H. Locht et al., Anti-lactoferrin antibodies and other types of anti-neutrophil cytoplasmicantibodies (ANCA) in reactive arthritis and ankylosing spondylitis, CLIN EXP IM, 117(3), 1999, pp. 568-573
Fifty-five serum samples from patients with reactive arthritis (ReA), 40 fr
om patients with ankylosing spondylitis (AS) and three from patients with c
hronic sacroiliac joint arthritis were analysed for the presence of ANCA of
IgG class by means of enzyme immunosorbent assay using lactoferrin (Lf), m
yeloperoxidase (MPO) and antigen extracted from azurophil granules ('alpha-
antigen') containing proteinase 3 (PR3) as substrate. IgG-ANCA were found i
n 31 (56%) patients with ReA. Twenty-three (42%) had anti-if antibodies, ni
ne (16%) had anti-MPO and eight (15%) had anti-alpha-antigen antibodies, no
ne of which reacted with PR3. Only six ( 14%) AS or sacroiliac joint arthri
tis patients had ANCA (P<0.001). Three (7%) had anti-if, two (5%) anti-MPO
and two (5%) anti-alpha-antigen antibodies. Yersinia and Salmonella bacteri
a were separated by SDS-PAGE and blots were incubated with serum from rabbi
ts immunized with human if. The hyperimmune serum recognized a band of 78 k
D from both bacteria which was not seen when preimmune serum was used. The
reaction to the 78-kD antigen could be completely inhibited when anti-if an
tibodies were absorbed on if coupled to cyanogen bromide-activated Sepharos
e, possibly indicating cross-reacting epitopes in if and enterobacterial an
tigen.