Research

Dominant Splice Site Mutations in PIK3R1 Cause Hyper IgM Syndrome, Lymphadenopathy and Short Stature.

J Clin Immunol. 2016 Apr 13;

Authors: Petrovski S, Parrott RE, Roberts JL, Huang H, Yang J, Gorentla B, Mousallem T, Wang E, Armstrong M, McHale D, MacIver NJ, Goldstein DB, Zhong XP, Buckley RH

Abstract
The purpose of this research was to use next generation sequencing to identify mutations in patients with primary immunodeficiency diseases whose pathogenic gene mutations had not been identified. Remarkably, four unrelated patients were found by next generation sequencing to have the same heterozygous mutation in an essential donor splice site of PIK3R1 (NM_181523.2:c.1425 + 1G > A) found in three prior reports. All four had the Hyper IgM syndrome, lymphadenopathy and short stature, and one also had SHORT syndrome. They were investigated with in vitro immune studies, RT-PCR, and immunoblotting studies of the mutation’s effect on mTOR pathway signaling. All patients had very low percentages of memory B cells and class-switched memory B cells and reduced numbers of naïve CD4+ and CD8+ T cells. RT-PCR confirmed the presence of both an abnormal 273 base-pair (bp) size and a normal 399 bp size band in the patient and only the normal band was present in the parents. Following anti-CD40 stimulation, patient’s EBV-B cells displayed higher levels of S6 phosphorylation (mTOR complex 1 dependent event), Akt phosphorylation at serine 473 (mTOR complex 2 dependent event), and Akt phosphorylation at threonine 308 (PI3K/PDK1 dependent event) than controls, suggesting elevated mTOR signaling downstream of CD40. These observations suggest that amino acids 435-474 in PIK3R1 are important for its stability and also its ability to restrain PI3K activity. Deletion of Exon 11 leads to constitutive activation of PI3K signaling. This is the first report of this mutation and immunologic abnormalities in SHORT syndrome.

PMID: 27076228 [PubMed – as supplied by publisher]

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Co-Occurrence of Chronic Spontaneous Urticaria with Immunoglobulin A Deficiency and Autoimmune Diseases.

Int Arch Allergy Immunol. 2016 Apr 14;169(2):130-134

Authors: Frossi B, De Carli S, Bossi F, Pucillo C, De Carli M

Abstract
BACKGROUND: Immunoglobulin (Ig) A deficiency is a primary immunodeficiency in which autoimmunity is frequently observed. Thirty to fifty percent of patients with spontaneous chronic urticaria have autoantibodies that are able to cross-link FcεRI on mast cells and basophils.
METHODS: We investigated whether spontaneous chronic urticaria in patients with IgA deficiency meets the criteria for autoimmunity. Four patients were screened for positivity to a skin prick test and an autologous serum skin test and for the presence of other autoimmune diseases. Patient sera were tested for the ability to activate basophils and mast cells in vitro by measuring surface CD63 expression and β-hexosaminidase release, respectively.
RESULTS: The autologous serum test was positive in all patients, and patient sera were found to induce CD63 upregulation on basophils and degranulation of an LAD2 mast cell line. Moreover, all patients were affected by other autoimmune disorders.
CONCLUSION: For the first time, these data point out chronic autoimmune urticaria in subjects with an IgA deficiency and confirm that different autoimmune disorders are common among patients with an IgA deficiency. Patients with chronic autoimmune spontaneous urticaria should be screened for IgA deficiency, especially if they are affected by other autoimmune disorders. Thus, spontaneous urticaria could mirror more complex systemic diseases, such as immune deficiency.

PMID: 27073906 [PubMed – as supplied by publisher]

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Autoimmunity in primary T-cell immunodeficiencies.

Expert Rev Clin Immunol. 2016 Apr 11;

Authors: Azizi G, Ghanavatinejad A, Abolhassani H, Yazdani R, Rezaei N, Mirshafiey A, Aghamohammadi A

Abstract
Primary immunodeficiency diseases (PID) are a genetically heterogeneous group of more than 270 disorders that affect distinct components of both humoral and cellular arms of the immune system. Primary T cell immunodeficiencies affect subjects at the early age of life. In most cases, T-cell PIDs become apparent as combined T- and B-cell deficiencies. Patients with T-cell PID are prone to life-threatening infections. On the other hand, non-infectious complications such as lymphoproliferative diseases, cancers and autoimmunity seem to be associated with the primary T-cell immunodeficiencies. Autoimmune disorders of all kinds (organ specific or systemic ones) could be subjected to this class of PIDs; however, the most frequent autoimmune disorders are immune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AIHA). In this review, we discuss the proposed mechanisms of autoimmunity and review the literature reported on autoimmune disorder in each type of primary T-cell immunodeficiencies.

PMID: 27063703 [PubMed – as supplied by publisher]

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Family Physician Perspectives on Primary Immunodeficiency Diseases.

Front Med (Lausanne). 2016;3:12

Authors: Orange JS, Seeborg FO, Boyle M, Scalchunes C, Hernandez-Trujillo V

Abstract
Primary immunodeficiency diseases (PIDs) include over 250 diverse disorders. The current study assessed management of PID by family practice physicians. The American Academy of Allergy, Asthma, and Immunology Primary Immunodeficiency Committee and the Immune Deficiency Foundation conducted an incentivized mail survey of family practice physician members of the American Medical Association and the American Osteopathic Association in direct patient care. Responses were compared with subspecialist immunologist responses from a similar survey. Surveys were returned by 528 (of 4500 surveys mailed) family practice physicians, of whom 44% reported following ≥1 patient with PID. Selective immunoglobulin A deficiency (21%) and chronic granulomatous disease (11%) were most common and were followed by significantly more subspecialist immunologists (P < 0.05). Use of intravenously administered immunoglobulin and live viral vaccinations across PID was significantly different (P < 0.05). Few family practice physicians were aware of professional guidelines for diagnosis and management of PID (4 vs. 79% of subspecialist immunologists, P < 0.05). Family practice physicians will likely encounter patients with PID diagnoses during their career. Differences in how family practice physicians and subspecialist immunologists manage patients with PID underscore areas where improved educational and training initiatives may benefit patient care.

