Prevalence of Duffy null and its impact on hydroxyurea in young children with sickle cell disease in the United States.

Consistent with studies showing a high prevalence of the Duffy null phenotype among healthy Black Americans, this retrospective study found that Duffy null was present in >75% of a young and contemporary cohort of children with sickle cell disease (SCD) in the United States. Despite the potential for this phenotype to impact absolute neutrophil counts, hydroxyurea (HU) dosing, and outcomes, it was not associated with being prescribed a lower HU dose or having increased acute SCD visits early in the HU treatment course. Future studies are needed to confirm these findings in older children with SCD.

Establishing Pediatric Reference Ranges for Rotational Thromboelastometry.

OBJECTIVES: The aim of our investigation was to establish normal pediatric reference intervals (PRIs) for rotational thromboelastometry (ROTEM) Delta assays in a representative group of healthy children, 0 to 18 years of age, at our institution. METHODS: This was a prospective study of healthy pediatric patients undergoing elective minor surgery requiring placement of an intravenous cannula. The sample size for patients was 20 per age group of either sex from 5 different age groups based on coagulation system maturity: 0 to 6 or fewer months, more than 6 to 12 or fewer months, more than 1 year to 5 or fewer years, more than 5 to 11 or fewer years, and more than 11 to 18 or fewer years. ROTEM Delta assays assessed include the EXTEM, INTEM, and FIBTEM. RESULTS: We defined 2 sets of ROTEM PRIs for our patient population: one for patients 11 years or younger and one for children more than 11 years of age. For those 11 years or younger, the PRIs were derived from the 2.5th and 97.5th percentiles from the 0 to 11 age groups. For those older than 11 years, previously published adult reference intervals validated internally with adult normal samples were used. CONCLUSIONS: The 2 sets of PRIs were embedded into our electronic medical record, allowing clinicians to easily interpret their patient's ROTEM results against age-verified reference ranges, enabling them to make informed transfusion decisions.

Pediatric traumatic hemorrhagic shock consensus conference recommendations.

ABSTRACT: Hemorrhagic shock in pediatric trauma patients remains a challenging yet preventable cause of death. There is little high-quality evidence available to guide specific aspects of hemorrhage control and specific resuscitation practices in this population. We sought to generate clinical recommendations, expert consensus, and good practice statements to aid providers in care for these difficult patients.The Pediatric Traumatic Hemorrhagic Shock Consensus Conference process included systematic reviews related to six subtopics and one consensus meeting. A panel of 16 consensus multidisciplinary committee members evaluated the literature related to 6 specific topics: (1) blood products and fluid resuscitation for hemostatic resuscitation, (2) utilization of prehospital blood products, (3) use of hemostatic adjuncts, (4) tourniquet use, (5) prehospital airway and blood pressure management, and (6) conventional coagulation tests or thromboelastography-guided resuscitation. A total of 21 recommendations are detailed in this article: 2 clinical recommendations, 14 expert consensus statements, and 5 good practice statements. The statement, the panel's voting outcome, and the rationale for each statement intend to give pediatric trauma providers the latest evidence and guidance to care for pediatric trauma patients experiencing hemorrhagic shock. With a broad multidisciplinary representation, the Pediatric Traumatic Hemorrhagic Shock Consensus Conference systematically evaluated the literature and developed clinical recommendations, expert consensus, and good practice statements concerning topics in traumatically injured pediatric patients with hemorrhagic shock.

Blood banking considerations in pediatric trauma.

ABSTRACT: Transfusion of blood products to a hemorrhaging pediatric trauma patient requires seamless partnership and communication between trauma, emergency department, critical care, and transfusion team members. To avoid confusion and delays, understanding of blood banking principles and mutually agreed upon procedures and policies must be regularly updated as knowledge evolves. Because pediatric patients require specialized considerations distinct from those in adults, this brief review covers transfusion principles, policies, and procedures specific to the resuscitation of pediatric trauma patients.

Pediatric traumatic hemorrhagic shock consensus conference research priorities.

