Evaluation of a new technique using artificial intelligence for quantification of plasma cells on CD138 immunohistochemistry.

INTRODUCTION: The diagnosis of plasma cell neoplasms depends on the accurate quantification of plasma cells, traditionally done by immunohistochemical CD138 staining of bone marrow biopsies. Currently, there is no fully satisfactory reference method for this quantification. In our previous study, we compared the commonly used overview estimation method (method A) with a novel method for counting plasma cells in three representative areas (method B). Results showed comparable concordance parameters between the two methods. In this follow-up study, we compared the previously evaluated methods with a digital analysis method (method C) that uses artificial intelligence in open-source software, QuPath. METHODS: Archived CD138 immunohistochemically stained trephine sections of bone marrow samples used in our previous study were used (n = 33). Reviewers selected three representative areas on each sample by taking images with a light microscope and camera. Digital analysis was performed using the positive cell detection function in QuPath. The entire process was repeated by each reviewer to test intraobserver concordance (concordance correlation coefficient [CCC]) in addition to interobserver concordance (intraclass correlation coefficient [ICC]). RESULTS: Intraobserver concordance of method C showed strong agreement for all reviewers with the lowest CCC = 0.854. Interobserver concordance for method C using ICC was 0.909 and 0.949. This showed high interobserver agreement with significant differences between method C and previously assessed method A (ICC = 0.793 and 0.713) and method B (ICC = 0.657 and 0.658). CONCLUSION: We were able to successfully count CD138-positive plasma cells in bone marrow biopsies using artificial intelligence. This method is superior to both manual counting and overview estimation, regardless of tumour load.

Multicentre verification of haematology laboratory blood collection tubes during a global blood collection tube shortage.

INTRODUCTION: Verification of blood collection tubes is essential for clinical laboratories. The aim of this study was to assess performance of candidate tubes from four alternative suppliers for routine diagnostic haematology testing during an impending global shortage of blood collection tubes. METHODS: A multicentre verification study was performed in Cape Town, South Africa. Blood from 300 healthy volunteers was collected into K2 EDTA and sodium citrate tubes of BD Vacutainer® comparator tubes and one of four candidate tubes (Vacucare, Vacuette®, V-TUBE™ and Vacutest®). A technical verification was performed, which included tube physical properties and safety. Routine haematology testing was performed for clinical verification. RESULTS: Vacucare tubes did not have a fill-line indicator, Vacuette® tubes had external blood contamination on the caps post-venesection and Vacutest® tubes had hard rubber stoppers. K2 EDTA tubes of Vacuette®, Vacucare and Vacutest® performed similarly to the comparator. Unacceptable constant bias was seen for PT in Vacucare (95% CI -2.38 to -0.10), Vacutest® (95% CI -1.91 to -0.49) and Vacuette® (95% CI 0.10-1.84) tubes and for aPTT in Vacuette® (95% CI 0.22-2.00) and V-TUBE™ (95% CI -2.88 to -0.44). Unacceptable %bias was seen for aPTT in Vacucare (95% CI 2.78-4.59) and Vacutest® tubes (95% CI 2.53-3.82; desirable ±2.30), and in V-TUBE™ for mean cell volume (95% CI 1.15-1.47, desirable ±0.95%) and mean cell haemoglobin concentration (95% CI -1.65 to -0.93, desirable ±0.43%). CONCLUSION: Blood collection tubes introduce variability to routine haematology results. We recommend that laboratories use one brand of tube. Verification of new candidate tubes should be performed to ensure consistency and reliable reporting of results.

The value of bone marrow examinations performed in the investigation of HIV infected patients with cytopenias.

INTRODUCTION: Bone marrow examination (BME) is a reliable and effective tool in the diagnosis of many haematological and non-haematological diseases and may be used to investigate unexplained cytopenia in human immunodeficiency virus (HIV) infected patients. The objective of this study was to determine the diagnoses made, diagnostic yield and unique diagnostic yield of BMEs performed to investigate cytopenias in HIV infected patients. METHOD: A retrospective cross-sectional descriptive study was performed involving all BMEs performed on HIV-infected adult patients with the main indication of unexplained cytopenia over a period of 5 years and 4 months. Data was extracted from the National Health Laboratory Service's laboratory information system and clinicians' BME request forms. RESULTS: The study included 128 BMEs, performed on 124 patients. The diagnostic yield was 32% and the unique diagnostic yield was 30.5%. The most common diagnosis was pure red cell aplasia (10.9%), followed by immune thrombocytopenic purpura (ITP) (7%), iron deficiency anaemia (6.3%), malignancy (4.7%) and disseminated infection (3.9%). CONCLUSION: BME is a useful investigation for unexplained cytopenia in HIV-infected patients. Less invasive investigations to exclude haematinic deficiencies, haemolysis and sepsis are recommended on an individualised basis prior to BME. In HIV-infected patients with therapy refractory ITP or ITP with atypical clinicopathological findings, BME is strongly recommended. As Mycobacterial and other infections are common in this group of patients, staining and culture of specimens are advised if BME is undertaken.

Epidemiology of Adult T-Cell Leukaemia/Lymphoma in South Africa over a 10-Year Period.

Introduction: Adult T-cell leukaemia/lymphoma (ATLL) is a rare and aggressive malignancy of mature T-cells. Limited epidemiological studies have shown that there is substantial variation in age at diagnosis and subtype distribution between different geographical regions. This is the first epidemiological study of ATLL in South Africa. Methods: A national epidemiological study of ATLL in South Africa was performed. All new cases of ATLL from 2009 to 2019 were identified by laboratory database search in public and private health care sectors. Demographic and diagnostic data were obtained, and the cases were subtyped according to the Shimoyama classification. Results: There were 31 patients with ATLL over the 10-year period, with an incidence of 0.06 per 100000 population. The male to female ratio was 1 : 1 and the median age at diagnosis was 37 years. Acute ATLL was the most commonly seen subtype in South Africa. Conclusion: In this, the first epidemiological study of ATLL in South Africa, we demonstrate that ATLL is a rare disease, that acute ATLL is the most commonly diagnosed subtype, and that ATLL is likely under diagnosed. Patients present at a considerably younger age than the reported age in other nations.