Lepromatous leprosy is characterized by extensive bacillary invasion, a high level of
circulating immune complexes of Mycobacterium leprae and a marked impairment of
specific T cell mediated immunity (Bjorvatn et al, 1976; Bullock, 1978). With increasing
burden of M. leprae or infection, i.e. moving to polar lepromatous form, there is a
decrease in cell mediated immunity; reduced in vitro response to phytohemagglutinin
(PHA) (Han et al, 1974) and M. leprae (Dierk and Shepard, 1965), and reduced delayed
hypersensitivity reaction to lepromin or dinitrichlorobenzene (DNCB) (Waldorf et al.
1966). In the others hand, circulating immune complexes are thought to be responsible
for tissue lesions in lepromatous leprosy, particularly iota those in erythema nodosum
leprosum (ENL). In the present study, circulating immune complexes by polyethylene
glycol-complement consumption(PEG-CC) test and leukocyte migration inhibitory factor
(LIF) production by PHA-stimulated peripheral blood lymphocytes in leprosy patients
was detected. Furthermore we also have attempted to test whether HLA-linked gene
acts as a genetic marker for responding and clearing M. leprae antigen and immune
complex.
In conclusion:
1. Circulating immune complexes are significantly increased in the sera from
lepromatous leprosy and tuberculoid leprosy compared to normal controls. However there
are no significant differences between the level of circulating immune complexes in the
sera from lepromatous leprosy patients and that from tuberculoid leprosy patients.
2. Circulating immune complexes in the sera from lepromatous leprosy patients with
ENL or neuralgia are significantly increased.
3. It is suggested that circulating immune complexes in the sera from lepromatous
leprosy patients are decreased after bacteriologically negative conversion by the
treatment, but not significant.
4. There is no correlation between HLA-DR2, DR4 or DRw9 antigens and circulating
immune complexes in leprosy patients.
5. With PHA stimulation, the leukocyte migration indices were 70.5±18.8 in lepromatous
leprosy, 56.0±15.4 in tuberculoid leprosy and 57.0±13.9 in healthy control group. LIF
production is significantly impaired in leprosy, particularly in circulating immune complex
positive leprosy patients.(p<0.05)
It is conclude4 that in lepromatous leprosy, circulating immune complexes in sera are
increased, but the production of LIF by peripheral blood lymphocytes with stimulation of
PHA is impaired.
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