X chromosome monosomy: a common mechanism for autoimmune diseases.
The majority of human autoimmune diseases are characterized by female predominance. Although sex hormone influences have been suggested to explain this phenomenon, the mechanism remains unclear. In contrast to the role of hormones, it has been suggested, based on pilot data in primary biliary cirrhosis, that there is an elevation of monosomy X in autoimmune disease. Using peripheral white blood cells from women with systemic sclerosis (SSc), autoimmune thyroid disease (AITD), or healthy age-matched control women, we studied the presence of monosomy X rates using fluorescence in situ hybridization. We also performed dual-color fluorescence in situ hybridization analysis with a chromosome Y alpha-satellite probe to determine the presence of the Y chromosome in the monosomic cells. In subsets of patients and controls, we determined X monosomy rates in white blood cell subpopulations. The rates of monosomy X increased with age in all three populations. However, the rate of monosomy X was significantly higher in patients with SSc and AITD when compared with healthy women (6.2 +/- 0.3% and 4.3 +/- 0.3%, respectively, vs 2.9 +/- 0.2% in healthy women, p < 0.0001 in both comparisons). Importantly, X monosomy rate was more frequent in peripheral T and B lymphocytes than in the other blood cell populations, and there was no evidence for the presence of male fetal microchimerism. These data highlight the thesis that chromosome instability is common to women with SSc and AITD and that haploinsufficiency for X-linked genes may be a critical factor for the female predominance of autoimmune diseases.
Division of Internal Medicine, Department of Medicine, Surgery and Dentistry, San Paolo School of Medicine, University of Milan, Italy. pietro.invernizzi@unimi.it
Pietro
P
Invernizzi
Monica
M
Miozzo
Carlo
C
Selmi
Luca
L
Persani
Pier Maria
PM
Battezzati
Massimo
M
Zuin
Simona
S
Lucchi
Pier Luigi
PL
Meroni
Bianca
B
Marasini
Silvana
S
Zeni
Mitchell
M
Watnik
Francesca R
FR
Grati
Giuseppe
G
Simoni
M Eric
ME
Gershwin
Mauro
M
Podda
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000235:genetics*; D001402:B-Lymphocytes / Q000648:ultrastructure; D016022:Case-Control Studies; D002678:Chimera / Q000235:genetics; D041321:Chromosomes, Human, X / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics; D005260:Female; D006111:Graves Disease / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D066298:In Vitro Techniques; D008875:Middle Aged; D009006:Monosomy; D012595:Scleroderma, Systemic / Q000235:genetics*; D012727:Sex Characteristics; D012729:Sex Chromosome Aberrations; D013601:T-Lymphocytes / Q000648:ultrastructure; D013967:Thyroiditis, Autoimmune / Q000235:genetics*