Eryptosis and circulating blood cells microparticules in sickle cell diseases

Sickle cell disease(SCD)is a monogenic disease, in which the severity and symptoms vary widely.The sickle cell mutation is the origin of all functional and structural alterations of red blood cell(RBC)which induces the acceleration of eryptosis and formation of Circulating blood cells microparticules(MPs)which has the consequence of acute anemia and increasing the thrombotic risks in sickle cell patients. Eryptosis is the suicidal erythrocyte death characterized by erythrocyte membrane scrambling by phosphatidylserine(PS)externalization. MPs are an extracellular vesicules released following cellular activation, stress or apoptosis. These parameters are able to modulate many biological functions, and considered as biomarkers of preventive diagnostic of SCD. This present study aims to determine the cellular biomarkers to implementation new and innovative methods of the preventive diagnosis of SCDacute complications. We propose to study the mechanisms involved in the triggering of eryptosis and to quantify microparticles derived from platelets and erythrocytes of homozygous sickle cell patients.

Following clinical diagnosis, homozygous SCDpatients and healthy donors were sampled for hematological and cellular assays. The exploration of eryptosis and MPs was performed by a flow cytometry by determining the viability parameters of red blood cells.

The outcome of our study indicated that Eryptosis in sickle cell patients is triggered essentially by high Ca2 + entry and narrowing of red blood cells. However, the pathway of ceramides and ERO can also considered a stimulating factor of eryptosis. Eryptosis ensures healthy erythrocyte quantity in circulation whereas excessive eryptosis is the cause of acute anemia and may contribute to vaso-occlusive crisis in SCD patients.For MPs study,microparticles derived from platelets and erythrocytes clearly increased in SCD patients. This suggests that erythrocytes MPs may contribute to thrombotic risk andchronic hemolytic anemia.

Key messages

Potentiel biomarkers in the preventive diagnosis of sickle cell disease. Eryptosis and plasmatic microparticules as potentiel biomarkers.

Genetic link with cholelithiasis among pediatric SCA Tunisian patients: Examples of UGT1A1, SLCO1A2 and SLCO1B1

AIMS AND BACKGROUND

Hyperbilirubinemia is often observed in chronic hemolysis and results in the formation of pigment cholelithiasis that could be increased by the presence of defected enzymes involved in the bilirubin metabolism. Indeed, this is the first report that interested in the study of polymorphisms in genes encoded for enzymes involved in the bilirubin metabolism: rs 4149056 of SLCO1B1 and rs4149000 of SLCO1A2 in combination with rs8175347 and rs887829 of UGT1A1 in order to find a correlation between the polymorphisms studied and the presence of gallstones in a population of sickle cell anemia (SCA) pediatric Tunisians.

MATERIAL AND METHODS

Our study involved 102 unrelated Tunisian subjects. All SCA patients are children (less than 16 years old) and were characterized by hyperbilirubinemia and 52 of them have cholelithiasis. The polymorphisms of the candidate genes were analyzed for all subjects by PCR/sequencing. Genotype and allele frequencies between cases and controls were compared using Pearson's chi-square test with a significance threshold of P < 0.05 (compare 2, version 1.02).

RESULTS

The novelty of this report is that children carrying the combined genotype of the rs studied: (TA7TA7)/TT/TC/GA have a higher risk to develop gallstones (P = 0.0027, RR = 18.27 (20.0061-915.28)).

CONCLUSION

Altogether our data provide the implication of UGT1A1 and SLCO1A2 in sickle cell anemia-related cholelithiasis.

High frequency of autoimmunization among transfusion-dependent Tunisian thalassaemia patients

BACKGROUND

Limited data are available on the frequency of RBC alloimmunization and autoimmunization in transfusion-dependent Tunisian β thalassaemia patients.

MATERIALS AND METHODS

We analyzed the clinical and transfusion records of 130 patients (57 females and 73 males; mean age 119 months; range 12-11 months) with β thalassaemia major and who had regular blood transfusions for periods ranging from 12 to 311 months.

RESULTS

Of the 130 patients, ten (7.7%) developed RBC alloantibodies. The most common alloantibodies were directed against antigens in the Rh systems. Erythrocyte-autoantibodies as determined by a positive direct antiglobulin Coombs test, developed in 52(40%) patients with and without underlying RBC alloantibodies, thereby causing autoimmune haemolytic anaemia in eleven patients (21%).

