Epithelial Barrier Hypothesis and Its Comparison with the Hygiene Hypothesis

Chronic inflammatory conditions including allergic, autoimmune, metabolic, and neuropsychiatric disorders are constantly increasing and leading to a high burden, especially in more industrialized countries. The prevalence is still on the rise in developing countries. The start of the steep increase in asthma, atopic dermatitis, and allergic rhinitis dates to the 1960s, whereas a second wave with an increase in eosinophilic gastrointestinal disease, food allergy, and drug hypersensitivity started after the 2000s. These diseases also started to appear more with neuropsychiatric and autoimmune conditions during the last few decades. Many theories have been proposed to explain this outbreak. The hygiene hypothesis was consolidated by "old friends" and biodiversity, although some gaps remained unresolved. The introduction of the epithelial barrier hypothesis gave us a new perspective to explain the effects of industrialization without environment control and health concerns creeping into our daily lives. The present review touches on the possible explanations of why epithelial barrier hypothesis covers all previous ones, which are not contradictory but mostly complementary.

Natural history and genetic spectrum of the Turkish metaphyseal dysplasia cohort, including rare types caused by biallelic COL10A1, COL2A1, and LBR variants

BACKGROUND

Metaphyseal chondrodysplasias are a heterogeneous group of diseases characterized by short and bowed long bones and metaphyseal abnormality. The aim of this study is to investigate the genetic etiology and prognostic findings in patients with metaphyseal dysplasia.

METHODS

Twenty-four Turkish patients were included in this study and 13 of them were followed for 2-21 years. COL10A1, RMRP sequencing and whole exome sequencing were performed.

RESULTS

Results: Seven heterozygous pathogenic variants in COL10A1 were detected in 17 patients with Schmid type metaphyseal chondrodysplasia(MCDS). The phenotype was more severe in patients with heterozygous missense variants (one in signal peptide domain at the N-terminus of the protein, the other, class-1 group mutation at NC1 domain) compared to the patients with truncating variants. Short stature and coxa vara deformity appeared after 3 and 5 years of age, respectively, while large femoral head resolved after the age of 13 years in MCDS group. Interestingly, one patient with severe phenotype also had a biallelic missense variant in NC1 domain of COL10A1. Three patients with biallelic mutations in RMRP had prenatal onset short stature with short limb, and typical findings of cartilage hair hypoplasia (CHH). While immunodeficiency or recurrent infections were not observed, resistant congenital anemia was detected in one. Biallelic mutation in LBR was described in a patient with prenatal onset short stature, short and curved limb and metaphyseal abnormalities. Unlike previously reported patients, this patient had ectodermal findings, similar to CHH. A biallelic COL2A1 mutation was also found in the patient with lower limb deformities and metaphyseal involvement without vertebral and epiphyseal changes.

CONCLUSION

Long-term clinical characteristics are presented in a metaphyseal dysplasia cohort, including rare types caused by biallelic COL10A1, COL2A1, and LBR variants. We also point out that the domains where mutations on COL10A1 take place are important in the genotype-phenotype relationship.

[Analysis of IFN-γR1 (CD119) and IL-12Rβ1 (CD212) Deficiency by Flow Cytometry]

Mendelian susceptibility to mycobacterial diseases (MSMD) is a rare primary immune deficiency (PID). IL-12Rβ1 deficiency is the most frequently observed of more than 16 genetic defects that have been identified for MSMD. Genetic and immunological tests are remarkable in the diagnosis of PID. In this study, it was aimed to determine the expression of IFN-γR1 and IL-12Rβ1 in patients with MSMD, their relatives, and healthy individuals and to evaluate the importance of flow cytometry as a fast and reliable method in the diagnosis of MSMD. IFN-γR1 and IL-12Rβ1 expression levels were analyzed in 32 volunteers including six patients, six relatives, and 20 healthy individuals. The normal range of IFN-γR1 and IL-12Rβ1 levels among healthy individuals were determined. IL-12Rβ1 expression level in lymphocytes was found to be low in one patient's relative, and less than 1% in three patients and in one patient's relative. It was observed that the IL-12Rβ1 expression levels of the patient with STAT1 deficiency were increased compared to the healthy individuals. No difference was found in the expression levels of IFN-γR1 and IL-12Rβ1 in one patient, but IFN-γR1 expression was decreased in one patient compared to healthy individuals. Our results show that the determination of IL-12Rβ1 and IFN-γR1 deficiencies by flow cytometry can be used as a rapid and reliable method for the diagnosis of MSMD. The use of this method as a screening test will enable early diagnosis especially in patients whose genetic diagnosis has not been confirmed and clinically compatible with MSMD. In addition, it is thought that IL-12Rβ1 and IFN-γR1 range data obtained from healthy individuals will be considered as a reference source in routine and research studies to be conducted with MSMD.

