Fine-needle aspiration cytology of liver allografts in the pig.

We have analyzed the inflammatory changes in pig liver allografts and autografts by fine needle aspiration biopsy (FNAB) and correlated the cytological findings with transplant histology and changes in recipient blood. In nonimmunosuppressed piglets (n = 9) the inflammatory episode of rejection occurred promptly, peaked on days 4-7, and thereafter subsided in cases in which the graft was accepted (n = 6). The early inflammatory infiltrate consisted of all major types of inflammatory leukocytes, including T lymphoblasts, B plasmablasts, and plasma cells, lymphocytes and monocytes; macrophages dominated the late inflammatory lesion of irreversible rejection. In piglets that died of rejection (n = 3), the inflammation peaked earlier and the total amount of inflammation, including the frequency of blast cells and mononuclear phagocytes, was higher. These differences were, however, statistically insignificant and not predictive for irreversible rejection. In sham-operated autograft recipients (n = 5) no inflammation was recorded in the graft. Application of cyclosporine (n = 5), significantly suppressed the total inflammation (P = 0.02 and 0.06 on days 4 and 7, respectively) and delayed the peak; in addition, both the blastogenic component (P = 0.08 on day 4) and the mononuclear phagocyte component (P = 0.03 on day 7) were clearly suppressed. These inflammatory changes, recorded by the FNAB, had a close correlation with biopsy histology. On the other hand, determinations of S-ASAT, S-ALAT, and S-AFOS was not correlated with the episodes of rejection, and no characteristic changes were seen in blood cytology during the rejection episodes either.