Background We investigated 7 male patients (from 5 different families) presenting with profound lymphopenia, hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a poor immune response ...to vaccine antigens, and increased susceptibility to bacterial and varicella zoster virus infections. Objective We sought to characterize the genetic defect involved in a new form of X-linked immunodeficiency. Methods We performed genetic analyses and an exhaustive phenotypic and functional characterization of the lymphocyte compartment. Results We observed hemizygous mutations in the moesin (MSN) gene (located on the X chromosome and coding for MSN) in all 7 patients. Six of the latter had the same missense mutation, which led to an amino acid substitution (R171W) in the MSN four-point-one, ezrin, radixin, moesin domain. The seventh patient had a nonsense mutation leading to a premature stop codon mutation (R533X). The naive T-cell counts were particularly low for age, and most CD8+ T cells expressed the senescence marker CD57. This phenotype was associated with impaired T-cell proliferation, which was rescued by expression of wild-type MSN. MSN-deficient T cells also displayed poor chemokine receptor expression, increased adhesion molecule expression, and altered migration and adhesion capacities. Conclusion Our observations establish a causal link between an ezrin-radixin-moesin protein mutation and a primary immunodeficiency that could be referred to as X-linked moesin-associated immunodeficiency.
Background Chronic granulomatous disease (CGD) is a rare phagocytic disorder that results in not only infections but also potentially severe inflammatory manifestations that can be difficult to ...diagnose and treat. Objective To describe inflammatory manifestations in a single-center cohort of patients with CGD. Methods Medical records of patients treated at Necker-Enfants Malades Hospital (Paris, France) between 1968 and 2009 and registered at the French National Reference Center for Primary Immunodeficiencies (CEREDIH) were retrospectively reviewed. Results In a study population of 98 patients, a total of 221 inflammatory episodes were recorded in 68 individuals (69.4%). The incidence rate of inflammatory episodes was 0.15 per person-year (0.18 in patients with X-linked XL CGD and 0.08 in patients with autosomal-recessive AR CGD). The most commonly affected organs were the gastrointestinal tract (in 88.2% of the patients), lungs (26.4%), the urogenital tract (17.6%), and eyes (8.8%). Inflammation at other sites (the skin, central nervous system, and tympanum) and autoimmune manifestations (lupus, arthritis, etc) were recorded in 19.1% and 10.3% of the patients, respectively. Granuloma was found in 50% of the 44 histological analyses reviewed. The risk of inflammatory episodes was 2-fold higher in patients with XL-CGD than in patients with AR-CGD (relative risk, 2.22; 95% CI, 1.43-3.46). Conclusions Patients with XL-CGD have a higher risk of developing inflammatory episodes than do patients with AR-CGD. Although the most commonly affected organ is the gastrointestinal tract, other sites can be involved, making the management of patients with CGD a complex, multidisciplinary task.
Background Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases, but the underlying molecular mechanisms remain largely unknown. Studies of monogenic diseases ...can provide insight into the pathogenesis of IBD. Objective We thought to determine the underlying molecular causes of IBD occurring in 2 unrelated families in association with an immune deficiency. Methods We performed genetic linkage analysis and candidate gene sequencing on 13 patients from a large consanguineous family affected by early-onset IBD, progressive immune deficiency, and, in some cases, autoimmunity and alopecia, a condition we named enteropathy-lymphocytopenia-alopecia. The candidate gene was also sequenced in an unrelated patient with a similar phenotype. We performed histologic analysis of patients' intestinal biopsy specimens and carried out functional assays on PBMCs. Gut organoids derived from a patient's biopsy specimen were analyzed. Results We identified biallelic missense mutations in tetratricopeptide repeat domain 7A (TTC7A) in all patients from both families. The resulting TTC7A depletion modified the proliferation, adhesion, and migratory capacities of lymphocytes through inappropriate activation of the RhoA signaling pathway. Normal function was restored by wild-type TTC7A expression or addition of a RhoA kinase inhibitor. The growth and polarity of gut epithelial organoids were also found to be dependent on the RhoA signaling pathway. Conclusions We show that TTC7A regulates the actin cytoskeleton dynamics in lymphocytes through the RhoA signaling pathway and is required in both lymphocytes and epithelial cells for maintaining equilibrium between cell proliferation, migration, polarization, and cell death. Our study highlights variability in the phenotypic expression resulting from TTC7A deficiency and outlines that impairment of both epithelial cells and lymphocytes cooperatively causes IBD.