Clinical, Genetic, and Outcome Characteristics of Pediatric Patients with Primary Hemophagocytic Lymphohistiocytosis

Objectİive:

In this study, we sought to describe the clinical, laboratory, and genetic characteristics of patients diagnosed with primary hemophagocytic lymphohistiocytosis. Thus, we aimed to evaluate the early diagnosis and appropriate treatment options for pediatric hemophagocytic lymphohistiocytosis patients.

Materials and Methods:

Medical records of 9 patients diagnosed with primary hemophagocytic lymphohistiocytosis between November 2013 and December 2019 were analyzed retrospectively. Clinical, genetic, and laboratory characteristics, family histories, initial complaints, physical examination findings, age at diagnosis, treatment choices, and clinical follow-up of all patients were investigated.

Results:

The mean age at diagnosis was 11 months (range: 1.5 months to 17 years). Genetic analysis was performed in all patients, and a disease-related mutation was detected in 8 (89%) of them. Among clinical features, 6 (66%) patients had fever, 5 (56%) had splenomegaly, 4 (44%) had lymphadenopathy, 4 (44%) had skin rash, and 4 (44%) had neurological findings. Hemophagocytosis was observed in the bone marrow samples of 6 (66%) patients. Disease remission was achieved in 7 (78%) patients. Hematopoietic stem cell transplantation was performed in 7 (78%) patients.

Conclusion:

Hemophagocytic lymphohistiocytosis may present with different clinical symptoms that can cause a significant diagnostic delay. The only curative treatment option in primary hemophagocytic lymphohistiocytosis patients is hematopoietic stem cell transplantation. The chemotherapy should be started as early as possible, in order to achieve a disease remission. Patients should be referred to the appropriate bone marrow transplant center for hematopoietic stem cell transplantation as soon as they reach the disease remission.

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.

Reference values for T and B lymphocyte subpopulations in Turkish children and adults

Background/aim

Established reference values are critical for the interpretation of immunologic assessments. In particular, the proportion and absolute counts of T- and B- cell subpopulations are subject to change with age and ethnicity. We aimed to establish age-specific reference values for lymphocyte subsets using updated immunophenotyping panels.

Materials and methods

We studied a total of 297 healthy Turkish subjects aged 0 to 50 years, stratified into major age brackets in a cluster factor of 10 per age-group. The predetermined age intervals contained randomly allocated participants enrolled over a period of 6 months, who were homogenously distributed by sex. We analyzed a complete blood count test and simultaneously with detailed immunophenotyping enumerated the percent and absolute cell counts of lymphocyte subsets.

Results

The percentage and absolute counts of lymphocyte subsets show a marked surge across the age-span. T helper, T cytotoxic, and the natural killer cell numbers were increasing from birth until 6 months, followed by a gradual decrease thereafter. B cell numbers were rising until 2 years, followed by a gradual decrease for the upcoming years, accompanied by a steady expansion of unclass-switched- and class-switched- B cells.

Conclusion

We provide updated extensive reference intervals for lymphocyte subpopulations in Turkish people.

LRBA deficiency: a rare cause of type 1 diabetes, colitis, and severe immunodeficiency

