Marked Underestimation of Platelet Count and a Characteristic Platelet Histogram as Clues to MYH9-Related Disorders.

BACKGROUND: The rapid development of automatic blood cell analyzers has greatly optimized complete blood count results. However, erroneous results relevant to automatic blood cell analyzers still exist. Pseudothrombocytopenia can be observed in both cases of anticoagulant-induced platelet aggregation, and the presence of large and giant platelets. METHODS: A rare case of a MYH9-related disorder, in which marked underestimation of platelet count was led by large and giant platelets using the impedance count by an automated hematology analyzer. Moreover, lancet-shaped and Dohle body-like cytoplasmic inclusions were detected in almost all white blood cells of the patient. RESULTS: The platelet count was done by an optical platelet counter or a fluorescence platelet counter, and peripheral blood smear was evaluated. In addition, the diagnosis of MYH9-related disorder was established by the molecular findings. CONCLUSIONS: Identification of the peripheral blood smear and familial history will eliminate the need for further laboratory testing and bone marrow examination.

Effects of Talaromyces marneffei on Complete Blood Count by a Sysmex XN-9000 Analyzer.

BACKGROUND: Talaromyces marneffei (T. marneffei) infection detected in the peripheral blood smears has been described by several reports. We studied the effects of T. marneffei in peripheral blood samples on complete blood count (CBC) using a Sysmex XN-9000 analyzer. METHODS: In a simulated T. marneffei infection model, blood samples with and without infectious diseases were selected, with high, medium, and low levels of white blood cell (WBC) and platelet (PLT) count, respectively. All samples were detected immediately and after a warm bath of 37℃ for 2 hours. RESULTS: WBC count of all samples was significantly increased by T. marneffei from a certain concentration and higher. For all samples, the effect of T. marneffei on WBC count after warm bath was significantly reduced compared to that on immediate WBC count from 4 - 6 x 109/L T. Marneffei and higher (p < 0.05). The presence of T. marneffei in all blood samples did not affect the results of PLT count. For all samples, the obvious effects of T. marneffei on WBC differential (WDF) and white cell nucleated red blood cell (WNR) scatter plots were from 4 - 6 x 109 T Marneffei and higher. CONCLUSIONS: As a kind of intracellular yeast, T. marneffei may affect WBC count, NRBC count, and WBC differential count of peripheral blood samples when the yeast concentration is (4 - 6) x 109 T Marneffei and higher. Moreover, the unique scatter plot cloud on WDF and WNR scatter plots caused by T. marneffei, may become an important clue pointing toward T. marneffei in peripheral blood.

Hemophagocytic Lymphohistiocytosis Secondary to Disseminated Talaromyces marneffei and Cytomegalovirus Infections in an HIV-Infected Patient.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a rare and potentially life-threatening syndrome led by a highly stimulated but invalid immune response, and Talaromyces marneffei (T. marneffei) is an opportunistic infection with high mortality commonly among acquired immunodeficiency syndrome (AIDS) patients. METHODS: Here is a rare case, in which secondary HLH is caused by dual infections of T. marneffei and cytomega-lovirus (CMV). A 15 year old man with a 20-day history of fatigue and intermittent fever (maximum 41.0℃) was admitted to the department of infectious diseases. Marked hepatosplenomegaly and pulmonary infection were detected by computed tomography. Examination of peripheral blood and bone marrow (BM) smears provided clues pointing toward T. marneffei infection, and indicated prominent hemophagocytosis. RESULTS: Cytomegalovirus (CMV) and T. marneffei infections were confirmed by CMV quantitative nucleic acid testing and culture of blood and bone marrow, respectively. A diagnosis of acquired HLH caused by dual infections of T. marneffei and CMV was established because 5 of the 8 HLH diagnostic criteria were met. CONCLUSIONS: The case highlights the contribution of the morphological examination on peripheral blood and bone marrow smears in the diagnosis, which sometimes are the only locations that HLH and T. marneffei can be diagnosed.

Immature Erythroid Precursors and/or Erythrocyte Dysplasia in Peripheral Blood.

BACKGROUND: With the progress of technology in automated hematology analyzers, in the vast majority of cases, nucleated red corpuscles (NRC) can be automatically identified by most types of automated hematology analyzers, thus correcting the leukocyte count and avoiding pseudoleukocytosis by the analyzers themselves. The objective of the study was to explore pseudoleukocytosis due to immature erythroid precursors and/or erythrocyte dysplasia in the peripheral blood resulting from different rare situations. METHODS: Four rare cases showing pseudoleukocytosis due to immature erythroid precursors and/or erythrocyte dysplasia in the peripheral blood were analyzed and the effects on complete blood count (CBC) performed on a Sysmex XN-2000 analyzer and microscopic morphological features of the peripheral blood were investigated. These cases were selected for their vital value in describing all pseudoleukocytosis due to immature erythroid pre-cursors and/or erythrocyte dysplasia in the peripheral blood. The causes of immature erythroid precursors and/or erythrocyte dysplasia in the peripheral blood were analyzed. RESULTS: In all these cases, proportions of NRC and leukocyte counts were affected to varying degrees by the presence of numerous immature erythroid precursors and/or obvious erythrocyte dysplasia in the peripheral blood. All cases associated with an alarm concerning NRC presentation, and abnormal scattergrams of WDF and WNR, thus leading to pseudoleukocytosis. CONCLUSIONS: Laboratory artifacts led by NRC may be an indicator towards the occurrence of numerous immature erythroid precursors and/or obvious erythrocyte dysplasia in the peripheral blood, and active extramedullary hematopoiesis, breakdown of the bone marrow barrier, and the stress response of acute bleeding and severe multiple infection.

Neutrophil-to-lymphocyte ratio and lactate dehydrogenase for early diagnosis of AIDS patients with Talaromyces marneffei infection.

BACKGROUND: This study aimed to explore the value of neutrophil-to-lymphocyte ratio (NLR) in combination with routine blood tests, lactate dehydrogenase (LDH), and T-lymphocyte subsets for the early diagnosis of acquired immunodeficiency syndrome (AIDS) combined with Talaromyces marneffei (TM) infection. METHODS: A total of 166 confirmed AIDS patients were enrolled in this study. The observation group included 80 AIDS patients with TM infection, and the control group consisted of 86 AIDS patients with other complications. Regression analysis was performed to evaluate the predictive value of each index and the combination of these indexes for AIDS combined with TM infection using receiver operating characteristic (ROC) curve analysis. RESULTS: NLR and LDH were significantly higher in patients in the observation group compared with those in the control group, and the differences were statistically significant (P<0.05). There was no statistical difference in platelets, infantile granulocytes (IGM), and nucleated red blood cells (NRBC) between the 2 groups (P>0.05). The area under the operating characteristic curve (AUC) of the observed indicators were: NLR, 0.628; hemoglobin (HGB), 0.704; LDH, 0.607; lymphocyte (LYM) count, 0.744; CD4+ T lymphocyte count, 0.789; and CD8+ T lymphocyte count, 0.701. The combined AUC of multiple indicators was 0.815, with a sensitivity and specificity of 76.2% and 76.1%, respectively. CONCLUSIONS: NLR, HGB, LYM, LDH, and T lymphocyte subsets were diagnostic for early AIDS combined with TM infection , and CD4+ T lymphocytes had the best diagnostic efficacy alone.