Comparison of mitogen-induced proliferation in child and adult healthy groups by flow cytometry revealed similarities.

The proliferation of antigen-specific lymphocyte clones, the initial step in acquired immunity, is vital for effector functions. Proliferation tests both in immunology research and diagnosis are gaining attendance gradually, while the use of adult healthy individuals as controls of pediatric patients is a question. This study aimed to investigate and compare mitogen-stimulated proliferation responses of total lymphocytes and T- and B-lymphocyte subsets in adult and children healthy donors. Nineteen children and 20 adult healthy donors were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) purified from peripheral blood samples of the donors, by Ficoll gradient centrifugation, were stained with CFSE and were cultured in a 37 â„ƒ CO2 incubator for 120 h with the absence or existence of polyclonal activators: PHA and CD-Mix. After cell culture, PBMCs were stained with monoclonal antibodies against CD4 and CD19, and proliferation percentages of CD4+ T and CD19+ B cells, together with total lymphocytes were determined by flow cytometry. This study revealed similarities between children and adult age groups, concerning mitogenic stimulation of the lymphocytes. The only difference was a significantly high proliferation of pediatric CD4+ T cells in response to PHA. CD4+ T cell responses against PHA were inversely correlated with altering age. When pediatric individuals were distributed into age groups of 0-2 years, 3-5 years, and 6-18 years, PHA responses of CD4+ cells were found to be diminished with advancing age. These findings propose the possibility of enrollment of adult healthy individuals as controls for pediatric patients.

Diagnosis of primary immunodeficiency diseases in pediatric patients hospitalized for recurrent, severe, or unusual infections.

BACKGROUND: Primary immunodeficiency diseases (PID) usually presents itself with recurrent, severe, and unusual infections, along with autoimmunity and various other malignancies. But, the diversity of PID often makes the diagnosis of patients difficult for physicians other than clinical immunologists. This study aimed to describe the characteristics of patients diagnosed with PIDs during the inpatient treatment for infectious diseases, and to highlight the cases in which a PID diagnosis should be considered. METHODS: The clinical, immunological, and molecular features of 81 pediatric patients treated for infectious diseases, who were diagnosed with a PID during hospitalization was retrospectively analyzed. The diagnosis was based on the PID criteria of the International Union of Immunological Societies. RESULTS: The five main PID sub-types were identified. Predominantly, antibody deficiencies were the most common (61.7%) group. The average delay in diagnosis was 34.6 months, and the positive family history rate was 24.7%, while the consanguineous marriage rate was 45.7%. Around thirty-five (43%) patients were found to have mutated PID-related genes. While lower respiratory tract infections were the most common symptom, a fever of unknown origin was another remarkable diagnosis. Eight (9.9%) patients underwent allogeneic hematopoietic stem cell transplantation. CONCLUSIONS: Clinicians should consider a PID diagnosis, especially in the cases of recurrent, severe, or atypical infections. Increased knowledge of the alarm features of PID can promote early diagnosis.

Evolution and long-term outcomes of combined immunodeficiency due to CARMIL2 deficiency.

