The role of CD8+ regulatory T cells and B cell subsets in patients with COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has a wide clinical spectrum from asymptomatic to mild, moderate, and severe cases. There are still many unknowns about the role of immunoregulatory mechanisms in COVID-19. We aimed to study regulatory T cells (Tregs) and B cell subsets and evaluate their correlations with severity of COVID-19. METHODS: In total, 50 patients with COVID-19 confirmed by PCR (mean age = 49.9 ± 12.8 years) and 40 healthy control (mean age = 47.9 ± 14.7 years) were included in this study. The patients were classified as 14 mild (median age = 35.5 [24-73] years), 22 moderate (median age = 51.5 [28-67] years) and 14 severe (median age = 55.5 [42-67] years). Within 24 h of admission, flow cytometry was used to assess the lymphocyte subsets, Tregs and Bregs without receiving any relevant medication. RESULTS: In all patients with COVID-19, the proportion of CD3+CD8+ T cells was reduced (p = 0.004) and the CD8+ Tregs were increased compared with control (p = 0.001). While the levels of regulatory B cells, plasmablasts, and mature naive B cells were found to be significantly high, primarily memory B-cell levels were low in all patients compared with controls (p < 0.05). Total CD3+ T cells were negatively correlated with the length of stay in the hospital (r = -0.286, p = 0.044). DISCUSSION: The changes in T and B cell subsets may show the dysregulation in the immunity of patients with COVID-19. In this context, the association between CD8+ Tregs and COVID-19 severity may help clinicians to predict severe and fatal COVID-19 in hospitalized patients.

The Role of Regulatory T and B Cells in the Etiopathogenesis of Idiopathic Granulomatous Mastitis.

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the role of T- and B-regulatory cells (Tregs and Bregs) in the pathogenesis of idiopathic granulomatous mastitis (IGM). METHODS: This study includes 47 patients with pathologically proven IGM (Group P) and 26 healthy subjects (Group C). The patients in Group P were divided into two groups according to whether their lesions were active (Group PA, n: 21) or in remission (Group PR, n: 26). By using flow-cytometry, the frequencies of CD3+CD4+CD45RA-Foxp3high activated Tregs (aTregs), CD3+CD4+CD45RA-Foxp3low non-suppressive Tregs, CD3+CD4+CD45RA+Foxp3low resting Tregs (rTregs), CD3+CD4+CD25+Foxp3- T-effector cells (Teff), total Tregs and Bregs were analyzed in all subjects. RESULTS: The frequency of the Teff cells was statistically higher in Group P when compared with Group C (p =.004). The Foxp3 expression of Treg cells and the frequency of non-suppressive Tregs in Group P were statistically lower than Group C (p =.032 and p =.02, respectively). In addition, Group PR's Foxp3 expressions were statistically lower than Group C (p =.027); Group PR's aTregs ratio was statistically lower than Group PA (p =.021); and the non-suppressive Tregs ratio of Group PR was lower than both Group PA and Group C (p =.006 and p <.0001). No significant differences were seen Bregs and B cell subsets. CONCLUSION: Significant changes in Foxp3 expression and Treg subsets were seen in patients with active IGM lesion and in remission. This study shows an intrinsic defect of Tregs in patients with IGM.

The alteration of lymphocyte subsets in idiopathic granulomatous mastitis

Background and aim: This study analyzed peripheral blood lymphocyte subsets to determine their role in the etiopathogenesis of IGM. Materials and methods: This study includes 51 pathologically proven IGM patients (active disease: 26 and in remission: 25) and 28 healthy volunteers. The analyses of lymphocyte subsets were performed by flow cytometric immunophenotyping. Results: The percentage of T helper lymphocyte of all IGM patients were lower than control groups (p = 0.001). Absolute cytotoxic T lymphocyte count (p = 0.03), both percentage (p = 0.035) and absolute count (p = 0.002) of the natural killer cells, and both percentage (p = 0.038) and absolute count (p = 0.008) of natural killer T cells, were higher than the control group. The T helper lymphocyte percentage of the patients with active disease was lower than the control group (p = 0.0003). The absolute cytotoxic T lymphocyte (p = 0.029) and natural killer T cells (p = 0.012) of the patients with active disease were higher than the control group. Conclusion: Idiopathic granulomatous mastitis is defined as a localized form of granulomatous disorders. However, the observed changes in T cells, NK, and NKT cells suggest that there is systemic immune dysregulation in patients with IGM.

Delayed Radiation Myelopathy in a Child With Hodgkin Lymphoma and ARTEMIS Mutation.

The authors present a case of delayed radiation myelopathy in a 12-year-old girl with Hodgkin lymphoma and Artemis mutation. This is the first of such a case presented in the literature.