Background: Genetic deficiencies of immune system, referred to as inborn errors of immunity (IEI), serve as a valuable model to study human immune responses. In a multicenter prospective cohort, we evaluated the outcome of SARS‐CoV‐2 infection among IEI subjects and analyzed genetic and immune characteristics that determine adverse COVID‐19 outcomes.Methods: We studied 34 IEI patients (19M/15F, 12 [min: 0.6‐max: 43] years) from six centers. We diagnosed COVID‐19 infection by finding a positive SARS‐CoV‐2 PCR test (n = 25) and/or a lung tomography scoring (CORADS) ≥4 (n = 9). We recorded clinical and laboratory findings prospectively, fitted survival curves, and calculated fatality rates for the entire group and each IEI subclass.Results: Nineteen patients had combined immune deficiency (CID), six with predominantly antibody deficiency (PAD), six immune dysregulation (ID), two innate immune defects, and one in the autoinflammatory class. Overall, 23.5% of cases died, with disproportionate fatality rates among different IEI categories. PAD group had a relatively favorable outcome at any age, but CIDs and IDs were particularly vulnerable. At admission, presence of dyspnea was an independent risk for COVID‐related death (OR: 2.630, 95% CI; 1.198–5.776, p < .001). Concerning predictive roles of laboratory markers at admission, deceased subjects compared to survived had significantly higher CRP, procalcitonin, Troponin‐T, ferritin, and total‐lung‐score (p = .020, p = .003, p = .014, p = .013, p = .020; respectively), and lower absolute lymphocyte count, albumin, and trough IgG (p = .012, p = .022, p = .011; respectively).Conclusion: Our data disclose a highly vulnerable IEI subgroup particularly disadvantaged for COVID‐19 despite their youth. Future studies should address this vulnerability and consider giving priority to these subjects in SARS‐Cov‐2 therapy trials.

Objective: Prolidase deficiency is a metabolic and immunological disorder that is inherited in an autosomal recessive manner. In prolidase deficiency, a broad spectrum of differences is observed in patients, ranging from asymptomatic to multisystem involvement. There is scarce information in the literature on the atypical features and immunophenotypes of this disease. Aim of this study is to present 4 new cases to provide information on the rare features of the disease and to raise awareness. Materials and Methods: This study included 4 female patients with prolidase deficiency. Their demographic, clinical, and immunologic characteristics were obtained from their medical records. Results: There were 4 female patients (P1-P4), with a mean age of 18.5 years (min-max: 10-29) and a mean age of symptom onset of 6.9 years (min-max: 0.04-27). The main presenting complaints of the patients were skin lesions (100%), dysmorphic features (100%), neurodevelopmental delay (100%), frequent infections (100%), and prolonged diarrhea (50%). P2 had diffuse large B-cell lymphoma, resulting in early death. Interestingly, P1 and P2 experienced opportunistic infections such as cytomegalovirus, Epstein-Barr virus, and Pneumocystis jirovecii. Three patients (75%) had lymphopenia. Two patients had elevated IgE levels. Lymphocyte subgroup analysis showed an inverted CD4/CD8 ratio in all patients. In patients P1 and P2, the percentages of naive T cells and recent thymic emigrants were reduced, suggesting combined immune deficiency at the time of diagnosis. CD19+ B cells were also low in P1 and P2. Metabolic evaluations revealed low prolidase enzyme activity in P1 and P2. Conclusion: Beyond the well-known classical dermatological findings, the presence of recurrent opportunistic infections, gastrointestinal involvement, malignancy, and flow cytometry findings suggestive of combined immunodeficiency indicate that the diagnosis of prolidase deficiency may be underestimated. Knowing the atypical and rare presentations will facilitate diagnosis and treatment of affected patients. Cite this article as: Yalcin Gungoren E, Meric Z, Pinar Sefer A, et al. Beyond dermatological findings: Multisystem involvement in prolidase deficiency – A report of four cases. Turk Arch Pediatr. 2025;60(1): 48-56.

