IgG4 Hypogammaglobulinemia Associated with Urinary Tract Infection in Kidney Transplant Recipients at the Centro Médico Nacional de Occidente, Guadalajara, Jalisco, Mexico

Background: In the era of precision medicine, the evaluation of IgG subclasses represents an attractive tool that could open a new scenario in the personalized pharmacological treatment of the patient. The measurement of immunoglobulins, specifically IgG, has taken importance in recent years as an instrument that allows reducing the risk of complications such as infectious processes in patients with a kidney transplant. Methods: Single-center, retrospective cohort study. 1-year follow-up. IgG subclasses were quantified using Luminex equipment. Results: The study included 143 patients diagnosed with chronic kidney disease who underwent kidney transplantation and 20 donors for reference values. Urinary tract infection events at 3 (20.4 ng/ml, p = 0.09) and 6 months (28.4 ng/ml, p = 0.04) were related to low IgG4 concentrations. IgG subclasses concentrations were not related to the presence of viral infections in patients. Conclusion: IgG4 subclass levels appear to be associated with urinary tract infection events, but not with viral processes. This is the first study, that analyzes the immunoglobulin G subclass profiles of transplant patients and relates them to clinical events (urinary tract infection and viral infections) using magnetic microspheres in Luminex equipment as a measurement technique in the Mexican population. Serum levels of IgG subclasses can be a surrogate in the management of immunosuppression in patients with kidney transplants, since it is not a one-dimensional measurement but rather the final result of a complex interaction of pathways that culminate in their formation.