Red blood cell alloimmunization in sickle cell disease: assessment of transfusion protocols during two time periods.

BACKGROUND: Prevention of red blood cell (RBC) alloimmunization in patients with sickle cell disease (SCD) focuses on phenotypic RBC matching. We assessed alloimmunization among transfused patients with SCD after implementing leukoreduction and prophylactic antigen matching (PAM). STUDY DESIGN AND METHODS: Retrospective review of transfusion and medical records for SCD patients 18 months to 81 years of age was performed covering two 5-year periods: Period 1, no PAM, occasional leukoreduction, and Period 2, consistent leukoreduction and extended PAM (Rh, Kell, S, Fy, Jk) for patients already alloimmunized. Patients transfused in Period 1 were excluded from Period 2. RESULTS: A total of 293 patients were transfused in Period 1 and 183 in Period 2. Median time between first sample and last type and screen after transfusion was 2.12 years in Period 1 and 1.03 years in Period 2. Initial alloimmunization prevalence was lower in Period 2 (26.2%) versus Period 1 (37.5%) and after subsequent transfusions in Period 2 (23.8%) versus Period 1 (45.7%), although without significant difference after adjusting for number of units transfused, percentage of leukoreduced RBCs, sex, and age. Alloimmunized patients received more nonleukoreduced RBCs in Period 1 than nonalloimmunized. Patients transfused during inflammatory conditions were not significantly more likely to become alloimmunized. CONCLUSIONS: The prevalence of initial and subsequent RBC alloimmunization in Period 2 was lower than that in Period 1; however, overall prevalence remained high. We recommend leukoreduced, hemoglobin S-negative Rh and Kell PAM RBCs for transfusion of patients with SCD. Component and recipient factors affecting alloimmunization should be studied further.

Next-generation HLA sequencing reveals the novel HLA-DPB1*1492:01 allele.

The novel HLA-DPB1*1492:01 allele contains a c.190C>T substitution in exon 2 compared to DPB1*19:01:01:01.

Unexpected Short-Tandem-Repeat Patterns in Posttransplant Chimerism Testing: Investigation of 3 Cases with Help from Forensic Science.

Chimerism testing by short tandem repeats (STRs) is used to monitor engraftment after allogeneic hematopoietic stem cell transplantation (HSCT). Generally, STR alleles are stable and transferred from parent to child or from donor to recipient. However, 3 cases did not follow this norm. Additional work-up with help from forensic literature solved these mysteries. In case 1, the patient received HSCT from his son. The son shared STR alleles in 22/23 loci except Penta E, which was explained by repeat expansion in the son. In case 2, the patient had been in remission for 14 years after HSCT for lymphoma and developed repeat expansion in CSF1PO in granulocytes. In case 3, a pre-HSCT patient demonstrated 3 alleles, with 2 peaks taller than the third, in the FGA locus (chromosome 4). A combination of a triallelic variant and leukemia-associated trisomy 4 explained the finding. STR number variants are rare and clinically inconsequential but can overlap malignancy-associated, clinically significant changes.

Dural Extranodal Marginal Zone Lymphoma in an XRCC2 Mutation Carrier.

Dural extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a rare entity without an associated recurrent genetic abnormality. Only one case has been described in a woman with history of breast carcinoma without a known genetic predisposition. Here, we report a case of a 56-year-old woman heterozygous for XRCC2 mutation with a history of Graves' disease and bilateral breast carcinomas, who was found to have a diffusely infiltrative extra-axial mass in the high parietal convexity with infiltration into the adjacent superior sagittal sinus. The morphologic, immunophenotypic, and molecular findings were diagnostic of MALT lymphoma. Staging bone marrow demonstrated involvement by the neoplasm. Although the study was limited to only the clinically significant laboratory evaluation, it may serve as an important addition to the current knowledge of the pathogenic potential of a loss of function mutation in this rarely reported cancer predisposition gene.

Synchronous Ipsilateral Parotid Tumors with Cytologic-Histologic Correlation.

Synchronous ipsilateral tumor formation within a major salivary gland is a very rare event. In this case, a 54-year-old female tobacco smoker presented with a slowly enlarging left parotid gland. Computed tomography of the neck demonstrated a solid mass superficial to a cystic mass in the deep lobe of the gland. Ultrasound-guided fine needle aspiration yielded oncocytic cells, lymphoid cells, and granular debris along with rare cohesive groups of basaloid cells. Parotidectomy was performed, and the resected gland was found to contain two adjacent but distinct masses. One mass, a predominantly solid, well-circumscribed lesion composed of ribbons of double-layered oncocytic cells and a lymphoid stroma with germinal center formation, was a Warthin tumor. The other mass, a predominantly cystic lesion composed of cords and nests of basaloid cells with associated deposits of basement membrane-like material, was a basal cell adenoma of the membranous type. To our knowledge, this is the first reported case of synchronous Warthin tumor and basal cell adenoma of the parotid gland with cytologic-histologic correlation attributable to each tumor.