This literature study report was received from the above literature article. The author stated that therapeutic intravenous immunoglobulin (IgIV) consists of normal polyclonal IgG obtained from the plasma of several thousand healthy donors. It has been used over the past 25 years as a substitutive treatment for primary and secondary immunodeficiencies, including severe cases of specific antibody deficiency (SAD) with normal serum immunoglobulin levels. We have observed that in SAD patients treated with IgIV for 12 months to 2 years, re-evaluation of their immune response 6 months after discontinuing IgG replacement often revealed that specific anti-pneumococcal antibody production in vivo was improved, both spontaneously and after revaccination with the PNEUMOVAX 23 vaccine. The author studies 37 consecutive pediatric patients, two years of age or older or both genders, referred to author's clinic for recurrent infections. Subjects were recruited regardless of race or ethnic background. Patients were evaluated in the clinic according to a standard protocol, which includes a detailed history of immunizations, infections and antibiotic use, laboratory evaluation, including immunoglobulin and IgG subclass determinations and the measurement of IgG antibodies specific to 14 pneumococcal polysaccharide serotypes by the WHO-recommended enzyme-linked immunosorbent assay (ELISA). As part of their evaluation, on an unknown date, the patients in this study received one dose of PNEUMOVAX 23 (dose and route of administration not provided). Anti-pneumococcal polysaccharide antibodies were measured before and 4 to 6 weeks after immunization. Patients were enrolled into the study at the time of the post-immunization samples, before knowing the outcome of their responses to immunization. Thus, in patients diagnosed with SAD who required IgIV replacement therapy, all studies were performed on blood samples taken prior to the start of treatment. For analysis, subjects were divided into two groups, 15 patients with diagnosis of SAD and 22 patients without SAD (No SAD). Patients with SAD were defined as having normal IgG, IgM, IgA and IgG subclass levels but poor IgG antibody responses to pneumococcal vaccines. Patients with immunoglobulin deficiencies, acute infections or debilitating conditions were excluded from the study. There has been a concern that the use of IgIV and therefore of passive IgG antibodies might interfere with the development of the patient's own immune response. The author's result showed that IgIV does not inhibit an antibody response in vitro. On the contrary, we demonstrate that IgIV had an enhancing effect on the spontaneous production of IgG antibodies in cell cultures from patients with recurrent respiratory infections. The outcome of the event was unknown. The author considered event to be related to suspect therapy. The author concluded that results showed that IgIV modulates, to some extent, the in vitro production of IgG anti-Pn19 antibodies and that the observation of cytokine production changes in vitro suggest that this modulation is associated with a Th1/Th2 regulatory mechanism. Our observation of antibody and cytokine production in patients with SAD suggest that this is a heterogeneous group of patients caused by different regulatory mechanisms that could also explain important differences in the long-term response to IgG replacement therapy. A copy of the published article is attached as further documentation of the patient's experience. Additional information has been requested.