Chimeric acceleration by donor CD4+CD25+T-reg depleted fraction in splenocyte transplantation.

BACKGROUND: We have established a splenocytic chimera model that can induce donor-specific tolerance and reconstitute the recipient immune system by donor splenocytes. AIM: To accelerate such reconstitution, we investigated the role of donor-derived CD4(+)CD25(+) regulatory T-cells (T-reg). METHODS: We established C3H/B6D2F1 mixed bone marrow chimeras in lethally irradiated C3H mice. We transplanted skin grafts from C57BL/6 mice 30 d later. After an additional 30 d, we transplanted the following types of splenocytes from B6C3F1 mice: total splenocytes (group A), CD4(+)CD25(+) T-reg depleted splenocytes (group B), CD8(+)-depleted splenocytes (group C), and CD4(+)-depleted splenocytes (group D). We assessed class I major histocompatibility complex, percentage of chimeric cells in peripheral blood, and survival of skin grafts in each group. RESULTS: Group A and B mice switched to splenocytic chimeras, permitting the long-term survival of skin grafts. The proportions of H-2K(b+)H-2K(k-) cells in group B were significantly lower than those in group A on day 14 (0.47% ± 0.68% versus 9.49% ± 8.30%; P = .01) and day 21 (0.16% ± 0.25% versus 3.35% ± 2.78%; P = .01). The initial increase in the proportion of H-2K(b+)H-2K(k+) double-positive cells in group B was faster than that in group A (from 0.33% ± 0.10% versus. 0.39% ± 0.14% before splenocyte injection to 39.03% ± 30.50% versus 10.73% ± 11.54% on day 7; P = .02). The initial increase in the proportion of CD8(+) T-cells was faster in group B than in group A (from 2.72% ± 0.52% versus 2.49% ± 1.07% before splenocyte injection to 29.61% ± 26.72% versus 4.92% ± 1.56% on day 7; P = .04). CONCLUSIONS: The depletion of CD4(+)CD25(+) T-reg fraction in donor splenocytes can accelerate switching to splenocytic chimera.

Partially MHC-matched donor CD8+ T cells are indispensable for switching to splenocytic chimerism.

BACKGROUND: We have shown that partially major histocompatibility complex (MHC)-matched splenocytes can replace bone marrow (BM) and maintain skin grafts by establishing splenocytic chimeras. Our aim was to identify the population of splenocytes that are indispensible for switching from BM to splenocytic chimerism. METHODS: C3H/B6D2F1 mixed BM chimeras were established in lethally irradiated C3H mice. Skin grafts from C57BL/6 mice were transplanted 30 d later. After an additional 30 d, splenocytes from B6C3F1 mice were transplanted to establish splenocytic BM chimeras using total splenocytes (group A), CD90(+)-depleted splenocytes (group B), CD4(+)-depleted splenocytes (group C), or CD8(+)-depleted splenocytes (group D). RESULTS: In group A, the BM switched to splenocyte-derived BM chimeras. Total B6C3F1 splenocytes created stable splenocyte BM chimeras that permitted long-term retention of skin grafts, without rejection. In groups B and D, the splenocytes failed to replace the recipient BM, and there was no decrease in the number of recipient-derived BM cells compared with group A from d 14 to 28 after splenocyte injection, as was the case for CD8(+) T cells. In group C mice, the recipient BM was slowly and incompletely replaced. CONCLUSIONS: Partially MHC-matched donor CD8(+) T cells are indispensable for generating splenocyte chimeras in BM and maintaining allogeneic skin grafts.

Arterial stimulation and venous sampling (ASVS) is useful for recurrent lesions of insulinoma: a case report.

We encountered a recurrent case of benign solitary insulinoma in the pancreatic tail, which may have been caused by an inadequate surgical margin in the use of an ultrasonic dissector. A 45-year-old man was referred with hypoglycemia and diagnosed solitary insulinoma in the pancreas. Laparoscopic pancreatic enucleation was performed using an ultrasonic dissector. The tumor was extracted and the surgical margins were microscopically negative. Six years later, he presented with hypoglycemia again. Multiple small well-enhanced lesions were detected by computed tomography distant from the resection stump of the first operation. He underwent resection of all visible lesions with omentum and wide excision of the soft tissue surrounding the pancreas after preoperative arterial stimulation and venous sampling test. The postoperative course of the second operation was uncomplicated and the patient presents no sign of hypoglycemia after 12 months.