Evaluation of the B-cell compartment in children with Common Variable Immunodeficiency (CVID)

ALMEJÚN MARÍA BELÉN; SAJAROFF ELISA; OLEASTRO MATÍAS; GALLICCHIO MIGUEL; BERNASCONI ANDREA; ZELAZKO MARTA; OPPEZZO PABLO; DANIELIAN SILVIA

Sao Paulo

Taller; Advanced School Course on Primary Immunodeficiencies: Unraveling Human Immuno-Physiology; 2010

Faculdade de Medicina da Universidade de São Paulo -Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Objective: The aim of our study is to elucidate biological and functional defects in peripheral blood B lymphocytes from a cohort of 32 CVID patients with paediatric presentation. This disorder is associated with defects in the responsiveness of mature B cells, generally with normal numbers of circulating B cells but with deficiencies of some but not all immunoglobulin classes. By analyzing somatic hypermutation and class switch recombination (before and after stimulation of patients’ B cells ex vivo) we could establish preliminary subgroups in our cohort of CVID patients. Genetic mutations have been found in some CVID patients that can either be B cell intrinsic (CD19, TACI) or extrinsic (ICOS). Still, for the majority of patients, the molecular basis for antibody deficiencies have yet to be unraveled. The identification in our cohort of 2 novel mutations in TACI gene led us to evaluate structural and functional consequences of theses changes.