CONCLUSIONS

Autoimmunization to erythrocyte antigens is a frequent complication in patients with β thalassaemia major. Several factors might have contributed to the high autoimmunization rate observed in this study, including non phenotypic blood exposure and alloantibody formation prior to positive Coombs test.

[Cryptosporidium infection in patients with major histocompatibility complex class II deficiency syndrome in Tunisia: description of five cases]

BACKGROUND

In Tunisia, Cryptosporidium is frequently identified in diarrheic stools of children and immunocompromised patients. The infection is usually self-limited in immunocompetent populations, but can be severe and life-threatening in immunocompromised individuals. Cryptosporidiosis is well-documented in patients with the human immunodeficiency virus; however, few data are available concerning children with primary immunodeficiencies (PIDs).

PATIENTS AND METHODS

A retrospective study was conducted on 5 cryptosporidiosis cases diagnosed in 11 children with PIDs. Cryptosporidium was systematically investigated when patients presented chronic diarrhea. Stool samples were examined for the parasite oocysts by modified Ziehl-Neelsen staining, and DNA was systematically extracted for a nested polymerase chain reaction (PCR). The species were identified by the analysis of restriction patterns. Epidemiological and clinicobiological data were presented for each patient.

RESULTS

All cryptosporidiosis cases presented a CMH class II deficiency syndrome. Chronic diarrhea was associated with failure to thrive in all cases. PCR provided the diagnosis in all patients, while Ziehl-Neelsen staining revealed Cryptosporidium oocysts in only 3 cases. Species identification yielded Cryptosporidium hominis in 2 cases, Cryptosporidium meleagridis in 1 case, and Cryptosporidium parvum in 1 case; a C. hominis/C. meleagridis co-infection was observed in the last case. C. hominis was isolated in children from rural areas, suggesting that the infection could have been contracted in the hospital and thus a probability of nosocomial transmission. One of the C. hominis carriers developed sclerosing cholangitis with a high parasite load.

CONCLUSION

Cryptosporidiosis with serious clinical symptoms is observed in PID patients, particularly those with CMH class II deficiency syndrome. Early, regular, and repeated screening, improved by PCR, is recommended in this group of patients. The predominance of C. hominis, the anthropophilic species, in children from rural areas should emphasize hygiene measures in care centers where PID cases are treated.

Successful treatment of influenza A virus by oseltamivir in bone marrow transplant recipients

INFVA is an important cause of pulmonary infections in patients receiving BMT, and is associated with considerable morbidity and mortality for a readily preventable and treatable infection. Few studies have addressed the impact of the new neuraminidase inhibitors in the prognosis of influenza after BMT. The aim of this study is to assess the impact of oseltamivir on the control of INFVA infection in BMT recipients. INFVA was screened in NPA and/or bronchoalveolar lavage using IF in all BMT recipients having respiratory symptoms. Three URTI and one associated upper and LRTI were diagnosed in three BMT recipients out of six patients admitted to the BMT unit, during eight-wk period (March and April 2008). All patients having INFVA respiratory infection were treated by oral oseltamivir 60 mg/day, begun more than 48 h after symptom onset. Respiratory symptoms disappeared within a mean of 60 h (48-96 h) of treatment. However, viral tests had remained positive for 8-39 days. Outside the initial associated URTI and LRTI, no further viral pneumonia occurred. No patient died of INFVA. Oseltamivir was well tolerated outside vomiting during the first three days of treatment in one patient. Oseltamivir appears to play an important role in the outcome of INFVA infection as well in URTI as in severe LRTI in patients receiving BMT.

[HLA-G: an immunoregulatory non classical class I HLA molecule]

HLA-G is a particular non classical HLA class I molecule. Despite its tissue-restricted expression and low polymorphism, this molecule plays an important role in innate and adaptative immunity. The tolerogenic propriety of HLA-G makes it an immunomodulatory molecule acting in the early phases of conception, protecting fetal tissues from the maternal immune system. Immunomodulatory functions of HLA-G and the associations of this molecule with some pathological states are reported in this review. So, little amounts of soluble HLA-G or particular allelic expression of this molecule are associated with some pregnancy complications. HLA-G expression on tumor cells by preventing antitumor responses via a trogocytosis mechanism and regulatory T cells induction is associated with invasiveness and clinical evolution of some tumor types. HLA-G is also involved in the protection of the transplanted tissues from rejection. Revealing of new more functional homomultimeric isoforms of this molecule offers new insight in a better understanding of clinical and biological role of HLA-G.

