López-Herrera, G., et al. “Low Percentages of Regulatory T Cells in Common Variable Immunodeficiency (CVID) Patients With Autoimmune Diseases and Its Association With Increased Numbers of CD4+CD45RO+ T and CD21 Low B Cells”. Allergologia Et Immunopathologia, vol. 47, no. 5, Oct. 2019, pp. 457-66, https://all-imm.com/index.php/aei/article/view/284.