Intravenous immunoglobulins in immunodeficiencies: more than mere replacement therapy.

Intravenous immunoglobulin (IVIG) is a therapeutic compound prepared from pools of plasma obtained from several thousand healthy blood donors. For more than 20 years, IVIG has been used in the treatment of a wide range of primary and secondary immunodeficiencies. IVIG now represents a standard therapeutic option for most antibody deficiencies. Routinely, IVIG is used in patients with X-linked agammaglobulinaemia (XLA), common variable immunodeficiency (CVID), X-linked hyper-IgM, severe combined immunodeficiency, Wiskott-Aldrich syndrome, and selective IgG class deficiency. In addition, IVIG is used extensively in the treatment of a wide variety of autoimmune disorders. IVIG is administered at distinct doses in the two clinical settings: whereas immunodeficient patients are treated with replacement levels of IVIG, patients with autoimmune and inflammatory diseases are administered with very high doses of IVIG. Several lines of experimental evidence gathered in the recent years suggest that the therapeutic beneficial effect of IVIG in immunodeficiencies reflects an active role for IVIG, rather than a mere passive transfer of antibodies.

Absence of heat intolerance (panting) syndrome in foot-and-mouth disease-affected Indian cattle (Bos indicus) is associated with intact thyroid gland function.

Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease with high morbidity and reduced productivity of affected animals. We studied the heat intolerance (HI) (panting) syndrome and the effect of FMD virus (FMDV) infection on thyroid gland function in Indian cattle (Bos indicus). Experimental infection with FMDV Asia 1 resulted in a mild form of disease with superficial lesions. Heat intolerance syndrome and its signs were not observed among the recovered animals. Subtle changes in the serum level of thyroid hormones, triiodothyronine (T3) and thyroxine (T4) were observed. However, there were no distinct histological changes in the thyroid gland, and FMDV antigens were not detected in the thyroid tissues. Our results thus suggest that the absence of panting syndrome in FMD-affected Bos indicus cattle may be associated with intact thyroid gland function.

[Intravenous immunoglobulins in autoimmune and inflammatory disorders: beyond a simple substitution]. / Immunoglobulines intraveineuses dans les maladies auto-immunes et inflammatoires: au-delà d'une simple substitution.

Despite their widespread use since many years in autoimmune and inflammatory disorders, the mechanisms of action of IVIg have not been completely understood. These mechanisms depend on Fc and/or F(ab')2. IVIg interacts with the different components of the immune system: Fc receptors, complement, cytokines, T and B lymphocytes, dendritic cells, granulocytes and NK cells. Here, we discuss the recent advances in the understanding of the mechanisms of action of IVIg, in particular the importance of the sialylated Fc fragment. These advances maybe help us conceive better therapeutic strategies against autoimmune and inflammatory disorders.