Intravenous immunoglobulin prophylaxis with or without IgM enrichment in very-low-birth-weight infants

Objectives The aim of the study was to compare an IgM-enriched intravenous immunoglobulin (IVIG) preparation to a conventional preparation containing mainly IgG in the prophylaxis of infections in very-low-birth-weight infant s and to evaluate whether IVIG administration would have any suppressive ef fect on the infants' immunoglobulin production, interferon-gamma concentrat ions and responses to vaccines. Methods Fourty-four infants were randomly allocated to receive either IgM-e nriched immunoglobulin (IgM group) or a conventional preparation (IgG group ) of 1000 mg/kg weekly during intensive care and biweekly thereafter until a weight of 1500 g was reached, or to a control group. The immunoglobulin A , E, M, G and IgG subclass levels and responses to diphtheria, tetanus and pertussis vaccines were measured regularly during follow-up. Infections wer e registered during and after primary hospitalization up to the age of 36 w eeks. Results The serum levels of IgA, IgG, IgG(1), IgG(2) and IgG(4) increased a nd were significantly higher in both the IVIG substituted groups compared t o the control group at the ages of 1-8 weeks. IgM and IgG(3) concentrations were increased only in the IgM group. The incidence of infections was 0.43 per patient-month in the IgM group, 0.50 in the IgG group and 1.11 in the control group during the primary hospitalization, 0.20, 0.34 and 0.36 after discharge from hospital, and, during the total follow-up period, 0.29, 0.5 0 and 0.63, respectively. Differences were not statistically significant du ring the primary hospitalization, but during the follow-up period the rate of infections was significantly lower in the IgM group compared to the cont rol group. The interferon-gamma levels and responses to vaccinations did no t differ among the groups. Conclusions A tendency toward reduced incidence of infections in the IgM gr oup indicates the need for larger studies to evaluate the real benefit of t his therapy. IVIG administration did not suppress own immunoglobulin produc tion or responses to vaccinations.