Human leucocyte antigen-defined microchimerism early post-transplant does not predict for stable lung allograft...

Area of Science:

• Transplantation immunology
• Cellular biology
• Immunogenetics

Background:

• Microchimerism involves the presence of foreign cells, typically below 1% of total cells, a phenomenon observed in solid organ transplantation.
• Understanding donor-derived cell dynamics is crucial for managing post-transplant outcomes.

Purpose of the Study:

• To quantify donor-derived cellular subsets longitudinally in human leucocyte antigen (HLA)-mismatched lung transplant recipients (LTR) within the first post-operative year.
• To evaluate the pattern of peripheral microchimerism and its association with clinical outcomes.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) were isolated from LTR who received HLA-B44 allografts but were not HLA-B44 matched.
• Cells were sorted flow cytometrically into three subsets: B cells/monocytes, T/NK cells, and dendritic cells (DC).
• Real-time quantitative polymerase chain reaction (q-PCR) was used to detect and quantify donor-derived HLA-B44 cells.

Main Results:

• Donor-derived HLA-B44 microchimerism was a common finding, detected in 61% of patients.
• The frequency of donor-derived cells varied over time and between cellular subsets: 38% in B cells/monocytes, 56% in T/NK cells, and 11% in DCs.
• Microchimerism was not consistently associated with favorable clinical outcomes in the first year post-lung transplantation.

Conclusions:

• Donor-derived microchimerism is prevalent in the early post-lung transplant period.
• The distribution of microchimeric cells varies significantly across different immune cell populations.
• The presence of microchimerism alone does not predict favorable clinical outcomes in lung transplant recipients within the first year.