Ma. Carmen Zarate-Hernández

Chronic granulomatous disease (CGD) is an inborn error of immunity (IEI) caused by mutations in genes encoding components of the NADPH oxidase complex, leading to defective microbial killing and increased susceptibility to infections. This study analyzed clinical, genetic, and geospatial data from 238 CGD patients across eight Latin American countries. Genetic variants were identified in 141 patients (59%), with XL-CGD being the most common form (77%). Pneumonia (80%), lymphadenopathy (63%), and skin infections (55.5%) were frequent, with bacteria and fungi, such as Staphylococcus aureus, Aspergillus spp., and mycobacteria, as major pathogens. Antimicrobial prophylaxis was widely used, while IFN-γ was mainly prescribed in Mexico, mainly in cases of classic CGD (XL-CGD). Hematopoietic stem cell transplantation (HSCT) did not improve survival compared to prophylaxis. The leading cause of death was infection, particularly pneumonia and sepsis. XL-CGD patients had worse survival outcomes. The study highlights the need for improved genetic diagnosis, newborn screening, regional treatment guidelines, and expanded access to HSCT.

Background: Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by defective antibody production and impaired differentiation of B cells. B cell proliferation is an essential step for antibody synthesis. Depending on the nature of the stimulus, their response may be either T-cell-dependent or T-cell-independent. Methods: We studied 23 CVID patients and 14 healthy donors (HD). The patients were categorized based on their percentage of memory B cells. In addition to standard immunophenotyping of circulating human B and T cell subsets, an in vitro CFSE dilution assay was used to assess the proliferative capacity of B cells and to compare the activation of the T cell-dependent and T cell-independent response among the patients. Results: Patients with a reduction in memory B cells exhibited an increase in follicular T cells (Tfh) and showed low proliferation in response to PKW, CpG, and SAC stimuli (Condition II) (p= 0.0073). In contrast, patients with a normal percentage of memory B cells showed a high expression of IL-21R and low proliferation in response to CPG (Condition III); IL-21, CD40L, and anti-IgM (Condition IV) stimuli (p= 0.0163 and p = 0.0475, respectively). Conclusion: Defective proliferation in patients depends on the type of stimulus used and the phenotypic characteristics of the patients. Further studies are necessary to understand the disease mechanisms, which may guide us toward identifying genetic defects associated with CVID.