Neslihan Edeer Karaca

Inherited and acquired immunodeficiencies underlying tuberculosis in childhood.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb) and a few related mycobacteria, is a devastating disease, killing more than a million individuals per year worldwide. However, its pathogenesis remains largely elusive, as only a small proportion of infected individuals develop clinical disease either during primary infection or during reactivation from latency or secondary infection. Subacute, hematogenous, and extrapulmonary disease tends to be more frequent in infants, children, and teenagers than in adults. Life‐threatening primary TB of childhood can result from known acquired or inherited immunodeficiencies, although the vast majority of cases remain unexplained. We review here the conditions conferring a predisposition to childhood clinical diseases caused by mycobacteria, including not only M.tb but also weakly virulent mycobacteria, such as BCG vaccines and environmental mycobacteria. Infections with weakly virulent mycobacteria are much rarer than TB, but the inherited and acquired immunodeficiencies underlying these infections are much better known. Their study has also provided genetic and immunological insights into childhood TB, as illustrated by the discovery of single‐gene inborn errors of IFN‐γ immunity underlying severe cases of TB. Novel findings are expected from ongoing and future human genetic studies of childhood TB in countries that combine a high proportion of consanguineous marriages, a high incidence of TB, and an excellent clinical care, such as Iran, Morocco, and Turkey.

Clinical Features of Candidiasis in Patients With Inherited Interleukin 12 Receptor β1 Deficiency

BACKGROUND Interleukin 12Rβ1 (IL-12Rβ1)-deficient patients are prone to clinical disease caused by mycobacteria, Salmonella, and other intramacrophagic pathogens, probably because of impaired interleukin 12-dependent interferon γ production. About 25% of patients also display mucocutaneous candidiasis, probably owing to impaired interleukin 23-dependent interleukin 17 immunity. The clinical features and outcome of candidiasis in these patients have not been described before, to our knowledge. We report here the clinical signs of candidiasis in 35 patients with IL-12Rβ1 deficiency. RESULTS Most (n = 71) of the 76 episodes of candidiasis were mucocutaneous. Isolated oropharyngeal candidiasis (OPC) was the most common presentation (59 episodes, 34 patients) and was recurrent or persistent in 26 patients. Esophageal candidiasis (n = 7) was associated with proven OPC in 2 episodes, and cutaneous candidiasis (n = 2) with OPC in 1 patient, whereas isolated vulvovaginal candidiasis (VVC; n = 3) was not. Five episodes of proven invasive candidiasis were documented in 4 patients; 1 of these episodes was community acquired in the absence of any other comorbid condition. The first episode of candidiasis occurred earlier in life (median age±standard deviation, 1.5 ± 7.87 years) than infections with environmental mycobacteria (4.29 ± 11.9 years), Mycobacterium tuberculosis (4 ± 3.12 years), or Salmonella species (4.58 ± 4.17 years) or other rare infections (3 ± 11.67 years). Candidiasis was the first documented infection in 19 of the 35 patients, despite the vaccination of 10 of these 19 patients with live bacille Calmette-Guérin. CONCLUSIONS Patients who are deficient in IL-12Rβ1 may have candidiasis, usually mucocutaneous, which is frequently recurrent or persistent. Candidiasis may be the first clinical manifestation in these patients.

Increases in serum immunoglobulins to age‐related normal levels in children with IgA and/or IgG subclass deficiency