The biological role of the lipopolysaccharide-responsive beige-like anchor (LRBA) protein associated with the immune system is not to date well known. However, it is thought to regulate the CTLA4 protein, an inhibitory immunoreceptor. Chronic diarrhea, autoimmune disorders, organomegaly, frequent recurrent infections, hypogammaglobulinemia, chronic lung manifestations, and growth retardation are some features of LRBA deficiency. This rare disease is observed as a result of homozygous mutations in the LRBA gene. An 11.3-year-old male patient presented because of short stature and high blood glucose level. He had a previous history of lymphoproliferative disease, chronic diarrhea, and recurrent infections. His parents were first-degree consanguineous relatives. A diagnosis of type 1 diabetes mellitus (T1DM) was added to the preexisting diagnoses of immunodeficiency, recurrent infection, enteropathy, chronic diarrhea, lymphadenopathy, hepatomegaly, and short stature. Genetic analysis revealed a homozygous mutation in the LRBA gene, c.5047C>T (p.R1683*) (p.Arg1683*). Abatacept treatment was started: the patient's hospital admission frequency decreased, and glucose regulation improved. At follow-up, growth hormone (GH) deficiency was diagnosed, although it was not treated because the underlying disease was not under control. Nevertheless, the patient's height improved with abatacept treatment. LRBA deficiency should be considered in the presence of consanguineous marriage, diabetes, immunodeficiency, and additional autoimmune symptoms. LRBA phenotypes are variable even when the same variants in the LRBA gene are present. Genetic diagnosis is important to determine optimal treatment options. In addition to chronic malnutrition and immunosuppressive therapy, GH deficiency may be one of the causes of short stature in these patients.

Proven Food-Induced Acute Urticaria and Predictive Factors for Definitive Diagnosis in Childhood

BACKGROUND

Urticaria can be the only sign of a food allergy or can be seen together with other signs and symptoms of a food allergy.

OBJECTIVE

To determine the demographic, etiologic, and clinical features of food-induced acute urticaria in childhood.

METHODS

Patients suspected of food-induced acute urticaria were included in this prospective cross-sectional multicenter study.

RESULTS

Two hundred twenty-nine urticaria cases were included in this study. Seventeen patients who did not meet the inclusion criteria of the study were excluded. Of the 212 included cases, 179 (84.4%) were diagnosed with definitive food-induced acute urticaria. The most common foods causing acute urticaria were cow's milk, hen's eggs, and nuts in 56.4, 35.2, and 19% of cases, respectively. The positive predictive value of a history of milk-induced acute urticaria together with a milk-specific IgE >5 kU/L for cow's milk-induced acute urticaria was 92% (95% CI: 81-96%). A history of cow's milk-induced and/or hen's egg-induced acute urticaria was consistent with a definitive diagnosis of food-induced urticaria (Chen's kappa: 0.664 and 0.627 for milk and eggs, respectively). Urticaria activity scores were higher in patients with food-induced acute urticaria (p = 0.002).

CONCLUSION

Cow's milk, hen's eggs, and nuts were the most common allergens in the etiology of childhood food-induced acute urticaria. Although the urticaria activity score provides guidance for diagnosis, an oral food challenge is often essential for the definitive diagnosis of a patient with a history of food-induced acute urticaria.

Telemedicine Applications in a Tertiary Pediatric Hospital in Turkey During COVID-19 Pandemic

Background: A novel type of Coronavirus emerged at Wuhan in late 2019 involving preferentially the respiratory system. Owing to the rapid spread, almost 22 million people became infected and 700,000 died. Similar to other countries, the need for additional hospital beds and intensive care units required diversion of health care resources toward the care for those with COVID-19 in Turkey. Telemedicine appeared as a safe and low-cost alternative for the maintainability of pediatric health services during the pandemics. Within this context, we aimed to deliver the health services through telemedicine during the follow-up of chronic childhood diseases. Materials and Methods: This prospective study included five pediatric subspecialties, including allergy immunology, hematology and oncology, nephrology, rheumatology, and inborn metabolic disorders. After the interview, patients and involved physicians were requested to fill out a questionnaire designed to measure the level of satisfaction and the quality of the service we offered. Results: Of the 263 interviews, overall patient and physician satisfaction was 99% and 87%, respectively. As results of the interviews, 250 routine visits were performed, 181 acute complaints were assessed, drug changes were made in 118 patients, 9 patients were determined to be unable to get their drugs, and 12 who misused their drugs. The main advantage of the telemedicine declared by the patients was "not to waste time for transportation." The main concerns of the participants were inability to perform physical and laboratory examinations. Conclusion: Consequently, we considered telemedicine as a feasible alternative not only during pandemics but also in daily practice in Turkey.

