Novel paradigm enables accurate monthly gestational screening to prevent congenital toxoplasmosis and more.

Background: Congenital toxoplasmosis is a treatable, preventable disease, but untreated causes death, prematurity, loss of sight, cognition and motor function, and substantial costs worldwide. Methods/Findings: In our ongoing USA feasibility/efficacy clinical trial, data collated with other ongoing and earlier published results proved high performance of an Immunochromatographic-test(ICT) that enables accurate, rapid diagnosis/treatment, establishing new paradigms for care. Overall results from patient blood and/or serum samples tested with ICT compared with gold-standard-predicate-test results found ICT performance for 4606 sera/1876 blood, 99.3%/97.5% sensitive and 98.9%/99.7% specific. However, in the clinical trial the FDA-cleared-predicate test initially caused practical, costly problems due to false-positive-IgM results. For 58 persons, 3/43 seronegative and 2/15 chronically infected persons had false positive IgM predicate tests. This caused substantial anxiety, concerns, and required costly, delayed confirmation in reference centers. Absence of false positive ICT results contributes to solutions: Lyon and Paris France and USA Reference laboratories frequently receive sera with erroneously positive local laboratory IgM results impeding patient care. Therefore, thirty-two such sera referred to Lyon's Reference laboratory were ICT-tested. We collated these with other earlier/ongoing results: 132 of 137 USA or French persons had false positive local laboratory IgM results identified correctly as negative by ICT. Five false positive ICT results in Tunisia and Marseille, France, emphasize need to confirm positive ICT results with Sabin-Feldman-Dye-test or western blot. Separate studies demonstrated high performance in detecting acute infections, meeting FDA, CLIA, WHO ASSURED, CEMark criteria and patient and physician satisfaction with monthly-gestational-ICT-screening. Conclusions/Significance: This novel paradigm using ICT identifies likely false positives or raises suspicion that a result is truly positive, rapidly needing prompt follow up and treatment. Thus, ICT enables well-accepted gestational screening programs that facilitate rapid treatment saving lives, sight, cognition and motor function. This reduces anxiety, delays, work, and cost at point-of-care and clinical laboratories. Author's Summary: Toxoplasmosis is a major health burden for developed and developing countries, causing damage to eyes and brain, loss of life and substantial societal costs. Prompt diagnosis in gestational screening programs enables treatment, thereby relieving suffering, and leading to > 14-fold cost savings for care. Herein, we demonstrate that using an ICT that meets WHO ASSURED-criteria identifying persons with/without antibody to Toxoplasma gondii in sera and whole blood with high sensitivity and specificity, is feasible to use in USA clinical practice. We find this new approach can help to obviate the problem of detection of false positive anti- T.gondii IgM results for those without IgG antibodies to T.gondii when this occurs in present, standard of care, predicate USA FDA cleared available assays. Thus, this accurate test facilitates gestational screening programs and a global initiative to diagnose and thereby prevent and treat T.gondii infection. This minimizes likelihood of false positives (IgG and/or IgM) while maintaining maximum sensitivity. When isolated IgM antibodies are detected, it is necessary to confirm and when indicated continue follow up testing in ∼2 weeks to establish seroconversion. Presence of a positive ICT makes it likely that IgM is truly positive and a negative ICT makes it likely that IgM will be a false positive without infection. These results create a new, enthusiastically-accepted, precise paradigm for rapid diagnosis and validation of results with a second-line test. This helps eliminate alarm and anxiety about false-positive results, while expediting needed treatment for true positive results and providing back up distinguishing false positive tests.

Clinical and prognostic significance of in vivo differentiation in acute myeloid leukemia.

Bromodeoxyuridine (BrdU) was administered to 86 newly diagnosed patients with standard risk acute myeloid leukemia (AML) prior to starting induction therapy and the labeling index (LI), durations of S-phase (Ts), and the cell cycle (Tc) of myeloblasts were determined. Induction therapy with cytosine arabinoside and daunomycin was subsequently started. Bone marrow biopsies were obtained on days 6 and 17 and weekly thereafter, and were treated with a monoclonal anti-BrdU antibody to determine the fate of cells labeled on day 0 by BrdU. BrdU labeled granulocytes indicating the presence of in vivo differentiation (Diff+) were identified in 48 patients ranging from 1+ (1-10 labeled cells) to 4+ (greater than 31 labeled granulocytes). When compared to 38 differentiation negative (Diff-) patients, Diff+ group had longer Ts (14.5 hr vs. 10.95 hr, P = 0.015) and Tc (59.7 hr vs. 41.7 hr, P = 0.017). Remission duration was significantly longer (no median) for 3-4+ Diff+ as compared to Diff- (median = 220 days) patients (Wilcoxon P = 0.04). We conclude that the detection of in vivo differentiation in AML patients indicates a favorable long-term prognosis either due to the presence of a substantial amount of normal residual hematopoiesis prior to starting induction therapy or due to the ability of leukemic cells to undergo differentiation.

Relationship of [3H]Ara-C incorporation and response to therapy with high-dose Ara-C in AML patients: a Leukemia Intergroup study.

Pretherapy bone marrow (BM) aspirates of 143 patients with acute myeloid leukemia (AML) were incubated simultaneously with bromodeoxyuridine (BrdU) and tritiated cytosine arabinoside ([3H]Ara-C) to determine the labeling index (LI) and extent of [3H]Ara-C incorporation. Of 143 AML patients, 121 received high-dose Ara-C (HDAra-C) as a single agent for induction therapy (55 newly diagnosed, 66 in first relapse), whereas 22 received HDAra-C plus mAMSA. The data demonstrate that a subset of patients who will fail HDAra-C remission induction therapy because of drug-resistant disease can be prospectively identified on the basis of the low amount of Ara-C incorporated by their leukemia cells.

Direct relationship between remission duration in acute myeloid leukemia and cell cycle kinetics: a leukemia intergroup study.

Cell cycle characteristics including labeling indices (LI), duration of S-phase (Ts), and total cell cycle time (Tc) were determined in 54 standard-risk, newly diagnosed patients with acute myeloid leukemia following an infusion of bromodeoxyuridine. Remission induction therapy consisting of cytosine arabinoside and daunomycin was then administered to all patients, followed by three courses of consolidation to those who achieved complete remissions (CR). Older patients appeared to have more rapidly cycling cells (P = .003). No unique cell cycle characteristics were identified for patients who achieved remission versus those who had resistant disease. However, the pretherapy cell cycle characteristics were a strong prognosticator for remission duration. CR patients were divided into those whose leukemic cell Tc were above median (A) and below median (B). Among 14 B patients, median duration of response was 211 days, and all relapsed by day 600. Among 18 A patients, the median has not as yet been reached, with nine patients in continuous complete remission (log rank P = .007, Wilcoxon P = .04). We conclude that cell cycle characteristics of leukemic cells play a role in determining remission duration, perhaps because the leukemic cells of the former patients regrow slowly between courses of chemotherapy.