The South East England Thrombotic Thrombocytopenic Purpura Registry.

Thrombotic thrombocytopenic purpura (TTP) is an acute, rare, life threatening disorder. We present data from the South East (SE) England registry for TTP, from April 2002–December 2005. Included are 156 patients and 179 acute episodes. Seventy four percent of cases were female and 26% males, median age at presentation, 41 and 47.5 years respectively. Mortality to December 2003 was 12%, and from January 2004 to December 2005 was 5%; 5/12 died before treatment was instigated. The main ethnic groups were Caucasian (63%), Afro Caribbean (22%) and Asian (12%). In 61%, this was their first TTP episode; 39% represented with acute relapse. Precipitating events (n=123); idiopathic (56%), a defined infection (11%), pregnancy (6%), HIV disease (7%), congenital (5%) and associated autoimmune disease (6%). Features at presentation include: neurological disease (39%), temperature (15%), abdominal symptoms (12%), renal impairment (10%), symptomatic cardiac disease (7%), symptoms related to low platelets (17%) and no symptoms (2%). From April 2002–December 2003, the median number of plasma exchanges until complete remission (CR) recorded in 36 patients was 20 (5–79). One patient received plasma infusion (PI) in conjunction with PEX. 33 patients received 3 doses of pulsed intravenous methylprednisolone (IV MP) and 9 orally. Other therapies used were Rituximab (1), defibrotide (5), cyclosporine (9) and vincristine (15). In the second cohort (January 2004–December 2005), the median number of PEX to CR in 88 episodes was 8 (3–80). PI was used in 5 cases, 48 patients received 3 doses of pulsed IV MP on admission and 6 patients oral prednisolone. Other therapies used were Rituximab (26), defibrotide (2), cyclosporine (3), vincristine (5) and BPL 8Y (9). The latter is an intermediate purity Factor VIII concentrate used in congenital TTP. The median Haemoglobin (Hb) was 9.9g/dL at presentation and platelet count 18 ×10⁹/L. The 2002–2003 group had 48% cases with platelet counts <150 ×10⁹/L at 7 days, but only 25% of cases in 2004–2005. ADAMTS 13 activity, measured by collagen binding assay (CBA) (normal range 66–126%), in 136 episodes was <5% in 60%, 5–40% in 21%, 40–66 in 12% and >66% in 7% at presentation. Antibody to ADAMTS 13 (determined by mixing studies using CBA and/or anti-ADAMTS 13 IgG antibodies) was present in 61% of all cases. In those patients with acute idiopathic TTP, 93% had associated antibody. In conclusion: Improved recognition and prompt diagnosis of TTP may be associated with reduction in mortality and changes in treatment protocols reduced the number of PEX to achieve CR. Acute idiopathic TTP is the most common presentation, but improved identification of subgroups such as HIV and congenital TTP have resulted in appropriate tailoring of therapy.