GLYCOCALICIN IN THE DIAGNOSIS AND MANAGEMENT OF IMMUNE THROMBOCYTOPENIA

We studied glycocalicin (GC), expressed as plasma GC concentration and as GC index (ratio to platelet count), in 129 thrombocytopenic patien ts (platelet count < 100x10(9)/l) and 60 sex- and age-matched controls . Seventy-two patients had idiopathic immune thrombocytopenia, 32 seco ndary immune thrombocytopenia, 8 microangiopathic thrombocytopenia and 17 thrombocytopenia secondary to bone marrow aplasia. Patients with i mmune thrombocytopenia (ITP) were also subclassified, according to the ir clinical behaviour, as having active disease or being in spontaneou s or therapy-induced partial remission. A significant correlation was found between glycocalicin levels and platelet count both in normals a nd in patients with bone marrow aplasia (r=0.75). ITP patients showed a GC index significantly higher than controls (6.02+/-7.87 vs. 0.9+/-0 .2, p<0.001). When ITP patients with similar platelet count (30-50x10( 9)/l) were studied, the mean level of GC and the GC index were signifi cantly higher in those patients with active disease than in those in r emission (0.97+/-0.38 vs. 0.58+/-0.17 mu g/ml, p<0.05; 6.41+/-2.64 vs. 3.44+/-0.94, p<0.05, respectively). A longitudinal study performed in 10 patients with different subtypes of ITP suggested a positive corre lation between GC index and the activity of the disease. The GC value and GC index were significantly higher in patients with microangiopath ic thrombocytopenia than in controls (1.44+/-0.73 vs. 0.8+/-0.16 mu g/ ml, p<0.01; and 18.77+/-22.23 vs. 0.9+/-0.2, p<0.001, respectively). T he GC value was significantly lower in bone marrow failure (0.15+/-0.0 4 mu g/ml, p<0.01) compared to controls, while no difference was obser ved in the GC index. Our data confirm that the GC index is helpful in differentiating thrombocytopenia due to increased platelet destruction from the one due to impaired production. In addition, the assay has b een proven useful in the differential diagnosis of different ITP subty pes and their follow-up.