RESUMEN
BACKGROUND: The severity of the 2009 pandemic H1N1 influenza (H1N1 pdm 09) in immune deficient children is unknown. The aim of the present study was to investigate this in a case of complete IgG3 deficiency complicated by pneumonia and asthma attack. METHODS: The clinical parameters of the IgG3 deficiency patient were compared with those of four control patients using 95% confidence intervals. These control patients were selected from 71 patients admitted due to pneumonia or bronchitis caused by H1N1 pdm 09, and were chosen according to age, absence of pretreatment with oseltamivir before admission, presence of a past history of asthma, use of antibiotics, and combination of inhalation of a beta2 agonist and treatment with i.v. methylprednisolone for asthma attack. RESULTS: The IgG3 deficiency patient had significantly longer duration of admission and period of oseltamivir, with a significantly decreased pulse oxygen saturation and increased maximum serum C-reactive protein, creatine kinase and urinary excretion of ß2-microglobulin/creatinine, compared with the controls (P < 0.05). CONCLUSIONS: Complete IgG3 deficiency is possibly associated with severity of the clinical course of pneumonia and asthma attack in children suffering from H1N1 pdm 09.