Peripheral blood marker of residual acute leukemia after hematopoietic cell transplantation using multi-plex digital droplet PCR.

Background: Relapse remains the primary cause of death after hematopoietic cell transplantation (HCT) for acute leukemia. The ability to identify minimal/measurable residual disease (MRD) via the blood could identify patients earlier when immunologic interventions may be more successful. We evaluated a new test that could quantify blood tumor mRNA as leukemia MRD surveillance using droplet digital PCR (ddPCR). Methods: The multiplex ddPCR assay was developed using tumor cell lines positive for the tumor associated antigens (TAA: WT1, PRAME, BIRC5), with homeostatic ABL1. On IRB-approved protocols, RNA was isolated from mononuclear cells from acute leukemia patients after HCT (n = 31 subjects; n = 91 specimens) and healthy donors (n = 20). ddPCR simultaneously quantitated mRNA expression of WT1, PRAME, BIRC5, and ABL1 and the TAA/ABL1 blood ratio was measured in patients with and without active leukemia after HCT. Results: Tumor cell lines confirmed quantitation of TAAs. In patients with active acute leukemia after HCT (MRD+ or relapse; n=19), the blood levels of WT1/ABL1, PRAME/ABL1, and BIRC5/ABL1 exceeded healthy donors (p<0.0001, p=0.0286, and p=0.0064 respectively). Active disease status was associated with TAA positivity (1+ TAA vs 0 TAA) with an odds ratio=10.67, (p=0.0070, 95% confidence interval 1.91 - 59.62). The area under the curve is 0.7544. Changes in ddPCR correlated with disease response captured on standard of care tests, accurately denoting positive or negative disease burden in 15/16 (95%). Of patients with MRD+ or relapsed leukemia after HCT, 84% were positive for at least one TAA/ABL1 in the peripheral blood. In summary, we have developed a new method for blood MRD monitoring of leukemia after HCT and present preliminary data that the TAA/ABL1 ratio may may serve as a novel surrogate biomarker for relapse of acute leukemia after HCT.

Dynamics of microvesicle generation in B-cell chronic lymphocytic leukemia: implication in disease progression.

Previously, we reported that B-cell chronic lymphocytic leukemia (CLL) patients contained elevated levels of microvesicles (MVs). However, given the quiescent nature of CLL B-cells and the relative indolence of the disease, the dynamics of MV generation and their unique phenotypes are not clearly defined. In this study, we find that CLL B-cells generate MVs spontaneously and can be further induced by B-cell receptor-ligation. Most interestingly, CLL B-cells predominantly generate CD52+ MVs, but not CD19+ MVs in vitro, suggesting preferential usage of CD52 into leukemic-MVs and that the CLL plasma MV phenotypes corroborate well with the in vitro findings. Importantly, we detected increased accumulation of CD52+ MVs in previously untreated CLL patients with progressive disease. Finally, sequential studies on MVs in pre- and post-therapy CLL patients demonstrate that although the plasma CD52+ MV levels drop significantly after therapy in most and remain at low levels in some patients, a trend of increased accumulation of CD52+ MVs was detected in majority of post-therapy CLL patients (25 of 33). In total, this study emphasizes that dynamic accumulation of CD52+ MVs in plasma can be used to study CLL progression and may be a useful biomarker for patients as they progress and require therapy.

Life after acquired thrombotic thrombocytopenic purpura: morbidity, mortality, and risks during pregnancy.

Patients who have recovered from their acute episode of acquired ADAMTS13-deficient thrombotic thrombocytopenic purpura (TTP) were once thought to have complete recovery except for risk of relapse. Data from previous publications from the Oklahoma TTP-hemolytic uremic syndrome (HUS) Registry are summarized. Patients have decreased cognitive function and increased prevalence of hypertension, systemic lupus erythematosus, major depression, and albuminuria as compared to the expected values from the US population. The proportion of patients that died during the follow-up period was greater than expected based on the US population reference population. Among women who had a pregnancy following recovery from TTP, relapse during pregnancy or postpartum is uncommon, but the occurrence of preeclampsia may be increased. Thirteen of 16 pregnancies in these women resulted in healthy children. Increased morbidity and mortality in TTP patients following recovery suggest that TTP may be more of a chronic disorder than a disorder with acute episodes and complete recovery.

The Oklahoma Thrombotic Thrombocytopenic Purpura-haemolytic Uraemic Syndrome Registry. A model for clinical research, education and patient care.

