Predictors of acute ischemic cerebral lesions in immune-mediated thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.

BACKGROUND: The immune form of thrombotic thrombocytopenic purpura (iTTP) and the hemolytic and uremic syndrome (HUS) are two major forms of thrombotic microangiopathy (TMA). Their treatment has been recently greatly improved. In this new era, both the prevalence and predictors of cerebral lesions occurring during the acute phase of these severe conditions remain poorly known. AIM: The prevalence and predictors of cerebral lesions appearing during the acute phase of iTTP and Shiga toxin-producing Escherichia coli-HUS or atypical HUS were evaluated in a prospective multicenter study. METHODS: Univariate analysis was performed to report the main differences between patients with iTTP and those with HUS or between patients with acute cerebral lesions and the others. Multivariable logistic regression analysis was used to identify the potential predictors of these lesions. RESULTS: Among 73 TMA cases (mean age 46.9 ± 16 years (range 21-87 years) with iTTP (n = 57) or HUS (n = 16), one-third presented with acute ischemic cerebral lesions on magnetic resonance imagery (MRI); two individuals also had hemorrhagic lesions. One in ten patients had acute ischemic lesions without any neurological symptom. The neurological manifestations did not differ between iTTP and HUS. In multivariable analysis, three factors predicted the occurrence of acute ischemic lesions on cerebral MRI: (1) the presence of old infarcts on cerebral MRI, (2) the level of blood pulse pressure, (3) the diagnosis of iTTP. CONCLUSION: At the acute phase of iTTP or HUS, both symptomatic and covert ischemic lesions are detected in one third of cases on MRI. Diagnosis of iTTP and the presence of old infarcts on MRI are associated with the occurrence of such acute lesions as well as increased blood pulse pressure, that may represent a potential target to further improve the therapeutic management of these conditions.

Guadecitabine vs treatment choice in newly diagnosed acute myeloid leukemia: a global phase 3 randomized study.

This phase 3 study evaluated the efficacy and safety of the new hypomethylating agent guadecitabine (n = 408) vs a preselected treatment choice (TC; n = 407) of azacitidine, decitabine, or low-dose cytarabine in patients with acute myeloid leukemia unfit to receive intensive induction chemotherapy. Half of the patients (50%) had poor Eastern Cooperative Oncology Group Performance Status (2-3). The coprimary end points were complete remission (19% and 17% of patients for guadecitabine and TC, respectively [stratified P = .48]) and overall survival (median survival 7.1 and 8.5 months for guadecitabine and TC, respectively [hazard ratio, 0.97; 95% confidence interval, 0.83-1.14; stratified log-rank P = .73]). One- and 2-year survival estimates were 37% and 18% for guadecitabine and 36% and 14% for TC, respectively. A large proportion of patients (42%) received <4 cycles of treatment in both the arms. In a post hoc analysis of patients who received ≥4 treatment cycles, guadecitabine was associated with longer median survival vs TC (15.6 vs 13.0 months [hazard ratio, 0.78; 95% confidence interval, 0.64-0.96; log-rank P = .02]). There was no significant difference in the proportion of patients with grade ≥3 adverse events (AEs) between guadecitabine (92%) and TC (88%); however, grade ≥3 AEs of febrile neutropenia, neutropenia, and pneumonia were higher with guadecitabine. In conclusion, no significant difference was observed in the efficacy of guadecitabine and TC in the overall population. This trial was registered at www.clinicaltrials.gov as #NCT02348489.

Immune-mediated thrombotic thrombocytopenic purpura prognosis is affected by blood pressure.

Background: The prevalence, prognostic role, and diagnostic value of blood pressure in immune-mediated thrombotic thrombocytopenic purpura (iTTP) and other thrombotic microangiopathies (TMAs) remain unclear. Methods: Using a national cohort of iTTP (n = 368), Shigatoxin-induced hemolytic uremic syndrome (n = 86), atypical hemolytic uremic syndrome (n = 84), and hypertension-related thrombotic microangiopathy (n = 25), we sought to compare the cohort's blood pressure profile to assess its impact on prognosis and diagnostic performances. Results: Patients with iTTP had lower blood pressure than patients with other TMAs, systolic (130 [interquartile range (IQR) 118-143] vs 161 [IQR 142-180] mmHg) and diastolic (76 [IQR 69-83] vs 92 [IQR 79-105] mmHg, both p < 0.001). The best threshold for iTTP diagnosis corresponded to a systolic blood pressure <150 mmHg. iTTP patients presenting with hypertension had a significantly poorer survival (hazard ratio 1.80, 95% confidence interval 1.07-3.04), and this effect remained significant after multivariable adjustment (hazard ratio = 1.14, 95% confidence interval 1.00-1.30). Addition of a blood pressure criterion modestly improved the French clinical score to predict a severe A disintegrin and metalloprotease with thrombospondin type 1 deficiency in patients with an intermediate score (i.e., either platelet count <30 × 109/L or serum creatinine <200 µM). Conclusions: Elevated blood pressure at admission affects the prognosis of iTTP patients and may help discriminate them from other TMA patients. Particular attention should be paid to blood pressure and its management in these patients.