BACKGROUND: Traumatic injury is the leading cause of death in children and adolescents. Hemorrhagic shock remains a common and preventable cause of death in the pediatric trauma patients. A paucity of high-quality evidence is available to guide specific aspects of hemorrhage control in this population. We sought to identify high-priority research topics for the care of pediatric trauma patients in hemorrhagic shock. METHODS: A panel of 16 consensus multidisciplinary committee members from the Pediatric Traumatic Hemorrhagic Shock Consensus Conference developed research priorities for addressing knowledge gaps in the care of injured children and adolescents in hemorrhagic shock. These ideas were informed by a systematic review of topics in this area and a discussion of these areas in the consensus conference. Research priorities were synthesized along themes and prioritized by anonymous voting. RESULTS: Eleven research priorities that warrant additional investigation were identified by the consensus committee. Areas of proposed study included well-designed clinical trials and evaluations, including increasing the speed and accuracy of identifying and treating hemorrhagic shock, defining the role of whole blood and tranexamic acid use, and assessment of the utility and appropriate use of viscoelastic techniques during early resuscitation. The committee recommended the need to standardize essential definitions, data elements, and data collection to facilitate research in this area. CONCLUSION: Research gaps remain in many areas related to the care of hemorrhagic shock after pediatric injury. Addressing these gaps is needed to develop improved evidence-based recommendations for the care of pediatric trauma patients in hemorrhagic shock.

Skull base chondroblastoma with aneurysmal bone cyst-like changes treated with percutaneous radiofrequency ablation and doxycycline sclerotherapy: illustrative case.

BACKGROUND: Chondroblastomas (CBs) are rare benign bone tumors that are often difficult to treat because of their locations. CBs can be even more challenging to successfully manage when they present alongside aneurysmal bone cyst (ABC)-like changes. To minimize operative morbidity, especially in hard-to-reach lesions, percutaneous approaches for both lesions have been individually described. We present a skull base CB with associated ABC-like changes treated by combining two different previously described percutaneous modalities. OBSERVATIONS: The authors report successful percutaneous treatment of a skull base CB with adjacent ABC-like changes in a 17-year-old male. The CB was treated with radiofrequency ablation (RFA) and the adjacent ABC area with doxycycline sclerotherapy. After 3 years of follow-up, there has been no clinical or radiological evidence of recurrence. LESSONS: CBs occur in the skull base and, as elsewhere in the body, can be associated with ABC-like changes. Successful percutaneous treatment of such a CB with ABC-like changes is possible by combining previously described techniques of RFA and doxycycline sclerotherapy.

Pediatric adaptions are needed to improve the diagnostic accuracy of thyroid ultrasound using TI-RADS.

BACKGROUND/PURPOSE: Thyroid Imaging Reporting and Data System (TI-RADS) is validated in adults but not yet in children. The purpose of this study was to determine the sensitivity, specificity, and accuracy of TI-RADS in predicting thyroid malignancy for pediatric nodules, and to compare the diagnostic accuracy to the current American Thyroid Association (ATA) guidelines. METHODS: A single institution retrospective review was performed of patients younger than 21 years who underwent thyroid nodule fine needle aspiration biopsy (FNAB). Two radiologists were blinded to the pathology and independently classified all biopsied thyroid nodules based on TI-RADS. ATA and TI-RADS guidelines were analyzed to determine the diagnostic sensitivity and specificity of both scoring systems. RESULTS: 115 patients (median age 15.5 years, 90 females) with 138 nodules were scored using TI-RADS. There was moderate inter-rater agreement between radiologists (Kappa = 0.51; p < 0.0001). Evaluating several potential TI-RADS criteria, 23.2%-68.1% of nodules were recommended for FNAB, compared to 82.6% of nodules using ATA guidelines. Using TI-RADS ≥ 3 (without size cutoff) as an indication for FNAB had 100% sensitivity with no missed suspicious or malignant nodules on cytology or pathology. CONCLUSIONS: Using TI-RADS for diagnostic management of pediatric thyroid nodules improves accuracy in predicting malignancy.

Evaluating Age-related Disparity of Outcomes in Ewing Sarcoma Patients Treated at a Pediatric Academic Medical Center.

Adolescent and young adult (AYA) patients with Ewing sarcoma have inferior survival compared with pediatric patients even when treated with similar regimens. Investigation into specific explanations is lacking. A retrospective chart review of Ewing sarcoma patients at a single institution was performed, and 104 patients were identified, 45 were 15 to 39 years of age (AYA cohort) and 59 younger than 15 years (pediatric cohort). AYA patients demonstrated more metastatic disease (50% vs. 24%, P=0.009), peripheral tumor location (64% vs. 41%, P=0.025), percentage of male patients (76% vs. 51%; P=0.010), and tumor size ≥5 cm (93% vs. 70%, P=0.016) than pediatric patients. Five-year overall survival was 77.7% and 53.0% and event-free survival was 68.7% and 40.6% for pediatric versus AYA, respectively. Similar rates of toxicity and chemotherapeutic dose adjustments were demonstrated. In this cohort, increased AYA patient mortality appears to be related to disease characteristics rather than treatment-related differences.