Background Absent T-cell immunity resulting in life-threatening infections provides a clear rationale for hematopoetic stem cell transplantation (HSCT) in patients with severe combined ...immunodeficiency (SCID). Combined immunodeficiencies (CIDs) and “atypical” SCID show reduced, not absent T-cell immunity. If associated with infections or autoimmunity, they represent profound combined immunodeficiency (P-CID), for which outcome data are insufficient for unambiguous early transplant decisions. Objectives We sought to compare natural histories of severity-matched patients with/without subsequent transplantation and to determine whether immunologic and/or clinical parameters may be predictive for outcome. Methods In this prospective and retrospective observational study, we recruited nontransplanted patients with P-CID aged 1 to 16 years to compare natural histories of severity-matched patients with/without subsequent transplantation and to determine whether immunologic and/or clinical parameters may be predictive for outcome. Results A total of 51 patients were recruited (median age, 9.6 years). Thirteen of 51 had a genetic diagnosis of “atypical” SCID and 14 of 51 of CID. About half of the patients had less than 10% naive T cells, reduced/absent T-cell proliferation, and at least 1 significant clinical event/year, demonstrating their profound immunodeficiency. Nineteen patients (37%) underwent transplantation within 1 year of enrolment, and 5 of 51 patients died. Analysis of the HSCT decisions revealed the anticipated heterogeneity, favoring an ongoing prospective matched-pair analysis of patients with similar disease severity with or without transplantation. Importantly, so far neither the genetic diagnosis nor basic measurements of T-cell immunity were good predictors of disease evolution. Conclusions The P-CID study for the first time characterizes a group of patients with nontypical SCID T-cell deficiencies from a therapeutic perspective. Because genetic and basic T-cell parameters provide limited guidance, prospective data from this study will be a helpful resource for guiding the difficult HSCT decisions in patients with P-CID.
Background Ataxia-telangiectasia (A-T) is a rare genetic disease caused by germline biallelic mutations in the ataxia-telangiectasia mutated gene (ATM) that result in partial or complete loss of ATM ...expression or activity. The course of the disease is characterized by neurologic manifestations, infections, and cancers. Objective We studied A-T progression and investigated whether manifestations were associated with the ATM genotype. Methods We performed a retrospective cohort study in France of 240 patients with A-T born from 1954 to 2005 and analyzed ATM mutations in 184 patients, along with neurologic manifestations, infections, and cancers. Results Among patients with A-T, the Kaplan-Meier 20-year survival rate was 53.4%; the prognosis for these patients has not changed since 1954. Life expectancy was lower among patients with mutations in ATM that caused total loss of expression or function of the gene product (null mutations) compared with that seen in patients with hypomorphic mutations because of earlier onset of cancer (mainly hematologic malignancies). Cancer (hazard ratio, 2.7; 95% CI, 1.6-4.5) and respiratory tract infections (hazard ratio, 2.3; 95% CI, 1.4-3.8) were independently associated with mortality. Cancer (hazard ratio, 5.8; 95% CI, 2.9-11.6) was a major risk factor for mortality among patients with null mutations, whereas respiratory tract infections (hazard ratio, 4.1; 95% CI, 1.8-9.1) were the leading cause of death among patients with hypomorphic mutations. Conclusion Morbidity and mortality among patients with A-T are associated with ATM genotype. This information could improve our prognostic ability and lead to adapted therapeutic strategies.
...neither patient displayed autoimmune cytopenia. Because no infectious cause of colitis could be demonstrated in patient 7, both manifestations might be explained by immune dysregulation.
Background Combined immunodeficiencies (CIDs) form a heterogeneous group of inherited conditions that affect the development, function, or both of T cells. The treatment of CIDs with allogeneic ...hematopoietic stem cell transplantation (HSCT) is complicated by a high incidence of life-threatening infections and an increased risk of graft-versus-host disease (GVHD). Objective In view of the growing evidence that alloreactivity is mainly derived from human naive T cells, the selective depletion of naive T cells from allografts might constitute a way of reducing alloreactivity while maintaining memory T-cell responsiveness to pathogens. Methods Five consecutive patients with CIDs and chronic viral infections underwent an allogeneic, HLA-mismatched HSCT. Given the patients' infection status and the potential risk of severe GVHD in the mismatched setting, the CD34− fraction of the allograft was depleted of naive T cells by using magnetic CD45RA beads. Results Engraftment occurred in 4 of the 5 patients. No severe GVHD occurred. In the 4 engrafted patients viral infections were cleared within 2 months of the HSCT, and both cellular and humoral immunity were re-established within a year of the HSCT. An early T-cell response against viral pathogens was documented in 2 patients. Conclusion The present pilot study shows that clinical-grade depletion of naive T cells from an allograft through the use of magnetic CD45RA beads seems to be a feasible and efficacious option for the treatment of patients with CIDs at high risk of GVHD, infection, or both in an HLA-mismatched setting.
