Auto Anti-P is a biphasic hemolysin that binds to red blood cells at cold temperatures and causes complement-mediated hemolysis after warming to body temperature. This autoantibody is found in Paroxysmal Cold Hemoglobinuria (PCH).
PCH was historically associated with syphilis but is now common in children post viral infection. Symptoms may include fever, chills, body aches, headache, and blood in the urine. Treatment generally includes treating the primary infection or may resolve on its own with supportive therapy. Avoidance of cold temperatures is recommended to prevent hemolysis.
Workup in the blood bank is significant for a positive DAT, specifically the complement component.
Auto Anti-P is determined by performing a Donath Landsteiner test. In the Donath Landsteiner test, the patient's sample is incubated at a cold temperature allowing the antibody to attach. The sample is then incubated at body temperature to activate complement and activate hemolysis.
