Necil Kutukculer

Low Penetrance, Broad Resistance, and Favorable Outcome of Interleukin 12 Receptor β1 Deficiency Medical and Immunological Implications

The clinical phenotype of interleukin 12 receptor β1 chain (IL-12Rβ1) deficiency and the function of human IL-12 in host defense remain largely unknown, due to the small number of patients reported. We now report 41 patients with complete IL-12Rβ1 deficiency from 17 countries. The only opportunistic infections observed, in 34 patients, were of childhood onset and caused by weakly virulent Salmonella or Mycobacteria (Bacille Calmette-Guérin -BCG- and environmental Mycobacteria). Three patients had clinical tuberculosis, one of whom also had salmonellosis. Unlike salmonellosis, mycobacterial infections did not recur. BCG inoculation and BCG disease were both effective against subsequent environmental mycobacteriosis, but not against salmonellosis. Excluding the probands, seven of the 12 affected siblings have remained free of case-definition opportunistic infection. Finally, only five deaths occurred in childhood, and the remaining 36 patients are alive and well. Thus, a diagnosis of IL-12Rβ1 deficiency should be considered in children with opportunistic mycobacteriosis or salmonellosis; healthy siblings of probands and selected cases of tuberculosis should also be investigated. The overall prognosis is good due to broad resistance to infection and the low penetrance and favorable outcome of infections. Unexpectedly, human IL-12 is redundant in protective immunity against most microorganisms other than Mycobacteria and Salmonella. Moreover, IL-12 is redundant for primary immunity to Mycobacteria and Salmonella in many individuals and for secondary immunity to Mycobacteria but not to Salmonella in most.

Clinical picture and treatment of 2212 patients with common variable immunodeficiency

BACKGROUND Common variable immunodeficiency (CVID) is an antibody deficiency with an equal sex distribution and a high variability in clinical presentation. The main features include respiratory tract infections and their associated complications, enteropathy, autoimmunity, and lymphoproliferative disorders. OBJECTIVE This study analyzes the clinical presentation, association between clinical features, and differences and effects of immunoglobulin treatment in Europe. METHODS Data on 2212 patients with CVID from 28 medical centers contributing to the European Society for Immunodeficiencies Database were analyzed retrospectively. RESULTS Early disease onset (<10 years) was very frequent in our cohort (33.7%), especially in male subjects (39.8%). Male subjects with early-onset CVID were more prone to pneumonia and less prone to other complications suggesting a distinct disease entity. The diagnostic delay of CVID ranges between 4 and 5 years in many countries and is particularly high in subjects with early-onset CVID. Enteropathy, autoimmunity, granulomas, and splenomegaly formed a set of interrelated features, whereas bronchiectasis was not associated with any other clinical feature. Patient survival in this cohort was associated with age at onset and age at diagnosis only. There were different treatment strategies in Europe, with considerable differences in immunoglobulin dosing, ranging from 130 up to 750 mg/kg/mo. Patients with very low trough levels of less than 4 g/L had poor clinical outcomes, whereas higher trough levels were associated with a reduced frequency of serious bacterial infections. CONCLUSION Patients with CVID are being managed differently throughout Europe, affecting various outcome measures. Clinically, CVID is a truly variable antibody deficiency syndrome.

DOCK8 functions as an adaptor that links TLR-MyD88 signaling to B cell activation

The adaptors DOCK8 and MyD88 have been linked to serological memory. Here we report that DOCK8-deficient patients had impaired antibody responses and considerably fewer CD27+ memory B cells. B cell proliferation and immunoglobulin production driven by Toll-like receptor 9 (TLR9) were considerably lower in DOCK8-deficient B cells, but those driven by the costimulatory molecule CD40 were not. In contrast, TLR9-driven expression of AICDA (which encodes the cytidine deaminase AID), the immunoglobulin receptor CD23 and the costimulatory molecule CD86 and activation of the transcription factor NF-κB, the kinase p38 and the GTPase Rac1 were intact. DOCK8 associated constitutively with MyD88 and the tyrosine kinase Pyk2 in normal B cells. After ligation of TLR9, DOCK8 became tyrosine-phosphorylated by Pyk2, bound the Src-family kinase Lyn and linked TLR9 to a Src–kinase Syk–transcription factor STAT3 cascade essential for TLR9-driven B cell proliferation and differentiation. Thus, DOCK8 functions as an adaptor in a TLR9-MyD88 signaling pathway in B cells.

