In case of genetically-based TTP due to a congenital deficit of ADAMTS13, the infusion of plasma 30ml/Kg daily is the treatment of choice. Plasma exchange is preferable in patients with acquired TTP. It is performed once a day and replaces 1 plasma volume with either fresh frozen plasma

There are no indications on the number of sessions of plasma exchange necessary in order to obtain a remission of the acute phase. It is advisable to carry out daily sessions of plasma exchange with an exchange of 3-5 liters of plasma until achieving remission of clinical symptoms, a stable platelet count above 150x109/L, normalisation of serum levels of LDH and correction of the anemia.

It is recommended that daily treatment with plasma exchange is continued for at least 3 days after the remission has been obtained (41). Anyway consolidation treatment is empirical and is based only on observations that exacerbations of TTP are common when plasma exchange is stopped. Other considerations, such as complications with venous access, may override a decision to extend treatment. In many patients, repeated reinitiation of daily plasma exchange is required before durable complete remission is established.

Corticosteroids are almost always used in the acute treatment of immune-mediated TTP, although the efficacy of this strategy has not been demonstrated by controlled studies. The recommended dose of prednisone is 1.0-1.5 mg/Kg (35-39).

The dose used for high-dose intravenous immunoglobulins treatment is 400 mg/Kg for 5 days or 1g/Kg for 2 days (35-39).

Its efficacy, which is controversial, is based on the removal of an important site of production of anti-ADAMTS13 autoantibodies (35-39).

The use is still controversial. Including ticlopidine, clopidogrel, acetylsalicylic acid and dypiridamole. Their use is not based on a pathogenic rationale, since the platelet aggregation induced by the ULVWF multimers is not inhibited by these drugs (9). They must not, in any case, be used when the platelet count is below 50x109/L, in order to avoid increasing the risk of hemorrhage (35-39).

Its use increased in recent years for the treatments of TTP, particularly in those cases not responding to treatment with plasma exchange and characterised by multiple relapses. The aim of treatment with rituximab in TTP is to block the production of anti-ADAMTS13 antibodies by depleting B lymphocytes. The recommended dose is 375 mg/m2 every 7 days, repeated for usually four cycles. Several case reports and small series suggest that rituximab induces complete response in the majority of patients with TTP refractory to plasma exchange, corticosteroids and other treatments such as vincristine or splenectomy. Responsens to rituximab correlate with disappearance of ADAMTS13 inhibitors and a rise of the ADAMTS13 level into the normal range. The duration of the response varying from 10 to 20 month after the last dose (40-41).

For genetically-based TTP there are several reports in which prophylactic treatment of recurrent episodes has been given, based on the administration of plasma (30ml/Kg) at regular intervals (every 5-7 days) (41).
No guide line are available for prophylactic treatment in acquired TTP. The efficacy of low doses of corticosteroids in the prevention of relapses of chronic recurrent forms of TTP has not been demonstrated, although such treatment is often given, particularly in whom the defects of ADAMTS13 is due to auto-antibodies (35-39).
Others available treatments are splenectomy, aspirin, dipyridamole, but their efficacy is unclear. The variable clinical course of TTP makes all anecdotal reports uninterpretable.
A new therapeutically possibility is the anti CD-20 monoclonal antibody Rituximab. Its use increased in recent years for the treatments of TTP, particularly in those cases characterised by multiple relapses(40).