The Archbishop of Sydney is in hospital after being diagnosed with a serious condition of the nervous system. Most Reverend Anthony Fisher OP, 55, was hospitalised after doctors discovered Guillain-Barré syndrome, a condition in which the body’s immune system attacks the nervous system, usually caused by a viral or bacterial condition. One of the main symptoms of the illness is muscle weakness. The Archbishop became ill before Christmas and was admitted to St Vincent's Hospital in the city. Most sufferers recover fully and the Archbishop has responded well to medical treatment. On the diocesan website the archbishop has thanked people for their messages of support.