Abstracts
1999 Digestive Disease Week

# 2199 PERIPHERAL LYMPHOCYTE REDUCTION IN SEVERE ACUTE PANCREATITIS IS CAUSED BY APOPTOSIS
Yoshifumi Takeyama, Kozo Takase, Takashi Ueda, Yuichi Hori, Masahiro Goshima, Masahiro Yamamoto, Yoshikazu Kuroda, Kobe Univ Sch of Medicine, Kobe Japan

Sepsis due to infectious complication has become the most serious problem in severe acute pancreatitis (SAP). To investigate significance of impairment of cellular immunity in SAP, alterations of peripheral lymphocyte in acute pancreatitis were examined. Clinically, 48 cases with SAP were divided into two groups; 30 cases without infectious complications, 18 cases with infectious complications. Peripheral lymphocytes were counted on admission, and subclasses of the lymphocytes were analyzed. In addition, peripheral lymphocytes were collected on admission, and cell cycle analysis was made by FACscan using propidium iodide staining. Experimentally, peripheral lymphocytes were counted and analyzed for their subclasses in rats with SAP, which was induced by retrograde infusion of 20% deoxycholate into biliopancreatic ducts. Furthermore, intracellular Ca2+ concentration ([Ca2+]i) was measured. Clinically, peripheral lymphocytes were significantly reduced on admission in the cases with infection (622±90/ml) in comparison with those in the cases without infection (1095±138/ml). Both B- and T-lymphocytes were reduced from peripheral circulation in the cases with infection, and CD8-positive lymphocytes were dominantly reduced in T-lymphocytes (105±32/ml with infection, vs. 313±60/ml without infection, p£0.05). Cell cycle analysis after 24-h incubation showed that apoptotic change occurred in the lymphocytes from the cases with SAP, but not in the lymphocytes from healthy controls. In experimental pancreatitis, total peripheral lymphocytes and T-lymphocytes were significantly reduced 5 h after induction of pancreatitis (p£.05, vs. sham operation). [Ca2+]i of lymphocyte was significantly significantly elevated in the rats with pancreatitis, and the sera collected from the rats with pancreatitis induced [Ca2+]i elevation on normal lymphocytes in vitro. In conclusion, peripheral lymphocytes, mainly CD8-positive T lymphocytes are eliminated from systemic circulation due to apoptosis in SAP, possibly resulting in development of infectious complications. [Ca2+]i elevation induced by serum factor(s) may be involved in lymphocyte apoptosis in SAP.

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