Authors’ reply to Vincent et al.

Excerpt

Sir: The primary goal of our study was to describe the features and outcome of critically ill patients with thrombotic microangiopathy (TMA) [1]. Some of the limitations emphasized by Dr. Vincent and colleagues are inherent to the retrospective aspect of the study, which was justified by the low incidence of the disorder, and we recognize that some patients may not have been included. We agree that treatment with plasma requires caution in the case of TMA related to pneumococcal infection, as the disorder may be exacerbated by preformed antigen T-targeted antibodies present in exogenous plasma. However, this assumption is based on a single case report of a child with Streptococcus pneumoniae-associated TMA, and the efficacy of plasma exchange has been reported in an adult with TMA associated with S. pneumoniae bacteremia [2]. Exclusion of plasma therapy is hazardous in the setting of severe TMA, and adverse effects of plasma remain to be established. In this setting exogenous plasma should be supplied through plasma exchange to remove such antibodies, if present, and the patient must be closely monitored to detect exacerbation of the disease. BMT and end-stage cancer related TMA were excluded as plasma treatment has been shown to be ineffective in both disorders, where manifestations and outcome are related mainly to the underlying disease. …