[A clinical study of congenital thrombotic thrombocytopenic purpura].

OBJECTIVE

To study on the first Chinese congenital thrombotic thrombocytopenic purpura (TTP) patient with respect to peripheral blood platelet count and ADAMTS13 activity, ADAMTS13 antigen, anti-endothelial cell antibody (ACEA), and thrombospondin1 (TSP1) etc. to compared it with idiopathic TTP and to explore something special and meaningful in the pathogenesis of congenital TTP.

METHODS

A total of 30 volunteers served as controls. The congenital TTP patient and 10 carriers in her pedigree as well as 7 idiopathic TTP patients were included in this study. Residue collagen binding assay and a newly developed sandwich ELISA were used for determination of ADAMTS13 activity and antigen respectively. An ELISA for ACEA and a commercial kit for TSP1 were use in the study.

RESULTS

After a "3-4 weeks regular relapse" of the congenital TTP, which is similar to that in other reports, the Chinese patient moved into a new relapse cycle. The average of the antigen levels of this patient before plasma exchange (PE) and at the interval between relapses was (22.79 +/- 14.61) U/L (P < 0.01), while that of Chinese normal control (NC) turned out to be (600.93 +/- 145.36) U/L. TSP1 detected at the same time (4.67 +/- 1.62) mg/L in the congenital TTP patient was much lower than that in NC (18.34 +/- 7.24) mg/L (P < 0.01). A value in ACEA assay was 0.58 +/- 0.06 (P < 0.01) for congenital TTP, which was a little higher than that in NC (0.40 +/- 0.13).

CONCLUSIONS

Congenital TTP may have changeable relapse cycles during episodes. ADAMTS13 antigen and TSP1 and ACEA in congenital TTP showed significant difference as compared with those in NC. ADAMTS13 and ACEA in congenital TTP were also markedly lower than those in idiopathic TTP.