RESUMO
We conducted a retrospective study on hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC) in 96 adults enrolled in the cohort of the National Reference Center for Thrombotic Microangiopathies network in France during 2009-2017. Most infections were caused by STEC strains not belonging to the O157 or O104 serogroups. Thirty (31.3%) patients had multiple risk factors for thrombotic microangiopathy. In total, 61 (63.5%) patients required dialysis, 50 (52.1%) had a serious neurologic complication, 34 (35.4%) required mechanical ventilation, and 19 (19.8%) died during hospitalization. We used multivariate analysis to determine that the greatest risk factors for death were underlying immunodeficiency (hazard ratio 3.54) and severe neurologic events (hazard ratio 3.40). According to multivariate analysis and propensity score-matching, eculizumab treatment was not associated with survival. We found that underlying conditions, especially immunodeficiency, are strongly associated with decreased survival in adults who have hemolytic uremic syndrome caused by STEC.
Assuntos
Infecções por Escherichia coli , Síndrome Hemolítico-Urêmica , Escherichia coli Shiga Toxigênica , Adulto , França , Humanos , Estudos Retrospectivos , Toxina ShigaRESUMO
The anti-von Willebrand factor nanobody caplacizumab was licensed for adults with immune-mediated thrombotic thrombocytopenic purpura (iTTP) based on prospective controlled trials. However, few data are available on postmarketing surveillance. We treated 90 iTTP patients with a compassionate frontline triplet regimen associating therapeutic plasma exchange (TPE), immunosuppression with corticosteroids and rituximab, and caplacizumab. Outcomes were compared with 180 historical patients treated with the standard frontline treatment (TPE and corticosteroids, with rituximab as salvage therapy). The primary outcome was a composite of refractoriness and death within 30 days since diagnosis. Key secondary outcomes were exacerbations, time to platelet count recovery, the number of TPE, and the volume of plasma required to achieve durable remission. The percentage of patients in the triplet regimen with the composite primary outcome was 2.2% vs 12.2% in historical patients (P = .01). One elderly patient in the triplet regimen died of pulmonary embolism. Patients from this cohort experienced less exacerbations (3.4% vs 44%, P < .01); they recovered durable platelet count 1.8 times faster than historical patients (95% confidence interval, 1.41-2.36; P < .01), with fewer TPE sessions and lower plasma volumes (P < .01 both). The number of days in hospital was 41% lower in the triplet regimen than in the historical cohort (13 vs 22 days; P < .01). Caplacizumab-related adverse events occurred in 46 patients (51%), including 13 major or clinically relevant nonmajor hemorrhagic events. Associating caplacizumab to TPE and immunosuppression, by addressing the 3 processes of iTTP pathophysiology, prevents unfavorable outcomes and alleviates the burden of care.
Assuntos
Corticosteroides/uso terapêutico , Troca Plasmática , Púrpura Trombocitopênica Trombótica/terapia , Rituximab/uso terapêutico , Anticorpos de Domínio Único/uso terapêutico , Proteína ADAMTS13/sangue , Adulto , Terapia Combinada , Ensaios de Uso Compassivo , Progressão da Doença , Quimioterapia Combinada , Feminino , Hemorragia/induzido quimicamente , Estudo Historicamente Controlado , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Estudos Prospectivos , Púrpura Trombocitopênica Trombótica/sangue , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Púrpura Trombocitopênica Trombótica/mortalidade , Índice de Gravidade de Doença , Anticorpos de Domínio Único/efeitos adversos , Anticorpos de Domínio Único/economia , Tromboembolia/etiologia , Resultado do Tratamento , Fator de von Willebrand/antagonistas & inibidoresRESUMO
