Defining the clinical relevance of red blood cell autoantibodies by Monocyte Monolayer Assay.
BACKGROUND
The Monocyte Monolayer Assay (MMA) is an in vitro simulation of red blood cell (RBC) alloantibody behavior. It has been classically applied to predict the risks of post-transfusion hemolytic reactions when transfusing incompatible RBC units. Quantifying erythrophagocytosis by MMA may be an interesting option for situations where there is doubt whether a RBC autoantibody is mediating significant hemolysis. Here, we present three situations involving RBC autoantibodies in which the MMA was decisive for clarifying the diagnosis and choosing the best clinical treatment.


CASE REPORT
Case 1. Pregnant patient with severely anemic fetus exhibited warm autoantibody without signs of hemolysis. MMA revealed 30% of monocyte index (MI) highlighting that fetal hemolysis was caused by maternal autoantibody. Prednisone was prescribed with fetal clinical improvement. Cases 2 and 3. Two patients with the diagnosis of mixed auto-immune hemolytic anemia and poor response to corticosteroids were evaluated using MMA. The resulting MI was less than 10% in both cases, suggesting that the cold-agglutinin rather than the warm auto-IgG was responsible for overt hemolysis. Treatment with rituximab was begun, with good clinical response.


CONCLUSION
MMA can be used to evaluate the ability of RBC autoantibodies to mediate overt hemolysis. It can be especially useful to determine the role played by cold and warm auto-antibodies in mixed auto-immune hemolytic disease, helping to define the best treatment option.
['Conrado|Marina C A V|MCAV|', "D'Avila|Amanda N|AN|", 'Vieira|Juliana B|JB|', 'Bonifacio|Silvia L|SL|', 'Gomes|Francisco C A|FCA|', 'Dezan|Marcia R|MR|', 'Oliveira|Valeria B|VB|', 'Ribeiro|Ingrid H|IH|', 'Tucunduva|Luciana T C M|LTCM|', 'Mendrone-Júnior|Alfredo|A|', 'Rocha|Vanderson|V|', 'Dinardo|Carla L|CL|http://orcid.org/0000-0002-0453-7863']
D000328:Adult D000368:Aged D000743:Anemia, Hemolytic D001323:Autoantibodies D003584:Cytological Techniques D004912:Erythrocytes D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009000:Monocytes D011247:Pregnancy D011250:Pregnancy Complications, Hematologic
autoantibody Monocyte Monolayer Assay hemolysis hemolytic anemia