Evaluation of Immunoglobulin Levels in Children Aged 1-5 Years With Recurrent Lower Respiratory Tract Infections

INTRODUCTION: Immunodeficiency plays a crucial role in the etiology of recurrent pneumonia. Humoral immunodeficiencies account for approximately 60% of all primary immunodeficiencies, and in such patients, antibody deficiencies are the leading cause of immunodeficiency. That study aimed to investigate the effect of immunoglobulin levels on the frequency of pneumonia episodes and the relationship between immunoglobulin levels and risk factors for pneumonia in children aged 1-5 years with recurrent pneumonia caused by humoral immunity.
METHODS: The prospective study included a total of 92 randomly selected children aged 1-5 years, comprising a group of 70 patients hospitalized due to pneumonia and a group of 22 healthy controls who had no chronic diseases and infections.
RESULTS: Body height and weight were significantly lower in the patient group compared to the control group (p=0.012 and p=0.022, respectively). The mean breastfeeding duration was significantly lower (p=0.001), the prevalence of exposure to environmental tobacco smoking (ETS) was significantly higher (p=0.018) compared to the control group. In the patient group, 65% of the participants had a deficiency of an immunoglobulin isotope and/or IgG subclasses in isolation or combination. IgG4 deficiency was the most common deficiency (38.5%), followed by IgG1 (21.4%), IgG2 (18.5%), IgA (15.7%), and IgG3 deficiency (12.8%), respectively.
DISCUSSION AND CONCLUSION: Our results indicated that inadequate breastfeeding and environmental tobacco smoking prepare the ground for pneumonia, a significant cause of morbidity and mortality in children, and contributes to the recurrence of this disease. Humoral immunodeficiencies, a significant underlying cause of recurrent pneumonia that leads to growth retardation, may have different clinical manifestations.