Impulse oscillometry assessment of respiratory function in pediatric patients with a history of COVID-19.

OBJECTIVE: While coronavirus disease 2019 (COVID-19) is generally considered to exhibit a less severe clinical course in children than in adults, studies have demonstrated that respiratory symptoms can endure for more than 3 months following infection in at least one-third of pediatric cases. The present study evaluates the respiratory functions of children aged 3-15 years within 3-6 months of their recovery from COVID-19 using impulse oscillometry (IOS) and compares them with the values of healthy children. METHODS: Included in this prospective cross-sectional study were 63 patients (patient group) aged 3-15 years who contracted COVID-19 between December 2021 and May 2022, as well as 57 healthy children as a control group, matched for age and sex. The demographic, clinical, and laboratory data of the patients were recorded, and respiratory function was assessed based on airway resistance (zR5, zR20, R5-20) and reactance (zX5, zX20, reactance area [AX], resonant frequency [Fres]) using an IOS device. RESULTS: There were no significant differences in the age, weight, height, and body weight z score values of the two groups (p > .05). While the zR5 and R5-20 levels of the patient group were higher (p = .008 and p < .001, respectively) than those of the controls, the zR20, AX, and Fres values did not differ significantly between the groups (p > .05). The parameters indicating the reactance, including zX5 and zX20, were significantly lower in the patient group than in the control group (p = .028 and p < .001, respectively). CONCLUSION: Total and peripheral airway resistances were found to be elevated in children who had recovered from COVID-19 in the preceding 3-6 months.

MHC class II deficiency: Clinical, immunological, and genetic insights in a large multicenter cohort.

BACKGROUND: Major Histocompatibility Complex Class II (MHC-II) deficiency, a combined immunodeficiency, results from loss of Human Leukocyte Antigen class II expression on antigen-presenting cells. Currently, hematopoietic stem cell transplantation (HSCT) stands as the sole curative approach, though factors influencing patient outcomes remain insufficiently explored. OBJECTIVE: Our aim was to elucidate the clinical, immunological, and genetic profiles associated with MHC-II deficiency and identify prognostic indicators that affect survival rates. METHODS: In this multicenter retrospective analysis, we gathered data from 35 patients diagnosed with MHC-II deficiency across 12 centers in Turkey. We recorded infection histories, gene mutations, immune cell subsets, and surface MHC-II expression on blood cells. We conducted survival analyses to evaluate the impact of various factors on patient outcomes. RESULTS: Predominant symptoms observed were pneumonia (n=29, 82.9%), persistent diarrhea (n=26, 74.3%), and severe infections (n=26, 74.3%). The RFXANK gene mutation (n=9) was the most frequent, followed by mutations in RFX5 (n=8), CIITA (n=4), and RFXAP (n=2) genes. Patients with RFXANK mutations presented with later onset and diagnosis compared to those with RFX5 mutations (p=0.0008 and p=0.0006, respectively), alongside a more significant diagnostic delay (p=0.020). A notable founder effect was observed in 5 patients with a specific RFX5 mutation (c.616G>C). The overall survival rate for patients was 28.6% (n=10), showing a significantly higher proportion in individuals with HSCT (n=8, 80%). Early demise (p=0.006) and higher CD8+ T-cell counts were observed in patients with the RFX5 mutations compared to RFXANK-mutant patients (p=0.006 and p=0.009, respectively). CONCLUSION: The study delineates the genetic and clinical panorama of MHC-II deficiency, emphasizing the prevalence of specific gene mutations such as RFXANK and RFX5. These insights facilitate early diagnosis and prognosis refinement, significantly contributing to the management of MHC-II deficiency.