Promyelocytic Leukemoid Reaction: Unusual Findings in a Patient with Sepsis

Neutrophilic leukemoid reaction may occur in many situations, including hemolysis, malignancy, infection, and exposure to certain toxins. It usually shows morphological overlap with chronic myeloid leukemia in which promyelocytes are not majorly associated. Here, we present a case of promyelocytic leukemoid reaction in a patient with sepsis. A 28-year-old man was admitted for renal stone removal. After percutaneous nephrolithotomy, his condition deteriorated with fever (37.8℃), tachycardia (130/min), acute renal failure, pleural effusion, and pulmonary edema. Complete blood count indicated a white blood cell count of 73.39×10⁹/L including 82% promyelocytes, hemoglobin 8.9 g/dL, and platelet count of 85×10⁹/L. A bone marrow aspirate showed that promyelocytes accounted for 73.8% of all nucleated cells. Following bone marrow examination, treatment with all-trans retinoic acid (ATRA) was started immediately. Reverse transcription polymerase chain reaction (RT-PCR) study revealed the absence of PML-RARA (promyelocytic leukemia-retinoic acid receptor alpha) and other RARA (retinoic acid receptor alpha) rearrangements. Once the chromosome analysis of bone marrow cells demonstrated the normal karyotype, ATRA was discontinued.

Detection of PML/RARA Rearrangement by Reverse Transcriptase-PCR and Sequencing in a Case of Microgranular Acute Promyelocytic Leukemia Lacking t(15;17) on Karyotype and FISH / 대한진단검사의학회지

We report a case of morphologically microgranular acute promyelocytic leukemia with PML/RARA fusion transcripts demonstrated by reverse transcriptase-PCR and cDNA sequencing, and no PML/RARA fusion detected by karyotype and FISH analyses. Karyotype was 47,XX,+8[19]/46,XX[1]. Although the newer FISH probes provide more accurate detections of t(15;17), it would be necessary to perform other molecular tests to further identify the masked PML/RARA fusions.

Utility of RARa Fluorescence In Situ Hybridization for Follow-up in Acute Promyelocytic Leukemia: Comparison with PML/RARa Fluorescence In Situ Hybridization / 대한임상병리학회지

BACKGROUND: The most noted rearrangement identified in acute promyelocytic leukemia (APL) involves the PML and RARa genes, which results in the formation of the PML/RARa gene fusion. In the fluorescence in situ hybridization (FISH) for PML/RARa, the two signals may coincidentally overlap in normal nuclei. We investigated whether a new RARa rearrangement probe could discriminate the false-positive fusion signal of the PML/RARa translocation probe. METHODS: A total of 51 cases, which showed the results from 1% to the borderline level by PML/ RARa FISH, were re-tested with the RARa rearrangement probe. Also, we compared the RARa FISH with the PML/RARa FISH on 16 patients with newly diagnosed APL and performed the RARa FISH on 20 bone marrow specimens without hematologic malignancies in order to set up the cut-off value. RESULTS: The cut-off for the RARa FISH was determined as 1.02%. For patients with newly diagnosed APL, the PML/RARa FISH showed positive signals in 95.3+/-6.5% of the cells and RARa FISH showed positive signals in 97.0+/-7.0% (r=0.83). Of a total of 41 cases consisting of hematological disorders other than APL, five cases showed results equal to or greater than 5% with PML/RARa FISH and one case showed a positive result with RARa FISH. Of 10 follow-up APL cases, seven cases showed results equal to or greater than 5% with the PML/RARa FISH and four cases showed positive results with the RARa FISH. CONCLUSIONS: The cut-off value for the RARa FISH is 1.02% and we consider RARa FISH as the proper method for follow-up of APL.