BACKGROUND: Biallelic loss-of-function mutations in CARMIL2 cause combined immunodeficiency associated with dermatitis, inflammatory bowel disease (IBD), and EBV-related smooth muscle tumors. Clinical and immunological characterizations of the disease with long-term follow-up and treatment options have not been previously reported in large cohorts. We sought to determine the clinical and immunological features of CARMIL2 deficiency and long-term efficacy of treatment in controlling different disease manifestations. METHODS: The presenting phenotypes, long-term outcomes, and treatment responses were evaluated prospectively in 15 CARMIL2-deficient patients, including 13 novel cases. Lymphocyte subpopulations, protein expression, regulatory T (Treg), and circulating T follicular helper (cTFH ) cells were analyzed. Three-dimensional (3D) migration assay was performed to determine T-cell shape. RESULTS: Mean age at disease onset was 38 ± 23 months. Main clinical features were skin manifestations (n = 14, 93%), failure to thrive (n = 10, 67%), recurrent infections (n = 10, 67%), allergic symptoms (n = 8, 53%), chronic diarrhea (n = 4, 27%), and EBV-related leiomyoma (n = 2, 13%). Skin manifestations ranged from atopic and seborrheic dermatitis to psoriasiform rash. Patients had reduced proportions of memory CD4+ T cells, Treg, and cTFH cells. Memory B and NK cells were also decreased. CARMIL2-deficient T cells exhibited reduced T-cell proliferation and cytokine production following CD28 co-stimulation and normal morphology when migrating in a high-density 3D collagen gel matrix. IBD was the most severe clinical manifestation, leading to growth retardation, requiring multiple interventional treatments. All patients were alive with a median follow-up of 10.8 years (range: 3-17 years). CONCLUSION: This cohort provides clinical and immunological features and long-term follow-up of different manifestations of CARMIL2 deficiency.

Primary antibody deficiencies in Turkey: molecular and clinical aspects.

Primary antibody deficiencies (PAD) are the most common subtype of primary immunodeficiencies, characterized by increased susceptibility to infections and autoimmunity, allergy, or malignancy predisposition. PAD syndromes comprise of immune system genes highlighted the key role of B cell activation, proliferation, migration, somatic hypermutation, or isotype switching have a wide spectrum from agammaglobulinemia to selective Ig deficiency. In this study, we describe the molecular and the clinical aspects of fifty-two PAD patients. The most common symptoms of our cohort were upper and lower respiratory infections, bronchiectasis, diarrhea, and recurrent fever. Almost all patients (98%) had at least one of the symptoms like autoimmunity, lymphoproliferation, allergy, or gastrointestinal disease. A custom-made next-generation sequencing (NGS) panel, which contains 24 genes, was designed to identify well-known disease-causing variants in our cohort. We identified eight variants (15.4%) among 52 PAD patients. The variants mapped to BTK (n = 4), CD40L (n = 1), ICOS (n = 1), IGHM (n = 1), and TCF3 (n = 1) genes. Three novel variants were described in the BTK (p.G414W), ICOS (p.G60*), and IGHM (p.S19*) genes. We performed Sanger sequencing to validate pathogenic variants and check for allelic segregation in the family. Targeted NGS panel sequencing can be beneficial as a suitable diagnostic modality for diagnosing well-known monogenic PAD diseases (only 2-10% of PADs); however, screening only the coding regions of the genome may not be adequately powered to solve the pathogenesis of PAD in all cases. Deciphering the regulatory regions of the genome and better understanding the epigenetic modifications will elucidate the molecular basis of complex PADs.

Determining T and B Cell development by TREC/KREC analysis in primary immunodeficiency patients and healthy controls.

T cell receptor excision circles (TRECs) and kappa-deleting excision circles (KRECs) are DNA fragments potentially indicative of T and B cell development, respectively. Recent thymic emigrants (RTEs) are a subset of peripheral cells that may also represent thymic function. Here, we investigated TREC/KREC copy numbers by quantitative real-time PCR in the peripheral blood of patients with primary immunodeficiencies (PIDs, n = 145) and that of healthy controls (HCs, n = 86) and assessed the correlation between RTEs and TREC copy numbers. We found that TREC copy numbers were significantly lower in children and adults with PIDs (P < .0001 and P < .002, respectively) as compared with their respective age-matched HCs. A moderate correlation was observed between TREC copies and RTE numbers among children with PID (r = .5114, P < .01), whereas no significant correlation was detected between RTE values and TREC content in the HCs (r = .0205, P = .9208). Additionally, we determined TREC and KREC copy numbers in DNA isolated from the Guthrie cards of 200 newborns and showed that this method is applicable to DNA isolated from both peripheral blood samples and dried blood spots, with the two sample types showing comparable TREC and KREC values. We further showed that RTE values are not always reliable markers of T cell output. Although additional confirmatory studies with larger cohorts are needed, our results provide thresholds for TREC/KREC copy numbers for different age groups.

