Immunological basis of inflammation in dialysis

Several studies indicate that chronic inflammation is the major determinant of the 'dialysis syndrome' characterized by malnutrition, cachexia and vasculopathy and responsible for the high mortality and morbidity rate in dialysed patients. Uraemia together with repeated contact with the dialytic devices are considered the most important factors eliciting the immune system response resulting in inflammation. Dialysis may also contribute by means of bacterial contamination of dialysis fluids or acetate-containing dialysis buffers. Chronic infections (Chlamydia pneumoniae) in combination with a defective immune system and favourable genetic background can also be involved. The chronic inflammation of long-term dialysed uraemic patients induces an increased production of reactive oxygen species which cannot be counterbalanced due to defective antioxidant capability typical of uraemia: the resulting altered redox state is responsible for the accelerated senescence characteristic of the dialysis syndrome. The most important immunological mechanisms underlining the development of the dialysis syndrome are reviewed.