Molecular classification and prognosis in younger adults with acute myeloid leukemia and intermediate-risk cytogenetics treated or not by gemtuzumab ozogamycin: Final results of the GOELAMS/FILO acute myeloid leukemia 2006-intermediate-risk trial.

In this randomized phase 3 study, the FILO group tested whether the addition of 6 mg/m2 of gemtuzumab ozogamycin (GO) to standard chemotherapy could improve outcome of younger patients with de novo acute myeloid leukemia (AML) and intermediate-risk cytogenetics. GO arm was prematurely closed after 254 inclusions because of toxicity. A similar complete remission rate was observed in both arms. Neither event-free survival nor overall survival were improved by GO in younger AML patients (<60 years) ineligible for allogeneic stem-cell transplantation. (P = .086; P = .149, respectively). Using unsupervised hierarchical clustering based on mutational analysis of seven genes (NPM1, FLT3-ITD, CEBPA, DNMT3A, IDH1, IDH2, and ASXL1), six clusters of patients with significant different outcome were identified. Five clusters were based on FLT3-ITD, NPM1, and CEBPA mutations as well as epigenetic modifiers (DNMT3A, IDH1/2, ASXL1), whereas the last cluster, representing 25% of patients, had no mutation and intermediate risk. One cluster isolated FLT3-ITD mutations with higher allelic ratio and a very poor outcome. The addition of GO had no impact in these molecular clusters. Although not conclusive for GO impact in AML patients <60 years, this study provides a molecular classification that distinguishes six AML clusters influencing prognosis in younger AML patients with intermediate-risk cytogenetic.

Conventional chemotherapy for acute myeloid leukemia in older adults: Impact on nutritional, cognitive, and functional status.

OBJECTIVES: The impact of conventional treatment for acute myeloid leukemia (AML) on the nutritional, cognitive, and functional status of elderly patients is seldom studied. This assessment was performed in the context of the LAMSA 2007 trial. METHODS: The trial enrolled 424 patients with de novo AML. Among them, 316 benefited from geriatric assessment (GA) including nutritional, cognitive, and functional status and were scored according to Eastern Cooperative Oncology Group (ECOG) and sorror for the prediction of treatment toxicity, morbidity, and mortality. Patients were investigated at diagnosis for three times during follow-up. RESULTS: This study showed that AML and its treatment have no impact on cognitive (P = .554) nor functional status (P = .842 for Activity of Daily Living and P = .087 for Instrumental Activities of Daily Living). The nutritional status improved over time (P = .041). None of these three parameters at baseline, associated or not with ECOG and sorror scores, impacted survivals or toxicities. CONCLUSIONS: The cognitive, functional, and nutritional status had no impact in this cohort of fit elderly AML patients without unfavorable cytogenetics. The GA tools used provided no additional information compared with ECOG and sorror scores, to predict toxicity, morbidity, or mortality due to intensive chemotherapy.

Good Profile of Efficacy/Tolerance of Bortezomib or Idelalisib in Waldenström Macroglobulinemia Associated with Acquired Von Willebrand Syndrome.

Acquired von Willebrand syndrome (AVWS) in the setting of Waldenström macroglobulinemia (WM) is a challenging condition. No real standard of care is recommended for these patients, although the therapeutic strategy should include a rapid approach to the emergency bleeding events and to the underlying malignant lymphoid disorder. We report here our experience treating three elderly patients with these concomitant hematologic entities. The use of a bortezomib-based chemotherapy regimen showed a good profile of tolerance and efficacy even in a long-term follow-up period. These patients were treated for several years before switching their therapy to idelalisib, a targeted oral therapy that inhibits phosphatidylinositol 3-kinase isoform-delta (PI3KD), which is part of the signaling pathway downstream B-cell receptor. This approach was well tolerated and efficacious, although some adverse effects were observed, particularly at hepatic levels, but were all reversible. The same profile of tolerance/efficacy was observed in one very old patient who received idelalisib as a first-line therapy. We think that bortezomib-based therapy could be considered in refractory patients with AVWS associated with WM.

