Red cell destruction in cold agglutinin disease.
OBJECTIVE
The severity of autoimmune hemolytic anemia (AIHA) caused by cold agglutinins (CAs) is known to differ markedly in chronic CA disease as well as in postinfection cold agglutination. The various cold agglutinin specificities and mechanisms of red cell destruction are described.


METHODS
Original papers and reviews of the German and English literature (Medline research); own results.


METHODS
Original papers and reviews of the recent years on studies of the biochemistry and specificity of CAs and the pathophysiology of AIHA.


RESULTS
A crucial point for the severity of AIHA caused by CAs is the CA-binding capacity to red cells in vivo. This is reflected by the serologic behavior of the actual CA in vitro, represented by its thermal amplitude. Because most CAs are IgM molecules, red cell destruction by CAs is limited to mechanisms initiated by complement (C) activation. In recent years, several CA specificities, in addition to anti-I/i, have been identified on a serological and biochemical basis. CAs of the IgG and rarely of the IgA isotypes have been found.


CONCLUSIONS
The CA-induced red cell destruction does not only depend on CA titer or its thermal amplitude. The severity of CA-induced AIHA may also depend on CA isotype and/or specificity. Therefore, the complement activation capacity of CAs with a given isotype but different specificities has to be elucidated in further studies.
Zilow
G
G
Institut für Immunologie, Universität Heidelberg, FRG.
Kirschfink
M
M
Roelcke
D
D
D000373:Agglutinins / Q000276:immunology*; D000744:Anemia, Hemolytic, Autoimmune / Q000276:immunology*; D003450:Cryoglobulins; D004912:Erythrocytes / Q000276:immunology*; D006461:Hemolysis / Q000276:immunology*; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000276:immunology
D000373:Agglutinins; D003450:Cryoglobulins; D007132:Immunoglobulin Isotypes; C029443:cold agglutinins