Biomarkers of splenic function in infants with sickle cell anemia: baseline data from the BABY HUG Trial.

We evaluated spleen function in 193 children with sickle cell anemia 8 to 18 months of age by (99m)Tc sulfur-colloid liver-spleen scan and correlated results with clinical and laboratory parameters, including 2 splenic biomarkers: pitted cell counts (PIT) and quantitative Howell-Jolly bodies (HJB) enumerated by flow cytometry. Loss of splenic function began before 12 months of age in 86% of infants in association with lower total or fetal hemoglobin and higher white blood cell or reticulocyte counts, reinforcing the need for early diagnosis and diligent preventive care. PIT and HJB correlated well with each other and liver-spleen scan results. Previously described biomarker threshold values did define patients with abnormal splenic function, but our data suggest that normal spleen function is better predicted by PIT of ≤1.2% or HJB ≤55/10(6) red blood cells and absent function by PIT ≥4.5% or HJB ≥665/10(6). HJB is methodologically advantageous compared with PIT, but both are valid biomarkers of splenic function. This trial was registered at www.clinicaltrials.gov as #NCT00006400.

Hyposplenism revealed by Plasmodium malariae infection.

BACKGROUND: Hyposplenism, due to splenectomy, inherited red blood cell disorders or acquired conditions such as celiac disease, has an important impact on the severity of malaria, especially in non-immune patients. Conversely, that malaria may reveal functional hyposplenism has not been described previously. METHODS: A 31-year old gardener was diagnosed with an uncomplicated attack of Plasmodium malariae 11 years after leaving the endemic area. In addition to trophozoites and schizonts, thick and thin smears also showed Howell-Jolly bodies, pointing to functional hyposplenism. This was later confirmed by the presence of a calcified spleen in the context of S/ß + sickle-cell syndrome in a patient previously unaware of this condition. CONCLUSION: Malaria may reveal hyposplenism. Although Howell-Jolly bodies are morphologically similar to nuclei of young Plasmodium trophozoite, distinction on smears is based on the absence of cytoplasm and irregular size of Howell-Jolly bodies. In the patient reported here, hyposplenism was revealed by the occurrence of P. malariae infection relatively late in life. Timely diagnosis of hyposplenism resulted in the implementation of appropriate measures to prevent overwhelming infection with capsulated bacteria. This observation highlights the importance of diagnosing hyposplenism in patients with malaria despite the morphological similarities between ring nuclei and Howell-Jolly bodies on thick smears.

A case of functional asplenia and pneumococcal sepsis.

Asplenia may refer to the spleen's surgical removal, functional impairment, or congenital absence. It is a risk factor for the development of severe bacterial infection. Functional asplenia is likely the most common presentation of this entity and has many etiologies. Those that are previously undiagnosed may present completely well until an episode of overt sepsis develops. The true incidence of mortality secondary to functional asplenia remains elusive. As lifetime mortality remains exceedingly high in the asplenic population regardless of etiology, markers of hyposplenism are important to detect. The present report describes an infant with trisomy 21 and previously undiagnosed functional asplenia who ultimately experienced overwhelming pneumococcal sepsis with features of Waterhouse-Friderichsen syndrome and died within 12 hours of initial presentation. It is a poignant reminder of what features to be cognizant of on peripheral blood smear in a previously well child, who may be at risk for a devastating consequence.

Karyopyknotic cytoplasmic inclusions in neutrophils.

Karyopyknotic cytoplasmic inclusions in neutrophils (KPCI) have been previously called "Howell-Jolly" like inclusions and identified in immunosuppressed patients with human immunodeficiency virus (HIV) and in patients with various malignancies who have undergone chemotherapy. Attempts to characterize these inclusions have included the Grocott's methenamine silver (GMS), periodic acid Schiff (PAS), Gram, and Feulgen stains. Previous authors have concluded that these inclusions are of deoxyribonucleic acid (DNA) origin. We present a case describing an additional method to confirm this observation and to document previously undescribed curvilinear forms.