[Antiphospholipid syndrome: pathophysiology and clinicobiological aspects]

Due to its heterogeneity and pathogenesis diversity, antiphospholipid syndrom remains a challenge for researchers more than a century after first antibody, the anticardiolipin antibody for syphilis diagnosis was discovered. After a review of the etiology and epitopic specificities of antiphospholipid antibodies, we propose a detailed overview of mechanisms and clinical aspects of antiphospholipid syndrome. We emphasize on the role of innate immunity and the involvement of endothelial cells Toll like receptors in the transduction signal of anti-beta2-glycoprotein I antibodies fixation, which induce a thrombogenic state. The thrombogenic role of the anti-beta2GPI antibodies direct against beta2GPI domain I in the clinical onset of this syndrome is also evoked. Diagnosis problems and clinicobiological manifestations in the light of the last international consensus statement of the classification criteria for antiphospholipid syndrome end this review.

[The use of hydroxyurea in severe forms of sickle cell disease: study of 47 Tunisian paediatric cases]

INTRODUCTION

The Sickle Cell Disease (SCD) is a serious illness considering its complications. For the children seriously affected, three therapeutic options are currently validated: transfusion therapy, hydroxyurea and bone-marrow transplantation.

OBJECTIVES

To see the contribution of hydroxyurea therapy on severe forms of SCD in affected Tunisian children.

MATERIAL AND METHODS

This investigative study lasted over 6 years and 9 months, (September 2000-May 2007), enrolling 47 patients including 27 homozygous SCD and 20 double heterozygote SCD-S/beta thalassemia. The median age was 12 years and a half. The average dosage were 20mg/kg/d (14-30 mg/kg/d). The average duration of treatment was 52 months (18-81 months).

RESULTS

The main indication for hydroxyurea treatment was prevention of recurrence of an acute chest syndrome in seven cases; episodic vaso-occlusive crises exceeding three events per year in 38 cases and prevention of deterioration of cerebral vascular accident in two cases. We observed a fast and sustained improvement of the clinical expression of the disease with a significant decrease of the number of days of hospitalization per patient and per annum from 29.3 d (10-84 d) to 3.2 d/(p<0.01). Treatment was well tolerated. We observed a significant increase of haemoglobin fetus (HbF) rates from 3 to 30% (p<0.01), hemoglobin from 7.8 to 9.6g/dl (p<0.05), average blood cells volume from 79.1 to 100.3 fl (p<0.05) and a significant fall of the white blood cells rates from 14,914 to 8464 per millimetre cube (p<0.05), polynuclear neutrophils from 6799 to 3486 per millimetre cube (p<0.05) and platelets from 508,666 to 293,500 per millimetre cube (p<0.05).

CONCLUSIONS

Hydroxyurea represents a privileged choice of treatment in the severe forms of SCD in children, for homozygous SCD-SS as well as for double heterozygote SCD-S/beta thalassemia. Used carefully, with frequent monitoring, it appeared as a safe treatment in short and medium term, but studies of long-term tolerance should be undertaken.

Mutations du gène HFE chez des β-thalassémiques majeurs tunisiens et surcharge en fer

OBJECTIVES

In this study we have determined the allele frequency of HFE mutations H63D and C282Y in a group of Tunisian beta-thalassemia major patients. These two mutations are implicated in hereditary hemochromatosis among Caucasians. In this study we wanted to correlate these mutations with the iron status in major beta-thalassemia patients.

DESIGN AND METHODS

Fifty Tunisian major beta-thalassemia were screening for the C282Y and H63D by digestion of polymerase chain reaction products (RFLP). Serum ferritin level was measured by immunoenzymatic microparticular essay.

RESULTS

The allele frequency of H63D mutation was 17%. C282Y mutation was not present in our studied patients. No statistically significant difference of serum ferritin level was found between major beta-thalassemia with and without HFE mutations.

CONCLUSION

Our results suggest that H63D mutation is so frequent in Tunisian major beta-thalassemia patients than in the general population and that the coinheritance of H63D mutation does not influence the severity of iron overload in these patients.

