Chronic lymphocytic leukaemia/ Small lymphocytic lymphoma (CLL/SLL) is a post- germinal center neoplasm characterised by clonal proliferation and accumulation of mature- looking lymphocytes in the blood, bone marrow, lymph nodes and spleen. The CLL/SLL cells are typically B- cell in origin, and T- cell variants rarely occur. CLL/SLL is the most common leukaemia in Western countries, and it accounts for approximately one- third of all leukaemias in the United States (Siegel, et al. 2013).
Most patients are asymptomatic and the diagnosis of CLL/SLL is frequently made on routine blood count. The leukaemic cells usually co-express cluster of differentiation, CD5+, CD19 and CD 23+ and the diagnosis can be established by the demonstration of greater or equal to (? ) 5.0 × 109/ l monoclonal cells with this phenotype in the peripheral blood even in the absence of lymphadenopathy, organomegaly, or other clinical features (Hallek, et al. 2010).
CLL/SLL is a heterogeneous disease as reflected by its highly variable natural history ranging from indolent to aggressive clinical course. Some patients die within two or three years from the time of initial diagnosis, whereas others with the condition live much longer for about ten to twenty years (Rai, 2008). To provide useful prognostic information, CLL/SLL patients, are stratified into prognostic groups by the Rai and Binet clinical staging systems, which appear to correlate with degree of gross tumor burden(Rai, 2008).
However, these staging systems lack accuracy to predict disease progression particularly in early stage or low risk disease. As such, adverse cytogenetic abnormalities and molecular markers are utilized to better identify patients with more rapidly progressive disease (Crespo, et al. 2003).
Although chronic lymphocytic leukaemia (CLL) is the most common leukemia in the west and over the past two decades the incidence of infection with the human immunodeficiency virus (HIV) has significantly increased, few reports of the coincidence of these diseases exist in the literature. Other lymphoid malignancies such as non-Hodgkin’s lymphomas (NHL) and Hodgkin’s disease (HD) occur frequently with HIV and indeed the former is an acquired immune deficiency syndrome (AIDS)-defining illness. It is not clear why HIV infected patients have a predisposition for some B-cell disorders and not others. This may be related to the different age ranges for patients with CLL and HIV infection although an overlap clearly does exist. Here, we describe our experience with a patient with co-existing HIV infection and CLL and explore possible implications. (Farhad R et al: 2003)
1.2: Statement of the problem
There is little data on the characteristics of CLL/SLL in Zambia. It has however, been observed that there is a steady increase in the number of CLL/SLL cases diagnosed at the University Teaching Hospital (UTH). This observation is supported by data obtained from the peripheral blood samples (PBS) and bone marrow (BM) register of the UTH. The Haematology laboratory indicated 22 cases of CLL/SLL from August (third quarter) 2013 to 31st May, 2016, 29 new cases of ALL, 32 cases of AML and 44 cases of CML.Approximately a total of 127 new cases of leukaemia was diagnosed during this period under study. This number is of clinical significance because most of these cases were referrals from other provincial hospitals. Hence, a research to characterise these leukaemias is of great importance.
It has been noted so far that only complete blood counts (CBC) and peripheral blood smears (PBS) are widely used in Zambia for the diagnosis of CLL/SLL. Currently, there are no molecular techniques like immunophenotyping being used. There are no prognostic tests done as clinicians only depend on clinical features which may not be specific.
1.3: Study justification:
A cross sectional study in whichconsecutive cases of different types of leukaemias occurring between June 2014 and June 2015 were analyzed from records and laboratory results. On frequency of leukaemias our results showed that a total of 90 cases of leukaemia were available for analysis. The most frequent leukaemia was chronic myeloid leukaemia (CML) at 43.3%, followed by undefined leukaemias at 16.7%, then 15.6 % acute myeloid leukaemia (AML) , 13.3% chronic lymphocytic leukaemia/ small lymphoblastic lymphomas (CLL/SLL) , and lastly 11.1% acute lymphoblastic leukaemia (ALL).The median age of all Leukaemia types was 33 and age range was from 1 to 88 years and 17 (18.9%) were children ( 15 years) Of the 90 cases 39 (43.3%) were females and 51 (56.7%) were males (M: F ratio 1.3: 1).
CLL/SLL accounts for about 20% of all haematological malignancies. In the absence of more relevant data , one cannot be certain if the increased number of cases diagnosed at UTH is a true rise in incidence or just an increase in the awareness of the condition as a result of improved diagnostic approaches that doctors have employed in disease management.
The study will help clinicians to understand the characteristics features of CLL/SLL in Zambia thereby introduce a targeted disease treatment modality. Further studies will help clinicians classify the aggressive forms of CLL/SLL from the indolent type hence reduce the disease fatalities. This study provides a baseline for monitoring the impact of HIV and management thereof on chronic lymphocytic leukaemia/ small lymphoblastic lymphoma and other lymphoma trends. The high prevalence of HIV in certain lymphoma categories emphasizes the need for capacity to diagnose and manage dual conditions. This study highlights the need for strengthening of cancer registries within Zambia and the region.