Lyme disease—another transfusion risk?

Lyme disease (or Lyme borreliosis) is caused by a spirochetal bacteria, Borrelia burgdorferi. Increased recognition of the disease and increased exposure to the vector (ticks) capable of spreading B. burgdorferi from animal hosts have resulted in a rise in the number of cases of Lyme borreliosis reported in the United States. There are three stages of the clinical course of Lyme borreliosis; however, not all those infected will have typical manifestations of each stage, such as the arthritis of the third stage. Routine blood cultures will rarely document bacteremia and serologic testing is not yet reliable. Early treatment can prevent later stages of Lyme borreliosis. There is evidence that transmission of B. burgdorferi by blood transfusion is possible, but, to date, there has been no documentation of transfusion- associated Lyme borreliosis. Thus, no new recommendations for screening donors to identify possible carriers of B. burgdorferi are suggested at this time.     

Accelerated immune red cell destruction in the absence of serologically detectable alloantibodies

Two patients are described in whom clinically significant red blood cell alloantibodies could be demonstrated only by in vivo 51chromium (51Cr) survival studies. The first patient had experienced a severe delayed hemolytic transfusion reaction to four units of crossmatch compatible blood. Serial phenotype studies suggested the presence of a serologically undetectable anti-c (hr') antibody. 51Cr survival of c- positive red blood cells was one per cent at 24 hours, while survival of c-negative red blood cells was 80 per cent at 24 hours. The second patient had multiple red blood cell alloantibodies. An anti-c antibody was suspected but could not be convincingly demonstrated by in vitro techniques. 51Cr survival of c-positive red blood cells, however, was 57 per cent at 24 hours and 17 per cent at 48 hours. 51Chromium red blood cell survival studies should be considered whenever an unexplained hemolytic transfusion reaction occurs, or when an expected red blood cell alloantibody cannot be demonstrated by in vitro laboratory studies.