Unusually high concentrations of cTnI and cTnT in a patient with catastrophic antiphospholipid antibody syndrome

Background: We present a case of a patient with catastrophic antiphospholipid antibody syndrome with unusually high concentrations of cardiac Troponin I (cTnI) and cardiac Troponin T (cTnT). Troponins are sensitive and specific markers of myocardial injury. The degree of their elevation, in the context of the chronic autoimmune condition of the patient, elicited a thorough investigation for the presence of interfering antibodies. Methods: Cardiac markers, including total CK, CK-MB, cTnI, and cTnT, were measured in this patient over a period of 14 days after the onset of symptoms. In order to rule out a possible interference, serum samples were subjected to serial dilutions and were incubated with a blocking reagent (HBR) prior to analysis. Results: The time release of the cardiac markers into the systemic circulation of this patient followed the typical pattern after a myocardial infraction. Serial dilutions of the samples, and incubation with the blocking reagent revealed no indication of the presence of interfering antibodies. Conclusions: The results strongly suggest that the extremely high concentrations of cTnT and cTnI in this patient were real and indicative of a massive myocardial infarction (MI). These may be the highest concentrations of cTnI and cTnT reported in the systemic circulation of a single patient.