Diagnostic Modalities Based on Flow Cytometry for Chronic Granulomatous Disease: A Multicenter Study in a Well-Defined Cohort.

BACKGROUND: Chronic granulomatous disease (CGD) is characterized by defective microbial killing due to mutations affecting subunits of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. Definitive genetic identification of disease subtypes may be delayed or not readily available. OBJECTIVE: Sought to investigate the role of intracellular staining of NADPH oxidase enzyme subunits in predicting the respective genetic defects in patients with CGD and carriers. METHODS: Thirty-four patients with genetically inherited CGD, including 12 patients with X-linked CGD (gp91phagocyte oxidase (phox) deficiency due to cytochrome b-245, beta polypeptide [CYBB] mutations) and 22 patients with autosomal-recessive CGD (p22phox, p47phox, and p67phox deficiency due to cytochrome b-245, alpha polypeptide [CYBA], neutrophil cytosolic factor 1 [NCF1] and NCF2 mutations, respectively) were recruited from different immunology centers and followed up prospectively. Dihydrorhodamine testing and NADPH oxidase subunit expression in white blood cells were determined by flow cytometry. RESULTS: gp91phox and p22phox defects, which result in simultaneous loss of both proteins due to their complex formation, were differentiated only by comparative analysis of patients' and mothers' intracellular staining. p47phox and p67phox protein expression was almost undetectable in patients compared with carrier mothers and healthy controls. The expression values of the respective subunits were found to be significantly higher in all controls as compared with carrier mothers, which in turn were higher than those of patients. CONCLUSIONS: Analysis of NADPH oxidase enzyme subunits by flow cytometry in patients and carriers is useful in the rapid prediction of the genetic defect of patients with CGD, thus guiding targeted sequencing and aiding in their early diagnosis.

The epidemiologic and clinical features of viral agents among hospitalized children with lower respiratory tract infections.

AIM: Acute respiratory tract infections are among the most common infectious diseases worldwide. Respiratory viruses are the leading cause of respiratory infections in children. Herein, we aimed to determine the epidemiologic and clinical feautures of viral agents among hospitalized children with lower respiratory tract infections. MATERIAL AND METHODS: Nasopharyngeal swab specimens were obtained from the 422 patients hospitalized with a diagnosis of lower respiratory tract infections between December 2012 and December 2016. Multiplex reverse-transcription polymerase chain reaction was performed for the detection of viruses. RESULTS: Viral respiratory pathogens were detected in 311 patients (73.7%). In regard to respiratory virus subtypes, 103 patients (33.1%) had respiratory syncytial virus, 102 (32.7%) had human rhinovirus, 49 (15.7%) had multiple viruses, 15 (4.8%) had parainfluenzavirus, 13 (4.1%) had adenovirus, nine (2.8%) had human metapneumovirus, eight (2.5%) had human coronaviruses, six (1.9%) had bocavirus, five (1.6%) had influenza virus, and one patient (0.3%) had enterovirus. The median age was lower in patients with multiple viruses (p<0.001). The respiratory syncytial virus was more commonly detected in patients with a history of prematurity (p<0.001). Stridor was more common in other viruses including parainfluenza viruses (p<0.001). CONCLUSION: Respiratory viruses are the main causative agents of respiratory tract infections in children. Timely and accurate detection of viruses is necessary in terms of public health. The detection of respiratory viruses also contributes to epidemiologic results and vaccine studies.

Epstein-Barr virus, cytomegalovirus and BK polyomavirus burden in juvenile systemic lupus erythematosus: correlation with clinical and laboratory indices of disease activity.