Introduction: Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency, yet its clinical presentation ranges from asymptomatic cases to individuals suffering from recurrent infections, allergic manifestations, and autoimmune disorders. Limited data exist regarding the immunological and clinical profiles of pediatric patients with sIgAD in Türkiye. Methods: We conducted a retrospective analysis of 45 pediatric patients (20 females and 25 males) diagnosed with sIgAD and followed at two tertiary care centers. Demographic features, allergic and autoimmune comorbidities, and immunological parameters were evaluated. Lymphocyte subset analyses and immunoglobulin subclass levels were recorded. Associations between IgG3/IgG4 subclass deficiencies and infection frequency were assessed using the Mann–Whitney U test. Results: The median current age was 102 months (range: 48–204), with a median age of symptom onset at 24 months (range: 1–186), referral at 88 months (range: 6–199), and diagnosis at 87 months (range: 48–192). A history of at least one allergic disease, including asthma, allergic rhinitis, and/or atopic dermatitis, was present in 66.7% of patients. Autoimmune conditions were identified in 13.3%, including Hashimoto’s thyroiditis, vitiligo, and immune thrombocytopenic purpura. No statistically significant differences in the frequencies of upper respiratory tract infections, pneumonia, otitis, or viral infections were observed between patients with low versus normal/high IgG3 or IgG4 levels (all P > 0.05). Conclusion: Our findings highlight the high prevalence of allergic diseases and the clinical heterogeneity of sIgAD in children. Moreover, isolated IgG3 or IgG4 subclass deficiencies may not independently influence infection susceptibility. Longitudinal studies are warranted to better define the prognostic role of immunoglobulin subclasses in pediatric sIgAD.

Background: Management of pediatric anaphylaxis in the emergency department remains clinically important. The research investigated pediatric anaphylaxis medical indicators together with physician adherence to international treatment protocols at a Turkish tertiary medical center. Methods: Between September 2014 and July 2025, 166 pediatric anaphylaxis patients were retrospectively reviewed for triggering factors, clinical findings, treatment approaches, and quality indicators. Results: The mean age of the patients was 7.4 ± 5.6 years. Food allergy was the main cause with 53%, followed by drugs with 24.7%. Food allergy in infants was 85.7%, while drug reactions in adolescents reached 37.2% (p < 0.001). Skin findings were present in 93.4% of the patients, and respiratory symptoms were present in 67.5% of the patients. Epinephrine was administered to 97.6% of patients, 95.2% of whom were given intramuscularly. The rate of epinephrine administration in the first 30 min was 61.1%. Drug-induced anaphylaxis showed the highest proportion of severe cases (81.6%, p < 0.001). A biphasic reaction was seen in 6%. The auto-injector prescription rate was 7.8%, and the allergist referral rate was 15.7%. No deaths were observed. Conclusions: While acute-phase management largely adheres to international guidelines, significant gaps persist in post-discharge care with low auto-injector prescription and allergist referral rates.

Childhood cancers, with leukemia at the forefront, comprise 97% acute leukemia and 3% chronic leukemia, with 75% of acute leukemias being of lymphoblastic origin. Over the past 50 years, survival rates have witnessed a remarkable increase, progressing from around 10% to achieving cure rates exceeding 90% in certain childhood ALL subgroups with the advent of combined therapies. Between 1999 and 2018, a total of 123 patients diagnosed with B-ALL were initially identified, but after applying exclusion criteria, 105 patients were included in the evaluation, who were treated with COG protocols at our center. The mean follow-up duration for patients was determined to be a median of 74 months (min to max: 2 to 228 months). When the cases were evaluated at the end of the study, 59 of 59 individuals in the standard risk group (100%), 21 of 26 individuals in the high-risk group (80.7%), and 14 of 20 individuals in the very high group (70%) were alive. Patients were categorized into 4 groups based on the methotrexate (MTX) doses they received during Phase 3 and Phase 5 of treatment. Event-free survival and overall survival were evaluated among these groups. It was observed that patients in the standard-risk group had significantly higher event-free and overall survival rates. However, no significant difference was found in survival rates when evaluated based on the treatment groups each risk group received by the patients.