Results
A total of 86 patients were enrolled, 12.8% (11/86 cases) patients were classified into the mild-moderate group, and 87.2% (75/86 cases) patients were classified into the severe group. There was no statistical difference in gender (χ2 =0.292, P =0.589) and age (Z =-0.770, P =0.442) between the two bleeding severity groups. The positive rate of platelet-specific antibodies was 73.3% (63/86). The positive rates of anti-GPIIb/IIIa and anti-GPIb/IX antibodies were 68.6% (59/86) and 65.1% (56/86), respectively. Details of baseline characteristics and different platelet-specific antibody types are shown in TABLE 1.
The respective distribution of anti-GPIIb/IIIa and anti-GPIb/IX antibodies in the two bleeding severity groups are shown in TABLE 2. There was no significant difference in the distribution of anti-GPIIb/IIIa (χ2 =0.530, P =0.467) and anti-GPIb/IX antibodies (χ2 <0.001,P =1.000) between the two bleeding severity groups.
The comprehensive distribution of anti-GPIIb/IIIa and anti-GPIb/IX antibodies in the two bleeding severity groups is shown in TABLE 3 and Fig. 1. There was no significant difference in the distribution of four different antibody combinations between the two bleeding severity groups (χ2 =2.071, P =0.558). We also analyzed the differences between any two of four different antibody combinations with the Chi-square test or Fisher’s exact test but did not find any significant difference (Fig. 1).
The antibody titer ratios of anti-GPIIb/IIIa and anti-GPIb/IX antibodies in plasma and eluent between the two bleeding severity groups are shown in Fig. 2. We found that the anti-GPIIb/IIIa antibody titer ratios in eluent were significantly higher than those in plasma (Z =-5.556,P <0.001), and the same was with anti-GPIb/IX antibody (Z =-5.862, P <0.001). Al-Samkari et al.11 reported that direct assays for platelet-specific antibodies on platelets, as opposed to indirect assays, which measured free antibodies in plasma, had higher sensitivity and specificity and were considered optimal for platelet-specific antibodies testing. Our results were consistent with this study result. However, we found no significant difference in antibody titer ratios between the two bleeding severity groups in both plasma and eluent (anti-GPIIb/IIIa antibody in plasma: Z =-0.601, P =0.548; anti-GPIIb/IIIa antibody in eluent: Z =-0.556, P =0.578; anti-GPIb/IX antibody in plasma: Z =-0.388, P =0.698; anti-GPIb/IX antibody in eluent: Z =-0.175, P =0.861).