Infectious Agents and Bone Marrow Failure: A Causal or a Casual Connection?

Area of Science:

• Immunology
• Hematology
• Infectious Diseases

Background:

• Acquired bone marrow failure (BMF) syndromes are increasingly viewed as immune-mediated disorders.
• Hematological recovery following immunosuppressive therapy provides indirect evidence for immune cell involvement in BMF pathogenesis.
• Current hypotheses suggest immune dysregulation due to chronic antigen exposure or molecular mimicry between pathogens and self-antigens.

Purpose of the Study:

• To investigate the potential role of infectious agents in the autoimmune response observed in BMF.
• To identify specific T-cell receptor (TCR) sequences associated with BMF and compare them to TCRs found in infectious diseases.

Main Methods:

• Analysis of T-cell receptor (TCR) sequences from patients with acquired bone marrow failure (BMF).
• Comparison of BMF-associated TCR sequences with known TCRs from various infectious diseases, including cytomegalovirus (CMV) and Mycobacterium tuberculosis.

Main Results:

• BMF-associated immunodominant T-cell clones (defined by specific TCR sequences) frequently matched TCRs previously identified in infectious diseases.
• Observed associations included TCRs linked to cytomegalovirus (CMV) and Mycobacterium tuberculosis infections.
• These findings suggest a potential cross-reactivity or an unspecific immune expansion driven by pathogens.

Conclusions:

• Infectious pathogens like CMV and M. tuberculosis may play a direct role in initiating autoimmune responses against hematopoietic stem cells in BMF.
• Pathogens might trigger autoimmunity through cross-reactivity or contribute to BMF via unspecific immune dysregulation.
• Further research is needed to elucidate the precise mechanisms by which these intracellular pathogens contribute to marrow failure.