Free oxygen radicals and immune profile in newborns with lung diseases.

Respiratory difficulties constitute the commonest cause of morbidity in new born infants and pulmonary pathology is the most frequent autopsy finding. Various components, such as free oxygen radicals, immunoglobulins, and compliment systems, play an important role in immunopathology and immune defence. The aim of the present study was to assess free oxygen radical markers in neonatal lung diseases, studying their relationship with immune profile and ascertaining their relevance as predictors of clinical outcome. Full term newborns with respiratory distress and X-ray proven lung disease formed the study group. Blood samples were assessed for lipid peroxide (LPO), superoxide dismutase (SOD), glutathione peroxidase (GPx), immunoglobulins IgM and G, CD4 and CD8 subpopulations of T-lymphocytes. Levels of free radical markers were significantly higher in the study group. The humoral immune response was seen in terms of raised IgM levels in the study group which were still within the normal range. The cellular immune response was demonstrated by a raised percentage of CD4 T-lymphocytes which in turn accentuated the CD4:CD8 ratio. Higher levels of reactive oxygen species (ROS) were associated with a prolonged duration of respiratory distress and oxygen dependence. Since the free radicals have emerged as the major final common pathway of tissue injury, free radical ablation offers substantial potential for treatment; but whether antioxidants, scavengers and other modalities would have a significant impact on clinical outcome, remains to be investigated.