Amani Mankaï

Purine-Rich Box-1–Mediated Reduced Expression of CD20 Alters Rituximab-Induced Lysis of Chronic Lymphocytic Leukemia B Cells

The anti-CD20 monoclonal antibody rituximab has been less successful in treating chronic lymphocytic leukemia (CLL) than lymphoma, possibly due to the lower density of CD20 on B lymphocytes from CLL patients than on those from lymphoma patients. This lowering may result from insufficiency of one of the transcription factors of cd20. Of these, purine-rich box-1 (PU.1) is poorly expressed in CLL. To estimate its weight in CD20 expression, pu.1 cDNA was transfected into CLL B cells and shown to raise the membrane expression of CD20 and to improve the rituximab-induced lysis of transfected cells. Granulocyte macrophage colony-stimulating factor and all-trans-retinoic acids were not involved in the defective expression of PU.1 or the excessive methylation of the pu.1 gene, because 6 of 14 CLL samples tested were normally methylated. This was confirmed by the failure of DNA methyltransferase inhibitors to restore pu.1 transcription in hypermethylated CLL, and, in fact, the expression of PU.1 was down-regulated by excessive expression of the FMS proto-oncogene-like tyrosine kinase 3 (Flt3) receptor. This abnormality is consistent with our finding of elevated levels of Flt3 ligand (FL) in 20 of 23 CLL sera tested. We propose that FL-dependent increased Flt3 signaling prevents the expression of PU.1, which down-regulates that of CD20, and accounts for resistance of leukemic B cells to rituximab-induced lysis.

Screening by anti-endomysium antibodies for celiac disease in Tunisian children with type 1 diabetes mellitus.

AIM Celiac disease (CD) and type 1 diabetes mellitus (DM1) can frequently coexist, presumably due to a common genetic predisposition. The present study was designed to evaluate the frequency of CD among Tunisian children with DM1. PATIENTS AND METHODS A total of 205 diabetic children (92 girls, 113 boys, age range 6 months-15 years, median 11 years) were screened for CD by determination of IgA anti-endomysium antibodies (EMA). RESULTS EMA were positive in 17 out of 205 (8.3%) children with DM1. The median age of DM1 at onset was significantly lower in patients with EMA than those without EMA (P<10(-7)). In 13 of 17 EMA-positive patients, duodenal biopsy could be performed and a destructive type of CD was confirmed in 11 of them: 8 patients showed total villous atrophy, 3 patients showed a partial villous atrophy. The other two patients showed a normal histological picture with normal number of intraepithelial lymphocytes. Parents of the remaining EMA-positive children refused endoscopy. Thus the prevalence of biopsy-proven CD was 5.3% (11/205). It was 7.6% (7/92) in girls and 3.5% (4/113) in boys but the difference was not statistically significant. Seventy three percent of patients with CD were asymptomatic. CONCLUSIONS The prevalence of clinically unrecognized CD, found by EMA screening, is high in Tunisian children with DM1. We suggest that children with diabetes should be screened for CD.

Anti-Saccharomyces cerevisiae antibodies in coeliac disease

Objective. To evaluate, retrospectively, the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with coeliac disease. Material and methods. ASCA, IgG and IgA were determined by ELISA in sera of 238 coeliac patients. The patients were divided into three groups: group I – 125 untreated patients; group II – 42 patients under a strict gluten-free diet (GFD); and group III – 71 patients who did not comply with a GFD. Sera of 80 healthy blood donors served as controls. Results. The frequency of ASCA (IgG or IgA) was significantly higher in untreated coeliac patients than in the control group (27.2% versus 3.7%, p=10−5). In 238 coeliac patients, the frequency of ASCA was significantly higher in adults than in children (35.4% versus 21.1%, p=0.01). In group III, the frequency of ASCA was significantly higher in adults than in children (60% versus 26.1%, p=0.004). In 238 coeliac patients, ASCA IgG were significantly more frequent than ASCA IgA in both children (19% versus 6.3%, p=0.001) and adults (33.3% versus 12.5%, p=5.10−4). In children, ASCA IgG were negative in group II and positive in 20% of group I (p=0.01). In adults, the frequency of ASCA IgG was also significantly lower in group II than in group I (9.5% versus 34%, p=0.03). Conclusions. A high frequency of ASCA has been found in coeliac patients. The frequency of ASCA was not statistically different between patients with successful adherence to GFD and healthy controls.

