A pair of naturally occurring antibodies may dampen complement-dependent phagocytosis of red cells with a positive antiglobulin test in healthy blood donors.

BACKGROUND AND OBJECTIVE: It is known that red blood cells (RBC) from healthy blood donors with a positive direct antiglobulin test (DAT) for IgG continue to circulate despite carrying elevated numbers of IgG molecules. To unravel the properties of these RBC-bound IgG, we studied them not only on whole RBC populations, but also on density-fractionated RBCs. MATERIALS AND METHODS: The properties of acid-eluted RBC-bound IgG and plasma IgG were studied by ELISA for binding to RBC proteins and opsonins, and by blotting. In vitro phagocytosis was studied on density-separated RBCs. RESULTS: IgG-DAT-positive blood donors carried most IgG molecules on dense RBCs and had more RBCs of high density than DAT-negative controls. Their densest RBCs were older than the oldest RBCs of DAT-negative controls, based on the band 4.1a/b ratio. In vitro phagocytosis of senescent RBCs from IgG-DAT-positive donors was 1.5 to 2 fold higher than that of senescent control cells, but the same or less in the presence of physiological IgG concentrations, implying that RBC-bound IgGs impaired complement-dependent uptake. The IgG molecules on these DAT-positive RBCs comprised anti-band 3 naturally occurring antibodies (NAbs) and were two- to fivefold enriched in anti-C3 and framework-specific anti-idiotypic NAbs as compared to controls. Correspondingly, anti-C3 and framework-specific anti-idiotypic NAbs were proportionally elevated in the plasma of two-thirds of DAT+ donors. CONCLUSIONS: Extra-binding of anti-C3 together with anti-idiotypic NAbs to senescent RBC-associated C3 fragments may suppress complement-dependent RBC phagocytosis and may prolong the in vivo life span of RBCs.

[Hormone therapy of postoperative recurrent pancreatic carcinoma with octreotide and tamoxifen]. / Hormontherapie des postoperativ rezidivierten Pankreascarcinoms mit Octreotid und Tamoxifen.

BACKGROUND: In a prospective trial (October 1996-April 1998) the effect of octreotide and tamoxifen on the recurrence of pancreatic carcinoma after R0 resection was evaluated. METHODS: Patients with a local recurrence after curative resection of ductal adenocarcinoma of the pancreas were treated with 100 micrograms of octreotide three times a day and tamoxifen 20 mg once daily. The median survival time, quality of life (EO-RTC-QLQ-30) and side effects of the octreotide-tamoxifen group were compared with a historic cohort (n = 14) of patients treated in our department (9/95-9/96) according to the "best supportive care" concept. RESULTS: Recurrences were diagnosed after R0 resection in a mean time of 13 +/- 6.8 months. Patients treated with octreotide and tamoxifen had a significantly (P < 0.05) longer median survival time (7 months; range: 3-12) vs 3.5 months; range: 1.5-5). The octreotide-tamoxifen group suffered less from lack of appetite, nausea, fatigue, and pain and needed fewer analgesics. The only side effect of the octreotide-tamoxifen therapy was moderate diarrhea in 2 patients at the beginning of the therapy. CONCLUSION: Since combined therapy with octreotide and tamoxifen can be administered comfortably for outpatient treatment, this seems to represent progress in the palliative therapy of pancreatic cancer.