Improving immunity to Haemophilus influenzae in children with chronic suppurative lung disease

Abstract

Background: Endobronchial infections related to non-typeable Haemophilus influenzae (NTHi) are common in children and adults with suppurative airway disease such as bronchiectasis and COPD. Impaired cell mediated immune responses to NTHi have been described in these patients. Currently there are no interventions known to correct the deficiency in cell mediated immune responses to NTHi. The aim of this study was to determine if receipt of a conjugate vaccine containing protein D from H. influenzae is associated with improvement in NTHi-specific cytokine responses in children with chronic suppurative lung disease.

Methods: Blood mononuclear cells from 107 young children with chronic suppurative lung disease and 32 healthy control children were stimulated in vitro with NTHi. We compared the cytokine production of stimulated mononuclear cells from children who had received the pneumococcal H. influenzae protein D conjugate vaccine with cells from children who received pneumococcal vaccines without protein D. Protein D-specific IgG1 was quantified in plasma.

Results: Children with chronic suppurative lung disease who received ≥ 3 doses of the protein D conjugate vaccine produced significantly more IFNγ than children who received the alternative vaccines without protein D (median 939 versus 338 pg/ml; p = 0.007). Importantly, the amount of IFNγ produced by those vaccinated with the conjugate vaccine approached the levels observed in cells from healthy children. The conjugate vaccine was also associated with small but significant increases in IL-13 (p < 0.001) and IL-5 (p = 0.007). Protein D-specific IgG1 levels correlated with the number of PHiD-CV doses (p = 0.02).

Conclusion: Vaccination with PHiD-CV is associated with improvements in NTHi-specific cell-mediated and humoral immune responses in children with chronic suppurative lung disease.

Keywords: Cell mediated immune response; Non-CF bronchiectasis; Non-typeable Haemophilus influenzae; Pneumococcal H. influenzae protein-D conjugate vaccine.