Who is the best matched donor or control based on the CPMs in a one-way MLC?

In a one-way mixed lymphocyte culture (MLC), the aim is to assess the compatibility between donor and recipient through cellular responses. The CPM, or counts per minute, reflects the level of cellular proliferation and indicates how well the recipient's cells can react to the donor's cells. The higher the CPM value, the greater the response, suggesting a stronger immunologic individuality.

The most suitable donor or control from siblings is typically the one that shows the lowest level of cellular proliferation when cultured with the patient's cells. This is indicative of better histocompatibility, as a low proliferation response suggests that the recipient's immune system does not perceive the donor cells as foreign, minimizing the likelihood of graft rejection.

In this scenario, sibling #2 is indicated as the best match based on the CPM, which means they produced the lowest response in the MLC testing with the patient’s cells. This outcome suggests that sibling #2 has a greater degree of matching antigens with the patient compared to the other options, indicating they would be the most immunologically compatible donor for transplantation or cellular therapy. A better match in this context can also mean a lower risk of complications post-transplant.