Immunoglobulins (Ig) A and G subclass deficiencies are common immune system disorders which cause morbidity especially between 2 and 6 yr of age. Prognosis of these defects and therapeutic approach is unclear. The aim of the present retrospective study was to review the clinical and laboratory records of 87 children with IgA and/or IgG subclass deficiency to determine whether these patients experience changes in serum Ig concentrations during follow‐up and to give more clinic and laboratory information to the families about the course of these diseases. Among 87 patients studied, the most frequent defect was partial IgA deficiency combined with IgG3 subclass deficiency (41%). The other groups were as follows; partial IgA deficiency (32%), selective IgA deficiency (8%), partial IgA combined with IgG2‐G4 subclass deficiency (6%), and IgG subclass deficiency (13%). The commonest clinical presentations were recurrent upper respiratory tract infections (76%), pneumonia (14%), acute gastroenteritis (3%), urinary tractus infection (3%), sinusitis (2%), and acute otitis media (2%). Atopy was widely represented in the patients studied (24%). The number of patients who were given prophylactic treatment with benzathine penicilline, prophylactic oral antibiotic, or oral bacterial extract to prevent infections was 68 (78%). Frequency of recurrent infections decreased from 7.9 ± 4.9 per year to 2.5 ± 2.3 in 68 patients receiving any prophylactic regimen; however, decrease in frequency of infections did not show any significant difference between different prophylactic groups. None of the patients in the selective IgA deficiency group had reached normal serum levels of IgA. At the age of 58.3 ± 21.4 months, 52% of patients in partial IgA deficiency group and 51% of patients in partial IgA + IgG subclass deficiency group, serum IgA increased to normal ranges. Serum IgG subclass levels increased to normal range for age in 67% of patients in partial IgA + IgG subclass deficiency group and in 30% of patients in isolated IgG subclass deficiency group. The mean age for reaching age‐related normal IgG subclass levels for these patients was 69.0 ± 14.5 months. In conclusion, findings of this study suggest that IgA and/or IgG subclass deficiency may be either progressive or reversible disorders and emphasize the value of monitoring Ig levels in affected individuals.

Mycobacterial disease in patients with chronic granulomatous disease: A retrospective analysis of 71 cases

BACKGROUND Chronic granulomatous disease (CGD) is a rare primary immunodeficiency caused by inborn errors of the phagocyte nicotinamide adenine dinucleotide phosphate oxidase complex. From the first year of life onward, most affected patients display multiple, severe, and recurrent infections caused by bacteria and fungi. Mycobacterial infections have also been reported in some patients. OBJECTIVE Our objective was to assess the effect of mycobacterial disease in patients with CGD. METHODS We analyzed retrospectively the clinical features of mycobacterial disease in 71 patients with CGD. Tuberculosis and BCG disease were diagnosed on the basis of microbiological, pathological, and/or clinical criteria. RESULTS Thirty-one (44%) patients had tuberculosis, and 53 (75%) presented with adverse effects of BCG vaccination; 13 (18%) had both tuberculosis and BCG infections. None of these patients displayed clinical disease caused by environmental mycobacteria, Mycobacterium leprae, or Mycobacterium ulcerans. Most patients (76%) also had other pyogenic and fungal infections, but 24% presented solely with mycobacterial disease. Most patients presented a single localized episode of mycobacterial disease (37%), but recurrence (18%), disseminated disease (27%), and even death (18%) were also observed. One common feature in these patients was an early age at presentation for BCG disease. Mycobacterial disease was the first clinical manifestation of CGD in 60% of these patients. CONCLUSION Mycobacterial disease is relatively common in patients with CGD living in countries in which tuberculosis is endemic, BCG vaccine is mandatory, or both. Adverse reactions to BCG and severe forms of tuberculosis should lead to a suspicion of CGD. BCG vaccine is contraindicated in patients with CGD.

Granulomatous skin lesions, severe scrotal and lower limb edema due to mycobacterial infections in a child with complete IFN-γ receptor-1 deficiency.

Interferon-γ receptor-1 (IFNγR1) deficiency is caused by mutations in the IFNγR1 gene and is characterized mainly by susceptibility to mycobacterial disease. Herein, we report an 8-month-old boy with complete recessive IFNγR1 deficiency, afflicted by recurrent mycobacterial diseases with Mycobacterium bovis, Mycobacterium tuberculosis, Mycobacterium avium intracellulare and Mycobacterium fortuitum. Genetic analysis showed a homozygous mutation (106insT) in the IFNγR1 gene leading to complete IFNγR1 deficiency. In addition, he had atypical mycobacterial skin lesions caused by M. avium intracellulare and developed scrotal and lower limb lymphedema secondary to compression of large and fixed inguinal lymphadenopathies. Hematopoietic stem cell transplantation was performed from a matched unrelated donor at 5 years of age; however, he died at 9 months post-transplant. To our knowledge, the patient is the first case with IL-12/IFN-γ pathway defect and severe lymphedema. We have also reviewed and summarized the literature related with IFNγR1 deficiency.

