WT1-specific CD8 + cytotoxic T cells with the capacity for antigen-specific expansion accumulate in the bone marrow in MDS.

Wilms' tumor 1 (WT1) is a tumor-associated antigen and immunotherapy target in myelodysplastic syndrome (MDS). Further information is needed on the characteristics of WT1-specific CD8 + T cells to develop immunotherapeutic strategies for MDS. To clarify the frequency, distribution, and phenotype of WT1-specific CD8 + T cells, which occur innately in MDS patients, we analyzed paired peripheral blood (PB) and bone marrow (BM) samples from 39 patients with MDS or acute myeloid leukemia with myelodysplasia-related changes. The median frequency of WT1 tetramer-binding CD8 + T cells in the CD8 + T cell population was 0.11% in PB and 0.18% in BM. A further tetramer assay combined with mixed lymphocyte peptide culture (MLPC assay) was used to detect functional WT1-specific CD8 + T cells that could respond to the WT1 peptide. Functional WT1-specific CD8 + T cells were detected in BM in 61% of patients, which was significantly higher than in PB (23%, p = 0.001). The frequency of these cells estimated by the MLPC assay was tenfold higher in BM than in PB. The majority of WT1 tetramer-binding CD8 + T cells in BM had a unique phenotype with co-expression of CD39 and CXCR4. These findings will facilitate the development of novel immunotherapeutic strategies for MDS.

Rhnull phenotype caused by a novel RHAG mutation, c.945+1G>A, in the Japanese population.

BACKGROUND: The Rh complex contributes to cell membrane structural integrity of erythrocytes. Rhnull syndrome is characterized by the absence of the Rh antigen on the erythrocyte membrane, resulting in chronic hemolytic anemia. We recently came across 3 Rhnull phenotype probands within two families with the same novel RHAG mutation in the Japanese population. MATERIALS AND METHODS: Detailed Rh phenotyping by hemagglutination was performed using monoclonal and polyclonal anti-D, -C, -c, -E, and -e; monoclonal and polyclonal anti-Rh17 antibodies; and polyclonal anti-Rh29 antibodies. RHAG mRNA transcripts were analyzed by reverse transcription-polymerase chain reaction, and the mutation was verified by genomic sequencing. RESULTS: The genomic region spanning exon 6 contained a G > A transition in the invariant GT motif of the 5' donor splice-site of Intron 6 (c.945+1G>A). The Rhnull phenotype was caused by an autosomal recessive mutation in Probands 1 and 2, determined by family history. Regarding clinical features, the degree of hemolysis varied slightly between these individuals, with Proband 3 displaying acute hemolytic anemia with an infection. While no standard therapy has been established, the condition of the patient in this study improved with conservative treatment, including hydration and antibiotics. CONCLUSION: The mechanisms of hemolysis due to the Rhnull phenotype can vary, but our findings indicate that acute hemolytic crisis caused by the Rhnull syndrome could be associated with infection.

Magnetic resonance imaging of bone marrow for TAFRO syndrome.

We report two cases of TAFRO syndrome, which is characterized by thrombocytopenia, anasarca, fever, renal insufficiency, and organomegaly. Magnetic resonance imaging (MRI) of the spine showed a dark medullary pattern in the bone marrow on the T1- and T2-weighted images of both patients. One patient showed complete resolution after treatment. Serial MRIs of the improved patient revealed a transition to a normal marrow pattern on both images, which might represent resolution of the disease.

Cladribine treatment for Erdheim-Chester disease involving the central nervous system and concomitant polycythemia vera: A case report.

Erdheim-Chester disease (ECD), a rare form of non-Langerhans cell histiocytosis, is characterized by the infiltration of foamy CD68+ and CD1a- histiocytes into multiple organ systems. Central nervous system (CNS) involvement has recently been reported to be a poor prognostic factor when treating ECD with interferon alpha. We report the case of a 66-year-old Japanese patient with ECD involving the CNS who harbored the BRAF V600E mutation and also concomitantly developed polycythemia vera with the JAK2 V617F mutation. We confirmed 2-chlorodeoxyadenosine (cladribine) therapy to be effective for the patient in this case.