Initially used as replacement therapy for patients with primary and secondary immune deficiencies, intravenous immunoglobulin (IVIG), the human serum immunoglobulin (Ig) fraction that is mainly composed of normal human polyclonal IgG obtained from plasma pools from a large number of healthy blood donors, is now widely used for the treatment of a large number of autoimmune and systemic inflammatory diseases. 1,2) Recently, great attention has been paid to IVIG potential use as adjuvant anti-neoplastic agent.3-5) Studies on the anticancer alkaloid vindesine (VDS) conjugates of the anti-CEA (carcinoembryonic antigen) antibodies against a colorectal tumor xenograft revealed that antibody 14.95.55 (IgG2a) suppressed tumor growth both alone and as a VDS conjugate, while 11.285.14 (IgG1) produced only a slight effect alone but an almost complete and lasting suppression of tumor growth as a VDS conjugate. Acute studies showed that VDS-11.285.14 conjugate was considerably less toxic than free VDS in Balb/c mice.6) It has been revealed that there are different transfer mechanism between the drug-protein conjugates and free drugs transferred into cells, and the conjugates can reduce the toxicity of drugs, resulting in a prolongation of survival time.7) Studies on the efficacy of an IgG F(ab) 2 preparation against taxol-induced C activation revealed that at a therapeutically relevant dose level (10 mg/ml), this Fc-depleted IgG caused significant suppression of taxol-induced SC5b-9 formation, but replacing IVIG with 10 mg/ml human serum albumin (HSA) caused no inhibition of taxolinduced rise of SC5b-9. 8) Also, it is reported that within a range of molar concentration ratio of taxol to IVIG, the interaction of IVIG with taxol can inhibit taxol from crystallizing in aqueous solution.9) Studies in vitro have revealed that IVIG may stimulate the production of IL-12, an anti-tumor and anti-angiogenic cytokine, and enhanced NK cell activity.4) Studies also revealed that IVIG can decrease the level of matrix metalloproteinase-9 (MMP-9) expression in the U937 monocyte line with a decrease in the m-RNA level of MMP-9 that participates in basement membrane degradation, a vital step in the invasion of metastatic cancer cells. So, IVIG may serve as an adjuvant therapy in cancer due to its anti-neoplastic properties that may synergize with more specific MMP inhibitors and other anti-cancer drugs. 10,11) In addition, IgG presents itself in the blood of adults at 9.5-12.5 mg/ml, and as one of human plasma proteins, it is capable of binding an extraordinarily diverse range of metabolites, drugs, organic compounds and relevant antigens. [12][13][14] With the remarkable binding properties, IVIG can serve as an important transport protein for drugs, which may have important roles in the discovery of novel drug delivery system and targeted drug therapy. By using its high-safety profile, clinicians may construct new protocols for patients.Flavonols are plant pigments that are ubiquitous in nature. Kaempferol (3,4Ј,5,7-pentahydroxyflavone), quer...