Historically, double or triple hit lymphoma (DHL and THL) have poor outcomes with conventional chemotherapy, but there is currently no guideline. We report the French experience in managing DHL and THL in first line using collective data on both survival and tolerance. All consecutive patients with newly diagnosis of large B-cell lymphoma with MYC, BCL2, and/or BCL6 rearrangements, as determined by FISH between January 2013 and April 2019 were included. Based on the eligibility criteria, 160 patients were selected among the 184 patients identified. With a median follow-up of 32 months, 2- and 4-year progression free survival (PFS) rates were 40% and 28% with R-CHOP compared with 57% and 52% with intensive chemotherapy (P = .063). There was no difference in overall survival (OS). For advanced stages, PFS was significantly longer with intensive chemotherapy than with R-CHOP (P = .029). There was no impact of autologous stem cell transplantation among patient in remission. For patients with central nervous system (CNS) involvement, the 2-year PFS and OS rate was 21% and 39%, vs 57% and 75% without CNS disease (P = .007 and P < .001). By multivariate analysis, elevated IPI score and CNS disease were strongly and independently associated with a poorer survival, whereas treatment was not significantly associated with OS. This is the largest series reporting the treatment of DHL and THL in Europe. The PFS was significantly longer with an intensive regimen for advanced stage, but no difference in OS, supporting the need for a prospective randomized trial.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Sistema Nervoso Central/patologia , Terapia Combinada , Avaliação de Medicamentos , Feminino , Seguimentos , França/epidemiologia , Gastroenteropatias/induzido quimicamente , Genes bcl-2 , Genes myc , Doenças Hematológicas/induzido quimicamente , Transplante de Células-Tronco Hematopoéticas , Humanos , Hibridização in Situ Fluorescente , Estimativa de Kaplan-Meier , Linfoma Difuso de Grandes Células B/genética , Masculino , Pessoa de Meia-Idade , Intervalo Livre de Progressão , Proteínas Proto-Oncogênicas c-bcl-6/genética , Indução de Remissão , Estudos Retrospectivos , Terapia de Salvação , Condicionamento Pré-Transplante , Transplante AutólogoAssuntos
Fatores Imunológicos/uso terapêutico , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Rituximab/uso terapêutico , Proteína ADAMTS13/imunologia , Adulto , Feminino , Humanos , Fatores Imunológicos/administração & dosagem , Masculino , Pessoa de Meia-Idade , Púrpura Trombocitopênica Trombótica/imunologia , Rituximab/administração & dosagem , Resultado do Tratamento , Adulto JovemRESUMO
Following an acute thrombotic thrombocytopenic purpura (TTP) episode, patients are at risk for relapse, and a careful long-term follow-up is needed. Adherence to the follow-up by patients implies a good understanding of the disease. However, TTP literacy in patients is currently unknown. To explore the TTP literacy in patients and identify factors associated with poor disease understanding, a questionnaire was developed focusing on patient's characteristics, knowledge about TTP and patients' actions in an emergency. The questionnaire was presented to 120 TTP patients in remission from the French National Registry for Thrombotic Microangiopathies. TTP literacy was low in 24%, intermediate in 43% and high in 33% of the patients. Low TTP literacy was associated with older age and low education level. Among the knowledge gaps identified, few patients knew that plasma exchange in acute phase is mandatory and has to be done daily (39%), 47% of participants did not consider themselves at risk for relapse, and 30% of women did not know that pregnancy exposes them to a greater risk of relapse. Importantly, few patients responded about life-saving actions in an emergency. Hence, the design of educational material should pay special attention to the age and education level of the target population focusing on the events leading to TTP, the importance of the emergency treatment, controllable predisposing factors for TTP development and patient attitude in an emergency.
RESUMO
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.
