A human IgM enriched immunoglobulin preparation, Pentaglobin, reverses autoimmune diabetes without immune suppression in NOD mice.

The immune system of healthy individuals is capable of regulating autoimmunity through multiple mechanisms. In Type 1 Diabetes (T1D) we recently discovered natural IgM, although present at normal levels, is unable to perform its normal immunoregulatory function. Treating diabetic mice with IgM from healthy donors led to reversal of disease without immune depletion. To investigate the therapeutic potential of a human preparation of IgM, we administered an IgM-enriched preparation of immunoglobulin called Pentaglobin. Administration of Pentaglobin therapy reversed disease in diabetic NOD mice and boosted CD4 + Foxp3 + Tregs. Importantly, the impact of Pentaglobin on the immune system was limited to inhibiting beta cell destruction but was not immune depleting nor did it inhibit the immunization response to an irrelevant antigen. These findings indicate that inhibition of deleterious autoimmunity in T1D is possible while leaving protective immunity fully intact.