Julio César Orrego

Somatic Mosaicism Caused by Monoallelic Reversion of a Mutation in T Cells of a Patient with ADA‐SCID and the Effects of Enzyme Replacement Therapy on the Revertant Phenotype

Patients with adenosine deaminase (ADA) deficiency exhibit spontaneous and partial clinical remission associated with somatic reversion of inherited mutations. We report a child with severe combined immunodeficiency (T‐B‐ SCID) due to ADA deficiency diagnosed at the age of 1 month, whose lymphocyte counts including CD4+ and CD8+ T and NK cells began to improve after several months with normalization of ADA activity in Peripheral blood lymphocytes (PBL), as a result of somatic mosaicism caused by monoallelic reversion of the causative mutation in the ADA gene. He was not eligible for haematopoietic stem cell transplantation (HSCT) or gene therapy (GT); therefore he was placed on enzyme replacement therapy (ERT) with bovine PEG‐ADA. The follow‐up of metabolic and immunologic responses to ERT included gradual improvement in ADA activity in erythrocytes and transient expansion of most lymphocyte subsets, followed by gradual stabilization of CD4+ and CD8+ T (with naïve phenotype) and NK cells, and sustained expansion of TCRγδ+ T cells. This was accompanied by the disappearance of the revertant T cells as shown by DNA sequencing from PBL. Although the patient’s clinical condition improved marginally, he later developed a germinal cell tumour and eventually died at the age of 67 months from sepsis. This case adds to our current knowledge of spontaneous reversion of mutations in ADA deficiency and shows that the effects of the ERT may vary among these patients, suggesting that it could depend on the cell and type in which the somatic mosaicism is established upon reversion.

Mutation screening in STAT1, CARD9 and PKC-DELTA in patients with chronic mucocutaneous candidiasis

Continued B) In homozygous IGHG diplotypes only one of the two alternative allotypes is expressed, which result in restricted qualities of IgG molecules and B cells. IGHG gene frequencies and the allotypic IgG subclass levels, the activity of the genes, are available for children and adults of healthy Caucasians (Fig. 4). IGHG genes have impact on disease and immunotherapy. The function of IgG is related to the constant part of the heavy γ chains the Fcγ part of the molecule in parallel with the variable adaptive antibody binding site. Different effects of polysaccharide and protein vaccines, with different amounts of specific antibodies were recorded for different IGHG genes. They are also associated to different severity of bacterial and viral infections and can be used as predisposing, prognostic and sometimes carrier markers. The IgG molecules of IGHG genes are differently affected by viruses acting as FcγRs modifying the disease. Suscepetibility/resistence of various infections both bacterial and viral, allergens and tumour antigens are influenced by IGHG genes. The IGHG genes are associated with different phenotypes of allergic, autoimmune, infectious, immunodeficiency and malignt disorders. In treatments with IVIG, the levels of foreign allelic IgG subclasses are recognized and can be followed. This is the ultimate evidence of that the allelic IgG subclasses are unique. IGHG genes and allotypic IgG subclasses are predisposing or prognostic genetic markers in various infections, immunodeficiencies, different phenotypes of allergic disease, autoimmune disorders and malignant diseases. Fig.1Fig. 2Fig.3Fig. 4 29 IMMUNOPHENOTYPING OF B LYMPHOCYTES IN PATIENTS WITH COMMON VARIABLE IMMUNODEFICIENCY (CVID) F. Mazzi, G. Patuzzo, A. Vella, R. Ortolani, A. Barbieri, A. Puccetti, E. Tinazzi, G. Marchi, O.M. Codella, R. Beri, C. Lunardi Department of Medicine, Unit of Autoimmune Diseases, University of Verona, Department of Pathology and Diagnosis, Section of Immunology, University of Verona, Verona, Immunopathology, Institute G. Gaslini and University of Genova, Genova, Italy Introduction: CVID is a primary immunodeficiency characterized by failure of B lymphocytes to differentiate in plasma cells, with deficient immunoglobulin secretion. The identified genetic defects account only for a minority of cases. Objective: The importance of B cells immunophenotyping in the classification of CVID is well known. This procedure can identify some alterations on cell surface molecule expression that could explain the immunological disorder at the basis of CVID. Moreover, some immunophenotipical aspects can correlate with clinical features, severity and prognosis of the disease. Aim: We studied a cohort of 16 patients affected by CVID, to identify alterations of B cells and to find correlations with clinical features. Methods: We studied circulating B cells in patients and controls by flow-cytometry, using a specific panel of antibodies for B cells. Conclusion: We compared the population of “switched memory” IgD-CD27+B lymphocytes, used in the Friburg classification, with the population of IgM-IgDCD23-CD27+B cells, we have analysed. IgM-IgDCD23-CD27+B cells were reduced in patients compared to healthy controls and in patients they were lower than IgD-CD27+B cells. The reduction of these lymphocytes was correlated more tightly than IgDCD27+B cells to lymphoadenopathy, splenomegaly, J Clin Immunol (2012) 32 (Suppl 1):S1–S379

Epidemiological assessment of mucocutaneous infections in patients with recurrent infection syndrome

Background  Recurrent infection syndrome (RIS) results from repeated interactions between hosts and environmental infectious agents and is considered normal (NRIS) because of its benign evolution and positive effects in the development of normal immune responses. Abnormal RIS (ARIS) is characterized by the unusually high frequency of severe infections, either as a result of anatomical or functional abnormalities or due to primary or secondary immunodeficiencies (PIDs and SIDs, respectively). Recurrent mucocutaneous infections (MCIs) can be manifestations of RIS or ARIS and could be more frequent in primary immunodeficiencies. Similarly, etiologic agents might vary from what is observed in the general population.

