HLA typing and karyotyping of limited numbers of lymphocytes is facilitated by in vitro expansion with TCGF.

It is often difficult to obtain sufficient quantities of leukocytes from bone marrow (BM) transplant recipients for post-transplant immunological monitoring and evaluation of engraftment. We have developed a cell culture expansion technique that allows HLA-A,B, and DR typing as well as karyotyping on limited numbers (less than 10(7)) of lymphocytes. Lymphocytes from healthy control donors were allo-activated in vitro and further expanded by culturing in T-cell growth factor (TCGF). After 14 days of culture, these cells were sent for blind HLA-A,B and DR typing and for karyotyping. Surface marker studies showed that 90% of the T-cells expanded in growth factor are OK-la positive. HLA typing with these DR-bearing in vitro expanded T-cells showed excellent correlation with HLA typing on fresh unexpanded lymphocytes. Karyotyping of expanded T-cells showed normal male or female cells as expected. This technique may be especially valuable when testing pediatric or adult patients with very low lymphocyte counts.