Hemolytic transfusion reaction due to interdonor kell incompatibility. Report of two cases and review of the literature

A 74-year-old man experienced an acute hemolytic reaction following transfusion of 4 units of red blood cells. The recipient was K negative, one of the transfused units was K positive, and another contained a previously undetected anti-K with an indirect antiglobulin titer of 512. Further investigation led to the discovery of a hemolytic transfusion reaction in a second K-negative patient who received a platelet transfusion containing 50 mL of plasma from the same donor. The clinical and serologic features of these two cases and five previously reported cases of hemolytic transfusion reaction due to interdonor Kell incompatibility are summarized.

Hematophagic histiocytosis. A report of 23 new patients and a review of the literature

The clinical and laboratory features of 23 new patients as well as 50 previously reported patients with the syndrome of hematophagic histiocytosis are reviewed. The syndrome occurs more often in men than women but has no age predilection. Common presenting features include fever, hepatic and splenic enlargement, lymphadenopathy, and profound depression of blood counts. The clinical course is generally fulminant and may be complicated by coagulation abnormalities, hepatic dysfunction and renal failure. In the majority of patients, however, the syndrome is self-limited with resolution of the clinical and laboratory abnormalities within several weeks. Hematophagic histiocytosis generally occurs in patients who develop infections in the setting of preexisting immunologic abnormalities or neoplasms. Viral infections are most commonly involved, but virtually any other infectious agent can precipitate this syndrome. The characteristic morphologic feature of the hematophagic histiocytosis is the proliferation of mature histiocytes actively ingesting other blood cells. These hematophagic histiocytes most commonly involve the bone marrow but may also be present in the lymph nodes, spleen and liver. Other bone marrow abnormalities include hypocellularity with preservation of megakaryocytes, and myelofibrosis. The principal features of this syndrome that distinguish it from malignant histiocytosis are the cytologic maturity and degree of hematophagic activity of the histiocytes as well as its more favorable prognosis. In some patients, however, a clear distinction of malignant from reactive histiocytosis will not be possible until a clonal marker for malignant histiocytes is identified. Based in our experience, the syndrome of hematophagic histiocytosis appears to be more common than malignant histiocytosis.

The fibrinolytic system in man

The existence of a system in the human body capable of inducing the dissolution of endogenous pathologically formed thrombi was appreciated in ancient times. Considered in detail in this article are the data that have elucidated the physiologic regulation of which plasmin formation is dependent on, the plasma concentration of plasminogen, availability of activators of plasminogen in the plasma and surrounding tissue environment, the concentration of naturally present inhibitors, and the existence of fibrin in the circulation. Important in this rapidly progressive scientific discipline is consideration of the factors which control the synthesis of the components of this proteolytic enzyme system. Recently abundant information has indicated that this plasminogen-plasmin proteolytic enzyme system can be utilized therapeutically. Knowledge of the mechanisms of this system has permitted identification of agents that can be exogenously administered to releave thrombotic obstruction to blood flow in the venous (pulmonary emboli, deep vein thrombosis) and arterial (peripheral and central vessels) circulatory systems. Particularly important is the demonstration that thrombolytic agents can directly attack and alleviate the immediate cause of acute myocardial infarction. As a result of the innovations in the present decade, it is evident that the plasminogen system can be advantageously employed to reverse the pathologic effects of all thrombotic diseases.