Immunophenotyping of actue leukaemias by flow cytometry: a review

Objective: To provide an overview of the utility of flow cytometry for phenotyping of acute leukaemias and selection of monoclonal antibodies.Data sources: The literature review was obtained through internet, journals and chapters in the relevant books.Data selection: Relevant articles and chapters on immunophenotyping of acute leukaemias were selected from respected international journals and books in the field of haematology and were reviewed.Data extraction and synthesis: Complete articles relevant to the topic were selected and reviewed and the necessary information extracted for this review.Conclusions: Flow cytometry has been used extensively in recent years to characterise haemopoeitic malignancies and done routinely in the developed world. This technique has greatly improved the diagnosis and classification of haemopoeitic malignancies and has been recommended by World Health Organisation classification (WHO) of tumours of haemopoeitic and lymphoid tissue. Application of flow cytometry for the diagnosis of leukaemias has been recently introduced in Kenya and is currently being undertaken in research using limited but appropriate panels of monoclonal antibodies. It is hoped that findings of this research will inform the use of flow cytometry as an ancillary diagnostic technique in our resource-constrained set up

Clinico-pathologic characteristics and treatment outcomes in children with neuroblastoma at the Kenyatta National Hospital, Nairobi.

Objective: To determine clinical-pathologic characteristics, treatment modalities and treatment outcomes of children diagnosed with neuroblastoma. Design: Cross- sectional descriptive study based on secondary data from patient records. Setting: Records department of Kenyatta National Hospital (KNH), a tertiary teaching and referral hospital based in Nairobi. Subjects: Children aged 15 years and below, admitted with the diagnosis of neuroblastoma, between January 1997 and December 2005. Main outcome measures: Presenting clinical features, diagnostic modalities including laboratory and imaging data, treatment modalities, response to treatment and patient survival. Results: Twenty six patients were eligible for the study; 13 males and 13 females giving a M: F ratio of 1: 1. The age range was 5 days to 12 years, with a median age of five years. Abdominal swelling (53.8%), inability to walk due to bone pains,(50%), and cranial or periorbital swelling, (38.5%) were the commonest presenting features. Diagnosis of neuroblastoma was based on tissue biopsy in 50% (95% CI40.6-79.8%) of the patients, and on fine needle aspiration cytology of mass or bone marrow in the rest. Bone marrow involvement was present in 16, (75%). Anaemia,was common with 72.7% patients having a haemoglobin (HB) \u3c8g/dl at presentation. Immunohistochemistry and cytological grading were done in two, (8%), patients. Urinary vanilly l mandelic acid (VMA), screening was positive in 50% (95% CI 29.9%-70.1%). The most frequently involved organs were abdomen (88.9%), and skeleton,(84.6%). Majority of patients, (92.3%), presented with advanced stage IV disease. Three patients died before commencement of treatment. All treated patients (100%), received cytotoxic therapy. Only two patients (8.6%) had surgery as part of treatment while one, (4.3%) was treated with radiotherapy. The initial treatment regimen was similar for all the patients. Although most patients had a complete initial response to treatment, early relapse, treatment failure, death or loss to follow up of patients with progressive disease were common. Overall survival (OS) at one year and two years were 19.2% (95% CI 6.6-39.4%) and 7.7% (95% CI 0.9%-25 1%) respectively. Only one patient was alive, (also free of disease), five years after diagnosis. Conclusion: Although other clinical- pathologic findings of the patients were similar to those reported elsewhere, virtually all study patients presented with advanced stage IV disease, which would be associated with poor prognosis irrespective of quality of care. Priority must therefore be on ensuring early diagnosis and referral of patients with neuroblastoma before any other interventions can be expected to positively impact on outcome. The limited role of surgery and radiotherapy observed over the study period may be attributed to late presentation of the patients. Pathologic evaluation of patients was inadequate, to some extent due to unavailability of facilities, but extra important information could have been availed at minimal extra cost. To be at par with current internationally accepted treatment approaches that have been associated with improved survival, there is need to base choice of regimens for individual patients on clinical and readily accessible pathologic markers

