PEG adsorption of autoantibodies and detection of alloantibodies in warm autoimmune hemolytic anemia.
BACKGROUND
The purpose of this study was to evaluate the effectiveness of PEG in the adsorption of autoantibodies and the detection of alloantibodies in patients with warm autoimmune hemolytic anemia (WAIHA).


METHODS
The study was divided into three parts. First, the effectiveness of antibody removal by a conventional adsorption procedure and that by the PEG adsorption method were compared by using commercial antisera adsorbed with antigen-positive RBCs. Second, patients' sera with known weak alloanti-E were used to test against screening cells after allogeneic adsorption to show nonspecific coating of antibodies and the dilution effect on the PEG adsorption procedure. Third, conventional and PEG one-cell sample allogeneic adsorptions of WAIHA patients' sera with and without alloantibodies were performed and compared.


RESULTS
In the first part, seven of the eight polyclonal antisera gave a lower titer and score when tested against antigen-positive RBCs in the indirect antiglobulin test; this indicated that PEG is more efficient in removing antibodies. In the second part, similar reaction patterns were observed in antibody screening tests on unadsorbed sera and on sera after the first, second, and third adsorptions, which indicated that there was no alloantibody loss, nonspecific antibody coating, or dilution effect when PEG was added in the allogeneic adsorption procedures. In the third part, a 40-percent increase in efficiency in reducing the number of adsorptions and an 85-percent decrease in completion time of the adsorption procedures were obtained when PEG was used for adsorbing sera from 16 patients with WAIHA. Both conventional and PEG procedures were capable of removing autoantibodies to identify the specificities of alloantibodies.


CONCLUSIONS
The PEG adsorption method is an effective, sensitive, and efficient method of enhancing auto- antibody adsorption and alloantibody detection. It can reduce the processing time and minimize the delay of urgent transfusions to patients with WAIHA and can indirectly enhance cost-effectiveness and decrease the labor-intensive testing required by these cases.
Cheng
C K
CK
Hematology Section, Department of Pathology, Queen Elizabeth Hospital, Howlon, Hong Kong.
Wong
M L
ML
Lee
A W
AW
D000743:Anemia, Hemolytic / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis; D001327:Autoimmune Diseases / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology; D006358:Hot Temperature; D006801:Humans; D007163:Immunosorbent Techniques; D007518:Isoantibodies / Q000032:analysis*; D011092:Polyethylene Glycols; D013997:Time Factors
D001323:Autoantibodies; D007518:Isoantibodies; D011092:Polyethylene Glycols