those not developing aGvHD. Nineteen healthy volunteers from a similar age group who needed their blood samples drawn for other reasons and who did not have any history of chronic disease, infection or medication use formed the control group. Blood samples of patients scheduled to have allogeneic HSCT were obtained before the administration of the preparative regimen, on Day +7 post-transplant and on the day of diagnosis if they developed aGvHD. Serum samples were stored at -20ºC until the day of processing. ST2 and Reg3α levels were measured using the ELISA method.

RESULTS: For patients who developed aGvHD (n = 13), ST2 levels obtained before the transplantation, on Day +7 post-transplant and on the day of aGvHD diagnosis (in patients developing GvHD) were significantly higher compared to the healthy Control Group (p-value <0.05). As regards to the samples obtained on the same days, ST2 levels did not differ significantly among patients who developed and those who did not develop GvHD (n = 14; p-value >0.05). ST2 levels of samples obtained on the days that acute skin and gastrointestinal tract GvHD developed did not differ significantly between these two groups (p-value >0.05). Reg3α levels of the pre-transplant samples, on Day +7 after the transplantation and on the day of aGvHD diagnosis did not show any difference between any of the groups (p-value >0.05). As only two patients died after transplantation, thus correlation of ST2 and Reg3α levels with transplant-related mortality could not be proven.

CONCLUSION: The results of this study suggest that ST2 and Reg3α levels are neither diagnostic nor prognostic or predictive biomarkers of aGvHD, steroid resistance or transplant-related mortality in pediatric patients. This study can be regarded as a pilot study because of the small patient population; more research involving a larger patient population is required.

PMID:38658297 | DOI:10.1016/j.htct.2024.02.026

Arch Argent Pediatr. 2024 Apr 25:e202310271. doi: 10.5546/aap.2023-10271.eng. Online ahead of print.

ABSTRACT

Cryptosporidium spp. is a diarrhea-causing protozoan. Immunocompromised patients may develop severe and persistent clinical forms. Here we describe the characteristics of patients with an underlying disease associated with immunosuppression (DAI) and Cryptosporidium spp. infection seen at a referral children’s hospital in Argentina between 2018 and 2023. Demographic data, DAI, diarrhea characteristics, and co-infections were analyzed. A total of 30 patients with DAI and cryptosporidiosis were included. Most of them had undergone a solid organ transplant, had a hematologic neoplasm, or primary immunodeficiency. Persistent diarrhea was observed in 18 patients at the time of diagnosis. Co-infections were recorded in 6 patients. Cryptosporidiosis should be considered in the differential diagnosis of acute or persistent diarrhea in children with different types of DAI, such as solid organ transplant, hematologic neoplasms, and primary immunodeficiencies.

PMID:38656885 | DOI:10.5546/aap.2023-10271.eng

Scand J Immunol. 2024 Apr 23:e13372. doi: 10.1111/sji.13372. Online ahead of print.

ABSTRACT

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease caused by molecular defects in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. p67^phox-CGD is an autosomal recessive CGD, which is caused by a defect in the cytosolic components of NADPH oxidase, p67^phox, encoded by NCF2. We previously established a flow cytometric analysis for p67^phox expression, which allows accurate assessment of residual protein expression in p67^phox-CGD. We evaluated the correlation between oxidase function and p67^phox expression, and assessed the relevancy to genotypes and clinical phenotypes in 11 patients with p67^phox-CGD. Reactive oxygen species (ROS) production by granulocytes was evaluated using dihydrorhodamine-1,2,3 (DHR) assays. p67^phox expression was evaluated in the monocyte population. DHR activity and p67^phox expression were significantly correlated (r = 0.718, p < 0.0162). Additionally, DHR activity and p67^phox expression were significantly higher in patients carrying one missense variant in combination with one nonsense or frameshift variant in the NCF2 gene than in patients with only null variants. The available clinical parameters of our patients (i.e., age at disease onset, number of infectious episodes, and each infection complication) were not linked with DHR activity or p67^phox expression levels. In summary, our flow cytometric analysis revealed a significant correlation between residual ROS production and p67^phox expression. More deleterious NCF2 genotypes were associated with lower levels of DHR activity and p67^phox expression. DHR assays and protein expression analysis by using flow cytometry may be relevant strategies for predicting the genotypes of p67^phox-CGD.