The Oklahoma Thrombotic Thrombocytopenic Purpura-Haemolytic Uraemic Syndrome (TTP-HUS) Registry has a 24 year record of success for collaborative clinical research, education, and patient care. This article tells the story of how the Registry began and it describes the Registry's structure and function. The Registry provides a model for using a cohort of consecutive patients to investigate a rare disorder. Collaboration between Oklahoma, United States and Bern, Switzerland has been the basis for successful interpretation of Registry data. Registry data have provided new insights into the evaluation and management of TTP. Because recovery from acute episodes of TTP has been assumed to be complete, the increased prevalence of hypertension, diabetes, depression, and death documented by long-term follow-up was unexpected. Registry data have provided opportunities for projects for students and trainees, education of physicians and nurses, and also for patients themselves. During our follow-up, patients have also educated Registry investigators about problems that persist after recovery from an acute episode of TTP. Most important, Registry data have resulted in important improvements for patient care.

Associations between youth assets and sexual activity: does adult supervision play a role?

BACKGROUND: Youth participation in sexual risk behaviours continues to be a critically important public health topic. Additionally, as youth are frequently being left alone during the day without adult supervision, there are increased opportunities for sexual risk-taking behaviour. This study examined how the relationships of nine youth assets and sexual activity may vary according to the stratification of youth into two groups: self-care and supervised. METHODS: Data were collected through at-home, in-person interviews from a random sample of inner-city youth (mean age = 15.4 years; 51.5% female; 48.8% White; 22.4% Black; 18.5% Hispanic; 10% Native American) and their parents (n = 1079 parent/youth pairs). Nine youth assets were analysed using multiple logistic regression. Examples of assets youth may possess are: positive role models, family communication, school connectedness, constructive use of time and aspirations for the future. The item used to assess sexual intercourse was 'Have you ever had sexual intercourse ("done it", "had sex", "made love", "gone all the way")?'. Asset/risk behaviour associations that were unique to one of the two strata were the focus of the study. RESULTS: Thirty-seven per cent of youth spent two or more hours per day home alone. Youth who were supervised had a greater number of unique significant associations between assets and sexual activity than youth who were in the self-care group. CONCLUSIONS: Youth in supervised settings may be less likely to participate in sexual activity because of the presence of assets. Certain assets may also be important in deterring sexual activity for youth who are in self-care.

A matched case-control study: investigating the relationship between youth assets and sexual intercourse among 13- to 14-year-olds.

BACKGROUND: The number of teenagers engaging in sexual intercourse has consistently changed over the past several years. This can become a major challenge when trying to determine why teens continue to have sex. The purpose of this paper was to investigate the relationship between youth assets and sexual intercourse among 13- to 14-year-olds. METHODS: Cross-sectional data were collected using in-person at-home interviews from a random sample of inner-city neighbourhood 13- to 14-year-old teenagers (n = 64 matched pairs; 36% 13-year-olds, 53% female, 45% white, 28% African-American, 16% Hispanic and 11% Native American). Nine individual youth assets were analysed using conditional logistic regression (matching for several demographic variables) to assess the association between assets and abstinence in younger teens. RESULTS: Conditional logistic regression analyses showed that two assets, positive Peer Role Models [odds ratios (OR) = 4.67, 95% confidence intervals (CI) = 1.93, 11.27] and Use of Time (Religion) (OR = 2.20, 95% CI = 1.04, 4.65), were significantly related (P < 0.05) to younger teens never having engaged in sexual activity. CONCLUSION: These findings suggest, when considering abstinence behaviour, involvement in religious activities and having positive peer role models appear to be protective factors related to delaying sexual intercourse among teens aged 13-14 years.

The incidence of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: all patients, idiopathic patients, and patients with severe ADAMTS-13 deficiency.

