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.

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.

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.

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.

A novel candidate species of Anaplasma that infects avian erythrocytes.

BACKGROUND: Anaplasma spp. are Gram-negative obligate intracellular bacteria transmitted by ticks. Even though numerous studies have detected DNA from Anaplasma spp. in the blood of birds, thus far mammals were the only vertebrates demonstrated to serve as competent hosts to these organisms. We report a novel candidate species of Anasplasma that was associated with cytoplasmic inclusions in the erythrocytes of an African penguin (Spheniscus demersus) in South Africa. METHODS: Cytoplasmic inclusions were morphologically characterized from freshly-produced blood smears, and phylogenetic analysis of 16S rRNA and groEL genes were used to evaluate the evolutionary relationships of the organism to other Anaplasmataceae. RESULTS: Dark-purple round or oval inclusions consistent with Anaplasmataceae morulae were observed in the cytoplasm of erythrocytes. Phylogenetic trees produced using different methods agreed that the organism detected in this study belongs to the genus Anaplasma, and suggested that it is most closely related to the cluster comprising A. centrale, A. capra, A. marginale and A. ovis. We propose provisionally naming the strain detected in this study as "Candidatus Anaplasma sphenisci". CONCLUSIONS: This is the first species of Anaplasma shown to produce cytoplasmic inclusions in avian cells, opening the possibility that cytoplasmic inclusions in avian erythrocytes that had previously been attributed to Aegyptianella sp. might in fact correspond to Anaplasma. Further studies on the molecular biology of avian-infecting Anaplasmataceae will be valuable to provide insight into the evolution and epidemiology of these organisms.

The case of the mysterious vanishing spleen: autosplenectomy complicating pneumococcal sepsis.

A 57-year-old previously healthy fisherman was admitted in fulminant pneumococcal septic shock, with disseminated intravascular coagulation, requiring aggressive management including bilateral below-knee amputations for ischaemic necrosis. He began to recover and was discharged for rehabilitation, however during his convalescence was found to be hypercalcaemic. No malignancy was found on CT scan, but it was noted that his spleen was absent, replaced by a 4 cm smooth-walled, fluid-filled lesion. This was unexpected as an ultrasound in intensive care 10 weeks previously had demonstrated a normal spleen. Functional hyposplenism was confirmed on a peripheral blood film with evidence of target cells, spherocytes and Howell-Jolly bodies. A diagnosis of autosplenectomy complicating pneumococcal sepsis was therefore made, of which there is just one case previously reported. The patient continues to recover well and was discharged on penicillin prophylaxis after receiving vaccinations for hyposplenism.

Howell-Jolly bodies and liver-spleen scanning for assessment of splenic filtrative function yields discordant results in renal transplant recipients.

Given discrepancies between methods for diagnosing hyposplenism, the purpose of this study was to evaluate the effect of the spleen size on the correlation between the methods, and to propose a model for improving the interpretation. Patients with renal allografts were included, in whom the spleen was assessed using Doppler ultrasound, scintiscan, and the presence of Howell-Jolly bodies (HJBs) in peripheral smears. In 35 subjects, scintiscan and HJBs were normal (Group 0); 20 had an abnormal result in both methods (Group 1); 34 had discordant results with HJBs present (Group 2); and 14 had discordant results with decreased spleen uptake (Group 3). There was no association between HJBs and scintiscan. The patients of Groups 1 and 2 had smaller spleens. The patients with smaller spleen had more hematological evidence of hyposplenism and exhibit smaller discrepancies between the methods than patients with larger spleen. The spleen can tip the balance from a normal to impaired function provided that the spleen size is below the critical mass required to maintain splenic function. A mild impairment of phagocytic function and slight dyserythropoiesis along with a small spleen would result in decreased take up of radiocolloid or the appearance of HJBs in blood smears.

Effects of GlyT1 inhibition on erythropoiesis and iron homeostasis in rats.

Glycine is a key rate-limiting component of heme biosynthesis in erythropoietic cells, where the high intracellular glycine demand is primarily supplied by the glycine transporter 1 (GlyT1). The impact of intracellular glycine restriction after GlyT1 inhibition on hematopoiesis and iron regulation is not well established. We investigated the effects of a potent and selective inhibitor of GlyT1, bitopertin, on erythropoiesis and iron homeostasis in rats. GlyT1 inhibition significantly affected erythroid heme biosynthesis, manifesting as microcytic hypochromic regenerative anemia with a 20% steady-state reduction in hemoglobin. Reduced erythropoietic iron utilization was characterized by down-regulation of the transferrin receptor 1 (TfR1) on reticulocytes and modest increased iron storage in the spleen. Hepatic hepcidin expression was not affected. However, under the condition of reduced heme biosynthesis with reduced iron reutilization and increased storage iron, hepcidin at the lower and higher range of normal showed a striking role in tissue distribution of iron. Rapid formation of iron-positive inclusion bodies (IBs) was observed in circulating reticulocytes, with an ultrastructure of iron-containing polymorphic mitochondrial remnants. IB or mitochondrial iron accumulation was absent in bone marrow erythroblasts. In conclusion, GlyT1 inhibition in rats induced a steady-state microcytic hypochromic regenerative anemia and a species-specific accumulation of uncommitted mitochondrial iron in reticulocytes. Importantly, this glycine-restricted anemia provides no feedback signal for increased systemic iron acquisition and the effects reported are pathogenetically distinct from systemic iron-overload anemias and erythropoietic disorders such as acquired sideroblastic anemia.