Objective To better describe the natural history, mode of inheritance, and the epidemiological and clinical features of isolated congenital asplenia, a rare and poorly understood primary ...immunodeficiency. Study design A French national retrospective survey was conducted in hospital pediatric departments. A definitive diagnosis of ICA was based on the presence of Howell-Jolly bodies, a lack of detectable spleen, and no detectable cardiovascular malformation. Results The study included 20 patients (12 males and 8 females) from 10 kindreds neither related to each other nor consanguineous. The diagnosis of ICA was certain in 13 cases (65%) and probable in 7 cases (35%). Ten index cases led to diagnosis of 10 additional cases in relatives. Five cases were sporadic and 15 were familial, suggesting autosomal dominant inheritance. Median age was 12 months at first infection (range, 2-516 months), 11 months at diagnosis of asplenia (range, 0-510 months), and 9.9 years at last follow-up (range, 0.7-52 years). Fifteen patients sustained 18 episodes of invasive bacterial infection, caused mainly by Streptococcus pneumoniae (61%). Outcomes were poor, with 9 patients (45%) dying from fulminant infection. Conclusions ICA is more common than was previously thought, with an autosomal dominant inheritance in at least some kindreds. Relatives of cases of ICA should be evaluated for ICA, as should children and young adults with invasive infection.
SMB cell subset Low (n = 30) Normal (n = 13) P value MZB cell subset Low (n = 17) Normal (n = 13) P value Normal (n = 13) Upper respiratory tract infections 13 11 NS 11 NS Lower respiratory tract ...infections 11 12 NS 9 NS Pneumonia 10 8 NS 2 .017 Bronchiectasis 6 3 NS 0 .041 Autoimmune diseases 2 3 NS 0 NS Splenomegaly 3 2 NS 0 NS Gastroenteritis 3 1 NS 6 .02 Invasive acute infection 4 1 NS 2 NS IgRT 17 6 .0008 11 NS No response to vaccines 9/14 3/11 NS 1/9 NS Normal CD40+IL4-induced proliferation 11/16 10/12 NS 9/9 NS Normal CD40 class-switch recombination 11/16 6/10 NS 9/9 NS Normal BAFF-induced proliferation 6/13 7/12 NS 2/6 NS Normal CpG-induced proliferation 6/13 8/12 NS 3/6 NS Normal anti-A/B allohemagglutinins 2/10 3/9 NS 5/7 NS Table II Characteristics of patients as a function of their SMB and MZB cell counts BAFF, B-cell activating factor; NS, not significant.Low SMB and MZB cell counts were defined as being at least 2 SDs below the age-adjusted normal value (NS, P > .05). Characteristic No. (%) or median (min; max) Sex: male 20 (45.4) Age at onset (y) 1.77 (0.06; 5.9) Age at diagnosis (y) 5.15 (0.33; 17.3) Age at last follow-up (y) 14.46 (4.17; 35.87) Time between symptom onset and diagnosis years 3.00 (0.0; 13.23) Follow-up period (y) 6.29 (0.23; 27.09) Patients with another case in their family 13 (29.5) IgG deficiency 6 (13.6) IgG and IgA deficiency 9 (20.4) IgG and IgM deficiency 3 (6.8) IgA and IgM deficiency 1 (2.2) IgG, IgA, and IgM deficiency 25 (56.8) Patients with upper respiratory tract infections 35 (79.5) Patients with lower respiratory tract infections 33 (75) * Repeated acute bronchitis 17 (38.6) * Pneumonia 20 (45.5) * Bronchiectasis 9 (20.4) Patients with gastroenteritis 10 (22.7) Patients with autoimmune diseases 5 (11.4) Patients with splenomegaly 5 (11.4) Patients with lymphoma 1 (2.2) Table E1 Demographic, clinical, and biological characteristics of patients
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