Immunoglobulin (Gm) allotype frequencies in patients with giant bell arteritis and polymyalgia rheumatica

The contribution of non-MHC genes to susceptibility to autoimmune diseases

Genetic studies of experimental models of autoimmune diseases, including systemic lupus-like syndromes and organ-specific autoimmunity, provide major information on genetic control of autoimmune diseases. In addition to genes known to be linked to the major histocompatibility complex (MHC), these studies point to multiple genes located outside the MHC that influence the onset and the progression of autoimmune diseases. Identification of these genes and of their interrelationships is now a major task that will be facilitated by recent progress in molecular biology and gene mapping. Among candidate genes, antigen-receptor genes (i.e., immunoglobulin- and T-cell receptor genes) most likely contribute an important part of the autoimmune susceptibility in several of these animal models. Available linkage data suggest a similar involvement of these antigen-receptor genes in several human autoimmune diseases. In addition to a better understanding of pathogenic mechanisms associated with autoimmunity, the knowledge of these disease-predisposing genes is expected to permit a better classification of often complex syndromes as well as the design of new treatments.

Immunoglobulin allotype Gm(1,2;21) in ankylosing spondylitis with peripheral arthritis

Frequencies of immunoglobulin G (Gm) allotypes were determined in 240 patients with ankylosing spondylitis (AS). The uncommon phenotype Gm(1,2;21) was increased in frequency in 55 patients with AS and peripheral arthritis (14.5% v 3.5% of healthy blood donors; p less than 0.05). In 16 patients with arthritis only of wrist/hand or ankle/forefoot, or both, the Gm(1,2;21) frequency was even higher (31.3%; p less than 0.0005). Patients with AS negative for the HLA antigen B27 (n = 28) differed from the B27 positive patients (n = 205) with regard to the frequency of the Gm(1,2,3;5,21) phenotype (39.3% v 9.3%; p less than 0.0005). These findings support the notion of genetic heterogeneity among patients with AS.

Immunoglobulin C mu gene restriction fragment length polymorphisms associated with chronic renal failure

The DNA's of 41 patients with various forms of renal disease and of 52 controls were investigated for restriction fragment length polymorphisms (RFLP), using a probe recognising the immunoglobulin Cmu heavy chain gene. With the restriction endonuclease Sst 1, 50 of the controls and 12 of the patients had the expected single 4.3 kilobase (kb) fragment. The remaining 29 patients and 2 controls displayed two patterns of banding, 8 patients and 1 control had a 6.8 kb band in addition to the 4.3 kb, and 21 patients and 1 control had a single band of 5.1 kb. In addition, a significant association between high creatinine levels (greater than 150 mumol/l) and abnormal bands was found (21/25 patients with high levels had abnormal bands compared with only 5/16 patients with normal levels). These results are evidence for an association between the human immunoglobulin heavy chain region and renal disease and they apparently confirm an association already reported at the protein level. However, the new RFLP bands, although reproducible and restricted to renal patients, occur in an area where few polymorphisms would be expected. Further, the association with high creatinine suggests some subtle interaction between the creatinine pathway and this area of the human chromosome.