Early-Onset Invasive Infection Due to Corynespora cassiicola Associated with Compound Heterozygous CARD9 Mutations in a Colombian Patient

PurposeCARD9 deficiency is an inborn error of immunity that predisposes otherwise healthy humans to mucocutaneous and invasive fungal infections, mostly caused by Candida, but also by dermatophytes, Aspergillus, and other fungi. Phaeohyphomycosis are an emerging group of fungal infections caused by dematiaceous fungi (phaeohyphomycetes) and are being increasingly identified in patients with CARD9 deficiency. The Corynespora genus belongs to phaeohyphomycetes and only one adult patient with CARD9 deficiency has been reported to suffer from invasive disease caused by C. cassiicola. We identified a Colombian child with an early-onset, deep, and destructive mucocutaneous infection due to C. cassiicola and we searched for mutations in CARD9.MethodsWe reviewed the medical records and immunological findings in the patient. Microbiologic tests and biopsies were performed. Whole-exome sequencing (WES) was made and Sanger sequencing was used to confirm the CARD9 mutations in the patient and her family. Finally, CARD9 protein expression was evaluated in peripheral blood mononuclear cells (PBMC) by western blotting.ResultsThe patient was affected by a large, indurated, foul-smelling, and verrucous ulcerated lesion on the left side of the face with extensive necrosis and crusting, due to a C. cassiicola infectious disease. WES led to the identification of compound heterozygous mutations in the patient consisting of the previously reported p.Q289* nonsense (c.865C > T, exon 6) mutation, and a novel deletion (c.23_29del; p.Asp8Alafs10*) leading to a frameshift and a premature stop codon in exon 2. CARD9 protein expression was absent in peripheral blood mononuclear cells from the patient.ConclusionWe describe here compound heterozygous loss-of-expression mutations in CARD9 leading to severe deep and destructive mucocutaneous phaeohyphomycosis due to C. cassiicola in a Colombian child.

Somatic Mosaicism Caused by Monoallelic Reversion of a Mutation in T Cells of a Patient with ADA-SCID and the Effects of Enzyme Replacement Therapy on the Revertant Phenotype: Revertant Mosaicism in ADA Deficiency and Effects of Enzyme Therapy

Patients with adenosine deaminase (ADA) deficiency exhibit spontaneous and partial clinical remission associated with somatic reversion of inherited mutations. We report a child with severe combined immunodeficiency (T‐B‐ SCID) due to ADA deficiency diagnosed at the age of 1 month, whose lymphocyte counts including CD4+ and CD8+ T and NK cells began to improve after several months with normalization of ADA activity in Peripheral blood lymphocytes (PBL), as a result of somatic mosaicism caused by monoallelic reversion of the causative mutation in the ADA gene. He was not eligible for haematopoietic stem cell transplantation (HSCT) or gene therapy (GT); therefore he was placed on enzyme replacement therapy (ERT) with bovine PEG‐ADA. The follow‐up of metabolic and immunologic responses to ERT included gradual improvement in ADA activity in erythrocytes and transient expansion of most lymphocyte subsets, followed by gradual stabilization of CD4+ and CD8+ T (with naïve phenotype) and NK cells, and sustained expansion of TCRγδ+ T cells. This was accompanied by the disappearance of the revertant T cells as shown by DNA sequencing from PBL. Although the patient’s clinical condition improved marginally, he later developed a germinal cell tumour and eventually died at the age of 67 months from sepsis. This case adds to our current knowledge of spontaneous reversion of mutations in ADA deficiency and shows that the effects of the ERT may vary among these patients, suggesting that it could depend on the cell and type in which the somatic mosaicism is established upon reversion.

Somatic mosaicism due to monoallelic reversion of a mutation in T cells of an ADA-SCID patient and the effects of enzyme replacement therapy on the revertant phenotype

Patients with adenosine deaminase (ADA) deficiency exhibit spontaneous and partial clinical remission associated with somatic reversion of inherited mutations. We report a child with severe combined immunodeficiency (T‐B‐ SCID) due to ADA deficiency diagnosed at the age of 1 month, whose lymphocyte counts including CD4+ and CD8+ T and NK cells began to improve after several months with normalization of ADA activity in Peripheral blood lymphocytes (PBL), as a result of somatic mosaicism caused by monoallelic reversion of the causative mutation in the ADA gene. He was not eligible for haematopoietic stem cell transplantation (HSCT) or gene therapy (GT); therefore he was placed on enzyme replacement therapy (ERT) with bovine PEG‐ADA. The follow‐up of metabolic and immunologic responses to ERT included gradual improvement in ADA activity in erythrocytes and transient expansion of most lymphocyte subsets, followed by gradual stabilization of CD4+ and CD8+ T (with naïve phenotype) and NK cells, and sustained expansion of TCRγδ+ T cells. This was accompanied by the disappearance of the revertant T cells as shown by DNA sequencing from PBL. Although the patient’s clinical condition improved marginally, he later developed a germinal cell tumour and eventually died at the age of 67 months from sepsis. This case adds to our current knowledge of spontaneous reversion of mutations in ADA deficiency and shows that the effects of the ERT may vary among these patients, suggesting that it could depend on the cell and type in which the somatic mosaicism is established upon reversion.