Relationship of raised platelet IgG in XXXX to total platelet protein content.

@entity1 @entity1200 @entity882
Platelet-associated IgG (PA IgG) of washed platelets of 20 normal controls and 45 @entity882 @entity1 was measured by radioimmunoassay and related to total platelet protein content. Mean values (+/- 2 SD) for 20 normals were 4.4 +/- 3.5 fg IgG per platelet (fg IgG/pl), 2.1 +/= 1.0 pg protein per platelet (pg protein/pl) and a ratio of IgG per g platelet protein of 2.1 +/- 1.8 mg IgG/g protein. @entity1 could be divided into two groups: Group I (31) with normal IgG/g protein ratios and either normal (16) or raised (15) fg IgG/pl, and Group II (14) with both fg IgG/pl and IgG/g protein raised. Of the 21 @entity1 with @entity882 ( @entity882 ), 13 were in Group I (seven with raised and six with normal fg IgG/pl), and eight in Group II. There was significant correlation between PA IgG (fg IgG/pl) and platelet protein for the entire Group I (r = 0.95, P less than 0.001). The @entity882 @entity1 in this group showed a similar correlation (r = 0.77, P less than 0.001), suggesting that raised PA IgG levels in Group I @entity1 may be a result of protein-rich platelets. 60-90% of PA IgG was found in the soluble fraction of lysates of platelets from both normals and @entity1 . Thus, it is either non-specifically associated with platelets or is antibody directed towards easily solubilized platelet antigens. Nine @entity882 @entity1 without @entity1200 had raised PA IgG. These results question the assumption that raised PA IgG always indicates specific antiplatelet antibody.