Amotosalen-inactivated fresh frozen plasma is comparable to solvent-detergent inactivated plasma to treat thrombotic thrombocytopenic purpura.

BACKGROUND: Therapeutic Plasma Exchange (TPE) is the primary therapy of immune-mediated Thrombotic Thrombocytopenic Purpura (iTTP). Efficacy and safety data for TPE of iTTP have been assessed with Quarantine and Solvent-Detergent inactivated (SD) plasma. Here, amotosalen-UVA pathogen inactivated (AI) plasma, also in routine use, was evaluated in iTTP. METHODS: We conducted a retrospective review of iTTP cases prospectively reported to the French national registry (2010-2013). Cases reviewed underwent TPE with ≥70% of either AI or SD plasma. The primary endpoint was time to platelet count recovery; secondary endpoints were related to follow-up (sustained remission, relapses, flare-ups and refractoriness). RESULTS: 30 Test patients were identified in the AI group which could be timely matched to 40 Control patients in the SD group. The groups were fairly comparable for clinical presentation. Major findings were: (i) iTTP patients were exposed to lower plasma volumes in the AI group than in the SD group; (ii) Recovery rates were comparable between the groups. Median time to platelet count recovery (>150 × 109/L) trended to be shorter in the AI group though non significantly. Tolerance of AI vs SD plasma was of comparable frequency and severity in either group. CONCLUSION: TPE with Amotosalen-inactivated plasma demonstrated therapeutic efficacy and tolerability for iTTP patients. In view of the retrospective design, confirmation of these results is required in larger prospective studies.

Improved Survival by Adding Lomustine to Conventional Chemotherapy for Elderly Patients With AML Without Unfavorable Cytogenetics: Results of the LAM-SA 2007 FILO Trial.

PURPOSE: Acute myeloid leukemia (AML) in elderly patients has a poor prognosis. In an attempt to improve outcome for these patients, the prospective open-label phase III LAM-SA 2007 (Adding Lomustine to Chemotherapy in Older Patients With Acute Myelogenous Leukemia (AML), and Allogeneic Transplantation for Patients From 60 to 65 Years Old) trial randomly assigned patients to a standard induction regimen with lomustine added or to a consolidation regimen with cytarabine and idarubicin. PATIENTS AND METHODS: Adults age 60 years or older with previously untreated AML who were fit to receive intensive chemotherapy and who were without unfavorable cytogenetics received standard chemotherapy with lomustine (idarubicin, cytarabine, and lomustine [ICL]) or without (idarubicin and cytarabine [IC]). The primary objective of the study was overall survival (OS); secondary objectives were response rate, cumulative incidence of relapse (CIR), event-free survival (EFS), and safety. RESULTS: From February 2008 to December 2011, 459 patients were enrolled. Comparing patients in the IC and ICL arms, complete response or complete response with incomplete recovery was achieved in 74.9% versus 84.7% (P = .01). The proportional hazards assumption was rejected for OS (P = .02), which led us to consider two separate time intervals: during and after induction. There was no significant difference between the two arms during induction, although induction deaths were 3.7% versus 7.7%, respectively (P = .11). However, significantly better results were observed after induction with an improved 2-year OS of 56% in the ICL arm versus 48% in the IC arm (P = .02). At 2 years, EFS was improved at 41% in the ICL arm versus 26% in the IC arm (P = .01). The CIR at 2 years was 41.2% in the ICL arm versus 60.9% in the IC arm (P = .003). Grade 3 and 4 toxicities, mostly hematologic, were significantly higher in the ICL arm (P = .04), and fewer patients required a second treatment after ICL. CONCLUSION: Adding lomustine to standard chemotherapy significantly improved the outcome of elderly patients with AML.

Thrombotic thrombocytopenic purpura misdiagnosed as autoimmune cytopenia: Causes of diagnostic errors and consequence on outcome. Experience of the French thrombotic microangiopathies reference centre.

