Natural human immunoglobulins are now widely used to treat many clinical diseases. Historically, this therapy began as a supplement for patients with agammaglobulinemia (Barandun et al. 1981/82). Pneumonia, bacterial meningitis and other infectious episodes often seen in patients with this disorder have been improved by intravenous administrations of natural immunoglobulin (Ersoy et al. 1992, Liese et al. 1992, Popescu et al. 1992). Rather than being just a supplement, immunoglobulin is now being used because of its therapeutic effects. One of its most prominent features is its antipyretic effects against infection (Iwata et al. 1987). Some specific antibody fractions against causative microorganisms may be present in natural immunoglobulin. However, it now appears that some unidentified mechanisms play important roles in the outcome of this therapy (Blanchette et al. 1992, Horiuchi et al. 1993, Ronda et al. 1993). Natural human immunoglobulin preparations have been widely used in cases of severe infection such as septic shock and bacterial meningitis {Ruiz et al. 1993, Saladino et al. 1992, Schedel et al. 1991, Wortel et al. 1993). Subsidence of an infection as evidenced by the alleviation of high-grade fever, and the improvement of survival rate have been noticed with the use of natural polyvalent immunoglobulin preparations from simple stock plasma, as well as IgM-enriched specific preparations (Ersoy et al. 1992, Iwata et al. 1987, Shimozato et al. 1990, Taylor et al. 1992). Another example ofthe clinically indicated disorders for this therapy is autoim-