Abstract
Anti-Jka was detected by solid-phase red cell adherence(SPRCA) anti-body detection and identification tests in the plasma of a 9-month-old female intant during a roatine presurgical evaluation. the pation and her nonidentical twin sister who also had anti-Jka in her plasma, were products at an uncomplicated in vitro fertilization, full -term preganancy, and vaginal delivery Neither twin had been tranfered recently infected. or treated with medication. their mother had no prior pregnancies or transfusions. Red blood cells (RBCs) from the patient and her sister typed as Jk(a-b+) by direct hemagghutination and this phenotype was confirmed by negative adsorption and elution studies. Both infants plasma samples were strongly reactive with 20 examples of Jk(a+) RBCs and nonreactive with 20 examples of Jk(a-) RBCs by SPRCA assays. Anti-Jka was not detected in either twins plasma by Indirect antiglobulin tests by tube method in lowionie-strength saline solution or polyethylene glycol, or with ficin- or papain-treated RBCs. Monocyte monolayer assays using Jk(a+) RBCs sensitized by either twins’ serum were nonreactive (0%). RBCs from both parents typed as Jk(a+b+). Both parents’ antibody detection test results by SPRCA assay were negative. The absence of a history of exposure to allogeneic RBCs or possible passive transfer of maternal or other alloantibody classifies these antibodies as natually-occurring anti-Jka. Immunohemalology 1999;15: 159-162.