Deb
                    
                    
                    
                    
                    
                    
                    
                        
                        
                        Can anyone tell me what T-cells are?  I have a friend who's brother has leukemia.  my friend donated bone marrow but now is going to give some of her T-cells and I'd like to know what a T-cell is.  If anyone can help I would appreciate it, I am trying to emotionally support my friend.thanks