Acetylator phenotypes in rheumatoid arthritis patients with or without adverse drug reactions to sodium-aurothiomalate or d-penicillamine

Multiple drug allergy syndrome: a distinct clinical entity

Multiple drug allergy syndrome is a clinical condition characterized by a propensity to react against different, chemically unrelated antibiotic or nonantibiotic drugs. The origin of this syndrome is still elusive. This article critically examines the medical literature on multiple drug allergy syndrome, compares and discusses recent personal observations obtained in patients with intolerance to multiple antibiotic or anti-inflammatory drugs, suggests possible pathogenic mechanisms for this type of drug allergy, and reports on current personal research in this field.

Polymorphic acetylation: lack of influence of rheumatic disease activity and concomitant drug administration

Acetylation polymorphisms have been linked with a tendency to develop rheumatic diseases. We investigated the effect of changes in the disease activity of patients with rheumatoid arthritis (RA) during disease-modifying antirheumatic drug (DMARD) treatment, and on the capacity of these patients to acetylate the sulphonamide sulphadimidine. Fifty-four patients with RA treated with gold, sulphasalazine or D-penicillamine, 12 patients with AS and 16 patients with non-inflammatory arthritis (NI) were investigated over a 24-week period. The capacity of these individuals to acetylate sulphadimidine was determined at baseline and after 12 and 24 weeks. Although there was a tendency for sulphadimidine acetylation to increase in patients with RA from a median of 84.5% [interquartile range (IQR) 77.0-95.0%] at baseline to 90.5% (IQR 77.5-96.0%) at week 24, this failed to reach statistical significance. In contrast, the trend in patients with AS or NI was towards a decrease in acetylation. There was no correlation between changes in disease activity and sulphadimidine acetylation during DMARD intervention.

Acetylator polymorphism in rheumatoid arthritis

Acetylator phenotype has been determined with sulphamethazine (sulphadimidine) in 69 Spanish patients with rheumatoid arthritis (48 females), all of whom were on second line therapy, and in 96 age-matched normal controls (54 females). Thirty-two patients (46.4%) and 56 controls (58.3%) were classified as slow acetylators. On analysing separately the females in both groups, 37.5% of patients and 63% of controls were found to be slow acetylators. No difference was found in the males (patients 66.3% and controls 52.4% slow acetylators). Rapid acetylator phenotype may be a risk factor for the development of severe rheumatoid arthritis in women.

Rheumatoid arthritis

The results of family and twin studies suggest that RA may result from an interaction between an oligogenic susceptibility and unknown environmental factors. Part of this genetic predisposition is accounted for by genes within the MHC where there is a well-documented association with HLA-DR4. Studies of DR and other MHC variants have shown different associations with particular subgroups. One subgroup is Felty's syndrome where there is a strong association with DR4, as well as associations with DQ-beta and C4B null variants when DR4-matched Felty's and RA subjects are analysed. These DQ-beta and C4B null variants may characterize a single haplotype which is associated with extra-articular disease. A further rheumatoid subgroup characterized by circulating antibodies to native type II collagen, shows an association with HLA-DR3 and 7. Genes on chromosome 14 may also influence susceptibility to RA, probably by interaction with MHC genes and there are different Gm associations for DR4-positive and collagen-antibody-positive rheumatoid subgroups. HLA and Gm markers so far identified only account for a small part of the total genetic predisposition to RA and a third or further loci may also be involved. Possible candidates include T-cell alpha- and beta-chain genes and immunoglobulin light chain genes. One present concept of the genetic predisposition to RA is of several independent immunogenetic pathways each including interactions at two or more loci.