Background: Systemic corticosteroids are the standard of care for acute asthma exacerbation. Respiratory infections are known as common triggers of asthma exacerbation, but the risk of immune suppression from frequent periodic use of systemic steroids in poorly controlled asthmatic children is not well studied. Materials and Methods: We conducted a retrospective chart review of 26 children, 3-15 years old with poorly controlled, moderate-to-severe persistent asthma who received ≥2 systemic corticosteroid/year. The data collected include absolute T cell, B cell, and natural killer (NK) cell counts; lymphocyte proliferation studies to phytohemagglutinin (PHA), concanavalin A (CON A), and pokeweed mitogen; immunoglobulin G and M; and antibody titers to tetanus, diphtheria, and pneumococcus. Frequency tables and crosstabs were used to analyze the data. Results: Low CD4+ T cell counts were found in 47.8% of the patients, and 45.8% had low CD3+ T cell counts. The lymphocyte proliferation studies data exhibited variability, but 21.4%-75% of the subjects who demonstrated normal T cell counts had decreased lymphocyte proliferation studies to PHA and CON A. All the patients had normal immunoglobulins, B cell, and NK cell counts. All but 1 patient had adequate antibody responses to Streptococcus pneumoniae. Conclusions: Frequent systemic corticosteroid use may suppress T cell number and function in asthmatic children. This can potentially lead to increase susceptibility for future infections and asthma exacerbations. Depressed lymphocyte proliferations are observed even in patients who demonstrated normal T cell counts. This emphasizes the importance of adherence to asthma controller medications, and control of asthma triggers, to limit the frequency of steroid use.
Keywords: acquired immunodeficiency; asthma exacerbation; asthma in children; corticosteroids; inner-city asthma.