SEROPREVALENCE OF HTLV-1 ANTIBODIES AMONG HEALTHY BLOOD DONORS AND PATIENTS WITH LYMPHOID MALIGNANCIES AT THE LAGOS STATE UNIVERSITY TEACHING HOSPITAL (LASUTH), IKEJA, LAGOS

Abstract

Background: The Human T-lymphotropic virus 1 (HTLV-1) is known to cause adult T-cell
leukaemia/lymphoma and may be transmitted through sexual activity and transfusion of
blood products. The study aims to determine the causative role of HTLV-1 in the
development of lymphoid malignancies and its risk of transmission by blood transfusion.
Methods: A cross-sectional study of blood donors and patients with lymphoid malignancies
attending LASUTH, Ikeja. Donors were randomly selected and patients with malignant
lymphoma, chronic lymphocytic leukaemia, multiple myeloma and acute lymphoblastic
leukaemia were consecutively recruited. A total of 10mls of blood was collected from each
subject after obtaining informed consent. Five milliliters of blood were collected in plain
bottle for serological tests (e.g. antibodies to HTLV-1, HIV, HbsAg and HCV) and 5mls in
K3EDTA (tripotassium ethylenediamine tetra-acetic acid) bottle for full blood count (Hb,
WBC with differentials and platelet count). Full blood count was performed using a Sysmex
KX-21N™ Automated Hematology Analyzer machine. The serum samples were stored at
20°C and batch tested according to standard protocol for each viral agent. Demographic
data and blood transfusion history were obtained using a questionnaire.
Results: A total of 249 subjects were studied, consisting of 210 healthy blood donors and 39
patients with lymphoid malignancies. The male: female ratio for the donors was 7.1: 1, while
that for patients was 1.2: 1 (P <0.001). Twenty four of the patients had solid lymphoid
malignancies [malignant lymphoma (20) and multiple myeloma (4)], while 15 patients had
lymphoid leukaemias [chronic lymphocytic leukaemia (13) and acute lymphoblastic
leukaemia (2)]. The results showed that one (0.5%) blood donor and two (5.1%) patients
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with lymphoid malignancies (one N.H.L. and one C.L.L.) were positive for HTLV-1 antibodies.
There was no significant difference in positivity to HTLV-1 antibodies between blood donors
and patients with lymphoid malignancies (*P = 0.065). None of the donors had been
previously transfused. Thirteen (33.3%) patients had history of previous blood transfusion
and none was positive for HTLV-1. However, two (7.7%) patients with no history of previous
blood transfusion were positive for HTLV-1. There was no association between history of
previous blood transfusion and positivity to HTLV-1 (*P = 0.544). All the healthy blood
donors were negative for HIV, HbsAg and HCV, while all the patients with lymphoid
malignancies were negative for HIV only. Four (10.3%) patients were positive for HbsAg (two
were previously transfused), while two (5.1%) were positive for HCV (one was previously
transfused). No relationship between history of previous blood transfusion and HbsAg (*P =
0.4073) or HCV (*P = 0.5614) was observed. The mean haemoglobin concentration (9.6 ± 2.6
g/L) and platelet count (224.4 ± 164.8 x109/L) of the patients with solid malignancies were
similar to those of patients with leukaemia (Hb = 9.6 ± 2.1 g/L and Plt = 225.7 ± 182.3 x109/L;
P = 0.9303 and P = 0.9809 respectively). The mean total WBC count of the patients with
leukaemia (77.7 ± 82.3 x109/L) was significantly higher than that of the patients with solid
malignancies (6.3 ± 2.9 x109/L; P <0.001) as expected. The mean haemoglobin concentration
of the donors (11.8 ± 0.9 g/L) was significantly higher than the mean haemoglobin
concentration of the patients (9.6 ±2.4 g/L; P <0.001). The mean total WBC count of the
patients with leukaemia (77.7 ± 82.3 x109/L) and solid malignancies (6.3 ± 2.9 x109/L) were
significantly higher than the mean total WBC count (4.7 ± 1.4 x109/L) of the donors. P <0.001
and 0.006 respectively. The mean platelet count of the patients (224.9 ±169.4 x109/L) was
not significantly higher than the mean platelet count of the blood donors (185.9 ± 52.9
x109/L; P = 0.922).

Conclusion: The seroprevalence of HTLV-1 in this environment is low among healthy blood
donors and is similar to that of patients with lymphoid malignancies. History of previous
blood transfusion could not be significantly associated with HTLV-1 infection. Haemoglobin
concentration and WBC count of patients may be used as markers of lymphoid
malignancies.
* Fischer’s exact