Southern Blot Analysis of Rheumatoid Arthritis

The methods and materials used in the Southern blot analysis of rheumatoid arthritis (RA) study were identical to the conditions used in the core and family study sections of the Tenth Workshop (10WS) Southern blot component. This allowed a direct comparison of the fragments seen in the study films with the fragments seen on the 10WS standard films. Informative data were available from three laboratories: SAF/DUT, US3/TER, and US7/HAN. The DUT laboratory studied 24 South African Blacks (12 patients and 12 controls). Ten pairs were complete DR matches. DUT used, the enzymes BamHI, EcoRI and TaqI, and probes for DRB, DQB, DPB, DQA, and class I. The TER laboratory studied 24 Caucasians (12 patients and 12 controls). Ten pairs were DR-matched. The two patients who were not DR matched with their controls were both typed as DR4, DN1. The HAN laboratory studied 12 patients and 12 controls, all of whom were DR-matched. Both TER and HAN used the enzymes BamHI, HindIII, and TaqI, and probes for DRB and DQB. TER also used DPB while HAN used DQA. When data for the same enzymes and probes were available, the TER and HAN data were combined. The frequencies of DR4 in these patient groups were: DUT, 3/12 (25%); HAN, 10/12 (83%); and TER, 5/12 (42%) (Table 1).