Potential role of Howell-Jolly bodies in identifying functional hyposplenism: a prospective single-institute study.

Although patients with cancer and immunosuppression are at a risk of functional hyposplenism, how to detect it promptly remains unclear. Since hyposplenism allows erythrocytes with nuclear remnants (Howell-Jolly bodies [HJBs]) to appear in the peripheral blood, HJB detection by a routine microscopic examination may help identify patients with functional hyposplenism. This prospective study was thus performed to determine the underlying diseases in patients who presented with HJBs. Of 100 consecutive patients presenting with HJBs, 73 had a history of splenectomy. The remaining 27 had hematologic cancer (n = 6, 22%), non-hematologic cancer (n = 8, 30%), hepatic disorders (n = 4, 15%), premature neonates (n = 3, 11%), hemolytic anemia (n = 2, 7%), autoimmune disorders (n = 2, 7%) and miscellaneous diseases (n = 2, 7%), and their prior treatments included chemotherapy (n = 8, 30%), steroids (n = 7, 26%) and molecular-targeted therapy (n = 3, 11%). Among the 27 patients, 22 had computed tomography scans available: 3 (14%) had underlying diseases in the spleen, and the remaining 19 (86%) were all found to have a decreased splenic volume, including 11 (50%) with more than 50% of the ideal value. The present findings suggest that HJB detection identifies patients with potentially functional hyposplenism who should receive appropriate interventional treatment, such as vaccination and prophylactic antibiotics.

[Benefit of Howell-Jolly bodies detection: finding of an acquired hyposplenism in a patient with Goodpasture syndrome]. / Intérêt de la détection des corps de Howell-Jolly : hyposplénisme acquis dans le cadre d'un syndrome de Goodpasture.

Howell-Jolly bodies are intraerythrocytic inclusions corresponding to a small portion of chromatin. Red blood cells that contain these nuclear remnants are removed from the circulation by the spleen. In most cases, presence of Howell-Jolly bodies on a blood smear is the result of functional asplenia and splenectomy. Observation. We report incidental finding of numerous Howell-Jolly bodies in a patient followed by the nephrology department. This microscopic observation of blood smear led to a diagnostic imaging and to the evidence of a reduced spleen, possibly favoured by a history of Goodpasture syndrome in this renal transplant patient without splenectomy. Vaccination and antibioprophylaxy were proposed to prevent infectious risk linked to this splenic hypoplasia. Conclusion. Seeking of Howell-Jolly bodies could be made in every condition associated with a risk of splenic hypoplasia to prevent infectious risk.

Newly recognized Anaplasma sp. in erythrocytes from Gopher Tortoises (Gopherus polyphemus).

BACKGROUND: In 2015, a previously unrecognized intracytoplasmic erythrocytic inclusion was discovered in anemic wild-caught adult gopher tortoises (Gopherus polyphemus). Subsequently, molecular diagnostics revealed this inclusion to be a novel Anaplasma sp. OBJECTIVES: The goal of this study was to morphologically characterize these erythrocytic inclusions by light and transmission electron microscopy (TEM). METHODS: Blood samples were taken from two car-injured wild-caught gopher tortoises for the preparation of Wright-Giemsa stained smears and TEM specimens. CBC data were serially performed and morphologically examined during treatment periods. RESULTS: Studies revealed a moderate to severe anemia with moderate regeneration as indicated by polychromasia and the presence of immature erythroid precursors. In addition, on light microscopy, one to two variably-sized round basophilic stippled paracentral erythrocytic inclusions were present per cell in both animals and involved 10%-25% of erythrocytes. TEM identified the intraerythrocytic inclusions as discrete membrane-bound cytoplasmic vacuoles (morulae) containing membrane-bound bacterial subunits that were of variable size, shape, and electron density. Serial hematologic data indicated complete remission of the infection in response to a single long-term course of doxycycline. CONCLUSIONS: The presence of a regenerative anemia in gopher tortoises from Florida revealed a newly recognized bacterial species that has morphologic characteristics similar to members of the genus Anaplasma.

