Evaluation of Human Leucocyte Antigen Mediated Platelet Transfusion Refractoriness and Platelet Crossmatching Assay in Patients with Hematologic Disorders.

Objectives: Platelet refractoriness complicates the platelet transfusion, which is essential for managing thrombocytopenia in patients with hematological disorders. It is associated with adverse clinical outcomes and increased health care costs. We conducted a prospective study to determine the effectiveness of cross-matched compatible platelets in a group of patients refractory to platelets from random donors and to evaluate human leukocyte antigen (HLA)-mediated refractoriness. Methods: This prospective study was conducted on 40 patients with different hematological disorders requiring platelet transfusions who were refractory to random platelets and presented to the hematology unit of Alexandria's main university hospitals between May 2020 and March 2021. They received 60 ABO-compatible platelet transfusions, either leuco-reduced or random donor platelets, stored for no more than 72 hours. A solid-phase red cell adherence technique (SPRCA) was used for platelet crossmatching. The corrected count increment (CCI) was used to monitor the effectiveness of each platelet transfusion with a cut-off value of 5 × 103/µL at 1 hour and 2.5 × 103/µL at 24 hours. Anti-HLA antibodies were assessed using the enzyme-linked immunosorbent assay technique. Results: Out of 60 cross matches, 47 (78.3%) were compatible, and 13 (21.7%) were incompatible. Among 47 compatible results, 30 (63.8%) showed adequate CCI and 17 (36.2%) showed inadequate CCI at 1-hour post-transfusion. Among the incompatible results, 3 (23.1%) had adequate CCI and 10 (76.9%) had inadequate CCI. Significant improvements were found in the mean CCI when comparing cross-matched compatible platelets and incompatible platelets at 1hour or 24 hours (p=0.009 and p < 0.001, respectively). From the 40 studied patients, HLA alloimmunization was present in 18 patients (45.0%) and absent in the remaining 22 patients (55.0%). In the absence of HLA alloimmunization, patients showed significantly better responses at 1 hour and 24 hours (p =0.001 and p =0.015, respectively). There was better sensitivity of platelet crossmatching with random donor platelet concentrates than single donor platelet concentrates. Conclusions: Platelet crossmatching using SPRCA and HLA screening are effective and rapid tools for better management of patients' refractory to platelet transfusions.

Acquired mutation of the tyrosine kinase JAK2V617F in Egyptian patients with myeloid disorders.

Janus Kinase 2 (JAK2) is a member of a family of four Janus Kinases, 2, and 3 and tyrosine kinase 2. Mutated JAK2 (V617F) has the ability to activate downstream signal transducer and activator of transcription (STAT)-mediated transcription in the absence of the ligand erythropoietin. The autoinhibitory activity of JAK2 is disrupted by the presence of the V617F mutation. Somatic mutation in JAK2 (V617F) gene has been reported in myeloid disorders. This study reports the prevalence of JAK2V617F using amplification refractory mutation system (ARMS)-polymerase chain reaction in 246 Egyptian patients with different myeloid disorders and studied the relationship between the JAK2V617F mutation and parameters in peripheral blood. The mutation was detected among 88 patients (35.8%) with different myeloid disorders. JAK2V617F was found among 81.4% of polycythemia vera (PV), 50% of essential thrombocythemia, 46.1% of primary myelofibrosis (PMF), 33.3% of philadelphia (Ph)-negative chronic myeloid leukemia, 33.3% of myelodysplastic syndrome (MDS)/myeloproliferative neoplasm (MPN), and 50% of refractory anemia with ringed sideroblasts associated with marked thrombocytosis (RARS-T) patients. Hemoglobin and white blood cells were significantly higher in the mutated group of MPN including PV, essential thrombocythemia, and PMF, whereas platelet counts were higher among the mutated PV, PMF, RARS-T, and MDS/MPN group. The identification of JAK2V617F mutations has raised the prospect of developing specific JAK2V617F inhibitors to treat mutated patients.

Dual color FISH on CBF primary acute myeloid leukemia.

In acute myeloid leukemia (AML), clonal chromosomal aberrations constitute markers of diagnostic value and the molecular characterization of numerous abnormalities has greatly improved the understanding of the biology of distinct subtypes of the disease. Two of the most common recurring chromosomal abnormalities in AML are t(8;21) and inversion of chromosome 16 or its variant which belong to core binding factor (CBF) AML group. We aimed to compare between cytogenetics and dual color Fluorescence In Situ Hybridization (FISH) regarding their sensitivity for detection of CBF AML associated translocations including t(8;21) and inv(16)/t(16;16). Fifty five consecutive patients diagnosed as de novo AML were studied by chromosome banding analysis. Among them 32 patients were studied by FISH for the detection of AML1/ETO fusion gene and 11 patients for the detection of CBFbeta/MYH11. Four cases of AML (M2) subtype were positive for t(8;21) and 1 (M4) subtype was positive for inv(16) by karyotyping analysis. When FISH was applied 6 cases all of AML (M2) subtype were positive for t(8;21), 2 of them were of normal karyotype, and 5 cases all of M4EO subtype were found to be positive for inv(16)/ t(16;16) and 4 of them showed normal karyotypes. In conclusion, FISH can be used as a complementary technique to identify t(8;21) and inv16/t(16;16) in de novo AML as these abnormalities are difficult to diagnose in most cases by conventional cytogenetics alone.