A Patient with Kabuki Syndrome Mutation Presenting with Very Severe Aplastic Anemia

Kabuki syndrome (KS) is a rare congenital disorder commonly complicated by humoral immunodeficiency. Patients with KS present with mutation in the histone-lysine N-methyltransferase 2D (KMT2D) gene. Although various KMT2D mutations are often identified in lymphoma and leukemia, those encountered in aplastic anemia (AA) are limited. Herein, we present the case of a 45-year-old Japanese man who developed severe pancytopenia and hypogammaglobulinemia. He did not present with any evident malformations, intellectual disability, or detectable levels of autoantibodies. However, B-cell development was impaired. Therefore, a diagnosis of very severe AA due to a hypoplastic marrow, which did not respond to granulocyte colony-stimulating factor, was made. The patient received umbilical cord blood transplantation but died from a Pseudomonas infection before neutrophil engraftment. Trio whole-exome sequencing revealed a novel missense heterozygous mutation c.15959G >A (p.R5320H) in exon 50 of the KMT2D gene. Moreover, Sanger sequencing of peripheral blood and bone marrow mononuclear cells and a skin biopsy specimen obtained from this patient identified this heterozygous mutation, suggesting that de novo mutation associated with KS occurred in the early embryonic development. Our case showed a novel association between KS mutation and adult-onset AA.

A Mosquito Bite with Devastating Complications in an Immunocompromised Patient

Infectious complications such as invasive aspergillosis or infection with Stenotrophomonas maltophilia (SM) in immunocompromised patients are associated with a high mortality rate. Our report concerns a 40-year-old male newly diagnosed very severe aplastic anemia (vSAA) who in consequence of a mosquito bite was suffering from skin lesion and consecutive soft tissue phlegmon subsequent to the administration of antithymocyte globulin; a full-thickness autologous meshed skin graft successfully performed to cover skin ulcera after allogeneic stem cell transplantation (SCT). This unusual case illustrates the importance of appropriate diagnosis, anti-infective therapy and close interdisciplinary diagnostic algorithms to minimalize side effects and the selection of resistant strains and to improve patients' outcome.

Regulatory T cells and CD20+ B cells in pediatric very severe aplastic anemia: possible clinical markers for evaluating the therapeutic efficacy and prognosis

OBJECTIVES

To investigate the immune status of children with very severe aplastic anemia (VSAA), and evaluate the frequencies of CD20⁺ B cells and Regulatory T cells (Tregs) as potential markers for evaluating the therapeutic efficacy and prognosis.

METHODS

We systematically analyzed CD20⁺ B cells and Tregs using Flow Cytometry in 36 children with VSAA (14 newly diagnosed cases and 22 cases in remission after therapy with HDIVIG + r-ATG + CSA).

RESULTS

In newly diagnosed VSAA patients, the percentage of CD20⁺ B cells was higher than that in healthy children (P < .01), whereas the percentage of Tregs was lower than that in healthy children (P < .001). After treatment with HDIVIG + r-ATG + CSA, the percentage of CD20⁺ B cells in peripheral blood was decreased obviously, and the percentage of Tregs was significantly increased.

CONCLUSION

There is a moderate negative correlation between the percentage of Tregs and CD20⁺ B cells in our study. Our results shed light on the roles of Tregs and CD20⁺ B cells as therapeutic efficacy and prognostic markers of pediatric VSAA. Moreover, the mechanism underlying the decrease of blood Tregs and increase of CD20⁺ B cells in pediatric VSAA patients have been discussed, indicating that Tregs may suppress B cell responses.