The document summarizes information about blood group systems and the Kidd blood group system. It discusses that there are over 30 recognized blood group systems in addition to ABO and Rh, including the Kidd system. The Kidd system involves the Jka and Jkb antigens which are carried on the SLC14A1 glycoprotein and can cause hemolytic transfusion reactions. It notes that a patient developed anti-Jkb antibodies after transfusions and now requires Jkb negative blood, which can be difficult to find due to availability and donor frequencies of the antigen.