Howell-Jolly Body-Like Inclusions in Neutrophils of Patients With Myelodysplastic Syndrome: A Novel Correlation.

CONTEXT.­: Howell-Jolly body-like inclusions have been previously associated with patients who are human immunodeficiency virus (HIV) infected, taking antiviral medications, and immunosuppressed. These inclusions appear in neutrophils and resemble Howell-Jolly bodies of normoblasts in abnormal erythropoiesis. In granulocytes, they are thought to represent detached nuclear fragments produced from dysplastic granulopoiesis. To the best of our knowledge, no association of Howell-Jolly body-like inclusions and myelodysplastic syndrome (MDS) has been reported previously. OBJECTIVE.­: To establish an unprecedented correlation of Howell-Jolly body-like inclusions in patients with MDS. DESIGN.­: Eleven bone marrow cases from patients diagnosed with MDS and 20 bone marrow cases with no significant pathologic alterations were retrospectively reviewed. Detailed medical record review was performed to ensure none of the patients had a history of HIV, or was taking immunosuppressants and/or antiviral medications. RESULTS.­: Eight of 11 cases (72%) from the study group show detached intracytoplasmic inclusions in a minority (<5%) of mature neutrophils consistent with Howell-Jolly body-like inclusions. No Howell-Jolly body-like inclusions were identified in the control group. Notably, none of the selected patients had a history of HIV or was taking immunosuppressants and antiviral medications. CONCLUSIONS.­: In review of the literature, Howell-Jolly body-like inclusions seem to correlate with immunosuppression and antiviral therapies with nucleoside analogs. We propose that the formation of Howell-Jolly body-like inclusions is the consequence of dysplasia, and hence its correlation not only with the abovementioned conditions, but also with MDS. The inclusions are, however, seen in only a minority of white cells (<5%), which is probably why they were not brought to practicing pathologists' awareness in the past. This study aims to raise awareness and correlate the presence of Howell-Jolly body-like inclusions in MDS.

Evaluation of Thalassaemia Screening Tests in the Antenatal and Non-Antenatal Populations in Singapore.

INTRODUCTION: Haemoglobinopathy testing is performed for carrier screening and evaluation of microcytic anaemia. We evaluated the effectiveness of thalassaemia screening tests at our institution and suggest ways of improving the testing algorithm. MATERIALS AND METHODS: A total of 10,084 non-antenatal and 11,364 antenatal samples with alkaline gel electrophoresis (AGE), capillary electrophoresis (CE), haemoglobin H (HbH) inclusion test, mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) were retrospectively reviewed. A subgroup of 187 samples with genetic testing was correlated with HbH inclusions and MCH/ MCV. The effect of iron deficiency on percentage hemoglobin A2 (HbA2) was studied. RESULTS: HbH inclusion test showed low sensitivity of 21.43% for α-thalassaemia mutations but higher sensitivity of 78.95% for --SEA deletion. By receiver operating characteristic (ROC) analysis, MCH ≤28 pg or MCV ≤80 fl for non-antenatal samples and MCH ≤27 pg or MCV ≤81 fl for antenatal samples had >98% sensitivity for HbH inclusions. Above these thresholds, the probability that HbH inclusions would be absent was <99% (negative predictive value [NPV] >99%). MCH ≥28 pg had 100% sensitivity (95% CI 95.63%-100%) for α-thalassaemia mutations and 97.68% calculated NPV in the antenatal population. Detection of haemoglobin variants by CE correlated highly with AGE (99.89% sensitivity, 100% specificity). Severe iron deficiency reduced HbA2 in hemoglobin (P <0.001) and α-thalassaemia (P = 0.0035), but not in ß-thalassaemia. CONCLUSION: MCH/MCV thresholds have adequate sensitivity for α-thalassaemia in the antenatal population, and genotyping plays an important role as HbH inclusion test shows low sensitivity. CE without AGE, may be used as initial screening for haemoglobin variants. Our study provides contemporary data to guide thalassaemia screening algorithms in Singapore.