Three different classifications, B lymphocyte subpopulations, TNFRSF13B (TACI), TNFRSF13C (BAFF-R), TNFSF13 (APRIL) gene mutations, CTLA-4 and ICOS gene polymorphisms in Turkish patients with common variable immunodeficiency.

B lymphocyte subpopulations, previously defined classification schemes (Freiburg, Paris, EuroClass), TNFRSF13B (TACI), TNFRSF13C (BAFF-R), TNFSF13 (APRIL) gene mutations, CTLA-4 and ICOS gene polymorphisms were analyzed in 25 common variable immunodeficiency (CVID) patients and 25 healthy controls. Patients were also divided into two subgroups due to some disease severity criteria. SG (severe disease group) (n:11) included patients who have splenomegaly and/or granulomatous diseases and/or bronchiectasis and/or lower baseline IgG values (<270 mg/dl). MG (moderate disease group) (n:14) patients diagnosed as having ESID/PAGID criteria but does not fulfill SG inclusion criteria. The onset of infectious symptoms and age at diagnosis were 50.0 ± 45.7 and 78.5 ± 54.5 months, respectively. Parental consanguinity rate was 54.5% in SG and 7.1% in MG. Switched-memory B cells (CD19 + 27 + IgD-IgM-) showed significant decrease in CVID patients and these cells were also significantly lower in SG compared to MG. CVID patients had significantly higher percentages of CD19 + κ + B cells and CD19 + λ + B cells than healthy controls. Freiburg classification: 87,5% of patients (n:21) were in group I and 12.5% were in Group II. Eighteen (75%) CVID patients with a low percentage of CD21low B cells were in Group Ib while three patients classified as Group Ia. The significantly lower levels of IgG and IgA in Group Ia is a novel finding. The percentages of patients for Paris Classification groups MB0, MB1, MB2 were 88%, 4% and 8%, respectively. There was a significant increase of splenomegaly, lymphadenopathy and autoimmune cytopenia in Group MB0. EuroClass: 45.8% of patients were smB+ and 54.2% were smB-. Splenomegaly and lymphadenopathy were significantly higher in smB- group. TACI: One patient carried heterozygous C104R mutation which was known as disease causing. APRIL: G67R and N96S SNPs were detected in most of the patients and healthy controls. BAFF-R: P21R/H159Y compound heterozygous mutation (n:1) and P21R heterozygous mutations (n:3) were detected. +49 A > G changes in exon 1 of CTLA-4 gene: GG and AG genotypes increase the risk of CVID development 1.32 and 2.18 fold, respectively. 1564 T > C polymorphisms on 3′UTR region in exon 2 of ICOS gene was not found to be significantly different in CVID patients. CVID classifications were not helpful in determining the genetic etiology of CVID.

Novel mutatıons and diverse clinical phenotypes in recombınase-activating gene 1 deficiency

BackgroundSevere combined immunodeficiency is within a heterogeneous group of inherited defects throughout the development of T- and/or B-lymphocytes. Mutations in recombinase-activating genes 1 or 2 (RAG1/2) represent approximately 10% of all SCID cases. RAG1/2 are essential for V(D)J rearrangement of the B- and T-cell receptors.ObjectivesThe aim of this study was to review clinical, immunological and molecular findings of Turkish SCID patients with RAG1 defects and to draw attention to novel mutations, genotype-phenotype correlations and the high rate of BCG infections within this group.MethodsEleven patients (F/M: 6/5) were included. Molecular, immunological and clinical data were evaluated.ResultsFive patients were classified as T-B-NK + SCID, four patients as T + B-NK + SCID (two of these patients were diagnosed as classical Omenn syndrome) and two patients as T + B + NK + SCID with respect to clinical presentations and immunological data. Mean age of the whole study group, mean age at onset of symptoms and mean age at diagnosis were: 33.0 ± 42.8, 3.1 ± 3.3 and 10.4 ± 13.5 months, respectively. Consanguinity rate was 54%. Some novel mutations were found in RAG1 gene in addition to previously reported mutations. Genotype-phenotype correlation was not significantly apparent in most of the cases. BCG infection was observed in 36.4% of patients (two BCG-osis and two BCG-itis).ConclusionEpigenetic factors such as compound genetic defects, enviromental factors, and exposure to recurrent infections may modify phenotypical characteristics of RAG deficiencies. Inoculation of live vaccines such as BCG should be postponed until primary immunodeficiency disease is excluded with appropriate screening tests in suspected cases.

