The clinical course and response to therapy of @entity1 with @entity3039 ( @entity3039 ) are not completely determined by the level of IgG present on the platelet surface. It is possible that antibodies of other immunoglobulin classes also play a role in @entity1423 in some of these @entity1 . Therefore, we studied 175 @entity1 with @entity3039 for the presence of IgM anti-platelet antibodies using radiolabeled polyclonal or monoclonal anti-IgM. We observed that 57% of @entity1 with clinical @entity3039 had increased levels of IgM on their platelets, compared with normal controls and @entity1 with @entity882 who did not have @entity3039 (less than 10%), (P less than 0.01). We obtained similar results using either radiolabeled polyclonal or monoclonal anti-IgM, reagents whose integrity was first characterized using erythrocytes coated with defined amounts of IgM antibody. Among @entity1 with increased platelet-IgM there was a significant correlation both with the presence of increased platelet-C3 as well as the amount of platelet-C3 (P less than 0.01, r = 0.53). We demonstrated the presence of warm-reacting IgM anti-platelet antibodies in the plasma of two of these @entity1 who were further studied. The isolated IgM fraction from these two plasmas was able to activate complement and place 3H-C3 on normal platelets. These studies demonstrate the presence of warm-reacting IgM anti-platelet antibodies in some @entity1 with @entity3039 . They suggest that the binding of complement to platelets by IgM antibodies may initiate platelet clearance as well as enhance the effect of IgG antibodies in @entity3039 .

Platelet antibodies of the IgM class in XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity3039 :: ('MESH:D016553', 'Disease') :: ['immune thrombocytopenic purpura', 'ITP'] @entity882 :: ('MESH:D013921', 'Disease') :: ['thrombocytopenia'] @entity1423 :: ('MESH:D001791', 'Disease') :: ['platelet destruction']
@entity3039 :: (MESH:D016553,Disease) :: ['immune thrombocytopenic purpura']
