Mycobacterium leprae infection and serum lactoferrin levels

Serum lactoferrin level, using competitive enzyme linked immunosorbent assay (ELISA) method, was estimated in 298 leprosy patients admitted into the hospital and attending the out-patient department of the Schieffelin Leprosy Research and Training Center. Serum from an equal number of non-leprosy individuals served as control. Mean (SD) of serum lactoferrin in non-leprosy individuals was 0.277 (0-092) microg/ml while in leprosy patients it was 0.494 (0.394) microg/ml, the difference being significant (P=0.0001). Serum lactoferrin levels were not significantly associated with type 2 reactions (P=0.613). Serum lactoferrin was significantly associated with age (P = 0.006), duration of the disease (P=0.0001), DDS monotherapy (P =0.007), deformity (P= 0.005), average bacterial index (BI) (P=0.01) and smear positivity (P=0.0001), orbicularis oculi weakness (P= 0.001), lagophthalmos (P = 0.002), corneal opacity (P = 0.001) and cataract (P=0.004) in simple regression analysis. All these variables, with the exception of smear positivity (P=0.019), lost their significance (P>0.05) when analysed using multiple regression. Serum lactoferrin showed poor association with type 1 (P = 0.286) and type II reactions (P = 0.613) and iridocyclitis (P = 0.207). We conclude that serum lactoferrin is strongly and inversely associated with increasing BI but does not show significant association with type 2 reactions.