Blood IgMs from healthy donors and patients with systemic lupus erythematosus reduce the inflammatory properties of platelets from healthy donors.

Uncontrolled inflammation is the underlining mechanism of many human diseases and the increasing prevalence of such diseases mandate to develop new anti-inflammatory treatments. Utilizing the anti-inflammatory properties as well as other protective/beneficial features of natural IgMs (nIgMs) for treatment of human disorders seems as an easily accessible goal by the use of blood-purified IgMs as an alternative for polyclonal nIgMs. Despite the other blood cells, the functions of platelets have not been inspected under the influence of blood IgMs adequately. However, platelets, the second most numerous blood cells, are involved in the pathology of many inflammatory disorders through the production/expression of many inflammatory molecules. Thus, in the present study, we purified IgMs from serum of healthy donors and plasma of patients with systemic lupus erythematosus (SLE). Subsequently, we carried out comparative analysis of the inflammatory functions of normal platelets (P-selectin expression, GPIIb/IIIa activation, and secretion of soluble CD40L and TNF-α) that were stimulated by SLE microparticles (as key endogenous inflammation-drivers) in the presence or absence of the two IgM preparations; one with normal level of nIgMs (healthy blood IgMs) and the other with likely altered nIgM content (SLE blood IgMs). Both blood IgM preparations could suppress the elevated activation parameters of platelets in response to SLE microparticles. Additionally, the impact of SLE blood IgMs on the platelets was not superior to that of normal blood IgMs. The anti-inflammatory effects of blood IgMs on the activated platelets have been shown for the first time in the present study. Thus, this study provides evidence in favor of use of healthy blood IgMs as an anti-inflammatory therapy in clinical settings.