Illustration of T cell white blood cells attacking a multiple myeloma cell. Multiple myeloma is type of cancer, it occurs when a plasma cell becomes abnormal and cancerous. The cancerous plasma cell divides and multiplies creating large amounts of abnormal antibodies. T lymphocytes, or T cells, are a type of white blood cell and a component of the bodys immune system. They recognise a specific site (antigen) on the surface of a pathogen or cancerous cell, bind to it, and attract antibodies or cells to eliminate it.