Heterophile antibodies in human transplantation

Sensitization of human recipients with transplantation antigens (leucocytes, skin, or kidney allografts) has resulted in the appearance of serum hemagglutinins directed against sheep, guinea pig, and rat erythrocytes. Such hemagglutinins have been identified as IgG and IgM antibodies. Their appearance was not related to AB0 erythrocyte group incompatibility between donors and recipients, and the antibodies were not of the Forssman or Paul-Bunnel type. The antibody responses appeared to be primarily directed against antigen(s) present on rat erythrocytes, but shared to varying extents by other species. The peak antibody titers occurred in association with allograft rejection. In this regard, they may be of interest as a possible early warning system for the diagnosis and prompt management of rejection crises in clinical organ transplantation.     

The Growing Problem of Pediatric Allergy in the United States of America

The dynamics of pediatric allergy in the United States—as, indeed, in probably most parts of the world—is a subject rich with fascinating and sometimes contradictory elements. On the one hand, with an expanding population and a generally rising level of education and wealth, there is an increased awareness of allergy and heightened interest in doing something about it. On the other hand, with a higher degree of sophistication in the general population, there is frequently a tendency to focus public interest—and, thus, public funds—on more dramatic conditions such as birth defects or cystic fibrosis. Yet, in terms of the harm it does, and in terms of the number of persons affected, allergy is the most significant chronic illness among children in the United States.     

Delayed Incorporation of [75Se]Selenomethionine into Fibrinogen: Its Effect upon Kinetic Studies of Fibrinogen with [75Se]Selenomethionine in Rabbits

Summary . When data-points on the descending phase of autoendogenous plasma [^75Se]selenomethionine-fibrinogen (⁷⁵SeM-fibrinogen) radioactivity curves in rabbits were expressed as per cent of maximum radioactivity, they could be fitted to single exponential curves both in controls and in animals with enhanced fibrinogen synthesis from multiple causes. Intravascular half-disappearance times (HDTs) determined from these slopes were inversely related to maximum per cent incorporation of ⁷⁵SeM into fibrinogen (r= 0.662, P<0.001). The mean HDT for 17 controls was 112 hr, whereas the mean HDT for animals with marked stimulation of fibrinogen production was close to 56 hr, the value for the mean HDT for the second slope of fibrinogen radioactivity in 13 normal recipient rabbits injected with donor ⁷⁵SeM-fibrinogen. Two kinetic compartmental models were proposed to account for the marked difference between the autoendogenous ⁷⁵SeM-fibrinogen decay slope of control animals and the second slope of fibrinogen radioactivity in recipient animals. Both models account for a random, delayed input from the liver of ⁷⁵SeM-fibrinogen, which decreases when fibrinogen synthesis is stimulated. In one model, the delay occurs before synthesis of labelled fibrinogen, whereas in the other model the delay occurs after synthesis of labelled fibrinogen. Both models indicate that in control animals only about 50% of ⁷⁵SeM-fibrinogen enters the plasma from the liver without delay. In contrast, in rabbits with ACTH-stimulated fibrinogen production, over 80% of ⁷⁵SeM-fibrinogen enters the plasma without delay. Although both models fit the kinetic data, a steady state calculation for the model in which delay occurs after synthesis of labelled fibrinogen molecules gives a size for the intracellular fibrinogen delay pool in the liver which exceeds the size for the plasma fibrinogen pool. Therefore, this model seems untenable. Our evidence of a marked effect of variation in delayed input of ⁷⁵SeM-fibrinogen upon the degradation phase of the autoendogenous fibrinogen radioactivity curve raises doubts about the validity of using isolated portions of such curves for separate estimations of fibrinogen synthesis and catabolism.