Microcapillary Agglutination for the Detection of Leukocyte Antibodies: Evaluation of the Method and Clinical Significance in Transfusion Reactions

The method for detection of anti‐leukocyte antibodies by microcapillary agglutination (MCA) is described in detail, as are the procedures used to establish positive and negative results and reproducibility. MCA was found to be more sensitive than lymphocytotoxicity (LC) and antisera which appeared to be monospecific by LC were multispecific when tested by MCA. In addition, MCA was found to have more clinical significance than LC. Eighty‐four per cent of 25 patients with nonhemolytic transfusion reactions and a temperature elevation of > 1 F had anti‐leukocyte antibodies detected by MCA, while only 36 per cent of these patients had anti‐leukocyte antibodies detected by LC. MCA defined a group of transfusion reactions in patients who had more previous transfusions, more pregnancies, and a higher average temperature elevation than did patients without detectable anti‐leukocyte antibodies. Although LC methods are currently in widespread use for organ matching in transplantation, other methods such as MCA for the detection of anti‐leukocyte antibodies may have more relevance to the problems of blood transfusion. 1974 AABB