Microcapillary agglutination assay for detection of specific antileukocyte reactivity in neutropenic patients

Serum leukoagglutinating activity against the leukocytes of four patients with neutropenia was demonstrated using a modified microcapillary agglutination test. Cells from a panel of donors proved useful in attempting to define the identity of the antigens involved. In one instance anti-HLA-A9 activity could be demonstrated in a patient possessing HLA-A9. In the other three individuals no definite antigen assessment to HLA Series A and B antigens or the Lalezari series of neutrophil antigens could be made. Two of the patients' sera showed cross-reactivity and may be reactive with the same antigen or antigenic group. The microcapillary agglutination test appears to be useful in the evaluation of possible cases of autoimmune neutropenia.