Eosinophilic Pneumonia and Lymphadenopathy Associated With Vaping and Tetrahydrocannabinol Use.

Idiopathic acute eosinophilic pneumonia is a rare and potentially life-threatening condition that is defined by bilateral pulmonary infiltrates and fever in the presence of pulmonary eosinophilia. It often presents acutely in previously healthy individuals and can be difficult to distinguish from infectious pneumonia. Although the exact etiology of idiopathic acute eosinophilic pneumonia remains unknown, an acute hypersensitivity reaction to an inhaled antigen is suggested, which is further supported by recent public health risks of vaping (electronic cigarette) use and the development of lung disease. In this case, a patient with a year-long history of vaping in conjunction with tetrahydrocannabinol cartridge use who was diagnosed with idiopathic acute eosinophilic pneumonia with associated bilateral hilar lymphadenopathy is described.

Refractory Thrombocytopenia Is a Valid Early Diagnostic Criteria for Hepatic Veno-Occlusive Disease in Children.

We compared the incidence of refractory thrombocytopenia (RT) and platelet transfusion requirements (PTR) in 35 children who developed veno-occlusive disease (VOD) with 35 matched control subjects who underwent hematopoietic stem cell transplant but did not develop VOD. RT developed in 100% of the VOD patients, at a median of 8 days before VOD diagnosis, as compared with 71.5% of the control group. VOD patients required more platelet transfusions than control subjects (median PTR, 6.9 mL/kg [range, .57 to 17.59] versus 3.57 mL/kg [range, 0 to 14.63], respectively) with a statistically significant difference (P < .0001). The number of days with platelet requirements was significantly higher for VOD patients as compared with control subjects (median 68% versus 39%, P =< .0001). The PTR peaked at ~12 mL/kg/day, 2 days before VOD diagnosis, whereas the PTR in the control population was 5 mL/kg/day. The positive predictive value of developing VOD was 88.9% (95% confidence interval, 66.5% to 97%) in patients who were given >7 mL/kg/day of platelets during the at-risk period of days +3 to +13 after transplant. For patients who received >8 mL/kg/day of platelets, the positive predictive value of developing VOD was 86.7% (95% confidence interval, 61.2% to 96.4%). There was no difference in the PTR in patients with mild to moderate VOD as compared with severe VOD; however, the PTR was higher in patients whose VOD did not resolve. The median daily PTR after the diagnosis of VOD in 17 patients who got defibrotide as compared with those who did not get defibrotide was 6.04 mL/kg and 5.72 mL/kg, respectively, but the difference was not statistically significant (P = .56). On univariate and multivariate analysis use of intravenous immunoglobulin was significantly associated with VOD (P = .0088) but was not significantly associated with fatal VOD. In conclusion, RT occurs in 100% of patients at a median of 8 days before VOD diagnosis. VOD should be suspected in any patient with RT after the exclusion of other causes of consumptive thrombocytopenia, especially if they require >7 mL/kg/day of platelets.

Lung T-Cell Profile Alterations are Associated with Bronchiolitis Obliterans Syndrome in Cystic Fibrosis Lung Transplant Recipients.

The contribution of T-cells after lung transplant (LTx) remains controversial with no current consensus of their role concerning chronic lung allograft dysfunction. Using flow cytometry to assess T-cell subsets of bronchoalveolar lavage fluid (BALF) in 16 cystic fibrosis (CF) LTx recipients, we identified a decline in CD4+ T-cell frequency and an increase in CD8+ T-cell frequency in patients who developed severe bronchiolitis obliterans syndrome (BOS) (N = 10) when comparing baseline (6 months post-LTx) and follow-up (most recent bronchoscopy-clinical or surveillance per protocol). Comparing BOS to No BOS cohorts, significant differences were found in CD4+ T-cell frequency [17.4 (12.5, 28.2) vs 46.6 (44.4, 48.4), p = 0.003] and CD8+ T-cell frequency [65.6 (62.8, 75.3) vs 39.2 (32.2, 43.3), p = 0.014], respectively. The mean difference of the CD4:CD8 ratio was 0.87 units lower (95% CI - 1.44 to - 0.30, p = 0.006) than patients without BOS, while the median difference of the CD4:CD8 ratio was 0.92 units lower (95% CI - 1.83 to - 0.009, p = 0.048). Therefore, our results suggest that T-cell profiles measured through flow cytometry of BALF in the CF LTx population are associated with the development of severe BOS. Further work is needed in larger patient populations to validate our findings and to determine if this is useful for recipients who underwent LTx for other indications.