Insights into determinants of spleen injury in sickle cell anemia.

Spleen dysfunction is central to morbidity and mortality in children with sickle cell anemia (SCA). The initiation and determinants of spleen injury, including acute splenic sequestration (ASS) have not been established. We investigated splenic function longitudinally in a cohort of 57 infants with SCA enrolled at 3 to 6 months of age and followed up to 24 months of age and explored the respective contribution of decreased red blood cell (RBC) deformability and increased RBC adhesion on splenic injury, including ASS. Spleen function was evaluated by sequential 99mTc heated RBC spleen scintigraphy and high-throughput quantification of RBCs with Howell-Jolly bodies (HJBs). At 6 and 18 months of age, spleen filtration function was decreased in 32% and 50% of infants, respectively, whereas the median %HJB-RBCs rose significantly (from 0.3% to 0.74%). An excellent correlation was established between %HJB-RBCs and spleen scintigraphy results. RBC adhesion to laminin and endothelial cells increased with time. Adhesion to endothelial cells negatively correlated with splenic function. Irreversibly sickled cells (ISCs), used as a surrogate marker of impaired deformability, were detected at enrollment and increased significantly at 18 months. %ISCs correlated positively with %HJB-RBCs and negatively with splenic uptake, indicating a relationship between their presence in the circulation and spleen dysfunction. In the subgroup of 8 infants who subsequently experienced ASS, %ISCs at enrollment were significantly higher compared with the asymptomatic group, suggesting a major role of impaired deformability in ASS. Higher levels of %HJB-RBCs were observed after the occurrence of ASS, demonstrating its negative impact on splenic function.

Quantitative analysis of Howell-Jolly bodies in children with sickle cell disease.

OBJECTIVES: Although functional asplenia in sickle cell disease (SCD) begins early in life and has important clinical consequences, quantitative measurement of splenic function is not readily available. A novel high-throughput flow cytometric method for quantitating Howell-Jolly bodies (HJB) has been developed which isolates HJB-containing CD71(+) and CD71(-) erythrocytes. Analysis of these cell populations allows quantitative measurement of splenic filtrative function and possible chromosomal damage. METHODS: Blood specimens from 147 children with SCD were analyzed using a high-throughput flow cytometric method. Enumeration of the following populations was accomplished: 1) CD71(+) reticulocytes among total erythrocytes, identifying the youngest erythroid cell population; 2) HJB-containing CD71(+) reticulocytes, which isolate young erythrocytes containing micronuclei as an index of cytogenetic damage; and 3) HJB-containing CD71(-) erythrocytes, identifying older erythrocytes containing micronuclei, indirectly measuring splenic function. RESULTS: Children with HbSC (n = 24) had slightly elevated HJB frequencies, while children with HbSS (n = 125) had highly elevated frequencies within CD71(+) cells (0.44% +/- 0.40%, normal 0.12% +/- 0.06%, p < 0.001) and CD71(-) cells (2493 +/- 2303 per million RBC, normal 20 +/- 11, p < 0.001). Using a multiple regression model, the frequency of HbSS CD71(+) reticulocytes containing HJB was significantly influenced by hydroxyurea use (p < 0.0001), age (p = 0.0288), and splenectomy (p = 0.0498). Similarly, mature CD71(-) erythrocytes containing HJB were positively correlated with hydroxyurea (p = 0.0001), age (p < 0.0001), and splenectomy (p = 0.0104). CONCLUSIONS: HJB quantitation by flow cytometry is a novel assay for measuring splenic function and may be valuable for investigating the efficacy and safety of therapeutic options for children with SCD.