Introduction: Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. It is characterized by secondary hypogammaglobulinemia and loss of B cell function. The objective is to analyze the clinical manifestations in Mexican patients with CVID grouped by their memory B cells, to identify patients at higher risk of developing clinical complications.

Method: Mexican patients diagnosed with CVID referred to the National Institute of Pediatrics (n=93) were studied. Through flow cytometry, subpopulations of B cells (naive, memory cells, and low CD21) were determined and grouped according to the Freiburg classification. In addition, the clinical severity of the patients was analyzed using the Grimbacher scale. The clinical and immunological phenotype was statistically analyzed.

Results: The patients were divided (38 men and 54 women) into groups IA (n=31), IB (n=35), and II (n=27). Mortality was higher in the IA group (IA=12.9%, IB=8.6%, and II=7.4%). Group IA had the highest clinical severity score with a significant difference (p=0.014) compared to groups IB and II. Also, the IA group was associated with autoimmunity (p=0.049) and inflammatory manifestations such as splenomegaly (p=0.012). This group was also characterized by a low number of total B cells in peripheral blood (p=0.0004). Lastly, there was a correlation between a lower IgG concentration and a higher clinical severity score (r=-0.291, p=0.0045).

Conclusions: Non-infectious manifestations have a negative impact on survival in CVID and occur more frequently in the IA group. It is important to determine the lymphocyte populations when CVID is suspected to classify and use strategies corresponding to the clinical manifestations expected for the patient.