There is much evidence that in human immunodeficiency virus type 1 (HIV-1)-infected individuals, strong cytotoxic T lymphocyte (CTL)-mediated immune pressure results in the selection of HIV-1 mutants that have escaped from wild-type-specific CTLs. If escape mutant-specific CTLs are not elicited in new hosts sharing donor HLA molecules, the transmission of these mutants results in the accumulation of escape mutants in the population. However, whether escape mutant-specific CTLs are definitively not elicited in new hosts sharing donor HLA molecules still remains unclear. A previous study showed that a Y-to-F substitution at the second position (2F) of the Nef138-10 epitope is significantly detected in HLA-A*2402 ؉ hemophilic donors. Presently, we confirmed that this 2F mutant was an escape mutant by demonstrating strong and weak abilities of Nef138-10-specific CTL clones to suppress replication of the wild-type and 2F mutant viruses, respectively. We demonstrated the existence of the 2F-specific CTLs in three new hosts who had been primarily infected with the 2F mutant. The 2F-specific CTL clones suppressed the replication of both wild-type and mutant viruses. However, the abilities of these clones to suppress replication of the 2F virus were much weaker than those of wild-type-specific and the 2F-specific ones to suppress replication of the wild-type virus. These findings indicate that the 2F mutant is conserved in HIV-1-infected donors having HLA-A*2402, because the 2F-specific CTLs failed to completely suppress the 2F mutant replication and effectively prevented viral reversion in new hosts carrying HLA-A*2402.

Mucinous cystic neoplasm (MCN) of the pancreas is characterized by mucin-producing columnar epithelium and an ovarian-type stroma. It occurs almost exclusively in women and is almost always located in the pancreatic body or tail. Here, we report a case of large MCN located in the pancreatic head but not in the body nor tail in a 32-year-old pregnant woman, which was thought to have grown rapidly during pregnancy. It was ruptured at 34 weeks of gestation and the patient was admitted to the emergency department of the University of Fukui Hospital with an acute abdomen. Emergency cesarean section followed by pancreaticoduodenectomy was performed. The tumor consisted of many small cysts lined by a single-layer of mucinous epithelium with papillary growth and partial solid parts showing invasive growth and sarcomatoid changes, indicating mucinous cystic neoplasm with an associated invasive carcinoma (previously referred as mucinous cystadenocarcinoma). Thickened septa revealed ovarian-type stroma strongly positive for α-inhibin and partly positive for progesterone receptor immunohistochemically. We also review and discuss previous reports of MCNs including those with an associated invasive carcinoma in pregnant patients.

HLA-B*52:01-C*12:02, which is found in approximately 20% of all Japanese persons, is well known to be associated with ulcerative colitis and Takayasu arteritis. This haplotype is also known to be protective in individuals infected with human immunodeficiency virus (HIV) type 1. Recent studies showed that HLA-B*52:01-restricted HIV-1-specific T cells suppress HIV-1 and that HLA-C*12:02 together with KIR2DL2 play an important role in natural killer cell-mediated control of HIV-1. However, the role of HLA-C*12:02-restricted cytotoxic T lymphocytes (CTLs) in suppressing HIV-1 replication remains unknown. In the present study, we demonstrated that HLA-C*12:02-restricted CTLs specific for 2 immunodominant epitopes, Pol IY11 and Nef MY9, contributed to the suppression of HIV-1 replication in HIV-1-infected individuals. Further analysis demonstrated that these 2 HLA-C*12:02-restricted CTLs together with 4 HLA-B*52:01-restricted ones effectively suppressed HIV-1 in individuals with the HLA-B*52:01-C*12:02 haplotype. Thus, both HLA-C*12:02 and HLA-B*52:01 alleles contribute to HIV-1 suppression via both HIV-1-specific CTLs and natural killer cells in individuals with this haplotype.

HIV‐1 mutants escaping from HLA‐A‐ or HLA‐B‐restricted CTL have been well studied, but those from HLA‐C‐restricted CTL have not. Therefore we investigated the ability of HLA‐C‐restricted CTL to select HIV‐1 escape mutants. In the present study, we identified two novel HLA‐Cw*1202‐restricted Pol‐specific CTL epitopes (Pol328‐9 and Pol463‐10). CTL specific for these epitopes were detected in 25–40% of chronically HIV‐1‐infected HLA‐Cw*1202+ individuals and had strong abilities to kill HIV‐1‐infected cells and to suppress HIV‐1 replication in vitro, suggesting that these CTL may have the ability to effectively control HIV‐1 in some HLA‐Cw*1202+ individuals. Sequence analysis of these epitopes showed that a V‐to‐A substitution at the 9th position (V9A) of Pol 463‐10 was significantly associated with the HLA‐Cw*1202 allele and that the V9A mutant was slowly selected in the HLA‐Cw*1202+ individuals. Pol 463‐10‐specific CTL failed both to kill the V9A virus‐infected cells and to suppress replication of the V9A mutant. These results indicate that the V9A mutation was selected as an escape mutant by the Pol463‐10‐specific CTL. The present study strongly suggests that some HLA‐C‐restricted CTL have a strong ability to suppress HIV‐1 replication so that they can select HIV escape mutants as in the case of HLA‐A‐restricted or HLA‐B‐restricted CTL.

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