Study of pro-inflammatory (TNF-alpha, IL-1alpha, IL-6) and T-cell-derived (IL-2, IL-4) cytokines in plasma and synovial fluid of patients with juvenile chronic arthritis: correlations with clinical and laboratory parameters.

Acute phase proteins, synovial fluid (SF) cellular infiltrates, pro-inflammatory (TNF-α, IL-1α, IL-6) and Th1 (IL-2) and Th2 (IL-4) derived cytokine levels both in plasma and SF were examined in pauciarticular and polyarticular juvenile chronic arthritis (JCA) patients during the active (n=22) and inactive (n=14) period in order to determine pathogenic mechanisms and correlations between cytokines and laboratory parameters showing disease activity. The erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) and IgG concentrations were found to be significantly elevated in the active period of JCA. In pauciarticular JCA patients, when compared with their peripheral blood lymphocyte subpopulations, SF CD3+ cells (73.1%) and HLA-DR+ active T cells (22.5%) were found to be significantly increased. In the active period of JCA, plasma TNF-α and IL-6 concentrations were significantly elevated. Plasma IL-2 and IL-4 levels were not elevated and were found to be similar to those in the inactive phase and in healthy controls. SF IL-6, TNF-α and IL-1α levels were extremely high in all the patients. SF IL-4 and IL-2 levels were all undetectable. There was a significant correlation between ESR values and plasma IL-6 levels and between serum CRP levels and plasma IL-6 and TNF-α concentrations. In conclusion, increased local production of pro-inflammatory cytokines appears to account for the articular manifestations of JCA. The impaired production of anti-inflammatory Th2-derived cytokines (IL-4) seems to cause increased production of inflammatory cytokines acting on the balance between them. The deficit in IL-2 production was not suggested to be primarily involved in the pathogenesis. In addition, not only CRP and ESR values, but also plasma IL-6 and TNF-α concentrations may be used as markers of disease activity.

IL-12Rβ1 Deficiency in Two of Fifty Children with Severe Tuberculosis from Iran, Morocco, and Turkey

Background and Objectives In the last decade, autosomal recessive IL-12Rβ1 deficiency has been diagnosed in four children with severe tuberculosis from three unrelated families from Morocco, Spain, and Turkey, providing proof-of-principle that tuberculosis in otherwise healthy children may result from single-gene inborn errors of immunity. We aimed to estimate the fraction of children developing severe tuberculosis due to IL-12Rβ1 deficiency in areas endemic for tuberculosis and where parental consanguinity is common. Methods and Principal Findings We searched for IL12RB1 mutations in a series of 50 children from Iran, Morocco, and Turkey. All children had established severe pulmonary and/or disseminated tuberculosis requiring hospitalization and were otherwise normally resistant to weakly virulent BCG vaccines and environmental mycobacteria. In one child from Iran and another from Morocco, homozygosity for loss-of-function IL12RB1 alleles was documented, resulting in complete IL-12Rβ1 deficiency. Despite the small sample studied, our findings suggest that IL-12Rβ1 deficiency is not a very rare cause of pediatric tuberculosis in these countries, where it should be considered in selected children with severe disease. Significance This finding may have important medical implications, as recombinant IFN-γ is an effective treatment for mycobacterial infections in IL-12Rβ1-deficient patients. It also provides additional support for the view that severe tuberculosis in childhood may result from a collection of single-gene inborn errors of immunity.