Genetic and mutational heterogeneity of autosomal recessive chronic granulomatous disease in Tunisia

NADPH oxidase, a multi-subunit protein consisting of cytosolic components and the membrane-bound heterodimer, plays an instrumental role in host defence mechanisms of phagocytes. Genetic deficiency of the enzymatic complex results in an inherited disorder, chronic granulomatous disease (CGD), which is characterized by an impaired phagocyte microbicidal activity. X-Linked (XL) CGD results from a mutation in the CYBB gene encoding the gp91phox subunit, while autosomal recessive (AR) CGD is associated with mutations in one of the NCF1, NCF2 and CYBA genes that encode the p47phox, p67phox and p22phox subunits, respectively. In the study reported here, we investigated genetic defects underlying CGD in 15 Tunisian patients from 14 unrelated families. Haplotype analyses and homozygosity mapping with microsatellite markers around known CGD genes assigned the genetic defect to NCF1 in four patients, to NCF2 in four patients and to CYBA in two patients. However, one family with two CGD patients seemed not to link the genetic defect to any known AR-CGD genes. Mutation screening identified two novel mutations in NCF2 and CYBA in addition to the recurrent mutation, DeltaGT, in NCF1 and a splice site mutation previously reported in a North African patient. Our results revealed the genetic and mutational heterogeneity of the AR recessive form of CGD in Tunisia.

[Immunoglobulin replacement therapy contribution in agammaglobulinemia: 10 case reports]

Intravenous immunoglobulin (Ig IV) has been used for many years in the treatment of primary antibody deficiencies. We performed a retrospective study of the clinical features and outcome of agammaglobulinemia children who received prolonged Ig IV infusions.

PATIENTS AND METHODS

Ten children, 9 male et 1 female, with agammaglobulinemia diagnosis were studied for the clinical manifestations before and during the Ig IV replacement therapy. Serum Ig levels were quantified by nephelometry. Circulating B ant T cells were counted by immunofluorescence labeling by monoclonal antibodies. T-cell functions were assessed by using mitogen and antigen -induced T-cell proliferation assays in vitro. Patients clinical status was evaluated respectively, before initiation and at every moment (when patients had an infection) of the replacement therapy.

RESULTS

Ig IV therapy was performed for 866 cumulated months, median 108 months. The median Ig IV doses administered to the 10 patients was 500 mg/kg/month. Residual serum IgG mean level was 3,9 g/L. All patients had 99 bacterial infections/year before Ig IV, mainly respiratory tract infections (48,5%), and 4 patients had bronchiectasis before Ig replacement therapy. The number of infection/year fall to 25 during IgIV replacement, and the infection/patient/year rate decreases significantly. One patient developed an Echovirus 27 meningoencephalitis during this treatment.

CONCLUSION

Ig IV therapy with residual IgG mean level of 3,9 g/l reduced significantly the rate of bacterial infections. The use of specific antibiotherapy and respiratory kinesitherapy led to a lower rate of respiratory tract infections, and the stabilisation of the bronchiectasis. However this intravenous replacement therapy does not protect against viral meningoencephalitis.

Treatment of a patient with chronic renal failure with rituximab for a follicular lymphoma: safe and successful option of rituximab therapy

A 47-yr-old woman presented a chronic renal failure for 5 yr, with a creatinine clearance of 12 mL/min. In June 2002, she had a right axillary lymph node (of 4 cm diameter). A biopsy revealed a follicular lymphoma (histology: follicular small cleaved-cell). She had Ann Arbor stage III disease, with a high tumor burden according to the GELF criteria. She received rituximab as single first-line treatment (375 mg/m2 by intravenous infusion for a total of four dosages: days 1, 8, 15 and 22). Rituximab therapy was extremely well tolerated, and we obtained a partial response, 4 wk after completing the treatment. In January 2003, she received one maintenance course of rituximab. Six weeks after maintenance therapy, a complete response was achieved.

[Successful treatment of Echovirus 27 meningoencephalitis in agammaglobulinaemia with intraventricular injection of gammaglobulin. A case report]

BACKGROUND

Meningoencephalitis due to enteroviruses is particularly serious when occurring in patients with agammaglobulinaemia. This disease is associated with a high mortality and a significant risk for neurological sequelae in such circumstances. We report here a new case treated with intraventricular immunoglobulin, whose evolution was favourable.

CASE REPORT

A three-year-old boy with agammaglobulinaemia, while he was treated with gammaglobulin with an IgG residual concentration of 10 g/l, presented neurological symptoms related to Echovirus 27 meningo encephalitis. Under treatment with intraventricular gammaglobulin by means of an Ommaya reservoir, the patient recovered.

CONCLUSION

Favourable evolution is rare in meningo encephalitis in agammaglobulinaemic patients. Prognosis depends on an early diagnosis and on the extent of dissemination of the infection. Intraventricular gammaglobulin administration may contribute to a favourable outcome.