Thrombotic thrombocytopenic purpura (TTP) has a devastating prognosis without adapted management. Sources of misdiagnosis need to be identified to avoid delayed treatment. We studied 84 patients with a final diagnosis of severe (<10%) acquired ADAMTS13 deficiency-associated TTP from our National database that included 423 patients, who had an initial misdiagnosis (20% of all TTP). Main diagnostic errors were attributed to autoimmune thrombocytopenia, associated (51%) or not (37%) with autoimmune hemolytic anemia. At admission, misdiagnosed patients were more frequently females (P = .034) with a history of autoimmune disorder (P = .017) and had organ involvement in 67% of cases; they had more frequently antinuclear antibodies (P = .035), a low/undetectable schistocyte count (P = .001), a less profound anemia (P = .008), and a positive direct antiglobulin test (DAT) (P = .008). In multivariate analysis, female gender (P = .022), hemoglobin level (P = .028), a positive DAT (P = .004), and a low schistocytes count on diagnosis (P < .001) were retained as risk factors of misdiagnosis. Platelet count recovery was significantly longer in the misdiagnosed group (P = .041) without consequence on mortality, exacerbation and relapse. However, patients in the misdiagnosed group had a less severe disease than those in the accurately diagnosed group, as evidenced by less organ involvement at TTP diagnosis (P = .006). TTP is frequently misdiagnosed with autoimmune cytopenias. A low schistocyte count and a positive DAT should not systematically rule out TTP, especially when associated with organ failure.

Impact of body-surface area on patients' outcome in younger adults with acute myeloid leukemia.

OBJECTIVES: Anthracyclines and cytarabine are cornerstones for intensive chemotherapy in acute myeloid leukemia (AML). The goals of this study were to comprehensively assess deviations from theoretical doses and the impact of body-surface area (BSA) on patients' characteristics, physicians' strategy, dose adjustment, and clinical outcome. METHODS: The GOELAMS 2001 phase III trial included 823 AML patients below 60 years of age. In the course of treatment, anthropomorphic parameters and chemotherapy doses were prospectively registered. RESULTS: Very high BSA (≥2.15 m2 ) was the factor most significantly associated with the physician's decision to reduce chemotherapy doses during induction and postremission therapy. Despite similar AML characteristics and therapeutic strategies, the very high BSA group exhibited a significantly worse survival (5-years OS of 27%) compared to the low (BSA≤1.5 m2 ), intermediate (1.5 m2

Assessment of sites of marrow and extramedullary hematopoiesis by hybrid imaging in primary myelofibrosis patients.

We investigated noninvasive procedures by hybrid imaging to assess the sites of active or inactive hematopoiesis in patients with primary myelofibrosis (PMF). To this end, we used two radionuclides, technetium 99m ((99m) Tc) and indium 111-chloride ((111) In-Cl3 ), coupled with single-photon emission tomography/computed tomography (SPECT/CT). We studied five patients with PMF and one with secondary myelofibrosis (MF). The classical pattern of lower fixation of both tracers at the axial skeleton where the myelofibrotic process occurs and the reactivation of sites of active hematopoiesis at the distal skeleton were confirmed. Coupling both radionuclides to SPECT/CT imaging allowed for more precise visualization of the sites of extramedullary hematopoiesis as those observed in the spleen and liver. Splenic high uptake of (111) In-Cl3 coupled with SPECT/CT represents a pathognomonic feature of PMF. We conclude that, the hybrid imaging procedures that we studied might constitute an alternative noninvasive method for the screening of the whole-body marrow and, by this way, to assess the impact of targeted therapies in PMF patients in whom it is well known that the distribution of the hematopoietic active areas is disturbed. Hybrid imaging could also be useful for diagnostic purposes in cases of early PMF or in suspected cases of myelofibrosis secondary to polycythemia vera or essential thrombocythemia.

Rituximab and dose-dense chemotherapy for adults with Burkitt's lymphoma: a randomised, controlled, open-label, phase 3 trial.

