HLA ANTIGENS AND COMPLEMENT C4 ALLOTYPES IN PATIENTS WITH CHRONIC BIOLOGICALLY FALSE-POSITIVE (CBFP) SEROREACTIONS FOR SYPHILIS - A FOLLOW-UP-STUDY OF SLE PATIENTS AND CBFP REACTORS

We report a follow-up of our previous study of HLA markers in 118 unre lated patients: 49 with definite systemic lupus erythematosus (SLE) (g roup 1), 32 with definite or probable SLE and chronic biologically fal se positive (CBFP) seroreactions for syphilis (group 2), and 37 CBFP r eactors (group 3). Definite SLE was confirmed in 28 (90.3%) of the pat ients in group 2, equally in HLA B8- and HLA B7-positive patients. Thr ee of the CBFP reactors developed SLE, two (40%) out of five HLA B8-po sitive as compared to one (6.6%) out of 15 HLA B7-positive CBFP reacto rs (P = 0.07). Fourteen patients died (groups 1 and 2). Eight of the 2 4 HLA B8-positive patients died in contrast to one of the 20 HLA B7-po sitive patients (P < 0.02). Of the CBFP reactors, 70.9% had complement C4 null alleles as compared to 47.9% in controls (P = 0.05) and 50% h ad C4A null alleles as compared to 17.8% in controls (P < 0.05). C4B n ull alleles were found in 28.6% (28.6% in controls, P is not significa nt). The null alleles for C4A were not solely in a linkage disequilibr ium with the HLA B8 DR3 haplotype. CBFP reactors with C4A null alleles had a higher risk of developing SLE, lupus-like disease or symptoms s uch as photosensitivity, cutaneous vasculitis and/or autoantibodies th an did those with no C4A null alleles (P < 0.02).