Assuntos
Detergentes/farmacologia , Furocumarinas/farmacologia , Plasma/metabolismo , Púrpura Trombocitopênica Trombótica/terapia , Adulto , Estudos de Coortes , Feminino , Furocumarinas/efeitos adversos , Humanos , Masculino , Troca Plasmática , Solventes , Resultado do TratamentoRESUMO
Plasmablastic lymphoma is a rare and aggressive diffuse large B-cell lymphoma commonly associated with Epstein-Barr virus co-infection that most often occurs in the context of human immunodeficiency virus infection. Therefore, its immune escape strategy may involve the upregulation of immune-checkpoint proteins allowing the tumor immune evasion. However, the expression of these molecules was poorly studied in this lymphoma. We have investigated 82 plasmablastic lymphoma cases of whom half were Epstein-Barr virus positive. Although they harbored similar pathological features, Epstein-Barr virus positive plasmablastic lymphomas showed a significant increase in MYC gene rearrangement and had a better 2-year event-free survival than Epstein-Barr virus negative cases (P=0.049). Immunostains for programmed cell death-1, programmed cell death-ligand 1, indole 2,3-dioxygenase and dendritic cell specific C-type lectin showed a high or moderate expression by the microenvironment cells in 60%-72% of cases, whereas CD163 was expressed in almost all cases. Tumor cells also expressed programmed cell death-1 and its ligand in 22.5% and 5% of cases, respectively. Both Epstein-Barr virus positive and negative plasmablastic lymphomas exhibited a high immune-checkpoint score showing that it involves several pathways of immune escape. However, Epstein-Barr virus positive lymphomas exhibited a higher expression of programmed cell death-1 and its ligand in both malignant cells and microenvironment as compared to Epstein-Barr virus negative cases. In conclusion, plasmablastic lymphoma expresses immune-checkpoint proteins through both malignant cells and the tumor microenvironment. The expression of programmed cell death-1 and its ligand constitutes a strong rationale for testing monoclonal antibodies in this often chemoresistant disease.
Assuntos
Biomarcadores Tumorais , Infecções por Vírus Epstein-Barr/complicações , Expressão Gênica , Herpesvirus Humano 4/genética , Imunomodulação/genética , Linfoma Plasmablástico/diagnóstico , Linfoma Plasmablástico/etiologia , Adulto , Idoso , Biópsia , Terapia Combinada , Feminino , Estudos de Associação Genética , Humanos , Imuno-Histoquímica , Imunofenotipagem , Hibridização in Situ Fluorescente , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Fenótipo , Linfoma Plasmablástico/mortalidade , Linfoma Plasmablástico/terapia , Prognóstico , Translocação Genética , Resultado do TratamentoRESUMO
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.
Assuntos
Infecções/complicações , Púrpura Trombocitopênica Trombótica/genética , Receptor Toll-Like 9/genética , Adulto , Feminino , França/epidemiologia , Predisposição Genética para Doença , Haplótipos , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Prevalência , Estudos Prospectivos , Púrpura Trombocitopênica Trombótica/etiologia , Sistema de Registros , Fatores de Risco , Microangiopatias Trombóticas/epidemiologia , Microangiopatias Trombóticas/genéticaRESUMO
BACKGROUND: Acquired thrombotic thrombocytopenic purpura is still associated with a 10-20% death rate. It has still not been possible to clearly identify early prognostic factors of death. This study involved thrombotic thrombocytopenic purpura patients with acquired severe (<10% of normal activity) ADAMTS13 deficiency and aimed to identify prognostic factors associated with 30-day death. DESIGN AND METHODS: The study involved a prospective cohort of patients and was carried out between October 2000 and August 2010. A validation cohort of patients was set up from September 2010 to August 2011. Altogether, 281 (analysis cohort) and 66 (validation cohort) consecutive adult thrombotic thrombocytopenic purpura patients with acquired severe ADAMTS13 deficiency were enrolled. The study evaluated 30-day mortality after treatment initiation according to characteristics at inclusion. RESULTS: Non-survivors (11%) were older (P=10(-6)) and more frequently presented arterial hypertension (P=5.10(-4)) and ischemic heart disease (P=0.013). Prognosis was increasingly poor with age (P=0.004). On presentation, cerebral manifestations were more frequent in non-survivors (P=0.018) and serum creatinine level was higher (P=0.008). The most significant independent variables determining death were age, severe cerebral involvement and LDH level 10 N or over. A 3-level risk score for early death was defined and confirmed in the validation cohort using these variables, with higher values corresponding to increased risk of early death. CONCLUSIONS: A risk score for early death was defined in patients with thrombotic thrombocytopenic purpura and validated on an independent cohort. This score should help to stratify early treatment and identify patients with a worse prognosis.