PMID: 27066486 [PubMed – as supplied by publisher]

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Impaired selective cytokine production by CD4(+) T cells in Common Variable Immunodeficiency associated with the absence of memory B cells.

Clin Immunol. 2016 Apr 4;

Authors: Laura BR, Gabriela LH, Alexander VH, Leopoldo SA, Constantino LM, Armando I, Hilda SN, Laura B

Abstract
Common Variable Immunodeficiency (CVID) is a primary immunodeficiency characterized by B cell dysfunction and decreased serum immunoglobulin. CVID patients are classified by the absence or presence of memory B cells. In addition, T cell defects have been demonstrated in only a proportion of CVID patients. The aim of this study was to evaluate the function of CD4(+) T cells from CVID patients and its association with memory B cells. Patients were classified according to their Freiburg groups: group Ia and Ib, with decreased switched memory B cells (<0.4 of PBL), and group II, with normal B cell subsets. Their T cell function was evaluated after stimulation. We observed normal and even increased CD4(+) T cell proliferation in group Ia (p=0.0277). The proliferation positively correlated with the clinical severity score (r=0.4796). We observed lower levels of IL-17A and IL-10 in group Ia (p=0.0177, 0.0109) and Ib (p=0.0009, 0.0084) patients. Group Ib patients also had low levels of IL-13 and IL-9 (p=0.0169, 0.010). Group II patients had similar cytokine production to that of the controls. BAFFR expression was reduced in groups Ia (p=0.0001) and Ib (p=0.0002) and showed an inverse correlation with the severity score (p=0.0262; r=0.5371). ICOS expression was reduced in group Ia (p=0.0364), and PD-1 was increased in group Ib (p=0.0432) patients. This study shows a selective impairment in cytokine production in group Ia patients, which was more extensive than in group Ib patients. The impairment was associated with BAFFR expression in B cells, with ICOS and PD-1 in T cells and, remarkably, with the absence of memory B cells and with the disease severity. Our results suggest that the evaluation of cytokine expression by T cells in combination with the study of B cell memory could be important for understand the pathogenesis of CVID patients.

PMID: 27057998 [PubMed – as supplied by publisher]

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Lentiviral vector mediated correction of a mouse model of Leukocyte Adhesion Deficiency Type I.

Hum Gene Ther. 2016 Apr 8;

Authors: Leon-Rico D, Aldea M, Sanchez-Baltasar R, Mesa-Nuñez C, Record J, Burns SO, Santilli G, Thrasher AJ, Bueren J, Almarza E

Abstract
Leukocyte Adhesion Deficiency Type I (LAD-I) is a primary immunodeficiency caused by mutations in the ITGB2 gene, and is characterized by recurrent and life-threatening bacterial infections. These mutations lead to defective or absent expression of β2 integrins on the leukocyte surface, compromising adhesion and extravasation at sites of infection. Three different LVs conferring ubiquitous or preferential expression of CD18 in myeloid cells were constructed and tested in human and mouse LAD-I cells. All three hCD18-LVs restored CD18 and CD11a membrane expression in LAD-I patient-derived lymphoblastoid cells. Corrected cells recovered the ability to aggregate and bind to sICAM-1 after stimulation. All vectors induced stable hCD18 expression in hematopoietic cells from mice with a hypomorphic Itgb2 mutation (CD18HYP), both in vitro and in vivo after transplantation of corrected cells into primary and secondary CD18HYP recipients. hCD18+ hematopoietic cells from transplanted CD18HYP mice also showed restoration of mCD11a surface co-expression. The analysis of in vivo neutrophil migration in CD18HYP mice subjected to two different inflammation models demonstrated that the LV-mediated gene therapy completely restored neutrophil extravasation in response to inflammatory stimuli. Finally, these vectors were able to correct the phenotype of human myeloid cells derived from CD34+ progenitors defective in ITGB2 expression. These results support for the first time the use of hCD18-LVs for the treatment of LAD-I patients in clinical trials.

PMID: 27056660 [PubMed – as supplied by publisher]

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Gene Therapy for the Treatment of Primary Immune Deficiencies.

Curr Allergy Asthma Rep. 2016 May;16(5):39

Authors: Kuo CY, Kohn DB

Abstract
The use of gene therapy in the treatment of primary immune deficiencies (PID) has advanced significantly in the last decade. Clinical trials for X-linked severe combined immunodeficiency, adenosine deaminase deficiency (ADA), chronic granulomatous disease, and Wiskott-Aldrich syndrome have demonstrated that gene transfer into hematopoietic stem cells and autologous transplant can result in clinical improvement and is curative for many patients. Unfortunately, early clinical trials were complicated by vector-related insertional mutagenic events for several diseases with the exception of ADA-deficiency SCID. These results prompted the current wave of clinical trials for primary immunodeficiency using alternative retro- or lenti-viral vector constructs that are self-inactivating, and they have shown clinical efficacy without leukemic events thus far. The field of gene therapy continues to progress, with improvements in viral vector profiles, stem cell culturing techniques, and site-specific genome editing platforms. The future of gene therapy is promising, and we are quickly moving towards a time when it will be a standard cellular therapy for many forms of PID.

PMID: 27056559 [PubMed – as supplied by publisher]

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