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]

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.