Evaluation of different confirmatory algorithms using seven treponemal tests on Architect Syphilis TP-positive/RPR-negative sera.

The Architect Syphilis TP is considered to be a suitable screening test due to its high sensitivity and full automation. According to the International Union against Sexually Transmitted Infections (IUSTI) 2014 guidelines, however, positive screening tests need confirmation with Treponema pallidum particle agglutination (TP.PA). Among Architect-positive results, samples with a negative non-treponemal test present the major diagnostic challenge. In this multicenter study, we investigated if other, preferable less labor-intensive treponemal tests could replace TP.PA. A total of 178 rapid plasma reagin (RPR)-negative sera with an Architect value between 1 and 15 S/CO were prospectively selected in three centers. These sera were analyzed with TP.PA and six alternative treponemal tests: three immunoblots and three tests on random-access analyzers. The diagnostic performance of the treponemal tests differed substantially, with the overall agreement between the six alternative tests ranging from 44.6 to 82.0%. Based on TP.PA as the gold standard, the INNO-LIA IgG blot, the BioPlex 2200 IgG, and the Syphilis TPA showed a high sensitivity, while the EUROLINE-WB IgG blot, recomLine Treponema IgG blot, and the Chorus Syphilis screen showed a high specificity. However, an Architect cut-off of 5.6 S/CO can serve as an alternative for these confirmatory treponemal tests in case of an RPR-negative result. Treponemal tests show poor agreement in this challenging group of Architect-positive/RPR-negative sera. The most optimal algorithm is obtained by assigning sera with an Architect value >5.6 S/CO as true-positives and sera with a value between 1 and 5.6 S/CO as undetermined, requiring further testing with TP.PA.

Diagnostic utility of the lymphoid screening tube supplemented with TRBC1 for the assessment of T-cell clonality.

INTRODUCTION: Flow cytometric panels for the investigation of lymphoproliferative disorders, such as the EuroFlow Lymphoid Screening Tube (LST), often fail to demonstrate T-cell clonality, as a suitable clonality marker was unavailable until recently. Aim of this study was to evaluate the added value of supplementing TRBC1, a flow cytometric T-cell clonality marker, to the LST. METHODS: Flow cytometric analysis was performed on 830 routine samples referred to our lab for suspicion of hematological malignancy. T-cells with monotypic TRBC1-expression were additionally characterized with a 12-color T-cell tube and molecular T-cell receptor gamma gene rearrangement (TRG). RESULTS: LST analysis revealed 97 (11.7%) samples with the presence of a monotypic T-cell population according to TRBC1, including 21 (2.5%) "high-count" (≥500 cells/µL blood or ≥15% of lymphocytes) and 76 (9.2%) "low-count" (<500 cells/µL blood or <15% of lymphocytes) populations. Clinical symptoms indicative for T-CLPD could be correlated to 11/21 "high-count" and 17/76 "low-count" monotypic T-cell populations. Molecular TRG analysis demonstrated a monoclonal result in 76% (16/21) of "high-count" samples and in 64% (42/66; 10 samples not tested) of "low-count" samples, but also in 9/20 samples with polytypic TRBC1 results. CONCLUSION: Analysis of an LST tube supplemented with TRBC1 led to the detection of a high number of monotypic T-cell populations. The detection of numerous small monotypic T-cell populations raises the question of their clinical significance. A possible flowchart for assessment of these populations, based on the available literature, is proposed. Molecular TRG analysis is complementary and cannot be omitted from T-cell clonality assessment.

The influence of COVID-19 on routine hematological parameters of hospitalized patients.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) was first discovered in Wuhan, China, in December 2019, and soon spread around the entire world. As no effective treatment is known, prediction of disease severity is very important in order to estimate a patients outcome. Aim of this study was to evaluate routine hematology parameters in time after admission. METHODS: Data from routine blood analyses from confirmed COVID-19 cases admitted to the University Hospital of Leuven in Belgium were collected. COVID-19 patients (n = 197) were assigned to three groups: a 'non-ICU' group, a 'ICU' group and a 'deceased' group. A control group of 60 Influenza A (non-COVID-19) patients was also included. The parameters evaluated were platelet count (PLT, 109/L), hemoglobin concentration (Hb, g/dL), leukocyte count (LEU, 109/L), neutrophil count (NEU, %), eosinophil count (EO, %), lymphocyte count (LYM, %) and monocyte count (MONO, %). RESULTS: Deceased COVID-19 patients had significant lower platelet count, higher leukocyte/neutrophil count, and lower eosinophil/lymphocyte/monocyte count compared to recovered patients. Especially lymphocyte count showed important differences; they were significantly lower between day 9 and 12 after admission making this time window important in predicting clinical worsening of a patient. CONCLUSION: Patients with COVID-19 with poor outcome showed significant differences in results of routine hematological parameters compared with patients that recovered. Especially lymphocyte count can be helpful in the prediction of a patients outcome.

[Painful nodular and plantar erythema in children]. / Erythème nodulaire plantaire douloureux de l'enfant.

INTRODUCTION: According to our knowledge, only twenty-three similar cases have been reported in the literature. Possible hypotheses for localised painful red nodules on the feet in children include erythema nodosum, neutrophilic eccrine hidradenitis, traumatic plantar urticaria, vasculitis and cold panniculitis. CASE REPORT: We report a typical case of painful erythematous plantar nodules of the child. A 13-yr-old boy was first seen by a paediatrician for intermittent fever. The fever was associated with red, painful nodules on the soles. He was unable to walk. Routine blood chemistry parameters were within normal limits. Histopathologic examination of lesional skin revealed an image of septal and lobular panniculitis with vasculitis. Direct immunofluorescence study was not contributive. With proper antibiotic therapy, pain resolved within one week while fever and nodules cleared within two weeks. DISCUSSION: Briefly, this observation concerns a child disease occurring as painful erythematous plantar nodules. The lesions are spontaneously resolutive and the children are in good health. Our observation should constitute a supplementary group with the same classical symptoms of nodular plantar painful erythema of the child but moreover accompanied by a septal and lobular panniculitis with vasculitis at the histological examination. Further studies are necessary to verify these hypotheses.