PMID:38654426 | DOI:10.1111/sji.13372

Int J Neonatal Screen. 2024 Apr 5;10(2):30. doi: 10.3390/ijns10020030.

ABSTRACT

This article presents the report of the session on “Newborn Screening for Primary Immunodeficiencies-Now What?” organised during the International Primary Immunodeficiency Congress (IPIC) held in November 2023. This clinical conference was organised by the International Patient Organisation for Primary Immunodeficiencies (IPOPI), the global patient organisation advocating for primary immunodeficiencies (PIDs) in patients. The session aimed at exploring the advances in newborn screening (NBS) for severe combined immunodeficiency, starting with the common practice and inserting the discussion into the wider perspective of genomics whilst taking into consideration the ethical aspects of screening as well as incorporating families and the public into the discussions, so as to ensure that NBS for treatable rare disorders continues to be one of the major public health advances of the 20th century.

PMID:38651395 | DOI:10.3390/ijns10020030

Clin Exp Immunol. 2024 Apr 23:uxae037. doi: 10.1093/cei/uxae037. Online ahead of print.

ABSTRACT

Patients with very early-onset inflammatory bowel disease (VEO-IBD) may present because of underlying monogenic inborn errors of immunity (IEI). Strong differences have been observed in the causes of monogenic IBD among ethnic populations. This multi-center study was carried out on 16 Iranian patients with VEO-IBD. We reviewed clinical and basic immunologic evaluation including flow cytometry and immunoglobulin levels. All patients underwent clinical whole exome sequencing (WES). Sixteen patients (8 females and 8 males) with a median age of 43.5 months were enrolled. The median age at the onset of symptoms was 4 months. Most patients (12, 75%) had consanguineous parents. Chronic non-bloody diarrhea (13, 81.3%) and perianal diseases including perianal abscess (6, 37.5%), anal fissure (6, 37.5%), or anal fistula (2, 12.5%) were the most common manifestations. WES identified a spectrum of genetic variants in 13 patients (81.3%): IL10RB (6, 37.5%), MVK (3, 18.8%), and CASP8, SLC35C1, G6PC3, and IKBKB in one patient, respectively. In 3 patients (18.7%) no variant was identified. Flow cytometry identified a spectrum of abnormalities that helped to assess the evidence of genetic diagnosis. At the end of the survey, 3 (18.8%) patients were deceased. This high rate of monogenic defects with a broad spectrum of genes reiterates the importance of investigating IEI in patients with infantile-onset IBD.

PMID:38651248 | DOI:10.1093/cei/uxae037

Front Immunol. 2024 Apr 8;15:1364957. doi: 10.3389/fimmu.2024.1364957. eCollection 2024.

ABSTRACT

INTRODUCTION: CARD11 is a lymphoid lineage-specific scaffold protein regulating the NF-κB activation downstream of the antigen receptor signal pathway. Defective CARD11 function results in abnormal development and differentiation of lymphocytes, especially thymic regulatory T cells (Treg).

METHOD: In this study, we used patients’ samples together with transgenic mouse models carrying pathogenic CARD11 mutations from patients to explore their effects on Treg development. Immunoblotting and a GFP receptor assay were used to evaluate the activation effect of CARD11 mutants on NF-κB signaling. Then the suppressive function of Tregs carrying distinct CARD11 mutations was measured by in vitro suppression assay. Finally, we applied the retroviral transduced bone marrow chimeras to rescue the Treg development in an NF-κB independent manner.

