CYTOKINE MESSENGER-RNA EXPRESSION BY DONOR-SPECIFIC CYTOTOXIC T-CELL CLONES AFTER ALLOGENEIC HEART-TRANSPLANTATION

Background: After heart transplantation, expression of various cytokin es can be detected in endomyocardial biopsy specimens both in the pres ence and in the absence of rejection. In this study we have analyzed t he contribution of donor-specific CD8(+) cytotoxic T cells to intragra ft cytokine expression. Methods: T cells were propagated from endomyoc ardial biopsy specimens in medium containing interleukin-2 and interle ukin-il. From the T-cell lines obtained, T-cell clones were generated by limiting dilution. A number of 15 CD8(+) donor-specific cytotoxic T -cell clones were generated from a single T-cell line and were analyze d for their cytokine messenger RNA expression. The cytokine profile of the clones was studied on the mRNA level by reverse transcriptase pol ymerase chain reaction. Results: Almost all clones expressed mRNA for interleukin-1 beta, interleukin-4, and interleukin-10, and 75% of the clones expressed mRNA for interleukin-1 alpha, interleukin-9, and tumo r necrosis factor-beta. In about half of the clones expression of inte rleukin-2, interleukin-6, interleukin-8, and interferon-gamma was dete cted. Tumor necrosis factor-alpha was only detected in one of the clon es. The cytokine profiles exhibited a considerable heterogeneity. The 15 clones had previously been analyzed for their T-cell receptor V bet a-gene family expression and T-cell receptor V-D-J region sequence. Ho mology in the V-D-J regions of the clones indicated that the 15 clones were derived from a limited number of progenitor cells. Interestingly , clones derived from one progenitor expressed a different mRNA cytoki ne profile. Conclusions: This study shows that donor-specific cytotoxi c T cells can contribute to the spectrum of locally produced cytokines . The cytokine expression of these cytotoxic T cells seems not to be l imited to a distinct profile.