Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks the insulin-producing beta cells in the pancreas. Without these beta cells, the body cannot maintain proper blood glucose levels in response to daily activities such as eating or exercise. With fewer insulin producing cells blood glucose increases, causing hunger, thirst, and unexplained weight loss. By the time these symptoms develop, 80-90% of a person's beta cells have already been destroyed. However, this also means that between 10-20% of these cells remain that continue to produce insulin.

Scientists have learned that two types of immune cells, B cells and T cells, are involved in causing type 1 diabetes. T cells are responsible for attacking and destroying the beta cells that make insulin. Although they don't attack insulin producing cells, B cells may be what trigger the T cells to attack.

This study will investigate the use of rituximab to see if it can help lower the number of immune B cells thereby preventing the destruction of any remaining insulin producing beta cells that remain at diagnosis. Rituximab is approved by the Food and Drug Administration (FDA) for the treatment of a condition called B-lymphocyte lymphoma. Its effects on the immune system are well understood through its use in organ transplantation. Research has shown that rituximab might be helpful in treating other conditions caused by T cells and B cells, including type 1 diabetes. The goal of this study is to find out if rituximab can preserve residual insulin secretion and prevent further beta cell destruction in type 1 diabetes.