BACKGROUND: Short intensive chemotherapy is the standard of care for adult patients with Burkitt's leukaemia or lymphoma. Findings from single-arm studies suggest that addition of rituximab to these regimens could improve patient outcomes. Our objective was to test this possibility in a randomised trial. METHODS: In this randomised, controlled, open-label, phase 3 trial, we recruited patients older than 18 years with untreated HIV-negative Burkitt's lymphoma (including Burkitt's leukaemia) from 45 haematological centres in France. Exclusion criteria were contraindications to any drug included in the chemotherapy regimens, any serious comorbidity, poor renal (creatinine concentration >150 µmol/L) or hepatic (cirrhosis or previous hepatitis B or C) function, pregnancy, and any history of cancer except for non-melanoma skin tumours or stage 0 (in situ) cervical carcinoma. Patients were stratified into two groups based on disease extension (absence [group B] or presence [group C] of bone marrow or central nervous system involvement). Patients were further stratified in group C according to age (<40 years, 40-60 years, and >60 years) and central nervous system involvement. Participants were randomly assigned in each group to either intravenous rituximab injections and chemotherapy (lymphome malin B [LMB]) or chemotherapy alone by the Groupe d'Etude des Lymphomes de l'Adulte datacentre. Randomisation was stratified by treatment group and centre using computer-assisted permuted-block randomisation (block size of four; allocation ratio 1:1). We gave rituximab (375 mg/m(2)) on day 1 and day 6 during the first two courses of chemotherapy (total of four infusions). The primary endpoint is 3 year event-free survival (EFS). We analysed all patients who had data available according to their originally assigned group. This trial is registered with ClinicalTrials.gov, number NCT00180882. RESULTS: Between Oct 14, 2004, and Sept 7, 2010, we randomly allocated 260 patients to rituximab or no rituximab (group B 124 patients [64 no rituximab; 60 rituximab]; group C 136 patients [66 no rituximab; 70 rituximab]). With a median follow-up of 38 months (IQR 24-59), patients in the rituximab group achieved better 3 year EFS (75% [95% CI 66-82]) than did those in the no rituximab group (62% [53-70]; log-rank p stratified by treatment group=0·024). The hazard ratio estimated with a Cox model stratified by treatment group, assuming proportionality, was 0·59 for EFS (95% CI 0·38-0·94; p=0·025). Adverse events did not differ between the two treatment groups. The most common adverse events were infectious (grade 3-4 in 137 [17%] treatment cycles in the rituximab group vs 115 [15%] in the no rituximab group) and haematological (mean duration of grade 4 neutropenia of 3·31 days per cycle [95% CI 3·01-3·61] vs 3·38 days per cycle [3·05-3·70]) events. INTERPRETATION: Addition of rituximab to a short intensive chemotherapy programme improves EFS in adults with Burkitt's leukaemia or lymphoma. FUNDING: Gustave Roussy Cancer Campus, Roche, Chugai, Sanofi.

Secondary thrombotic microangiopathy in two patients with Philadelphia-positive hematological malignancies treated with imatinib mesylate.

Drug-mediated thrombotic microangiopathy may cause life-threatening medical emergencies. Novel targeted therapies have dramatically changed the prognosis of a number of oncological diseases. Tyrosine kinase inhibitors of the Breakpoint Cluster Region-Abelson (BCR-ABL) oncoprotein are used in patients with chronic myeloid leukemia or Philadelphia chromosome-positive acute lymphoblastic leukemia. Imatinib mesylate, which was the first anti-BCR-ABL tyrosine kinase inhibitor, has demonstrated a high tolerance profile and efficacy in these patients for many years. Good results have also been observed in patients with gastrointestinal stromal tumors. In this study, we describe two patients with Philadelphia chromosome-positive hematological malignancies who presented with secondary thrombotic microangiopathy that was most likely linked to the use of imatinib. Other potential causes of thrombotic microangiopathy were discarded, and the predisposing role of some comorbidities and potential short or long-term drug-drug interactions was assessed. The clinical and biological data were more indicative of atypical secondary hemolytic uremic syndrome in one of the cases and of secondary thrombotic microangiopathy with renal and cardiac impairment in the other, which is also categorized as secondary hemolytic uremic syndrome. The outcome was favorable after imatinib discontinuation and the treatment of severe cardiac and renal failures.

Z-BeEAM (Ibritumomab tiuxetan, Bendamustine, Etoposide, Cytarabine, Melphalan) before autologous stem cell transplantation is safe and efficient for refractory large B-cell lymphoma.

