Fulminant Type 1 Diabetes-East and West.

Fulminant type 1 diabetes is a subtype of type 1 diabetes in which beta cells are destroyed within days or a few weeks. The first criterion indicates a rise in blood glucose levels shown in the patient's history. The second suggests that the increase occurs suddenly within a very short period, as shown by the laboratory findings of the discrepancy between the glycated hemoglobin concentration and plasma glucose level. The third indicates a marked reduction in endogenous insulin secretion, which indicates almost complete destruction of beta cells. Fulminant type 1 diabetes is a common subtype in East Asian countries, including Japan, but rare in Western countries. Class II human leukocyte antigen and other genetic factors may have contributed to the skewed distribution. Environmental factors may also be involved including entero and herpes viruses and immune regulation during drug-induced hypersensitivity syndrome; pregnancy may also affect it. In contrast, treatment with an immune checkpoint inhibitor of the anti-programmed cell death 1 antibody induces similar characteristics and incidence of diabetes as fulminant type 1 diabetes. Further studies are needed to clarify the etiology and clinical characteristics of fulminant type 1 diabetes. Although the incidence of this disease differs between the East and West, it is life-threatening; thus, it is important to diagnose fulminant type 1 diabetes without delay and treat it appropriately.