[Successful treatment of X-linked sideroblastic anemia with ALAS2 R452H mutation using vitamin B6].

A 45-year-old man presented with fatigue and pain in the finger joints. Despite having a history of suspected sideroblastic anemia since the age of 18 years, he had not been followed up for years. Upon presentation, laboratory data revealed microcytic anemia and elevated serum ferritin levels. In addition, ringed sideroblasts were increased in the bone marrow. A liver biopsy revealed hemochromatosis and cirrhosis. Furthermore, genetic analysis revealed that he harbored the ALAS2 R452H mutation, leading to the diagnosis of X-linked sideroblastic anemia (XLSA). Accordingly, oral folate or vitamin (Vit) B12 was administered, but his anemia did not respond. However, his hemoglobin level increased from 7 to 11 g/dl with an additional prescription of oral VitB6, which facilitated the patient to undergo phlebotomy to ameliorate organ dysfunctions caused by iron overload. Previous research has revealed that ALAS2 R452 mutations confer poor responses to VitB6 therapy. Hence, accrual of patients with an unexpectedly better response, which was observed in our case, may help elucidate the pathogenesis of and therapies for XLSA.

Severe Infection of Pseudomonas aeruginosa during Eculizumab Therapy for Paroxysmal Nocturnal Hemoglobinuria.

Eculizumab is the complement inhibitor administered to ameliorate intravascular hemolysis in paroxysmal nocturnal hemoglobinuria. Whether or not the inhibitory mechanism may also increase the susceptibility to non-Neisserial infection is unclear. A 73-year old woman presented with bacteremia, cholecystitis and liver abscess with Pseudomonas aeruginosa. Although she had been neutropenic for 21 years, she had no history of severe infection before eculizumab had been administered. The infection with P. aeruginosa was successfully controlled with antibiotics, granulocyte colony-stimulating factor and cholecystectomy. The present case might be representative of less common bacterial infections than Neisseria spp. among patients treated with eculizumab.

Oral cyclophosphamide was effective for Coombs-negative autoimmune hemolytic anemia in CD16+CD56- chronic lymphoproliferative disorder of NK-cells.

An 84-year-old woman was referred to our hospital presenting anemia. Her hemoglobin level was 5.8 g/dL, and white blood cell count was 9400/µL, consisting of 82% lymphocytes. Given the lymphocyte phenotype (CD2+, CD3-, CD16+, and CD56-) and negative whole blood EBV viral load, we made a diagnosis of chronic lymphoproliferative disorder of NK cells (CLPD-NK). We suspected hemolytic anemia because of the high levels of reticulocytes in the peripheral blood and the low haptoglobin value. Although the direct Coombs test was negative and there was no cold agglutination, we examined her red-blood-cell-bound IgG (RBC-IgG), which was elevated. She was diagnosed as having as Coombs-negative autoimmune hemolytic anemia (AIHA). We report the effectiveness of oral cyclophosphamide for Coombs-negative autoimmune hemolytic anemia in CLPD-NK.

Cell size variations of large granular lymphocyte leukemia: Implication of a small cell subtype of granular lymphocyte leukemia with STAT3 mutations.

Large granular lymphocyte leukemia (LGL-L) has been morphologically defined as a group of lymphoproliferative disorders, including T-cell large granular lymphocytic leukemia (T-LGL-L), chronic lymphoproliferative disorders of NK cells (CLPD-NK) and aggressive NK cell leukemia. We investigated the morphological features of LGL leukemic cells in 26 LGL-L patients in order to elucidate relationships with current classifications and molecular backgrounds. LGL-L cells were mostly indistinguishable from normal LGL. Patients with STAT3 SH2 domain mutations showed significantly smaller cells compared with patients without STAT3 mutations. Four patients with T-LGL-L showed smaller granular lymphocytes with a median diameter of less than 13µm, which were rarely seen in normal subjects. This small subtype of T-LGL-L was recognized among rather young patients and was associated with D661Y mutations in the STAT3 gene SH2 domain. In addition, all of them showed anemia including two cases with pure red cell aplasia. These results suggest the heterogeneity of T-LGL-L and a specific subtype with small variants of T-LGL-L.

STAT3 gene mutations and their association with pure red cell aplasia in large granular lymphocyte leukemia.

Large granular lymphocyte leukemia (LGL L) has been morphologically characterized as a group of lymphoproliferative diseases that include T-cell large granular lymphocytic leukemia (T-LGL L) and chronic lymphoproliferative disorders of natural killer cells (CLPD-NK). We investigated mutations in the Src homology 2 (SH2) domain of the signal transducer and activator of transcription 3 (STAT3) gene in Asian cohorts of T-LGL L and CLPD-NK (n = 42 and 11, respectively). Two mutations, Y640F and D661Y, were identified using direct sequencing or allele-specific (AS) PCR. Y640F and D661Y mutations were found in seven and 18 patients, respectively. Two patients were positive for both mutations. Frequencies of STAT3 mutations in T-LGL L and CLPD-NK were 47.6% and 27.2%, respectively. Pure red cell aplasia (PRCA) was associated with the mutations (P = 0.005). The mutations were persistently found at stable levels in some patients after more than 5 years using AS-quantitative PCR. The results of the present study indicate that the SH2 domain of the STAT3 gene is frequently mutated in Asian T-LGL L and CLPD-NK, and that PRCA is closely correlated with the mutations.