RESULTS AND DISCUSS: We found CARD11 mutations causing hyper-activated NF-κB signals also gave rise to compromised Treg development in the thymus, similar to the phenotype in Card11 deficient mice. This observation challenges the previous view that CARD11 regulates Treg lineage dependent on the NF-kB activation. Mechanistic investigations reveal that the noncanonical function CARD11, which negatively regulates the AKT/ FOXO1 signal pathway, is responsible for regulating Treg generation. Moreover, primary immunodeficiency patients carrying CARD11 mutation, which autonomously activates NF-κB, also represented the reduced Treg population in their peripheral blood. Our results propose a new regulatory function of CARD11 and illuminate an NF-κB independent pathway for thymic Treg lineage commitment.

PMID:38650932 | PMC:PMC11033321 | DOI:10.3389/fimmu.2024.1364957

Am J Dermatopathol. 2024 Apr 23. doi: 10.1097/DAD.0000000000002714. Online ahead of print.

ABSTRACT

Junctional epidermolysis bullosa (JEB) is a rare, incurable, devastating, and mostly fatal congenital genetic disorder characterized by painful blistering of the skin and mucous membranes in response to minor trauma or pressure. JEB is classified roughly into 2 subtypes: JEB-Herlitz is caused by mutations on genes encoding laminin-332. The authors present a patient consulted with a suspicion of primary immunodeficiency due to skin sores that started at the age of 1 month and a history of 3 siblings who died with similar sores, who was diagnosed with JEB-Herlitz after detecting a homozygous LAMC2 gene mutation in WES analysis. Microscopic evaluation of hematoxylin and eosin-stained sections showed vesicle formation with subepidermal separation, which is accompanied by striking neutrophil and eosinophil leukocyte infiltration both in the vesicle and papillary dermis (eosinophil-rich inflammatory infiltrate). Such a histopathological finding has been rarely reported in this condition.

PMID:38648026 | DOI:10.1097/DAD.0000000000002714

Australas J Dermatol. 2024 Apr 22. doi: 10.1111/ajd.14295. Online ahead of print.

NO ABSTRACT

PMID:38646889 | DOI:10.1111/ajd.14295

Blood. 2024 Apr 21:blood.2023022658. doi: 10.1182/blood.2023022658. Online ahead of print.

ABSTRACT

We investigated efficacy and safety of mavorixafor, an oral CXCR4 antagonist for participants with Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) syndrome, a rare immunodeficiency caused by CXCR4 gain-of-function variants. This randomized (1:1), double-blind, placebo-controlled, phase 3 trial enrolled participants aged ≥12 years with WHIM syndrome and absolute neutrophil count (ANC) ≤400/μL. Participants received once-daily mavorixafor or placebo for 52 weeks. Primary endpoint was time (hours) above ANC threshold ≥500/μL (TATANC; over 24 hours). Secondary endpoints included TAT absolute lymphocyte count ≥1000/μL (TATALC; defined similar to TATANC); absolute changes in white blood cell (WBC), ANC, and ALC from baseline; annualized infection rate; infection duration and total infection score (combined infection number/severity). In 31 participants (mavorixafor, n=14; placebo, n=17), mavorixafor least squares (LS) mean TATANC was 15.0 hours, placebo 2.8 hours (P<0.001). Mavorixafor LS mean TATALC was 15.8 hours, placebo 4.6 hours (P<0.001). Higher absolute WBC, ANC, and ALC levels were seen with mavorixafor than placebo at each timepoint assessed. Annualized infection rates were 60% lower with mavorixafor versus placebo (LS mean 1.7 versus 4.2; nominal P=0.007) and total infection scores were 40% lower (7.4 [95% CI, 1.6-13.2] versus 12.3 [95% CI, 7.2-17.3]). Treatment with mavorixafor reduced infection frequency, severity, duration, and antibiotic use. No discontinuations occurred due to treatment-emergent adverse events (TEAEs); no related serious TEAEs were observed. Overall, mavorixafor-treated participants showed significant increases in LS mean TATANC and TATALC, reduced infection frequency, severity/duration. Mavorixafor was well tolerated in participants with WHIM syndrome. Trial was registered at ClinicalTrials.gov NCT03995108.

PMID:38643510 | DOI:10.1182/blood.2023022658