Image-Guided Percutaneous Management of Skull and Spine Giant Cell Tumors: Case Report of 2 Challenging Cases Successfully Treated with Doxycycline Sclerotherapy.

BACKGROUND: A giant cell tumor (GCT) of bone is a benign, locally aggressive tumor that is often challenging to treat. When complete resection is not possible, curettage with or without adjuvants is the most common treatment. The high frequency of local recurrence and risk of injury to adjacent structures can limit this surgical approach, especially with skull and spine lesions. CASE DESCRIPTION: We report 2 cases of axial skeleton GCTs, 1 in the skull of a 58-year-old woman in whom operative management failed, who experienced local recurrence, and 1 in the cervical spine of an 8-year-old girl that grew extracompartmentally to surround her brachial plexus. Both patients were referred to us because of the surgically challenging nature of their tumors. After completion of the same percutaneous doxycycline sclerotherapy protocol previously described for aneurysmal bone cysts (ABCs), both patients were considered cured and were able to return to normal activities without loss of pretreatment function. After 4 and 10 years of follow-up, respectively, there has been no tumor recurrence in either patient. CONCLUSIONS: We successfully treated 2 patients with very challenging axial skeleton GCTs using a percutaneous doxycycline sclerotherapy protocol previously shown to have success with ABCs. We believe that this minimally invasive procedure should be considered a potential alternative treatment for GCTs, especially axial skeleton lesions, which may not be easily approached with standard surgical techniques.

Cytoplasmic Fibrillar Aggregates in Gallbladder Epithelium Are a Frequent Mimic of Cystoisospora in Pediatric Cholecystectomy Specimens.

CONTEXT.­: Cystoisospora belli is an intracellular parasite associated with gastrointestinal disease in immunocompromised hosts. Although infection has been classically associated with intestinal disease, studies have identified Cystoisospora in the gallbladder of immunocompetent patients based on hematoxylin-eosin morphology. Recently, the identity of this histologic finding as Cystoisospora has been questioned based on negative results of nucleic acid studies. OBJECTIVE.­: To determine the prevalence of this histologic feature in pediatric patients, we retrospectively reviewed all cholecystectomy specimens from a pediatric hospital during a 24-month period. DESIGN.­: In 180 cholecystectomy specimens, we identified 11 cases (6.1%) with classical histologic features previously described to represent Cystoisospora organisms. To further investigate these structures, we retrieved tissue from paraffin-embedded blocks and performed electron microscopy. RESULTS.­: Ultrastructural examination identified ovoid perinuclear cytoplasmic structures composed of dense fibrillar aggregates rather than organisms. Patients with positive cases were similar in age to controls (positive cases: mean patient age 13.4 years [range, 2-23 years]; negative cases: mean patient age 14.7 years [range, 12 weeks-31 years]; P = .35). There was no significant association of this finding with cholelithiasis (54.5% versus 65.1%, P = .52), cholesterolosis (0% versus 22.5%, P = .12), acute cholecystitis (9.1% versus 10.1%, P > .99), or chronic cholecystitis (45.5% versus 66.3%, P = .20). CONCLUSIONS.­: To our knowledge, this is the first positive identification of these structures as cytoplasmic fibrillar aggregates rather than parasitic inclusions by ultrastructural examination, and the first study of this histologic finding in pediatric cholecystectomies.

Expression of HBME-1 and CD56 in follicular variant of papillary carcinoma in children: An immunohistochemical study and their diagnostic utility.