Defects along the TH17 differentiation pathway underlie genetically distinct forms of the hyper IgE syndrome

BACKGROUND The hyper IgE syndrome (HIES) is characterized by abscesses, eczema, recurrent infections, skeletal and connective tissue abnormalities, elevated serum IgE, and diminished inflammatory responses. It exists as autosomal-dominant and autosomal-recessive forms that manifest common and distinguishing clinical features. A majority of those with autosomal-dominant HIES have heterozygous mutations in signal transducer and activator of transcription (STAT)-3 and impaired T(H)17 differentiation. OBJECTIVE To elucidate mechanisms underlying different forms of HIES. METHODS A cohort of 25 Turkish children diagnosed with HIES were examined for STAT3 mutations by DNA sequencing. Activation of STAT3 by IL-6 and IL-21 and STAT1 by IFN-alpha was assessed by intracellular staining with anti-phospho (p)STAT3 and -pSTAT1 antibodies. T(H)17 and T(H)1 cell differentiation was assessed by measuring the production of IL-17 and IFN-gamma, respectively. RESULTS Six subjects had STAT3 mutations affecting the DNA binding, Src homology 2, and transactivation domains, including 3 novel ones. Mutation-positive but not mutation-negative subjects with HIES exhibited reduced phosphorylation of STAT3 in response to cytokine stimulation, whereas pSTAT1 activation was unaffected. Both patient groups exhibited impaired T(H)17 responses, but whereas STAT3 mutations abrogated early steps in T(H)17 differentiation, the defects in patients with HIES with normal STAT3 affected more distal steps. CONCLUSION In this cohort of Turkish children with HIES, a majority had normal STAT3, implicating other targets in disease pathogenesis. Impaired T(H)17 responses were evident irrespective of the STAT3 mutation status, indicating that different genetic forms of HIES share a common functional outcome.

Proinflammatory cytokines, prostaglandins and zinc in febrile convulsions

Abstract 
 Background : Some changes in the levels of proinflammatory cytokines, prostaglandins and zinc (Zn) in peripheral blood and cerebrospinal fluid (CSF) have been suggested to occur for the pathogenesis of febrile convulsions (FC).

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.

Gingival Crevicular Fluid Levels of Cathelicidin LL-37 and Interleukin-18 in Patients With Chronic Periodontitis

BACKGROUND Cathelicidin LL-37, an antimicrobial peptide, is part of the host innate immune response in the oral cavity. Interleukin (IL)-18, a proinflammatory cytokine, could play a role in the progression of the inflammatory response. The aim of the present study was to determine the levels of cathelicidin LL-37 and IL-18 in the gingival crevicular fluid (GCF) of patients with gingivitis and chronic periodontitis. METHODS Fifty-nine subjects were included in the present study. Probing depth (PD), clinical attachment level (CAL), plaque index (PI), bleeding on probing, and papilla bleeding index (PBI) were assessed in patients with chronic periodontitis or gingivitis and in healthy controls. GCF levels of cathelicidin LL-37 and IL-18 were analyzed by enzyme-linked immunosorbent assay. RESULTS GCF levels of cathelicidin LL-37 were significantly elevated in patients with chronic periodontitis compared to the other groups (P <0.05). No significant difference was found in the total amount of GCF IL-18 among the study groups (P >0.05). Spearman correlation analysis revealed a positive relationship between levels of GCF cathelicidin LL-37 and PD, CAL, PI, and PBI at the sampled sites (P <0.01), whereas no correlation was found between the total amount of GCF IL-18 and clinical periodontal parameters at the sampled sites (P >0.05). CONCLUSION Elevated levels of GCF cathelicidin LL-37 in chronic periodontitis suggest that it may play a role in the host innate immune response during periodontal inflammation.

MYCOBACTERIUM FORTUITUM-CHELONAE COMPLEX INFECTION IN A CHILD WITH COMPLETE INTERLEUKIN-12 RECEPTOR BETA 1 DEFICIENCY

A 10-year-old boy had chronic diarrhea, abdominal pain, severe weight loss and hepatomegaly; multiple enlarged para-aortic and mesenteric lymph nodes. Mycobacterium fortuitum-chelonae complex was identified in the culture of the lymph nodes. Interleukin-12 receptor beta 1 expression could not be observed in phytohemagglutinin-driven T cell blasts. A homozygous missense interleukin-12 receptor beta 1 mutation was found (R173P).