[Chronic septic granulomatous disease. 14 cases]

OBJECTIVES

Chronic granulomatous disease (CGD) is a rare inherited immunodeficiency. Affected children are mostly boys. The most common clinical features are recurrent bacterial and fungal infections starting at early childhood. We report 14 cases, including 5 girls, of CGD in Tunisian children.

PATIENTS AND METHODS

This retrospective study concerned 14 clinical observations of CGD recorded between April 1988 and December 1998. The diagnosis was established upon determination of a defective respiratory burst in the patients' neutrophils at the tetrazolium nitroblue test (NBT). In 4 cases, the diagnosis was also confirmed by chemiluminescence assay.

RESULTS

The patients (9 boys and 5 girls) belonged to 12 families, 75% of which were consanguineous. In 6 families, there had been several deaths in early childhood. The mean age at onset of clinical signs was 6.8 months (7 days to 24 months). Clinical signs included lung (10 cases), nodal (8 cases), skin (7 cases), and intestinal (7 cases) infections. Seven patients developed invasive pulmonary aspergillosis with parietal extension in 4 cases. Salmonella and Staphylococcus infections were rare in our series. Six children (42.8%) including 2 girls, died. Aspergillosis was fatal in 4 cases.

CONCLUSION

Recurrent infections are the main clinical fetus of chronic granulomatous disease. Prognosis has been improved by the use of prophylactic antibiotics. Early diagnosis of the disease is crucial.

[Primary immunologic deficiency by deficiency of HLA class II antigens: nine new Tunisian cases]

BACKGROUND

Bare lymphocyte syndrome is a rare inherited primary immunodeficiency. The majority of the patients reported to date are from North Africa. We report nine new Tunisian cases.

POPULATION AND METHODS

Over a period of 5 years, we have established the diagnosis of bare lymphocyte syndrome in nine patients who belong to seven different families. Class II HLA antigen expression was studied on resting peripheral mononuclear cells and PHA blasts.

RESULTS

The clinical symptoms started at the mean age of 4.5 months (2-10 months) with chronic diarrhea. The evolution was characterized by appearance of other recurrent infections: pneumopathies (seven cases), thrush (seven cases), otitis (five cases) and septicemia (four cases). Allergic manifestations were observed in four cases. Six patients died at the mean age of 30 months from severe denutrition. Class II HLA antigens were not expressed on resting and activated lymphocytes. The absolute count of TCD4+ lymphocytes was decreased in seven patients. Lymphoproliferative response to specific antigens was absent. Four patients had panhypogammaglobulinemia.

CONCLUSION

This study confirms the frequency of this disease among the North African population. The severity of the recurrent infection suggests the diagnosis of bare lymphocyte syndrome. This disease is fatal in the absence of bone marrow transplantation.

[Agammaglobulinemia with the absence of circulating B-lymphocytes. 9 cases]

OBJECTIVES

Agammaglobulinemia with absence of circulating B lymphocytes is a rare genetically transmitted immunodeficiency that appears in early childhood and affect mainly boys. The clinical manifestations of the disease are rather heterogeneous.

PATIENTS AND METHODS

Nine patients (7 boys and 2 girls) were diagnosed as suffering from agammaglobulinemia with absence of circulating B lymphocytes, over a period of 6 years. Quantitation of immunoglobulins and search for circulating B lymphocytes were respectively performed by the Mancini method and immunofluorescence using T specific (anti-CD3, anti-CD4 and anti-CD8) and B (anti-CD19) monoclonal antibody.

RESULTS

The disease started to manifest clinically at the mean age of 8.7 months (4-16 months). The mean age at diagnosis is 4 years (1-11 years). The clinical manifestations were essentially recurrent infections of the lung and the gastrointestinal tract. However, bacterial meningitidis was observed in 3 patients. Severe complications such as an echovirus 27 meningoencephalitis and a chronic active hepatitis (1 patient) and a pericarditis (1 patient) were observed. All of our patients lacked circulating B lymphocytes and had low or null immunoglobulin levels. Five patients were treated by intravenous immunoglobulin (Ig) and 3 were treated by intramuscular immunoglobulin with a residual IgG level respectively of 5.5 g/l and 3.3 g/l.

CONCLUSION

Recurrent infections are the principal manifestation of the agammaglobulinemia, early Ig treatment is the only therapy allowing improved.