Immediate adverse reactions to intravenous immunoglobulin in primary immune deficiencies: a single center experience

BACKGROUND AND OBJECTIVE

Adverse reactions related to intravenous immunoglobulin (IVIG) infusions vary from 1 to 81%, with an average of 20%. They may be classified as immediate; occurring during the infusion itself or delayed; occurring after the infusion has been ceased. In the present study, we aimed to evaluate the frequency of immediate adverse reactions due to IVIG infusions in primary immune deficiency (PID) patients.

METHODS

The study population was composed of 109 patients. A total of 763 infusions were recorded for demographic data and adverse reactions.

RESULTS

The participants included 32 girls (29%) and 77 boys (71%). The mean age was 11.8 ± 5.7 years (0.6- 33.5 years). Early adverse events (AE) were recorded in 34 (4.5%) among 763 IVIG infusions including 30 mild (88.2%), 3 moderate (8.8%) and 1 severe (2.9%). The most common immediate adverse reactions were fever (29.4%) and headache (29.4%). The risk of AE was higher among primary antibody deficiency (PAD), compared to combined immunodeficiency (OR 2.61, 95%CI 1.061-6.475; p = 0.037).

CONCLUSIONS

Use of various intravenous immunoglobulin treatments should be considered with regard to side effect profiles observed. In our cohort, PID patient experienced mostly mild AE; PAD was associated with an increased risk of AE.

The plethora, clinical manifestations and treatment options of autoimmunity in patients with primary immunodeficiency

AIM

Although the association between primary immunodeficiency and autoimmunity is already well-known, it has once again become a topic of debate with the discovery of newly-defined immunodeficiencies. Thus, investigation of the mechanisms of development of autoimmunity in primary immunodefficiency and new target-specific therapeutic options has come to the fore. In this study, we aimed to examine the clinical findings of autoimmunity, autoimmunity varieties, and treatment responses in patients who were genetically diagnosed as having primary immunodeficiency.

MATERIAL AND METHODS

The files of patients with primary immunodeficiency who had clinical findings of autoimmunity, who were diagnosed genetically, and followed up in our clinic were investigated. The demographic and clinical features of the patients and their medical treatments were evaluated.

RESULTS

Findings of autoimmunity were found in 30 patients whose genetic mutations were identified. The mean age at the time of the first symptoms was 8.96±14.64 months, and the mean age of receiving a genetic diagnosis was 82.55±84.71 months. The most common diseases showing findings of autoimmunity included immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome (16.7%); autoimmune lymphoproliferative syndrome (10%); lipopolysaccharide-responsive beige-like anchor protein deficiency (10%); and DiGeorge syndrome (10%). Twelve (40%) patients showed findings of autoimmunity at the time of first presentation. The most common findings of autoimmunity included inflammatory bowel disease, inflammatory bowel disease-like findings (n=14, 46.7%), immune thrombocytopenic purpura (n=11, 36.7%), and autoimmune hemolytic anemia (n=9, 30.0%). A response to immunosupressive agents was observed in 15 (50%) patients. Ten patients underwent hematopoietic stem cell transplantation. Six patients were lost to follow-up due to a variety of complications.

CONCLUSION

Autoimmunity is frequently observed in patients with primary immunodeficiency. The possibility of primary immunodeficiency should be considered in patients with early-onset manifestations of autoimmunity, and these patients should be carefully monitored in terms of immunodeficiency development. Early diagnosis of primary immunodeficiency may provide favorable outcomes in terms of survival.

Use of subcutaneous immunoglobulin in primary immune deficiencies

AIM

Immunoglobulin replacement therapy is required to reduce the frequency and severity of infections in patients with primary antibody deficiencies. Immunoglobulin G (IgG) can be administered intramuscularly, intravenously or subcutaneously. We aimed to evaluate the efficacy, dose adjustment and adverse events in subcutaneous immunoglobulin therapy by retrospectively presenting the records of 16 patients who received subcutaneous immunoglobulin therapy.

MATERIAL AND METHODS

The demographic findings, clinical and laboratory findings, subcutaneous immunoglobulin dosage and dose frequency, infusion time, area and methods, adverse events and frequency of infections were obtained from patient files and recorded.

