Commercial DURAClone panels for extending the repertoire of multicolour immunophenotypic panels in an academic flow cytometry laboratory in South Africa.

Background: Commercial multicolour fixed immunophenotyping panels can improve flow cytometric diagnostic immunophenotyping repertoire. Objective: This study validated the commercially available, standardised Beckman Coulter lyophilised DURAClone RE panels to discriminate specific haematolymphoid subtypes. Methods: We compared the diagnostic capability of the DURAClone acute leukaemia B (ALB), chronic leukaemia B (CLB), and plasma cells (PC) panels to the predicate second-line panels in Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa, from April to August 2020. Clinical diagnostic concordance between the in-house second-line immunophenotyping (the predicate method) and DURAClone was established. The ALB panels tested for precursor B-cell acute lymphoblastic leukaemia (n = 11) or normal bone marrow haematogones (n = 9); CLB panels established haematolymphoid subtypes of mature B-cell lymphoproliferative disorders (B-LPD) (n = 20), while PC panels detected plasma cell dyscrasias (PCD) (n = 17). Flow cytometer setup and data interpretation to discriminate normal and aberrant immunophenotypes were per manufacturer's instructions. Results: There was 100% clinical diagnostic concordance between the predicate and the test panels for second-line diagnostic investigation of B-ALL (with additional CD56), mature B-LPD (with additional discernment of CD81, ROR-1, CD79b and CD43) and PCD. Conclusion: The DURAClone CLB exceeded the predicate second-line performance, offering extended second-line diagnostic discernment of mature B-LPD subtypes and discernment of CD5+ B-LPD from other non-CD5+ (or CD5-) B-LPD; likewise, the PC panels enabled discovery of PCD. While ALB testing offered no additional diagnostic advantage over existing predicate investigation, CD58 did offer additional information to discern haematogones from B-ALL.

Evaluation of fixed-panel, multicolour ClearLLab 10C at an academic flow cytometry laboratory in Johannesburg, South Africa.

Background: Flow cytometric immunophenotyping is well established for the diagnosis of haematological neoplasms. New commercially available systems offer fixed, pre-aliquoted multi-parameter analysis to simplify sample preparation and standardise data analysis. Objective: The Beckman Coulter (BC) ClearLLab™ 10C (4-tube) system was evaluated against an existing laboratory developed test (LDT). Methods: Peripheral blood and bone marrow aspirates (n = 101), tested between August 2019 and November 2019 at an academic pathology laboratory in Johannesburg, South Africa, were analysed. Following daily instrument quality control, samples were prepared for LDT (using > 20 2-4-colour in-house panels and an extensive liquid monoclonal reagent repertoire) or ClearLLab 10C, and respectively analysed using in-house protocols on a Becton Dickinson FACSCalibur, or manufacturer-directed protocols on a BC Navios. Becton Dickinson Paint-a-Gate or BC Kaluza C software facilitated data interpretation. Diagnostic accuracy (concordance) was established by calculating sensitivity and specificity outcomes. Results: Excellent agreement (clinical diagnostic concordance) with 100% specificity and sensitivity was established between LDT and ClearLLab 10C in 67 patients with a haematological neoplasm and 34 participants with no haematological disease. Similar acceptable diagnostic concordance (97%) was noted when comparing ClearLLab 10C to clinicopathological outcomes. Additionally, the ClearLLab 10C panels, analysed with Kaluza C software, enabled simultaneous discrimination of disease and concurrent background myeloid and lymphoid haematological populations, including assessing stages of maturation or sub-populations. Conclusion: ClearLLab 10C panels provide excellent agreement to existing LDTs and may reliably be used for immunophenotyping of haematological neoplasms, simplifying and standardising sample preparation and data acquisition.

Thrombotic thrombocytopenic purpura: A 5-year tertiary care centre experience.

INTRODUCTION: Thrombotic thrombocytopenic purpura (TTP) is associated with high mortality if not managed timeously with therapeutic plasma exchange (TPE). TTP secondary to human immunodeficiency virus (HIV) infection is unique to sub-Saharan Africa. The management and outcome of TTP in the era of improved access to therapy has not been described. METHODS: The present study describes the clinical presentation, treatment, therapeutic endpoints, and outcome of TTP patients at the Charlotte Maxeke Johannesburg Academic Hospital, South Africa. The inpatient and outpatient records of 41 consecutive adults with TTP were reviewed between 2012 and 2016. Patients were classified according to aetiology and treatment response. RESULTS: TTP was the initial presenting feature of HIV infection in 78.0%, and 12.5% were noncompliant with antiretroviral therapy (ART). Most study patients were of black ethnicity (95%) and female gender (78.1%). Treatment included initial TPE (87.8%), plasma infusion (78.1%), antiretroviral therapy (78.3%), corticosteroids (61.0%) intensive care admission (41.5%), renal dialysis (12.2%), and other immunosuppressive agents (4.9%). The median (range) number of TPEs was 10.0 (7.0-15.0). A high rate of refractory disease (63.4%) was reported. Haemoglobin, platelet count, lactate dehydrogenase, red cell distribution width, and creatinine were reliable therapeutic end-points (P < .05). The relapse rate was 9.8% and the mortality rate was 29.3%. CONCLUSION: The high mortality rate emphasises the importance of early diagnosis, referral, and appropriate management of TTP. Anti-retroviral therapy and adherence monitoring are essential to TTP management associated with HIV. Future studies to identify patients at risk for refractory disease are indicated.

A case of a drug reaction to sulfasalazine in a patient infected with HIV.

INTRODUCTION: The diagnosis of drug reaction with eosinophilia and systemic symptoms (DRESS) in human immunodeficiency virus (HIV) patients on multiple drugs with concomitant disorders presents a diagnostic challenge. PATIENT PRESENTATION: We describe a case of a drug reaction to sulfasalazine in a 46 year old HIV-infected female with concurrent rheumatoid arthritis which presented atypically with a marked peripheral blood plasmacytosis mimicking a lymphoproliferative neoplasm. MANAGEMENT AND OUTCOME: A diagnosis of DRESS was made in conjunction with the laboratory and clinical presenting findings. Sulfasalazine was immediately discontinued. The mucocutaneous rash and systemic symptoms (which included fever, lymphadenopathy and multi-organ dysfunction) resolved with supportive treatment. This included topical and systemic corticosteroids. CONCLUSION: In conclusion, it is important to consider drug reactions when evaluating patients infected with HIV.