Immunoglobulin gene polymorphisms are susceptibility factors in clinical and autoantibody subgroups of the idiopathic inflammatory myopathies.
OBJECTIVE
To investigate possible associations of GM and KM markers with adult and juvenile forms of the idiopathic inflammatory myopathies (IIMs) in Caucasian and African American patients.


METHODS
We performed serologic analyses of polymorphic determinants associated with immunoglobulin gamma heavy chains (GM) and kappa light chains (KM) in large populations of Caucasian patients (n= 514 [297 adults and 217 children]) and African American patients (n=123 [73 adults and 50 children]) with IIM representing the major clinical and autoantibody groups.


RESULTS
For Caucasian patients with dermatomyositis (DM), the Gm 3 23 5,13 phenotype was a risk factor in both adults (odds ratio [OR] 2.2, corrected P [Pcorr]=0.020) and children (OR 2.2, Pcorr=0.0013). Of interest, the GM 13 allotype was a risk factor for juvenile DM in both Caucasian subjects (OR 3.9, Pcorr<0.0001) and African American subjects (OR 4.8, Pcorr=0.033). However, the Gm 1,3,17 5,13,21 phenotype was a risk factor for juvenile DM in Caucasian subjects but not African American subjects. Among the IIM autoantibody groups, Gm 3 23 5,13 was a risk factor in Caucasian adults with anti-Jo-1 autoantibodies (OR 3.4, Pcorr=0.0031), while the GM 3 allotype was protective in adults with anti-threonyl-transfer RNA synthetase or anti-U RNP autoantibodies (OR 0.1, Pcorr=0.047 and OR 0.2, Pcorr=0.034, respectively). In contrast, GM 6 was a risk factor in African American adults with anti-signal recognition particle autoantibodies (OR 7.5, Pcorr=0.041).


CONCLUSIONS
These data suggest that polymorphic alleles of GM and KM loci are differentially associated with IIM subgroups defined by age, ethnicity, clinical features, and autoantibody status, and expand the list of immune response genes that are possibly important in the pathogenesis of myositis.
O'Hanlon
Terrance P
TP
National Institute of Environmental Health Sciences, NIH, Bethesda, Maryland 20892, USA. ohanlont@niehs.nih.gov
Rider
Lisa G
LG
Schiffenbauer
Adam
A
Targoff
Ira N
IN
Malley
Karen
K
Pandey
Janardan P
JP
Miller
Frederick W
FW
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D001323:Autoantibodies / Q000276:immunology; D016022:Case-Control Studies; D003882:Dermatomyositis / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D007129:Immunoglobulin Gm Allotypes; D007131:Immunoglobulin Km Allotypes; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D017285:Polymyositis / Q000235:genetics*; D012307:Risk Factors; D044465:White People
D001323:Autoantibodies; D007129:Immunoglobulin Gm Allotypes; D007131:Immunoglobulin Km Allotypes