The Immunological Status of the Low Birth Weight (≤ 2100 g) and Very Low Birth Weight (≤ 1200 g) Infant and Relationship to Infection

Abstract

We prospectively evaluated the immunologic status (IgG, IgM, C3, C4, CH50, and fibronectin) of 45 low (≤ 2100 g) or very low (≤ 1200 g) birth weight infants both during and after hospitalization. Data on infections and illness during the initial hospitalization and 2 to 12 months posthospitalization were obtained. The average nadir IgG, which occurred at 3 months of age, was 66 mg/dl for all infants and 56 mg/dl for very low birth weight (VLBW) infants. Until infants were 5 months of age, IgG was < 200 mg/dl for low birth weight (LBW) infants and < 100 mg/dl for VLBW. IgM increased during the first 7.5 months from an average of 14 mg/dl to an average of 87 mg/dl. The lowest C3 and C4 occurred during the first 3 months. Fibronection did not appear to vary significantly with age. VLBW infants had significantly more (p ≤ 0.002) infections than LBW infants. There was a negative correlation (r = -0.58) between birth weight and the number of hospital infections. There was a significant (p = 0.01) association be...