Childhood leukaemia and lymphoma: African experience supports a role for environmental factors in leukaemogenesis

Abstract

Major differences exist in the nature of leukaemia and lymphoma in low-income African children compared to those in the high-income countries. These include the absence of the peak incidence of acute lymphoblastic leukaemia (ALL) in under-five-year olds that characterizes the disease in high-income countries. Conversely, chloroma association with acute myelogenous leukaemia (CA-AML/AMML) and Burkitt's lymphoma (BL) are rare in the high-income countries. This report describes clinical and laboratory as well as epidemiological features of childhood leukaemia and lymphoma reported betwen 1982 and 1984 in the city of Ibadan, Nigeria. The observed pattern of distribution of childhood haematological malignancies in the city is more consistent with the observations of Ludwik Gross's experiments on environmental influences, such as malnutrition and infections, animal leukaemogenesis, and mirroring the consequences of the primordial pressures that have shaped human genetics and pathophysiology.

Keywords: childhood leukaemia; chloroma; environmental factors; leukaemogenesis; lifestyle; lymphoblastic; socio-economic.

Figure 1.. Incidence of childhood leukaemia correlated with HAV seroprevalence in the first decade of life. US Cau. = US Caucasians. Data based on Smith et al [40] a. Acute lymphoblastic leukaemia in 2–4 year olds. b. HAV seroprevalence rates. In developing countries of Africa, Asia, Latin America, and pre-1960 Okinawa, Japan, where age-specific variations are not observed, cited infection rates represent cross-sectional values. In the developed countries of USA and United Kingdom as well as post-1960 Okinawa, Japan, the HAV values represent infection rates in the childbearing age of 25–30 years [65].