Antiformaldehyde and anti-N-like antibodies in hemodialysis patients.

Seventy-one hemodialysis patients were tested for antibodies to red blood cell antigens; 19 of the 71 had been treated with formaldehyde-sterilized dialysis membranes. The sera of 3 (16%) of these 19 contained anti-N-like antibodies and those of 17 (89%) contained a second agglutinin specific for formaldehyde-treated red blood cells. Anti-N-like and "antiformaldehyde" antibodies appear to be serologically distinct. We suggest that residual formaldehyde in formaldehyde-sterilized dialysis membranes reacts with red blood cells to form an immunogen responsible for antiformaldehyde in patients treated with these membranes.