Acute Leukemias Immunophenotypes at Agakhan University Hospital, Nairobi

Objective: The aim was to determine relative frequencies of acute  leukemia immunophenotypes using commonly expressed markers and to describe the clinicopathological characteristics.Design: This was a prospective cross-sectional study.Setting: The study was based at Aga khan clinical laboratory department.Subjects: One hundred and thirty two (132) consecutive blood and bone marrow specimens from patients suspected to have acute leukemia were analysed for cytomorphological characteristics and immunophenotyping. The clinical-pathological characteristics were also recorded. Immunological category was assigned using the EGIL criteria.Results: There were 88 AML and 42 ALL patients analysed for  immunophenotypes. Only tw cases of biphenotypic leukemia were found. The commonest overall AML morphological sub-type was AML-M2, 26 (29.5%). Majority of ALL cases were B-cell immunological sub-type (96.6%). Early pre-B phenotype constituted 62.07% and Common B-cell ALL 37.93%. There were only 4 cases of T-cell ALL. Majority of patientspresented with anaemia with a median hemoglobin of 7.5g/dl (range 2-15g/dl). The median platelet count was 55 (range 4-462 × 109/L).Conclusion: Immunophenotyping of acute leukemia is beneficial in accurate diagnosis of patients with these malignancies in this setup. T-cell ALL, AML-M6 and M7 are less frequent than what has been reported in most studies in Africa.Key words: acute leukemia, immunophenotype, WHO, EGIL, CD marker

Comparing Papanicolau smear, visual inspection with acetic acid and human papillomavirus cervical cancer screening methods among HIV-positive women by immune status and antiretroviral therapy

Background: A rigorous comparison of cervical cancer screening methods utilizing data on immune status, antiretroviral therapy (ART) and colposcopy-directed biopsy has not been performed among HIV-positive women. Methods: Between June and November 2009, 500 HIV-positive women were enrolled at an HIV treatment clinic in Nairobi, Kenya, and underwent Papanicolau (Pap) smear, visual inspection with acetic acid (VIA), human papillomavirus (HPV) and colposcopydirected biopsy (gold standard). Positive Pap smear (ASCUS, LSIL, HSIL), VIA, HPV and their combinations were compared with CIN2/3+. Sensitivity, specificity and AUC (sensitivity and 1-specificity) were compared using pairwise tests and multivariate logistic regression models that included age, CD4+ cell count and ART duration. Results:Of 500 enrolled, 498 samples were collected. On histology, there were 172 (35%) normal, 186 (37%) CIN1, 66 (13%) CIN2, 47 (9%) CIN3 and 27 (5%) indeterminate. Pap (ASCUS+) was the most sensitive screening method (92.7%), combination of both Pap (HSIL+) and VIA positive was the most specific (99.1%) and Pap (HSIL+) had the highest AUC (0.85). In multivariate analyses, CD4+ cell count of 350 cells/ml or less was associated with decreased HPV specificity (P=0.002); ART duration of less than 2 years was associated with decreased HPV (P=0.01) and VIA (P=0.03) specificity; and age less than 40 years was associated with increased VIA sensitivity (P Conclusion: Pap smear is a robust test among HIV-positive women regardless of immune status or ART duration. Results should be cautiously interpreted when using HPV among those younger, immunosuppressed or on ART less than 2 years, and when using VIA among those aged 40 years or more

Drosophila Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu

DISSEMINATED HISTOPLASMOSIS DIAGNOSED ON BONE MARROW ASPIRATE CYTOLOGY: REPORT Of fOuR CASES

Histoplasmosis, caused by two varieties of dimorphic fungi, Histoplasma capsulatumvariant capsulatum and Histoplasma capsulatum variant duboisii is a systemic fungalinfection. It has a worldwide distribution and is shown to be more prevalent in NorthAmerica and Central America. Both variants occur in Africa. Disease spectrum rangesfrom asymptomatic primary infection to disseminated disease in immunocompromisedpatients. Since the upsurge of Acquired Immune Deficiency Syndrome (AIDS) anddespite the availability of High Active Anti-Retroviral Therapy (HAART) many patientsstill present with opportunistic infections of which histoplasmosis is one.four cases are presented; two infants and two adults. All had disseminated disease withmultiple organ involvement and the disease was not suspected clinically. Diagnosiswas made incidentally on bone marrow aspirate cytology. The two adult cases wereHIV positive, one with CD4 counts of 132 cells/microlitre and was not on HAART.The other was on HAART but the CD4 had not been determined. One of the infantstested HIV negative and the others status was unknown. A high index of suspicionis required for diagnosis as the disease may mimic tuberculosis(TB) and other causesof hepatosplenomegaly such as visceral leishmaniasis.Laboratory diagnosis includes culture, direct staining, antigen and antibody detection.Antibody detection may give false negative in the immunocompromised patient. Theinfection responds well to antifungal agents (amphotericin B is the drug of choice)and life long maintenance therapy may be required in AIDS especially if CD4 countsremain less than 150 cells/microlitre.Histoplasmosis should be a differential diagnosis in immunosuppressed patients withunexplained fever, weight loss, hepatosplenomegaly and chest findings especially ifnot responding to anti-TB treatment