OBJECTIVES: Clinical and laboratory investigations have revealed that Epstein-Barr virus (EBV) is involved in altered immunological response of systemic lupus erythematosus (SLE). Higher seroprevalence rates of anti-EBV antibodies and increased viral load are demonstrated in adult SLE patients. The prevalence of BK polyomavirus (BKV) reactivation is also suggested to be higher in SLE. Herein, we aimed to evaluate the immune response of children with SLE to EBV antigens in addition to EBV and BKV DNA. We also tried to evaluate whether these serological results differ from another connective tissue disease - juvenile systemic sclerosis (jSS) - and healthy individuals. METHODS: Serum levels of EBV early antigen diffuse (EA-D) IgG, EBV nuclear antigen-1 IgG, EBV viral capsid antigen (VCA), cytomegalovirus (CMV) IgG, EBV DNA, CMV DNA and urinary BKV DNA were evaluated in healthy controls and in patients with a diagnosis of juvenile SLE (jSLE) and jSS. RESULTS: A total of 70 jSLE patients, 14 jSS patients and 44 sex-matched healthy individuals were involved in the study. EBV VCA was positive in 84.2% of jSLE patients, 85.7% of jSS patients and 36.3% of healthy controls. EBV EA-D IgG positivity was significantly higher in jSLE patients compared to jSS patients and healthy controls (20% vs. 7.1% and 0%, p = 0.005). EBV VCA positivity was associated with malar rash and immunological disorder, but there was no statistical significance in other antibody positivity in terms of clinical and haemogram findings and autoantibody positivity. CMV DNA positivity was present in only 2.8% of jSLE patients. None of the jSS patients or the healthy controls had CMV DNA positivity. EBV DNA and BKV DNA were also negative in all three groups. CONCLUSION: The results of our study assume a relationship between SLE and EBV, but we could not demonstrate an association between CMV and BKV. The negative DNA results in contrast to serological positivity can be interpreted as an altered and impaired immune system and increased viral susceptibility. These results suggest that EBV contributes to disease continuity, even if it does not directly cause development.

Genetic Characteristics, Infectious, and Noninfectious Manifestations of 32 Patients with Chronic Granulomatous Disease.

BACKGROUND: Chronic granulomatous disease (CGD) is a rare genetic disorder characterized by failure of phagocytic leukocytes to destroy certain microbes. We present a study on CGD patients enrolled at a single medical center concerning the infectious and noninfectious complications and genetic properties of the disease. METHODS: Icotinamide adenine dinucleotide phosphate oxidase activity and the expression of flavocytochrome b558 were measured by flow cytometry, and clinical outcomes of the patients were listed in relation to the genetic results. RESULTS: The clinical and genetic findings of 32 pediatric cases with CGD from 23 families were enrolled. Pneumonia and anemia were the most common infectious and noninfectious symptoms. Genetic analysis showed that 10 families (43.5%) carried CYBB variants and 13 families (56.5%) have autosomal recessive (AR) CGD, in which 6 families (26%) carried NCF1 variants, 4 (17.4%) carried CYBA variants, and 3 (13%) carried NCF2 variants. The median age of clinical onset was 3.3 and 48 months for patients with X-linked CGD (X-CGD) and AR-CGD, respectively. The onset of symptoms before age 1 year was 94% in X-CGD, 28.5% in AR-CGD, and 12.5% in patients with oxidase residual activity. Moreover, a de novo germline mutation at c.1415delG in CYBB (OMIM#300481) and a novel c.251_263del13bp in CYBA (OMIM#608508) were also investigated. CONCLUSIONS: Ihydrorhodamine-1,2,3 assay could not detect carrier mother in de novo case with CYBB variant. Most X-CGD patients have the onset of symptoms before age 1 year. Additionally, residual oxidase activity in AR-CGD causes a delay in onset, diagnosis, and prophylaxis. The protective role of residual activity is limited while the infection is ongoing and becoming serious.

Serotype distribution of Streptococcus pneumonia in children with invasive disease in Turkey: 2015-2018.

