[Autoimmunity and Freiburg classification in common variable immunodeficiency]

Up to 25% of patients with common variable immunodeficiency (CVID) debut with autoimmunity, which is related to the Freiburg classification, which is based on flow cytometry.

to determine the frequency and type of autoimmune diseases and their association with the Freiburg classification in adults with CVID.

A cross-sectional, analytical and observational study was carried out with 33 patients belonging to the Primary Immunodeficiency Clinic of a third level hospital, with a diagnosis of CVID. They were divided into 3 phenotypes according to the Freiburg classification.

Of the 33 patients studied, 66.6% presented autoimmune diseases, 19 of them (86.3%) had cytopenia; 42.1% belonged to Freiburg group Ia, 36.8% to Ib and 21% to phenotype II. In 36.6% of the patients, autoimmune cytopenia were the first manifestation of CVID; and up to 70% of them belong to the Freiburg phenotype Ia (p = 0.086). Patients with autoimmune cytopenia had a lower percentage of isotype-switched memory B cells (p = 0.018), no higher percentage of CD21low B cells (p = 0.226).

Classification by CVID phenotypes allows the identification of the patient's profile according to the percentage of memory B cells with isotype change, which is useful to intentionally search for non-infectious complications of the disease.