Assuntos
Proteínas ADAM/deficiência , Modelos Estatísticos , Púrpura Trombocitopênica Idiopática/mortalidade , Proteína ADAMTS13 , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Púrpura Trombocitopênica Idiopática/etiologia , Curva ROC , Sistema de Registros , Reprodutibilidade dos TestesRESUMO
BACKGROUND: The objective was to assess the efficacy and safety of splenectomy and cyclophosphamide as salvage therapies in severe thrombotic thrombocytopenic purpura (TTP). STUDY DESIGN AND METHODS: During a 10-year period, patients who did not improve with plasma exchanges, steroids, vincristine, and/or rituximab were considered for splenectomy or cyclophosphamide. Patients with a documented severe (<10% of normal value) acquired ADAMTS13 deficiency are reported here. RESULTS: Eighteen patients with a severe acquired ADAMTS13 deficiency required a salvage therapy. Thirteen patients had a splenectomy 19 (interquartile range [IQR], 10-51) days after TTP diagnosis. One patient died the day after splenectomy. The remaining patients improved platelets (PLTs) until Day 6, along with a rapid and major lactate dehydrogenase improvement. Six patients, however, subsequently experienced a transient worsening. Durable PLT count recovery in survivors was observed within 13 (IQR, 11.5-25.5) days. Postoperative complications included thromboembolic events (two cases) and infections (five cases). Five patients received pulses of cyclophosphamide 12 (IQR, 12-15) days after TTP diagnosis. All patients recovered PLTs 10 (IQR, 9-24) days after the first pulse and two experienced a transient worsening. Three patients experienced infections. Three relapses occurred 5 months, 2.5 years, and 4.5 years after splenectomy and one relapse occurred 3.5 years after cyclophosphamide. After a 2.5 (IQR, 0.75-6.2)-year follow-up, the overall survival was 94%. CONCLUSION: Cyclophosphamide and splenectomy provide comparable high remission rates in severe TTP with acceptable side effects and should be considered in the more severe patients who do not improve with other therapies.
Assuntos
Ciclofosfamida/administração & dosagem , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Púrpura Trombocitopênica Trombótica/mortalidade , Terapia de Salvação/métodos , Esplenectomia/métodos , Adulto , Ciclofosfamida/efeitos adversos , Feminino , Seguimentos , França/epidemiologia , Humanos , Masculino , Agonistas Mieloablativos/administração & dosagem , Agonistas Mieloablativos/efeitos adversos , Pulsoterapia , Sistema de Registros/estatística & dados numéricos , Indução de Remissão , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
OBJECTIVE: To assess the efficacy and safety of rituximab in adults responding poorly to standard treatment for severe autoimmune thrombotic thrombocytopenic purpura. DESIGN: Open-label prospective study. Outcomes in the survivors were compared to those of 53 historical survivors who were given therapeutic plasma exchange alone or with vincristine. SETTING: Hospitals belonging to the Reference Network for Thrombotic Microangiopathies in France. PATIENTS: Twenty-two adults with either no response or a disease exacerbation when treated with intensive therapeutic plasma exchange. INTERVENTION: Add-on rituximab therapy, four infusions over 15 days. MEASUREMENTS AND MAIN RESULTS: One patient died despite two rituximab infusions. In the rituximab-treated patients, the time to a durable remission was significantly shortened (p = .03), although the plasma volume required to achieve a durable remission was not significantly different compared to the controls. Platelet count recovery occurred within 35 days in all 21 survivors, compared to only 78% of the historical controls (p < .02). Of the rituximab-treated patients, none had a relapse within the first year but three relapsed later on. In patients treated with rituximab, a rapid and profound peripheral B-cell depletion was produced, lasting for 9 months and correlating with higher a disintegrin and metalloproteinase with thrombospondin-13 activity and lower anti-a disintegrin and metalloproteinase with thrombospondin-13 antibody titers. These differences were no longer significant after 12 months. No severe side effects occurred. CONCLUSIONS: Adults with severe thrombocytopenic purpura who responded poorly to therapeutic plasma exchange and who were treated with rituximab had shorter overall treatment duration and reduced 1-yr relapses than historical controls.