Objectives: To determine the serotype distribution of pneumococcus causing invasive pneumococcal disease (meningitidis, bacteremia and empyema) in children in Turkey, and to observe potential changes in this distribution in time to guide effective vaccine strategies. Methods: We surveyed S. pneumoniae with conventional bacteriological techniques and with real-time polymerase chain reaction (RT-PCR) in samples of cerebrospinal fluid (CSF), blood and pleural fluid. S. pneumoniae strains were isolated from 33 different hospitals in Turkey, which are giving health services to approximately 60% of the Turkish population. Results: A total of 167 cases were diagnosed with invasive pneumococcal disease between 2015 and 2018. We diagnosed 52 (31.1%) patients with meningitis, 104 (62.2%) patients with bacteremia, and 11 (6.6%) patients with empyema. Thirty-three percent of them were less than 2 years old and 56% less than 5 years old. Overall PCV13 serotypes accounted for 56.2% (94/167). The most common serotypes were 19 F (11.9%), 1 (10.7%) and 3 (10.1%). Conclusions: Besides the increasing frequency of non-vaccine serotypes, vaccine serotypes continue to be a problem for Turkey despite routine and high-rate vaccination with PCV13 and significant reduction reported for the incidence of IPD in young children. Since new candidate pneumococcal conjugate vaccines with more serotype antigens are being developed, continuing IPD surveillance is a significant source of information for decision-making processes on pneumococcal vaccination.

Mutational landscape of severe combined immunodeficiency patients from Turkey.

Severe combined immunodeficiency (SCID) has a diverse genetic aetiology, where a clinical phenotype, caused by single and/or multiple gene variants, can give rise to multiple presentations. The advent of next-generation sequencing (NGS) has recently enabled rapid identification of the molecular aetiology of SCID, which is crucial for prognosis and treatment strategies. We sought to identify the genetic aetiology of various phenotypes of SCIDs and assessed both clinical and immunologic characteristics associated with gene variants. An amplicon-based targeted NGS panel, which contained 18 most common SCID-related genes, was contumely made to screen the patients (n = 38) with typical SCID, atypical SCID or OMENN syndrome. Allelic segregations were confirmed for the detected gene variants within the families. In total, 24 disease-causing variants (17 known and 7 novel) were identified in 23 patients in 9 different SCID genes: RAG1 (n = 5), RAG2 (n = 2), ADA (n = 3), DCLRE1C (n = 2), NHEJ1 (n = 2), CD3E (n = 2), IL2RG (n = 3), JAK3 (n = 4) and IL7R (n = 1). The overall success rate of our custom-made NGS panel was 60% (39.3% for NK+ SCID and 100% for NK- SCID). Incidence of autosomal-recessive inherited genes is more frequently found in our cohort than the previously reported populations probably due to the high consanguineous marriages in Turkey. In conclusion, the custom-made sequencing panel was able to identify and confirm the previously known and novel disease-causing variants with high accuracy.

Evaluation of Clinical and Laboratory Characteristics of Children with Pulmonary and Extrapulmonary Tuberculosis.

Background and objective: Tuberculosis (TB) is an important public health problem in both developing and developed countries. Childhood TB is also an important epidemiological indicator in terms of forming the future TB pool. The diagnosis of TB is difficult in children due to the lack of a standard clinical and radiological description. We aimed to evaluate and compare the clinical, laboratory, and radiologic findings of childhood pulmonary and extrapulmonary TB. Material and Methods: The medical records of patients hospitalized with the diagnosis of pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) between December 2007 and December 2017 were evaluated retrospectively. Results: There were 163 patients diagnosed with TB with 94 females (57.7%) and 69 males (42.3%). Seventy-three patients (44.8%) had PTB, 71 (43.6%) patients had EPTB, and 19 patients (11.7%) had both PTB and EPTB, called as disseminated TB. Ninety-six (58.9%) patients had tuberculin skin test (TST) positivity and 64 patients (39.3%) had interferon-gamma release assay (IGRA) positivity. Acid-resistant bacteria were observed in 34 (20.9%) body fluid samples and culture positivity was observed in 33 (20.2%) samples. Comparison of PTB, EPTB, and disseminated TB revealed that low socioeconomic status, TB contact, and low body weight were more common in disseminated TB, and TST positivity was more common in PTB. Conclusion: Malnutrition, low socioeconomic status, and TB contact were important diagnostic variables in our study and all three parameters were more common in disseminated TB. Tuberculosis should be considered in patients admitted with different complaints and signs in populations with high TB incidence and low socioeconomic status.

