PREVALENCE OF MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE IN NIGERIANS

Abstract

AIM

To determine the prevalence of Monoclonal Gammopathy of Undetermined
Significance (MGUS) in Nigerians.

OBJECTIVES
1. To identify the presence of an M protein component in the serum of the
general population in Nigeria
2 To determine the type and concentration of the M protein.
3. To determine an association if any between the presence of M protein
and some haematological parameter such as ESR, Haemoglobin level,
packed cell volume, lymphocyte count.
4. To identify the predisposing factors if any to the development of MGUS -
age, sex, history of chronic disease or infections.

Study design

This was a cross sectional study conducted on apparently healthy adult volunteers
selected by a multistage sampling technique from the general population in Lagos.
Lagos state is a cosmopolitan city located in the southwestern region of Nigeria.
Materials and Method. Four hundred and fourteen (414) participants who
satisfied the inclusion criteria were enrolled into the study. A 2-step screening was
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performed with a serum protein electrophoresis followed by Immunofixation and a
quantitative determination of serum concentration of immunoglobulins when a
monoclonal band was found. Haematological and biochemical parameters of the
participants were also evaluated.
Result: A total of 414 volunteers were enrolled into the study with a mean age of
45.68 ± 10.3 years, a median of 45.00 years and a range of 20 to 84 years. The
male to female ratio M: F was 2.3 to 1.
One subject (0.24%) out of 410 participants who had serum protein electrophoresis
done had a monoclonal gammopathy and had the second stage of screening;
Immunofixation and quantification of the immunoglobulin levels, whereas 37 (9%)
had polyclonal gammopathy. The study subject with a monoclonal gammopathy
was demonstrated to have a double monoclonal gammopathy IgGk 16.9g/L
(Normal 7.00-16.00 g/L) and IgAk. 8.5g/L. (Normal 0.70-3.50 g/L).
While, the mean age of subjects with polyclonal band 45.81 ± 11.10 years is not
significantly different from the mean age of subjects with normal Serum Protein
Electrophoresis (SPEP) 45.74 ± 10.27 years, there appears to be a likelihood of
increased prevalence of polyclonal band with increasing age. Whereas 2 (40%) of
5 subjects aged ≥ 70years had polyclonal band 21 (11.46%) of 183 subjects aged
40-49 years had polyclonal band. χ2=11.32, P = 0.045.
A significant association was demonstrable between the presence of polyclonal
band and the female sex. Twenty (16%) of the 125 females had polyclonal band
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whereas 17 (5.99%) of 284 males had polyclonal band. In this study, a female is
more likely to have polyclonal band than a male χ2=10.57, P =0.005. None of the
study subjects reported a significant medical condition.
Conclusion: There is clear evidence from this data that the prevalence of MGUS
which represents the earliest stage of monoclonal plasma/lymphoid cell
proliferation in Nigerians is low when compared with other prevalence studies
from other population. An association was established between increased age and
likelihood of polyclonal band. Female sex is more likely to have a polyclonal band
than male