IGA RED-CELL AUTOANTIBODIES AND AUTOIMMUNE HEMOLYSIS

Citation
Rj. Sokol et al., IGA RED-CELL AUTOANTIBODIES AND AUTOIMMUNE HEMOLYSIS, Transfusion, 37(2), 1997, pp. 175-181
Citations number
61
Categorie Soggetti
Hematology
Journal title
ISSN journal
00411132
Volume
37
Issue
2
Year of publication
1997
Pages
175 - 181
Database
ISI
SICI code
0041-1132(1997)37:2<175:IRAAAH>2.0.ZU;2-#
Abstract
BACKGROUND: The objective of the study was to examine the interrelatio nships and clinical significance of IgA red cell antibodies in the aut oimmune response. STUDY DESIGN AND METHODS: The records of 5235 patien ts referred to an immunohematology center over a 14-year period were c ritically examined for patients who had IgA autoantibodies, defined as elutable IgA immunoglobulins that would rebind to normal cells. RESUL TS: One hundred twenty-four patients (61 male) aged 6 to 98 years had warm-reacting IgA autoantibodies. In 75 individuals, these were idiopa thic; neoplasms were the most common associated conditions in the indi viduals with secondary IgA autoantibodies. IgA was the only immunoglob ulin present in 6 patients; all others also had IgG and/or IgM coating their cells, and 102 individuals also had increased amounts of cell-b ound complement. In a comparison by chi-square test of populations wit h haptoglobins of <0.1 g per L, IgA was shown to act synergistically w ith IgG in producing hemolysis (p<0.01). CONCLUSION: Autoimmune hemoly sis due to IgA antibodies alone is rare, with red cell destruction occ urring through mechanisms similar to those for IgG. Most commonly, IgA acts synergistically with other immunoglobulins (usually IgG) and com plement; the hemolysis may be severe. Whether IgA autoantibodies alone can activate complement remains controversial, but increasing evidenc e suggests that they can, possibly via the alternative pathway, and th at this activation may result in intravascular hemolysis.