Evaluation of Continuous Renal Replacement Therapy and Therapeutic Plasma Exchange, in Severe Sepsis or Septic Shock in Critically Ill Children.

Background and objective: Severe sepsis and septic shock are life-threatening organ dysfunctions and causes of death in critically ill patients. The therapeutic goal of the management of sepsis is restoring balance to the immune system and fluid balance. Continuous renal replacement therapy (CRRT) is recommended in septic patients, and it may improve outcomes in patients with severe sepsis or septic shock. Therapeutic plasma exchange (TPE) is another extracorporeal procedure that can improve organ function by decreasing inflammatory and anti-fibrinolytic mediators and correcting haemostasis by replenishing anticoagulant proteins. However, research about sepsis and CRRT and TPE in children has been insufficient and incomplete. Therefore, we investigated the reliability and efficacy of extracorporeal therapies in paediatric patients with severe sepsis or septic shock. Materials and methods: We performed a multicentre retrospective study using data from all patients aged <18 years who were admitted to two paediatric intensive care units. Demographic data and reason for hospitalization were recorded. In addition, vital signs, haemogram parameters, and biochemistry results were recorded at 0 h and after 24 h of CRRT. Patients were compared according to whether they underwent CRRT or TPE; mortality between the two treatment groups was also compared. Results: Between January 2014 and April 2019, 168 septic patients were enrolled in the present study. Of them, 47 (27.9%) patients underwent CRRT and 24 underwent TPE. In patients with severe sepsis, the requirement for CRRT was statistically associated with mortality (p < 0.001). In contrast, the requirement for TPE was not associated with mortality (p = 0.124). Conclusion: Our findings revealed that the requirement for CRRT in patients with severe sepsis is predictive of increased mortality. CRRT and TPE can be useful techniques in critically ill children with severe sepsis. However, our results did not show a decrease of mortality with CRRT and TPE.

Clinical and immunophenotypic characteristics of patients with chromosome 22q11.2 deletion syndrome: a single institution's experience.

AIM: The aim of this study was to identify the clinical and immunologic features of patients with 22q11.2 deletion syndrome who were followed up in our clinic. Thus, it is aimed to identify the syndrome early, choose the right treatment options according to humoral and cellular immunologic analysis, and enlighten how to follow up these kinds of patients with immunodeficiencies. MATERIAL AND METHODS: We retrospectively collected data by reviewing the files of 11 patients with 22q11.2 deletion syndrome who were followed up in our clinic between January 2003 and January 2015. The diagnoses were based on the patients' clinical, genetic, and immunologic features. Demographic features, family history, initial symptoms on admission, physical findings, and results of immunologic studies of the patients. Age of diagnosis, treatment options, and clinical follow-up were evaluated. RESULTS: The patients' diagnosis age ranged from 1-11 months and the most common symptoms of admission were cardiac murmur and atypical facial appearance, which were detected during a routine physical examination. All patients had cardiac anomalies, and four patients had a history of cardiovascular surgery. Eight patients (72.7%) had a history of severe infection; recurrent lower respiratory tract infections were reported in six patients (54.5%), pulmonary tuberculosis in one patient (9.1%), and moniliasis resistant to treatment was detected in one patient. None of the patients required intravenous immunoglobulin replacement therapy, and antibiotic prophylaxis was administered to two patients with lymphopenia. CONCLUSION: 22q11.2 deletion syndrome is a multi-systemic disorder that should be evaluated by a multidisciplinary team. It should be kept in mind for patients with neonatal hypocalcemic tetany or recurrent infections or atypical facial appearance with cardiac anomalies. Early diagnosis should lead to immunologic analysis and enable the choice of treatment. Preventive measures against infection is recommended for the patients with incomplete immunodeficiency, and thymus transplantation is recommended for patients with complete immunodeficiency.