BACKGROUND: Refractory or relapsed large B-cells lymphoma are usually treated with a high dose chemotherapy regimen followed by an autolougous stem cells transplantation. BEAM (carmustine, etoposide, cytarabine, melphalan) or more recently Z-BEAM (ibritumomab tiuxetan and BEAM) are commonly used regimens, but recently carmustine availability became difficult. The purpose of this study was to evaluate the feasibility and the safety of replacing carmustine by bendamustine in a new Z-BeEAM regimen (ibritumomab tiuxetan, bendamustine, etoposide, cytarabine, melphalan) prior to autologous stem cell transplantation. FINDINGS: This study was a retrospective analyze of six patients, with a median age of 60, treated by Z-BeEAM before autologous stem cell transplantation. We did not put in evidence any additional toxicities compared to conventional induction chemotherapy. The main toxicities were mucositis (3 grade III among 6 patients), gastrointestinal (2 grade III vomiting and 2 grade III diarrhea) and neutropenia (6 grade IV). Engraftment was successfully achieved for all patients. At the time of analysis of this study all patients were alive and in complete response based on the PET-CT evaluation. CONCLUSIONS: BeEAM plus ibritumomab tiuxetan combined regimen before autologous stem cell transplantation is feasible and safe in aggressive relapsing large B-cell lymphoma.

A Phase 2 study of L-asparaginase encapsulated in erythrocytes in elderly patients with Philadelphia chromosome negative acute lymphoblastic leukemia: The GRASPALL/GRAALL-SA2-2008 study.

PURPOSE: The GRASPALL/GRAALL-SA2-2008 Phase II trial evaluated the safety and efficacy of L-asparaginase encapsulated within erythrocytes (GRASPA®) in patients ≥ 55 years with Philadelphia chromosome-negative acute lymphoblastic leukemia. FINDINGS: Thirty patients received escalating doses of GRASPA® on Day 3 and 6 of induction Phases 1 and 2. The primary efficacy endpoint was asparagine depletion < 2 µmol/L for at least 7 days. This was reached in 85 and 71% of patients with 100 and 150 IU/kg respectively but not with 50 IU/kg. Grade 3/4 infection, hypertransaminasemia, hyperbilirubinemia and deep vein thrombosis occurred in 77, 20, 7, and 7% of patients, respectively. No allergic reaction or clinical pancreatitis was observed despite 17% of Grade 3/4 lipase elevation. Anti-asparaginase antibodies were detected in 50% of patients and related to a reduction in the duration of asparagine depletion during induction Phase 2 without decrease of encapsulated L-asparaginase activity. Complete remission rate was 70%. With a median follow-up of 42 months, median overall survival was 15.8 and 9.7 months, in the 100 and 150 IU/kg cohorts respectively. CONCLUSIONS: The addition of GRASPA®, especially at the 100 IU/kg dose level, is feasible in elderly patients without excessive toxicity and associated with durable asparagine depletion. (clinicaltrials.gov identifier NCT01523782).

High prevalence of infectious events in thrombotic thrombocytopenic purpura and genetic relationship with toll-like receptor 9 polymorphisms: experience of the French Thrombotic Microangiopathies Reference Center.

BACKGROUND: Infectious events have been reported as major environmental triggers of thrombotic thrombocytopenic purpura (TTP). We detail here the potential association between infections and TTP. STUDY DESIGN AND METHODS: We recruited randomly and prospectively a cohort of 280 consecutive TTP patients during a 9-year period. Features of infection were systematically recorded. RESULTS: Features consistent with an infectious event were observed in 114 patients (41%) at time of TTP diagnosis. Infectious agents were documented in 34 cases and were mainly Gram-negative bacilli. At time of diagnosis infected patients more frequently had fever (p < 0.001). Infections at diagnosis did not impact prognosis and outcome. Thirty-six percent of patients experienced an infectious event during hospitalization, which resulted in more exacerbation of TTP (p = 0.02). Infections were not overrepresented during treatment in patients who received steroids and/or rituximab. Further genetic analysis of toll-like receptor (TLR)-9 functionally relevant polymorphisms revealed that TLR-9 +2848 G and TLR-9 +1174 A genotypes were more frequent in TTP patients than in controls (p = 0.04 and p = 0.026, respectively) and more particularly in patients negative for the Class II human leukocyte antigen system susceptibility allele DRB1*11 (p = 0.001 and p = 0.002, respectively). Haplotypes estimation showed that 1174A-2848G haplotype was significantly more frequent in TTP (p = 0.004), suggesting a primary role for this haplotype variation in conferring a predisposition for acquired TTP. CONCLUSION: Infections should be considered as an aggravating factor during the course of TTP. Particular polymorphisms in TLR-9 gene may represent risk factors for TTP.