BACKGROUND: Accurate estimates of the incidence of thrombotic thrombocytopenic purpura (TTP) are important to assess the resources required for current treatments as well as to anticipate the need to develop new treatments. Previous estimates have been indirect and have not reported data on patients with ADAMTS-13 deficiency. OBJECTIVE: To determine the incidence of patients with TTP-hemolytic uremic syndrome (HUS) in three categories: all patients with clinically suspected TTP-HUS, patients with idiopathic TTP-HUS, and patients with severe ADAMTS-13 deficiency. METHODS: Incidence rates were estimated from the Oklahoma TTP-HUS Registry, analyzing all 206 consecutive patients from January 1, 1996 to June 30, 2004 who were treated with plasma exchange for their initial episode of clinically suspected TTP-HUS. ADAMTS-13 activity was measured in 186 (90%) of the 206 patients. RESULTS: The age-sex-race standardized annual incidence rates were 11.29 x 10(6) (95% CI: 9.70-12.88) for all patients with clinically suspected TTP-HUS; 4.46 x 10(6) (95% CI: 3.43-5.50) for patients with idiopathic TTP-HUS; and 1.74 x 10(6) (95% CI: 1.06-2.41) for patients with severe ADAMTS-13 deficiency (<5% activity). In all three categories, the incidence rates were greater for women and for blacks. For patients with severe ADAMTS-13 deficiency, the age-sex standardized incidence rate ratio of blacks to non-blacks was 9.29 (95% CI: 4.33-19.93). CONCLUSIONS: Accurate incidence rate estimates for all patients with clinically suspected TTP-HUS, idiopathic TTP-HUS, and TTP associated with severe ADAMTS-13 deficiency have been determined. The greater incidence among women and blacks is comparable with their increased risk for other autoimmune disorders.

Stability and convergent validity of the Physical Activity Scale for the Elderly (PASE).

AIM: The purpose of this study was to assess the stability and convergent validity of the Physical Activity Scale for the Elderly (PASE) among rural, community dwelling elderly persons using Computer Science and Applications, Inc. Actigraph Monitors (Actigraph) as the direct criterion measure. EXPERIMENTAL DESIGN: a correlational design was employed. SETTING: rural community in the United States. PARTICIPANTS: 56 subjects (age=75.7+/-7.9 years) who were living independently and volunteered to participate in the study. MEASURES: subjects wore an Actigraph monitor during all waking hours for 7 consecutive days. At the conclusion of the 7 days, each subject met with a trained interviewer to complete the PASE questionnaire. Three days later the subjects met with the same interviewer to complete the PASE a 2nd time recalling their physical activity for the same 7-day period. RESULTS: Actigraph data indicated that subjects averaged 168.1+/-76.3 counts x minute(-1) during the 7-day period. A high intraclass correlation coefficient (r=0.91) was calculated between the 1st interview total PASE score (115.97+/-59.91) and the 2nd interview total PASE score (115.71+/-50.97). In addition, there was a statistically significant Spearman correlation coefficient of 0.43 (p<0.01) between Actigraph mean counts x minute(-1) and 1st interview total PASE scores. CONCLUSION: In this rural elderly sample, the PASE was a stable instrument with validity indices similar to those previously reported in younger, more active, populations.

Unintentional platelet removal by plasmapheresis.

Therapeutic plasmapheresis may remove platelets as well as plasma. Unintentional platelet loss, if not recognized, may lead to inappropriate patient assessment and treatment. A patient with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is reported in whom persistent thrombocytopenia was interpreted as continuing active disease; thrombocytopenia resolved only after plasma exchange treatments were stopped. This observation prompted a systematic study of platelet loss with plasmapheresis. Data are reported on platelet loss during 432 apheresis procedures in 71 patients with six disease categories using three different instruments. Comparing the first procedure recorded for each patient, there was a significant difference among instrument types (P<0.001); platelet loss was greater with the Fresenius AS 104 (17.5%, N = 21) than with the COBE Spectra (1.6%, N = 26) or the Haemonetics LN9000 (2.6%, N = 24). With all procedures, platelet loss ranged from 0 to 71%. Among disease categories, platelet loss was greater in patients with dysproteinemias who were treated for hyperviscosity symptoms. Absolute platelet loss with the first recorded apheresis procedure, in the 34 patients who had a normal platelet count before the procedure, was also greater with the AS 104 (2.23 x 10(11) platelets) than with the Spectra (0.29 x 10(11) platelets) or the LN9000 (0.37 x 10(11) platelets). In 39 patients in whom data were collected on consecutive days, platelet removal by plasmapheresis correlated with a decreased patient platelet count (r = 0.40, P = 0.011). In these 39 patients, the platelet counts were significantly decreased at 24 hours (P = 0.002).

Quinine-associated thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: frequency, clinical features, and long-term outcomes.