AMAÇ: Bu çalismada klinigimizde 22q11.2 delesyon sendromu tanisi ile izlenmekte olan hastalarin klinik ve immünolojik niteliklerinin tanimlanmasi amaçlanmistir. Böylece hastaligin erken taninmasina yardimci olmak, humoral ve hücresel immünolojik verilere göre tedavi seçeneklerine yönlendirmek ve bu immün yetersizlik hastalarinin nasil izlenecegine isik tutmak hedeflenmistir. GEREÇ VE YÖNTEMLER: Klinigimizde, Ocak 2003-Ocak 2015 tarihleri arasinda 22q11.2 delesyon sendromu tanisi ile izlenmekte olan 11 olgunun dosya verileri geriye dönük olarak incelendi. Hastalarin tanisi; klinik, genetik ve immünolojik niteliklere göre konuldu. Çalismaya alinan tüm hastalarin demografik nitelikleri, aile öyküsü, basvuru yakinmalari, fizik baki bulgulari, immünolojik inceleme sonuçlari, tani yasi, tedavi seçenegi ile klinik izlemleri irdelendi. BULGULAR: Hastalarin tani yasi 1-11 ay arasinda degismekte olup, en sik basvuru yakinmasi fizik baki sirasinda farkedilen atipik yüz görünümü ve kalpte duyulan üfürüm idi. Tüm hastalarin kalbinde anomali bulunur iken, dört hastada kardiyovasküler cerrahi girisim öyküsü vardi. Sekiz hastada (%72,7) ciddi enfeksiyon geçirme öyküsü olup; alti hastada (%54,5) sik tekrarlayan alt solunum yolu enfeksiyonu, bir hastada (%9,1) akciger tüberkülozu ve bir hastada (%9,1) inatçi moniliazis saptandi. Lenfopenik olan iki hastaya (%18,2) antibiyotik profilaksisi uygulanirken, hiçbir hastada intravenöz immünglobulin replasman tedavisi gereksinimi olmadi. ÇIKARIMLAR: Kromozom 22q11.2 delesyon sendromu, çoklu organ tutulumu nedeniyle birçok uzmanlik daliyla birlikte izlenmelidir. Yenidogan döneminde hipokalsemik tetani geçiren, kalp anomalisine eslik eden atipik yüz görünümü olan ve yineleyen enfeksiyon öyküsü olan hastalarda mutlaka akla getirilmelidir. Erken tani ile hastalarin immün sistem incelemesinin yapilmasi; kismi eksiklik durumunda enfeksiyonlardan koruyucu önlemler alinmasini, tam hücresel immün bozukluk olmasi durumunda ise timus nakli yapilmasina olanak saglayacaktir.

Genotypic characterization of Pseudomonas aeruginosa isolates from Turkish children with cystic fibrosis.

Objective: To identify epidemic and other transmissible Pseudomonas aeruginosa strains, genotypic analyses are required. The aim of this study was to assess the distribution of P. aeruginosa strains within the Turkish pediatric cystic fibrosis (CF) clinic population. Methods: Eighteen patients attending the pediatric CF clinic of Cerrahpasa Medical Faculty were investigated in the study. Throat swab and/or sputum samples were taken from each patient at 3-month intervals. The isolates of patients were analyzed by pulsed-field gel electrophoresis (PFGE). The intra- and interpatient genotypic heterogeneity of isolates was examined to determine the clonal isolates of P. aeruginosa within the cohort. Results: A total of 108 clinical isolates of P. aeruginosa were obtained from 18 patients between May 2013 and May 2014. The pulsotypes of the first patient's isolates could not be obtained by PFGE. From the remaining 17 patients and 101 isolates, 55 distinct pulsotypes were detected. The number of pulsotypes observed in more than one patient (minor clonal strains, cluster strains) was 8 (14.5%), and one of them colonized three patients. However, none of them was detected in more than three patients. These pulsotypes were composed of 20 isolates. In addition, with the PFGE analysis of 81 isolates, we detected 47 (85.6%) pulsotypes, which belonged to only one patient. Over different periods of this study, only 2 (11.8%) patients were colonized with the same pulsotype. Conclusion: Our study indicates that there was considerable genomic diversity among the P. aeruginosa isolates in our clinic. The presence of shared pulsotypes supports cross-transmission between patients.

