[Evaluation of factors associated with recurrent and/or severe infections in patients with Down's syndrome].

Objective: To evaluate epidemiological, clinical and laboratorial aspects of patients with Down syndrome, who present recurrent and/or severe infections, as well as to evaluate the presence of immunodeficiency in this population.
Methods: Patients with Down syndrome diagnosed by chromosome analysis with recurrent and/or severe infections, followed at the Allergy and Immunology Unit of Children's Institute from 1990 to 1999, were submitted to an epidemiological, clinical and laboratorial protocol, including immunological aspects.
Results: Sex distribution was 1.6 M:1 F, with age ranging from 1 to 12 years and 10 months (average = 2y7m). Forty patients reported recurrent infections and five, sepsis. Out of all patients with recurrent infection, 31 fulfilled the repeated infection criteria, with pneumonia and rhinopharyngitis as the most common infections. Congenital heart diseases were found in 62.2% of cases, more frequent in the repeated pneumonia group. Immunological evaluation showed two cases with IgG2 deficiency, two with low lymphocytes CD4+ count, and two cases with reduced blastogenic response to mitogens. Five cases had reduced NK cells function. Seropositivity for CMV was found in 22 of 36 cases analyzed (61.1%).
Conclusions: Although the data found in this study are valid for this specific population, the authors point out the necessity of the immunodeficiency research in Down syndrome patients with maintenance of infection besides the appropriated control of associated diseases.