Because there are limited clinical reports on the impact of human T-lymphotropic virus type 1 (HTLV-1) on organ transplantation, its effects on the development of adult T-cell leukemia-lymphoma (ATL), post-transplantation lymphoproliferative disorder (PTLD) and HTLV-1–associated myelopathy (HAM) or atypical HAM after organ transplantation remain unclear.

We retrospectively analyzed the impact of HTLV-1 in 54 allogeneic hematopoietic stem cell transplantation (allo-HSCT) cases and 31 renal transplantation cases between January 2006 and December 2016.

Among the 54 allo-HSCT cases, nine recipients with ATL tested positive for HTLV-1, and one was found to be an HTLV-1 carrier. All donors tested negative for HTLV-1. Only one HTLV-1 carrier did not present with ATL or HAM development after allo-HSCT. Among nine ATL cases after allo-HSCT, four eventually relapsed due to proliferation of recipient-derived ATL cells. However, in one ATL case, atypical HAM developed rapidly at 5 months after allo-HSCT.

Among the 31 renal transplantation cases, all donors tested negative for HTLV-1, and only recipients tested positive. Only one HTLV-1 carrier recipient did not present with ATL or HAM development after renal transplantation. However, one HTLV-1-negative recipient developed PTLD in the brain 10 years after renal transplantation.

In clinical practice, careful follow-up of HTLV-1 infected recipients after organ transplantation is important because atypical HAM can develop in ATL patients after allo-HSCT. Furthermore, to clarify the risk of ATL or HAM development in HTLV-1 infected recipients, we prospectively followed up our cohort.

Recently, an in situ hybridization (ISH) and immunohistochemical study demonstrated that Epstein-Barr virus (EBV) infection may be involved in tonsillar hypertrophy and recurrent tonsillitis in children and young adolescents. The present study was based on 630 consecutive specimens from tonsillectomies performed at the Dokkyo University School of Medicine between 2002 and May 2017. Clinical findings were obtained from hospital records. Histologically, a “pale clear zone” was characterized by hyperplastic germinal centers with ill-defined borders and interfollicular expansion. Immunohistologically, the majority of immunoblasts were CD20-positive, whereas medium to large lymphoid cells usually expressed CD3. Among 14 lesions, numerous EBV-encoded small RNA (EBER)-positive cells were detected in 10. In 7 of these 10 lesions, EBER-positive cells were detected in germinal centers as well as in the interfollicular area. Based on our results, the “pale clear zone” suggests asymptomatic EBV infection of the tonsil. The present study demonstrated that “pale clear zones” should be taken into consideration when diagnosing asymptomatic EBV-associated LPDs in the tonsils of children and young adolescents as well as in middle-aged patients.

Follicular lymphoma (FL) is genetically characterized by BCL2/IGH translocation. Some FL cases histologically transform to high-grade lymphoma, and the majority of cases transform to diffuse large B-cell lymphoma. We report herein an unusual FL case that transformed to plasmablastic lymphoma (PBL) with MYC gene rearrangement as early as 12 months after FL diagnosis. IGH/MYC translocation, the most common cytogenetic abnormality seen in de novo PBL, was also detected in the transformed tumor (double-hit lymphoma). The patient became resistant to chemotherapy and died 4 months after transformation. We speculate that the “second hit” of MYC rearrangement played a crucial role in PBL transformation (PBL-T) in this case. Highly specific three-color FISH analysis demonstrated the presence of BCL2/IGH/MYC triple fusion signals on a single chromosome as we expected, but BCL2/IGH and IGH/MYC fusion signals also coexisted in a single nucleus. The PBL-T tumor was genetically heterogeneous, despite being histologically quite homogeneous PBL. Surprisingly, three-color FISH analysis revealed that the preceding FL tumor was also genetically heterogeneous, simultaneously harboring BCL2/IGH, IGH/MYC and BCL2/IGH/MYC fusion signals (i.e. double-hit lymphoma), despite being histologically quite homogeneous FL. This suggests that MYC rearrangement played a partial role in PBL-T. Genetic instability including MYC rearrangement in the preceding FL tumor would contribute to PBL-T and poor outcome in this case. This study will broaden our understanding of the pathogenesis of high-grade transformation of FL and help improve patient outcome.

Ibrutinib (IBR) covalently binds to the active site of Bruton’s tyrosine kinase (BTK) and is used for the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL). Approximately 5-10% of CLL is complicated by autoimmune cytopenia (AIC), such as autoimmune hemolytic anemia (AIHA). Several cases of AIC have reportedly demonstrated improvement during IBR treatment. However, in our case, the patient developed AIHA during oral IBR treatment. As AIHA is exacerbated by the increased number of CLL cells in the peripheral blood, it may have developed because of disease progression rather than IBR use. This phenomenon may also be attributed to the production of autoantibodies due to increased number of CD5+ B cells. In this case, withdrawal of IBR and administration of rituximab improved hemolysis. If AIHA develops during treatment, its etiology must be examined to confirm the effects of treatment.

An 80-year-old man presented with the accumulation of pleural fluid in the right thoracic cavity. Serum electrophoresis revealed an M-component and immunofixation confirmed IgM/λ. The level of IgM was 1,526 mg/dL. Imaging studies showed an infiltrative condition of the ipsilateral lung parenchyma. The fluid contained abundant neoplastic cells with the morphological and immunophenotypic features of plasma cells, which expressed IgM/λ monoclonal immunoglobulins on the cell surface and in the cytoplasm. The karyotype was 48,XY,+3,add(9)(p13),+12,add(14)(q32),del(16)(q22),−18,+mar, and a series of fluorescence in situ hybridization studies demonstrated that the add(14) chromosome represented der(14)t(14;18)(q32;q21), at which the MALT1-immunoglobulin heavy-chain (IGH) fusion gene was localized. A long-distance polymerase chain reaction amplified the fragment encompassing the two genes, showing that the junction occurred at the J6 segment of IGH and 3.7-kb upstream of the MALT1 breakpoint cluster. We propose that this case represents an extreme form of the plasmacytic differentiation of extranodal marginal zone lymphoma that developed in the lung.