Prevalence of Microchimerism in Women with Dilated Cardiomyopathy

Abstract

Microchimerism, or the existence of fetal cells in the maternal circulation, may pesists many years post-partum, and has been postulated as one mechanism for autoimmune illness in women. An auto-immune pathogenesis has been postulated for primary dilated cardiomyopathy in general and peripartum disease in particular. The prevalence of microchimerism in women with dilated cardiomyopathy (DCM) and peripartum disease (PPCM) has not been previously evaluated. Method: We screened for the presence of microchimerism in the peripheral circulation of 121 women with heart failure enrolled in the GRACE Study (Genetic Risk Assessment of Cardiac Events) at the University of Pittsburgh Medical Center. DNA was obtained from peripheral blood by the method of leukocyte centrifugation and cell lysis. The presence of microchimerism was evaluated by PCR amplification using primers which amplified a segment common to both the X and Y chromosome. This would therefore result in a single band in women, with second smaller band (Y band) of equal intensity in male subjects. Persistent microchimerism (of male but not of female orgin) would also be evident by a faint Y band. Eighty-three female subjects with DCM, 11 with PPCM, and 27 with cardiomyopathy due to ischemic heart disease (IschCM) were screened for the presence of microchimersim. Results: Microchimerism was seen in 6 of 83 (8%) subjects with primary dilated cardiomyopathy (Mean age 49 6 17, median age 52, range 29 to 81; LVEF 0.25 6 0.13). Of note, microchimerism was not evident in any of the 11 subjects with a primary diagnosis of PPCM. Microchimerism was also not evident in any of the 27 subjects with an ischemic cardiomyopathy (LVEF 0.25 6 0.07), though the ischemic cohort was older (Mean age 58 6 12, median 60, range 32 to 77). Conclusions: Microchimerism of was evident in women with primary dilated cardiomyopathy but not in a similar cohort with an ischemic etiology of heart failure. Microchimerism was no more prevalent with peripartum disease than in the subjects with primary idiopathic cardiomyopathy. Though the differences in women with ischemic and non-ischemic etiologies potentially are of interest, whether microchimerism is causative or just a reflection of a disturbance in autoimmunity requires further study.