[Interferon alpha antibodies show no cross reactions with typical autoantibodies]

Patients treated with natural human interferon alpha develop anti-interferon antibodies (IFN-AB) only in very rare cases. By contrast, patients with autoimmune disorders are able to generate high-titered IFN-AB against endogenous interferon alpha. One explanation for the development of auto-IFN-AB could be cross-reactivity with typical autoimmune antigens. We investigated the cross-reactivity of 3 high-titered IgG IFN-AB of female autoimmune patients (aged 32, 36, 74 years; two severe cases of SLE, one case of autoimmune thyroiditis) as well as 25 low-titered natural IgM IFN-AB of healthy blood donors (aged 19-48 years). Typical autoimmune antigens including dsDNA, ENA, as well as natural interferon beta and recombinant interferon gamma are not able to inhibit binding of IFN-AB to interferon alpha in an ELISA test system. Preincubation of sera containing either dsDNA antibodies (dsDNA-AB) (24 patients), thyroid peroxidase (TPO-AB) (9 patients) or thyroglobulin (TG-AB) (12 patients) with interferon alpha resulted in no change in the respective autoantibody titer. These data suggest that there is no cross-reactivity between IFN-alpha-AB and dsDNA-AB, TPO-AB or TG-AB. Thus, an explanation for the occurrence of IFN-AB in autoimmune disorders cannot be found in a cross-reaction between interferon alpha with typical autoimmune antigens.