Papillary thyroid carcinoma (PTC) is the most common differentiated thyroid cancer in children; and the follicular variant is the second most common variant after the classic subtype. The histological appearance of follicular variant of papillary thyroid cancer (FVPTC), can be mimicked by benign follicular nodules. Pediatric pathologists encountering such lesions with FVPTC-like appearance may err on diagnosing the benign lesions as malignant. In adult patients, several immunohistochemical markers have emerged recently as a useful adjunct to distinguish differentiated thyroid carcinomas from benign follicular lesions. We undertook an inter-institutional retrospective study to establish the diagnostic utility of immunohistochemical staining for HBME-1, Galectin-3 and CD56 in differentiating FVPTC from its benign mimics, follicular adenoma and adenomatoid nodules, in children. Our specific aim of the project was to define the sensitivity and specificity of the three antibodies in FVPTC. Based on institutional diagnoses, a total of 66 cases were obtained: 32 FVPTC and 34 benign follicular nodules that comprised of 23 follicular adenoma and 11 adenomatoid nodules. Five investigators, who were blinded to the original diagnoses, independently reviewed the slides following pre-determined criteria and semi-quantitatively scoring the immunohistochemical staining. The immunohistochemical staining revealed that a combination of positive HBME-1 and negative CD56 result gave 100% specificity and positive predictive value in distinguishing FVPTC from benign follicular nodules. However, the antibody combination suffered from a lower sensitivity (50%). We used a cutoff of 25% positivity of tumor cells in determining positivity of tumor cells to an antibody. In conclusion, our study found a very high specificity and strong positive predictive value for the combination of HBME-1 and CD56 immunohistochemical stains in distinguishing FVPTC from benign follicular lesions.

A Rare Case of an Intracardiac Myoepithelial Carcinoma in an Infant.

Myoepithelial carcinomas (MC) represent aggressive tumors that occur in a myriad of ages and anatomic locations. The rarity and histologic similarity with other tumors make them difficult to diagnosis. We report an extremely rare case of a right ventricular outflow tract mass identified to be an intracardiac MC in a 4-month-old male infant. Pathology revealed an EWS-KLF15 translocation. Treatment included gross total resection and intensive chemotherapy. Recurrent cardiac mass with brain metastasis was seen 16 months after primary diagnosis. We describe the rarity of intracardiac MC in pediatric patients and the challenges encountered in the multimodal management of this patient.

Immunomodulatory effects of plasma products on monocyte function in vitro.

BACKGROUND: Restoration of a balanced innate immune response is paramount to recovery from critical injury. Plasma transfusion may modulate innate immune responses; however, little is known about the immunomodulatory potential of various plasma products. We conducted in vitro experiments to determine the effects of fresh frozen plasma, thawed plasma, solvent/detergent plasma, and an investigational spray-dried solvent/detergent plasma product on monocyte function. METHODS: Monocytes were isolated from healthy adult volunteers and cocultured with aliquots of autologous plasma (control), fresh frozen plasma, thawed plasma, solvent/detergent treated plasma, or spray-dried solvent/detergent plasma. Monocyte function was assessed by cytokine production with and without lipopolysaccharide (LPS) stimulation, and flow cytometric assessment of HLA-DR cell surface expression. RESULTS: Monocyte cytokine production was not significantly altered after exposure to fresh frozen plasma or thawed plasma. In the absence of LPS, spray-dried solvent/detergent plasma exposure resulted in markedly increased IL-8 production compared to other plasma groups and controls (p = 0.01, analysis of variance [ANOVA]). Likewise, spray-dried SD plasma exposure resulted in higher LPS-induced IL-8, TNFα, and IL-1ß production compared with autologous plasma controls (p < 0.0001; p < 0.0001, p = 0.002, respectively; ANOVA). LPS-induced IL-8 and TNFα production was lowest after exposure to solvent/detergent plasma (p < 0.0001, ANOVA). CONCLUSION: Exposure to spray-dried solvent/detergent plasma resulted in marked augmentation of monocyte inflammatory cytokine production. Solvent/detergent plasma exposure resulted in the lowest cytokine production, suggesting lower immunomodulatory potential. Further work is needed to determine how these in vitro findings may translate to the bedside.

Consensus Report by the Pediatric Acute Lung Injury and Sepsis Investigators and Pediatric Blood and Marrow Transplant Consortium Joint Working Committees on Supportive Care Guidelines for Management of Veno-Occlusive Disease in Children and Adolescents: Part 2-Focus on Ascites, Fluid and Electrolytes, Renal, and Transfusion Issues.

Even though hepatic veno-occlusive disease (VOD) is a potentially fatal complication of hematopoietic cell transplantation (HCT), there is paucity of research on the management of associated multiorgan dysfunction. To help provide standardized care for the management of these patients, the HCT Subgroup of the Pediatric Acute Lung Injury and Sepsis Investigators and the Supportive Care Committee of the Pediatric Blood and Marrow Transplant Consortium, collaborated to develop evidence-based consensus guidelines. After conducting an extensive literature search, in part 2 of this series we discuss the management of fluids and electrolytes, renal dysfunction; ascites, pleural effusion, and transfusion and coagulopathy issues in patients with VOD. We consider the available evidence using the GRADE criteria.

