Sociedad Argentina de Pediatría Subcomisiones, Comités y Grupos de Trabajo

SUMMARY Primary immunodeficiencies are a group of infrequent diseases resulting in abnormal development and function of the immune system. They are usually diagnosed in childhood and infancy. In 1994 a group was constituted at the Argentinean Paediatric Society with the main objective of continuous long-term documentation of primary immunodeficiency diseases. In 2001, a first report of the National Registry for Primary Immunodeficiencies was published. There were 652 cases reported between January 1994 and June 1999. In the present updated report we analysed the evolution of the Registry in the last 6 years, the changes in frequency of diagnosis of the different entities and the contribution of molecular techniques, allowing us to identify gene abnormalities in this group of diseases. The Registry now includes 1319 patients; 918 (69.5%) humoral defects, 192 (14.5%) associated with major defects, 80 (6%) associated to phagocyte defects, 58 (4.3%) phagocyte defects, 52 (3.94%) cellular defects and 19 (1.4%) complement defects. Selective IgA (42% of cases), common variable immunodeficiency (10%), X-linked agammaglobulinemia (8%), DiGeorge syndrome and ataxia telangiectasia (5% each) were the most frequently reported disorders. A genetically defined defect was identified in 184 patients between 1995 and 2005. A significant and gratifying increase in the total number of cases reported per year was noticed in the present period. However, with the exception of Buenos Aires and Sante Fe, underregistry and/or underdiagnosis (incidence below 1/10.000 births) is still present in most provinces. More education programs are needed to achieve early diagnosis of primary immunodeficiency diseases in Argentina. With this report we pretend to inform paediatricians all over the country, inviting them to report their patients, and to obtain an useful, nation-wide, bank