Diverse phenotypic and genotypic presentation of RAG1 mutations in two cases with SCID.

Severe combined immunodeficiencies (SCID) comprise a spectrum of genetic defects that involve both humoral and cellular immunities. Defects in recombinating activating gene 1 (RAG1), RAG2, Artemis, or LIG4 can disrupt V(D)J recombination. Defective V(D)J recombination of the T and B cell receptors is responsible for T−B−NK+SCID. Amorphic mutations in RAG1 and RAG2 cause T−B−NK+SCID, whereas hypomorphic mutations cause an immunodeficency characterized by oligoclonal expansion of TCRγδ T cells, severe CMV infection and autoimmunity. First patient is a typical T−B−NK+SCID with clinical and immunologic findings while the second is atypical with normal immunoglobulin levels, CD4 lymphopenia, elevated TCRγδ T cells, persistent CMV infection, and autoimmune hemolytic anemia. These cases are presented to emphasize that mutations in RAG1 gene may lead to a diverse spectrum of clinical and immunologic findings while hypomorphic mutations may be related with autoimmunity and refractory CMV infection during infancy.

CD4+CD25+Foxp3+ T regulatory cells, Th1 (CCR5, IL-2, IFN-γ) and Th2 (CCR4, IL-4, Il-13) type chemokine receptors and intracellular cytokines in children with common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous group of primary antibody deficiencies characterized by decreased serum immunoglobulin G along with a decrease in serum IgA and/or IgM, defective specific antibody production, and recurrent bacterial infections. Abnormal lymphocyte trafficking, dysregulated cellular responses to chemokines, and uncontrolled T cell polarization may be involved in the pathogenesis and may help to understand the clinical complications. We evaluated T helper cell subsets (chemokine receptors CCR4, CCR5, and CCR7), expressions on T lymphocytes, intracellular cytokines – IL-2, IL-4, IL-13, IFN- γ-on CD4+ T cells, and expression of CD4+CD25+Foxp3+ regulatory T cells of 20 CVID patients and 26 healthy controls. Autoimmune clinical findings and other complications were also determined. Percentages and absolute numbers of CD4+CD25+ Foxp3+ cells did not show any significant difference between CVID cases and healthy controls nor between severe and moderate disease patients. The only significant difference regarding Th1 and Th2 type intracellular cytokines was the decreased absolute numbers of CD3+CD4+IL4+ cells in CVID cases. There were some findings about T helper cell type dominance in CVID patients such as positive correlation between hepatomegaly and high IL-2 and IFN-γ in CD3+CD4+ cells and very high expression of CCR5 (Th1) on CD3+CD4+ cells in patients with granuloma. Th1 (CCR5) and Th2 (CCR4) type chemokine receptors did not show any dominance in CVID cases. However, frequencies of CCR7 expressing CD3+ T cells, CD3+CD4+ T helper cells and CD3+CD8+ T cytotoxic cells were significantly lower in severe CVID patients. In addition, presence of autoimmune clinical findings was negatively correlated with CCR7+ cells. As CCR7 is a key mediator balancing immunity and tolerance in the immune system, the abnormality of this mediator may contribute to the profound immune dysregulation seen in CVID. In addition, Th1 cells seem to be more involved in the disease pathogenesis than Th2 cells.

Relapsing polychondritis in a child with common variable immunodeficiency.

Common variable immunodeficiency (CVID) is associated with recurrent infections and autoimmunity. The most common autoimmune conditions are idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia, chronic arthritis, and gastrointestinal inflammation. Relapsing polychondritis (RP) is an episodic and progressive systemic inflammatory disease, characterized by auricular chondritis, polyarthritis, nasal, and respiratory tract chondritis. Autoimmunity to cartilage‐related components is thought to be involved in its pathogenesis. So far, RP has not been included within many autoimmune conditions that have been reported in patients with either CVID or any other primary immunodeficiency. In this report, a case of CVID with RP and chronic arthritis is presented.