Infections with Carbapenem-Resistant Gram-Negative Bacteria are a Serious Problem Among Critically Ill Children: A Single-Centre Retrospective Study.

Children in paediatric intensive care units (PICUs) are vulnerable to infections because invasive devices are frequently used during their admission. We aimed to determine the prevalence, associated factors, and prognosis of infections in our PICU. This retrospective study evaluated culture results from 477 paediatric patients who were treated in the PICU between January 2014 and March 2019. Ninety patients (18.9%) had bacterial infections, with gram-negative bacteria being the predominant infectious agents. Culture-positive patients were younger than culture-negative patients, and age was related to mortality and various clinical factors. Culture-positive bacterial infections in the PICU were associated with increased use of invasive mechanical ventilation (odds ratio(OR); 2.254), red blood cell (RBC) transfusions (OR:2.624), and inotropic drugs (OR:2.262). Carbapenem resistance was found in approximately one-third of gram-negative bacteria, and was most common in tracheal aspirate specimens and cases involving Klebsiella spp. Total parenteral nutrition was a significant risk factor (OR:5.870). Positive blood culture results were associated with poorer patient survival than other culture results. These findings indicate that infections, especially those involving carbapenem-resistant bacteria, are an important issue when treating critically ill children.

Can Nebulised Colistin Therapy Improve Outcomes in Critically Ill Children with Multi-Drug Resistant Gram-Negative Bacterial Pneumonia?

In the past decade, multidrug-resistant (MDR) gram-negative bacteria have become a major problem, especially for patients in intensive care units. Recently, colistin became the last resort therapy for MDR gram-negative bacteria infections. However, nebulised colistin use was limited to adult patients. Thus, we investigated the efficacy and safety of nebulised colistin treatment against MDR microorganisms in the paediatric intensive care unit (PICU). Data of all patients admitted for various critical illnesses (January 2016 to January 2019) were reviewed. Differences between groups (with and without a history of nebulised colistin) were compared. Of 330 patients, 23 (6.97%) used nebulised colistin. Significant relationships were found between nebulised colistin usage and several prognostic factors (inotropic drug use (p = 0.009), non-invasive mechanical ventilation (p ≤ 0.001), duration in PICU (p ≤ 0.001), and C-reactive protein level (p = 0.003)). The most common microorganism in tracheal aspirate and sputum cultures was Pseudomonas aeruginosa (13 patients). The most common underlying diagnosis was cystic fibrosis, noted in 6 patients. No serious nephrotoxicity and neurotoxicity occurred. This study showed that colistin can be safely used directly in the airway of critically ill children. However, nebulised colistin use did not have a positive effect on mortality and prognosis.

Thyroid abscess due to Eikenella corrodens in a pediatric patient.

Eikenella corrodens is one of the HACEK bacteria that is commensal microorganism of the oropharngeal flora. E. corrodens has been increasingly reported to cause pyogenic abscesses, especially in diabetic or immunocompromised adults. It is less frequently reported in immunocompotent children. Here, we report a deep neck infection, including the thyroid gland, in a previously healthy girl. E. corrodens was the only microorganism isolated in two different cultures. Antibiotic susceptibility is variable, in contrast to other oropharyngeal pathogens. Thus, to avoid delayed treatment, E. corrodens should always be considered in infections of the head and neck area.