RESULTS

Sixteen patients (seven female, nine male) aged between 0-33 years who were diagnosed with primary immune deficiency and treated with subcutaneous immunoglobulin were enrolled. All patients had been receiving intravenous imunoglobulin (5-10%) at a dose of 0.33-1.25 gr/kg/dose with two-four week intervals before subcutaneous immunoglobulin. Subcutaneous immunoglobulin (10%) was administered at a dose of 0.03-0.43 gr/kg/dose with one-two week intervals. No significant difference was found between serum through IgG levels before administration of intravenous imunoglobulin and steady state IgG levels during subcutaneous immunoglobulin therapy. When five patients whose serum through IgG levels were below 600 mg/dL were evaluated, however, a significant increase was found in steady state IgG levels with subcutaneous immunoglobulin therapy (p=0.043). In a ten-month follow-up period, seven infections were observed in four patients (three upper respiratory infectons, two lower respiratory tract infections and three acute gastroenteritis). No acute severe bacterial infection was observed. Local advers reaction was reported in only 10 of 180 infusions (6%). No serious adverse events were reported. All 16 patients were willing to continue IgG replacement therapy by subcutaneous administration.

CONCLUSIONS

Ig replacement therapy by subcutaneous route is an efficient, safe and easy option which is eligible for individual administration. Home therapy is feasible for patients with primary immune deficiency, if informed consent is obtained and sufficient education is ensured.

Recurrent Acute Kidney Injury in Renal Transplant Patients: A Single-Center Study

OBJECTIVE

Renal transplant patients may have recurrent episodes of acute kidney injury (AKI) during the posttransplant period. Determination and management of risk factors may help to prevent recurrence of AKI and allograft loss. In this study, we investigated the clinical features of renal transplant patients with recurrent AKI and evaluated etiologies and risk factors.

MATERIALS AND METHODS

A total of 19 patients with 79 AKI episodes were examined retrospectively. AKI classes, etiologies, and risk factors were investigated. Their features were compared with 38 renal transplant patients without AKI.

RESULTS

Distribution of AKI episodes according to the type of injury was as follows: 15 prerenal, 43 renal, 6 postrenal, and 15 mixed. Renal transplant patients with recurrent AKI had a greater duration of dialysis before transplantation (P < .05). Logistic regression analysis revealed no predictor for recurrent AKI after renal transplantation. Infections participated in the development of 45 AKI episodes. Chronic kidney disease developed in 16 patients.

CONCLUSION

Infections are the leading condition associated with recurrent AKI in renal transplant patients. Recurrent AKI may contribute to the development and progression of chronic kidney injury.

Profile of the patients who present to immunology outpatient clinics because of frequent infections

AIM

We aimed to determine the rate of primary immune deficiency (PID) among children presenting to our immunology outpatient clinic with a history of frequent infections and with warning signs of primary immune deficiency.

MATERIAL AND METHODS

The files of 232 children aged between 1 and 18 years with warning signs of primary immune deficiency who were referred to our pediatric immunology outpatient clinic with a complaint of frequent infections were selected and evaluated retrospectively.

RESULTS

Thirty-six percent of the subjects were female (n=84) and 64% were male (n=148). PID was found in 72.4% (n=164). The most common diagnosis was selective IgA deficiency (26.3%, n=61). The most common diseases other than primary immune deficiency included reactive airway disease and/or atopy (34.4%, n=22), adenoid vegetation (12.3%, n=8), chronic disease (6.3%, n=4) and periodic fever, aphtous stomatitis and adenopathy (4.6%, n=3). The majortiy of the subjects (90.5%, n=210) presented with a complaint of recurrent upper respiratory tract infection. PID was found in all subjects who had bronchiectasis. The rates of the diagnoses of variable immune deficiency and Bruton agammaglubulinemia (XLA) were found to be significantly higher in the subjects who had lower respiratory tract infection, who were hospitalized because of infection and who had a history of severe infection compared to the subjects who did not have these properties (p<0.05 and p<0.01, respectively). Growth and developmental failure was found with a significantly higher rate in the patients who had a diagnosis of severe combined immune deficiency or hyper IgM compared to the other subjects (p<0.01). No difference was found in the rates of PID between the age groups, but the diagnosis of XLA increased as the age of presentation increased and this was considered an indicator which showed that patients with XLA were being diagnosed in a late period.

CONCLUSIONS

It was found that the rate of diagnosis was considerably high (72.4%), when the subjects who had frequent infections were selected by the warning signs of PID.