Immunophenotyping of palatine tonsils in children with OSAS versus recurrent tonsillitis

Abstract

Introduction - Obstructive Sleep Apnea Syndrome (OSAS) and Recurrent Tonsillitis (RA) are the main indications for performing tonsillectomy in children. Despite the growing knowledge in tissue immunology of palatine tonsils, the pathophysiology that leads to the development of OSAS or RA is not fully known.
Objectives - Comparative immunophenotypic analysis of children with OSAS versus RA. The epidemiological study of the selected patients was also carried out.
Material and Methods - Analysis by flow cytometry of palatine tonsils of children with OSAS versus RA. In processing the palatine tonsils, mononuclear cells are isolated and, from these, CD4+ T cells and follicular T cells. Cell size and viability and the Inducible T-cell costimulator (ICOS), a marker for the binding of follicular T cells to B cells, during antibody production, were also evaluated. 69 patients from Hospital Dona Estefânia, aged less than 18 years, between November 2018 and November 2022 were included.
Results - Palatine tonsils were removed by extracapsular dissection of 54 children diagnosed with OSAS and 15 with RA. In patients with OSAS, the mean age was 4.7 (± 2.2) years, with 24 males and 30 females. In patients with RA, the mean age was 6.1 (± 2.5) years, with 7 males and 8 females. Children submitted to tonsillectomy for OSAS were significantly younger than those for RA (p = 0.035). There were no significant differences between genders in the two groups (p = 0.881). Significant differences were found in the grade of the palatine tonsils, according to the Brodsky Classification, between the two groups of patients (p = 0.031). Children with OSAS were more likely to have otitis media with effusion requiring myringotomy and placement of transtympanic ventilation tubes at the same surgical time (p = 0.034). There were no statistically significant differences in operative complications of tonsillectomy between the two patient groups (p = 0.456). By flow cytometry analysis, the count of MNCs and CD4 T cells was not changed between the two groups. Palatine tonsils from patients with RA showed less TFH cells when compared with tonsils from patients with OSAS, but not significantly (p = 0.07). The size of CD4 T cells did not show significant differences between groups (p=0.840), however, the viability of these cells was significantly higher in patients with RA (p=0.015). In the patients studied, there is a greater intensity in the expression of ICOS in patients with RA compared to patients with OSAS.
Conclusions - Our results point to differences in the local lymphocyte response between patients with OSAS and RA, however, additional flow cytometry studies are still needed to investigate the immunological mechanisms underlying these two pathologies.