BACKGROUND: Quinine-associated thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is thought to be uncommon and to have a good prognosis. OBJECTIVE: To describe the frequency, clinical features, and long-term outcomes of quinine-associated TTP-HUS. DESIGN: Case series. SETTING: Hospitals in central-western Oklahoma. PATIENTS: 225 consecutive patients with TTP-HUS, 1989-2000. MEASUREMENTS: Presenting features and clinical outcomes. RESULTS: Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome was associated with quinine in 17 patients. Four patients died, and 7 survivors currently have chronic renal failure. Since 1 July 1995, 132 patients with clinically suspected TTP-HUS were explicitly asked about drug exposure. Fourteen (11%) had taken quinine, and 7 had taken other drugs associated with TTP-HUS. Neurologic abnormalities were as severe in patients with quinine-associated TTP-HUS as in the 118 patients who had not taken quinine. CONCLUSIONS: Quinine is a common cause of drug-associated TTP-HUS and can cause death and chronic renal failure. When the disorder is described as TTP-HUS rather than only as HUS, the severity of neurologic abnormalities and the occasional absence of renal failure are emphasized. If recurrent disease is to be prevented, clinicians must recognize quinine as a possible cause.

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: diagnosis and treatment.

Prompt recognition of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) and initiation of plasma exchange treatment is critical as it substantially decreases mortality. Nevertheless, death and long-term complications remain common. The recent relaxation of diagnostic criteria has dramatically increased the number of patients treated for clinically suspected TTP-HUS.

Thrombotic thrombocytopenic purpura-like syndromes following bone marrow transplantation: an analysis of associated conditions and clinical outcomes.

The diagnosis and treatment of thrombotic thrombocytopenic purpura (TTP) in patients following BMT are often uncertain and unsuccessful. To better understand the evaluation and management of these patients, we describe 17 patients treated with plasma exchange for a presumptive diagnosis of TTP following BMT during a 10 year period, 1989-1998. Because of the uncertainty of the diagnosis, these patients are described as having a 'TTP-like syndrome'. All 17 patients had received an allogeneic BMT. Comparison with the other 245 patients who had an allogeneic BMT during the same period demonstrated that patients with a TTP-like syndrome more frequently had unrelated and/or HLA-mismatched donors, and had also experienced more serious complications: grade III-IV acute GVHD and systemic bacterial, fungal, and viral infections. Three months after the diagnosis of the TTP-like syndrome, only four of 17 patients (24%) were alive; currently only one patient survives. These data emphasize: (1) the diagnosis of TTP following BMT is uncertain because of the presence of multiple BMT-associated complications. (2) The outcome of patients with TTP-like syndromes following BMT is poor. (3) Urgent intervention with plasma exchange when TTP is suspected following BMT may not always be appropriate. Alternative explanations for the signs and symptoms should be considered and treated aggressively.

Complications of plasma exchange in 71 consecutive patients treated for clinically suspected thrombotic thrombocytopenic purpura-hemolytic-uremic syndrome.

BACKGROUND: With the increased frequency of diagnosis and improved survival of thrombotic thrombocytopenic purpura-hemolytic-uremic syndrome (TTP-HUS), the morbidity of plasma exchange (PE) treatment has become more important. STUDY DESIGN AND METHODS: Data were prospectively collected on 71 consecutive patients referred to the Oklahoma Blood Institute (OBI) for PE treatment for clinically suspected TTP-HUS from mid-1996 to mid-1999. Complications were defined as major or minor, and distinguished between those related to central venous catheter access or to the plasma. RESULTS: Twenty-one patients (30%) had 27 major complications, which caused two deaths. The major complications included 2 episodes of hemorrhage after subclavian line insertion (1 death), 1 pneumothorax requiring a chest tube, 12 systemic infections (1 death), 7 episodes of catheter thrombosis requiring removal of the central venous catheter, 2 episodes of venous thrombosis requiring anticoagulant treatment, 2 episodes of hypoxemia and hypotension, and 1 episode of serum sickness. Minor complications occurred in 22 additional patients (31%). Twenty-eight patients (39%) had no complications. CONCLUSIONS: The morbidity and mortality of catheter placement and PE are important considerations when PE treatment for clinically suspected TTP-HUS is anticipated.

Management of patients with chronic, refractory idiopathic thrombocytopenic purpura.

Chronic refractory idiopathic thrombocytopenic purpura (ITP) is defined as ITP with persistent thrombocytopenia despite conventional initial management with prednisone and splenectomy. Rare in children, It may occur in as many as one third of adults with ITP. The goal of treatment is not cure of the ITP, but only to achieve a safe platelet count, which is arbitrarily assumed to be greater than 30,000 to 50,000/microL. The risk for major bleeding seems great only when the platelet count is less than 10,000/microL. Treatment of patients with moderate thrombocytopenia and no clinically important bleeding symptoms should be avoided. There is no accepted algorithm for management of patients with chronic refractory ITP. Observation without specific treatment must be considered a cornerstone of management. Combination regimens of Immunosuppressive agents may be required for patients with severe and symptomatic thrombocytopenia. Additional supportive care measures are also important.