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Updated: Jun 2, 2026
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Male microchimerism in peripheral blood leukocytes from women with multiple sclerosis
Evan M Bloch1, William F Reed, Tzong-Hae Lee
1International Research and Training; Blood Systems Research Institute (BSRI); San Francisco, CA, USA.
Background:
Fetal microchimerism (F-MC), the persistence of fetal cells in the mother, is frequently encountered following pregnancy. The high prevalence of F-MC in autoimmune disease prompts consideration of the role for immune tolerance and regulation. This study examines the association between F-MC and multiple sclerosis (MS), an autoimmune disorder, of undetermined etiology.
Results:
21 out of 51 MS-positive subjects (41%) were classified as positive for F-MC; 4 of 22 (18%) of MS-negative sibling controls, were also positive for MC (p = 0.066). Unanticipated F-MC in controls lead to re-evaluation using 30 female singleton cord blood units (CBUs) as a biological control. Four CBUs were low-level positive.
Study Design And Methods:
Seventy-three female subjects were assigned to three groups according to disease status and pregnancy history: (1) MS positive (+) women with a history of one male pregnancy before symptom onset (n = 27); (2) MS negative (-) female siblings of MS(+) women with a history of one male pregnancy (n = 22); and (3) MS(+) women that reported never having been pregnant (n = 24). Ten micrograms of genomic DNA obtained from peripheral blood leukocytes of each subject were analyzed for F-MC using allele-specific real-time PCR targeting the SR-Y sequence on the Y-chromosome. MC classification was dichotomous (positive vs. negative) based on PCR results.
Conclusion:
The association between F-MC and MS warrants further study to define this relationship. F-MC in women self-reporting as nulligravid, supports previous findings that a significant proportion of pregnancies go undetected. This lead to re-validation of a Y-chromosome based assay for F-MC detection.
Insights
Fetal microchimerism (F-MC), fetal cells persisting in mothers, was investigated for its association with multiple sclerosis (MS). While F-MC was detected in MS patients, its presence in controls suggests undetected pregnancies and necessitates further research.
Area of Science:
- Immunology
- Genetics
- Reproductive Biology
Background:
- Fetal microchimerism (F-MC) involves fetal cells persisting in mothers, a phenomenon observed post-pregnancy.
- The prevalence of F-MC in autoimmune diseases suggests a role in immune tolerance and regulation.
- The etiology of multiple sclerosis (MS) remains unclear, prompting investigation into F-MC's potential contribution.
Purpose of the Study:
- To examine the association between fetal microchimerism (F-MC) and multiple sclerosis (MS).
- To investigate the presence of F-MC in MS patients and compare it with controls.
- To explore the implications of F-MC detection in women reporting no pregnancies.
Main Methods:
- Seventy-three female subjects were categorized into MS-positive with male pregnancy history, MS-negative siblings with male pregnancy history, and MS-positive never-pregnant women.
- Genomic DNA from peripheral blood leukocytes was analyzed for F-MC using allele-specific real-time PCR targeting the Y-chromosome's SR-Y sequence.
- Microchimerism classification was dichotomous (positive/negative) based on PCR results.
Main Results:
- Fetal microchimerism (F-MC) was detected in 41% of MS-positive subjects and 18% of MS-negative sibling controls (p=0.066).
- Unanticipated F-MC in controls led to re-evaluation using cord blood units as a biological control, with four units showing low-level positivity.
- The presence of F-MC in women reporting nulligravidity suggests a proportion of pregnancies may go undetected.
Conclusions:
- The association between F-MC and MS requires further investigation to clarify the relationship.
- F-MC detection in nulligravid women supports the hypothesis of undetected pregnancies.
- The study led to re-validation of the Y-chromosome based assay for F-MC detection.