Vulvar Fibroepithelial Polyps in a Female Adolescent: A Case Report.

BACKGROUND: Fibroepithelial polyps (FEPs) are benign tumors, of possibly hormone-dependent nature, found in the vulvovaginal region of women of reproductive age. CASE: A 15-year-old adolescent girl, receiving hormonal contraceptive therapy, who presented with multiple vulvar masses with histopathology consistent with FEP. SUMMARY AND CONCLUSION: The spectrum of the morphology of FEPs might make their diagnosis challenging. We describe a rare presentation of vulvar FEPs in an adolescent girl receiving hormonal contraceptive therapy.

Classification of Indeterminate Melanocytic Lesions by MicroRNA Profiling.

PURPOSE: Identification of indeterminate melanocytic skin lesions capable of neoplastic progression is suboptimal and may potentially result in unnecessary morbidity from surgery. MicroRNAs (miRs) may be useful in classifying indeterminate Spitz tumors as having high or low risk for malignant behavior. METHODS: RNA was extracted from paraffin-embedded tissues of benign nevi, benign Spitz tumors, indeterminate Spitz tumors, and Spitzoid melanomas in adults (n = 62) and children (n = 28). The expression profile of 12 miRs in adults (6 miRs in children) was analyzed by real-time polymerase chain reaction. RESULTS: Benign Spitz lesions were characterized by decreased expression of miR-125b and miR-211, and upregulation of miR-22, compared with benign nevi (p < 0.05). A comparison of Spitzoid melanomas to benign nevi revealed overexpression of miR-21, miR-150, and miR-155 in the malignant primaries (p < 0.05). In adults, Spitzoid melanomas exhibited upregulation of miR-21, miR-150, and miR-155 compared with indeterminate Spitz lesions. Indeterminate Spitz lesions with low-risk pathologic features had lower miR-21 and miR-155 expression compared with Spitzoid melanoma tumors in adults (p < 0.05), while pathologic high-risk indeterminate Spitz lesions had increased levels of miR-200c expression compared with low-risk indeterminate lesions (p < 0.05). Pediatric Spitzoid melanomas exhibited increased miR-21 expression compared with indeterminate Spitz lesions (p < 0.05). Moreover, miR-155 expression was increased in indeterminate lesions with mitotic counts >1 and depth of invasion >1 mm, suggesting miR-155 expression is associated with histological characteristics. CONCLUSIONS: miR expression profiles can be measured in indeterminate Spitz tumors and correlate with markers of malignant potential.

Supernatants from stored red blood cell (RBC) units, but not RBC-derived microvesicles, suppress monocyte function in vitro.

BACKGROUND: We have previously shown that critically ill children transfused with red blood cells (RBCs) of longer storage durations have more suppressed monocyte function after transfusion compared to children transfused with fresher RBCs and that older stored RBCs directly suppress monocyte function in vitro, through unknown mechanisms. We hypothesized that RBC-derived microvesicles (MVs) were responsible for monocyte suppression. STUDY DESIGN AND METHODS: To determine the role of stored RBC unit-derived MVs, we cocultured monocytes with supernatants, isolated MVs, or supernatants that had been depleted of MVs from prestorage leukoreduced RBCs that had been stored for either 7 or 30 days. Isolated MVs were characterized by electron microscopy and flow cytometry. Monocyte function after coculture experiments was measured by cytokine production after stimulation with lipopolysaccharide (LPS). RESULTS: Monocyte function was suppressed after exposure to supernatants from 30-day RBC units compared to monocytes cultured in medium alone (LPS-induced tumor necrosis factor-α production, 17,611 ± 3,426 vs. 37,486 ± 5,598 pg/mL; p = 0.02). Monocyte function was not suppressed after exposure to MV fractions. RBC supernatants that had been depleted of MVs remained immunosuppressive. Treating RBC supernatants with heat followed by RNase (to degrade protein-bound RNA) prevented RBC supernatant-induced monocyte suppression. CONCLUSION: Our findings implicate soluble mediators of stored RBC-induced monocyte suppression outside of MV fractions and suggest that extracellular protein-bound RNAs (such as microRNA) may play a role in transfusion-related immunomodulation.