Assuntos
Anticorpos Monoclonais Murinos/uso terapêutico , Fatores Imunológicos/uso terapêutico , Troca Plasmática , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Adulto , Feminino , Humanos , Masculino , Rituximab , Terapia de Salvação , Falha de Tratamento , Resultado do TratamentoRESUMO
Severe ADAMTS13 deficiency occurs in 13% to 75% of thrombotic microangiopathies (TMA). In this context, the early identification of a severe, antibody-mediated, ADAMTS13 deficiency may allow to start targeted therapies such as B-lymphocytes-depleting monoclonal antibodies. To date, assays exploring ADAMTS13 activity require skill and are limited to only some specialized reference laboratories, given the very low incidence of the disease. To identify clinical features which may allow to predict rapidly an acquired ADAMTS13 deficiency, we performed a cross-sectional analysis of our national registry from 2000 to 2007. The clinical presentation of 160 patients with TMA and acquired ADAMTS13 deficiency was compared with that of 54 patients with detectable ADAMTS13 activity. ADAMTS13 deficiency was associated with more relapses during treatment and with a good renal prognosis. Patients with acquired ADAMTS13 deficiency had platelet count < 30 x 10(9)/L (adjusted odds ratio [OR] 9.1, 95% confidence interval [CI] 3.4-24.2, P<.001), serum creatinine level < or =200 micromol/L (OR 23.4, 95% CI 8.8-62.5, P<.001), and detectable antinuclear antibodies (OR 2.8, 95% CI 1.0-8.0, P<.05). When at least 1 criteria was met, patients with a severe acquired ADAMTS13 deficiency were identified with positive predictive value of 85%, negative predictive value of 93.3%, sensitivity of 98.8%, and specificity of 48.1%. Our criteria should be useful to identify rapidly newly diagnosed patients with an acquired ADAMTS13 deficiency to better tailor treatment for different pathophysiological groups.
Assuntos
Proteínas ADAM/deficiência , Valor Preditivo dos Testes , Microangiopatias Trombóticas/diagnóstico , Proteínas ADAM/imunologia , Proteína ADAMTS13 , Adulto , Idoso , Anticorpos , Anticorpos Antinucleares/sangue , Creatinina/sangue , Estudos Transversais , Feminino , França , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Sistema de Registros , Microangiopatias Trombóticas/complicações , Microangiopatias Trombóticas/epidemiologia , Adulto JovemRESUMO
OBJECTIVE: To specify the clinical and biological characteristics of thrombotic microangiopathies (TMAs) associated with a recent diagnosis of cancer. PATIENTS AND Methods. Multicenter study involving 14 national centers. Cross-sectional analysis of 20 patients with cancer-associated TMAs included in our national registry from October 2000 to July 2007. Patients were also compared with 134 adult patients with an acquired idiopathic TMA by univariate analysis. RESULTS: Patients with a cancer-associated TMA typically displayed severe weight loss, dyspnea, bone pain, as well as disseminated intravascular coagulopathy and massive erythromyelemia (75%, 55%, 50%, 41%, and 85% of cases, respectively). By contrast, these features were observed with a much lower incidence in patients with an idiopathic TMA (8.9%, 19.7%, 0.8%, 7.1%, and 17.5%, respectively). Moreover, median platelet count was higher (48 x 10(9)/l; range, 21-73 x 10(9)/l versus 19 x 10(9)/l; range, 10-38 x 10(9)/l, respectively) and median serum creatinine level was lower (74 microM [range, 68-102] versus 113 microM [range, 80-225], respectively). The activity of the specific von Willebrand factor-cleaving proteinase ADAMTS13 was detectable in 14/17 studied patients. Platelet count improvement was observed in only seven patients and paralleled the response to chemotherapy. Prognosis of patients with cancer-associated TMAs was very poor, with a 30-day and 2-year mortality rate of 50% and 95%, respectively. CONCLUSION: Cancer-associated TMAs display specific features at onset that should prompt investigation of an underlying disseminated malignancy. In this context, chemotherapy rather than plasma is mandatory since TMA prognosis parallels that of cancer.
Assuntos
Neoplasias/complicações , Microangiopatias Trombóticas/complicações , Proteínas ADAM/sangue , Proteína ADAMTS13 , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/sangue , Estudos Prospectivos , Microangiopatias Trombóticas/sangue , Microangiopatias Trombóticas/enzimologia , Resultado do Tratamento , Fator de von Willebrand/metabolismoRESUMO
The significance of ADAMTS13 deficiency in adult thrombotic microangiopathy (TMA) remains controversial. In an attempt to define the characteristics of adult TMA with severe ADAMTS13 deficiency, we determined 2 groups of patients on the basis of ADAMTS13 activity (undetectable or detectable). Clinical presentation, laboratory values, autoimmune manifestations, and outcome were compared between the groups. Patients were included retrospectively from 12 centers. All fulfilled the diagnosis criteria of TMA. Patients with a history of transplantation, cancer and chemotherapy, and Centers for Disease Control and Prevention (CDC) stage C human immunodeficiency virus (HIV) infection were not included. Forty-six patients were included. Thirty-one patients had an undetectable ADAMTS13 activity (<5%), and the remaining 15 patients had ADAMTS13 activity of >25%. Severe ADAMTS13 deficiency was associated with a plasmatic inhibitor in 17 cases (55%), suggesting an immune-mediated mechanism. Patients with undetectable ADAMTS13 were more frequently of Afro-Caribbean origin than patients with detectable ADAMTS13 activity (48.4% vs 13.3%, respectively; p = 0.03). As opposed to patients with detectable ADAMTS13 activity, patients with severe ADAMTS13 deficiency displayed various autoimmune manifestations that consisted of nondestructive polyarthritis (4 cases) associated in 1 case with malar rash and extramembranous glomerulonephritis, discoid lupus (3 cases), and autoimmune endocrinopathies, Raynaud phenomenon, and sarcoidosis-like disease (1 case each). In patients with severe ADAMTS13 deficiency, antinuclear antibodies, anti-double-stranded DNA antibodies, and anticardiolipin antibodies were positive in 22 (71%) cases, 3 (9.7%) cases, and 1 (3.2%) case, respectively. One patient fulfilled the criteria for the diagnosis of systemic lupus erythematosus. During follow-up, 1 patient with severe ADAMTS13 deficiency developed antinuclear antibodies, and 3 others developed anti-double-stranded DNA antibodies, in association with neurologic manifestations and anticardiolipin antibodies in 1 case. Patients with severe ADAMTS13 deficiency also had a lower platelet count (12 x 10(9)/L; range, 2-69 x 10(9)/L) and less severe renal failure (estimated glomerular filtration rate: 78 mL/min; range, 9-157 mL/min) than patients with detectable ADAMTS13 activity (49.5 x 10(9)/L; range, 6-103 x 10(9)/L; p = 0.0004, and 15.8 mL/min; range, 5.6-80 mL/min; p < 0.0001, respectively). End-stage renal failure occurred in 1 patient with severe ADAMTS13 deficiency and in 3 patients with detectable ADAMTS13 activity (3.2% vs 21.4%, respectively; p = 0.08). Flare-up and relapse episodes and survival were comparable between the groups. Taken together, these data indicate that adult idiopathic thrombotic thrombocytopenic purpura, as defined by severe ADAMTS13 deficiency, may occur preferentially in a particular ethnic group, and is characterized by severe thrombocytopenia, mild renal involvement, and a wide spectrum of autoimmune manifestations that may be completed during follow-up. Indeed, apparently idiopathic thrombotic thrombocytopenic purpura may be considered a specific autoimmune disease.