Severe osteomalacia due to undiagnosed cœliac disease: three case reports of Tunisian women

We describe three cases of osteomalacia presenting in Tunisian women, all of whom had previously-undiagnosed cœliac disease (CD). Direct enquiry revealed an important weight loss and a history of diarrhoea in two patients, and a 15-year history of anaemia in one patient. Laboratory tests showed severe anaemia in the three cases. Reduced calcium was found in two cases, and corrected calcium was found in one case. Radiological examination showed fissure in two cases. The diagnosis of osteomalacia was made by clinical, biochemical and radiological features. Antigliadin, antireticulin, antiendomysial and anti-tissue transglutaminase antibodies were all positive in the three cases, and a small-bowel biopsy confirmed the diagnosis of CD. Treatment with gluten-free diet (GFD), supplemental calcium and vitamin D was initiated for the three patients, but only one patient complies strictly with the GFD; she showed a marked resolution of her symptoms.

Anti-Saccharomyces cerevisiae Antibodies are Frequent in Type 1 Diabetes

Anti-Saccharomyces cerevisiae antibodies (ASCA) have been described in many autoimmune diseases in which there is an increased intestinal permeability. Also in type 1 diabetes (T1D), there is an increased intestinal permeability. Since no data are available about ASCA in T1D, we evaluated, retrospectively, the frequency of ASCA in this disease. ASCA, IgG, and IgA, were determined by ELISA in sera of 224 T1D patients in which coeliac disease has been excluded and 157 healthy control group. The frequency of ASCA (IgG or IgA) was significantly higher in T1D patients than in the control group (24.5% vs. 2.5%, p < 10−7). The same observation was found in children and in adult patients when we compare them to healthy children and blood donors group respectively. Compared to children, adult patients with T1D showed significantly higher frequencies of ASCA of any isotype (38% vs. 13.7%, p < 10−4), both ASCA IgG and IgA (12% vs. 1.6%, p = 0.002), ASCA IgG (35% vs. 9.8%, p < 10−5) and ASCA IgA (15% vs. 5.6%, p = 0.001). The frequency of ASCA was statistically higher in females of all T1D than in males (30.8% vs.17.7%, p = 0.03), in girls than in boys (22% vs.6.2%, p = 0.017), and significantly higher in men than in boys (35.7% vs. 6.2%, p < 10−4). The frequency of ASCA IgG was significantly higher than that of ASCA IgA in all T1D patients (21% vs. 9.8%, p < 0.002), in all females (26.5% vs. 10.2%, p < 0.002), in women (37.9% vs. 12%, p < 0.001). The frequency of ASCA was significantly higher in all long-term T1D than in an inaugural T1D (29% vs. 14.5%, p = 0.019). The same observation was found in adults (45.8% vs. 17.8%, p = 0.01). In long-term T1D patients, ASCA were significantly more frequent in adults than children (45.8% vs. 14.5%, p < 10−4). The frequency of ASCA IgG was significantly higher in long-term T1D than in an inaugural T1D (25.2% vs. 11.6%, p = 0.03). Patients with T1D had a high frequency of ASCA.

Type 1 diabetes mellitus, celiac disease, systemic lupus erythematosus and systemic scleroderma in a 15-year-old girl

We report a case of an association of four autoimmune diseases in a 15-year-old girl and we discuss the etiopathogenic of this association and difficulties of treatment.

Improvement of Rituximab Efficiency in Chronic Lymphocytic Leukemia by CpG‐Mediated Upregulation of CD20 Expression Independently of PU.1

Lipopolysaccharide (LPS), CpG‐containing phosphothioate oligonucleotides (CpG) and various cytokines impact chronic lymphocytic leukemia (CLL) B cells. For example, they influence cell cycle entry, expression of co‐receptors, and CD20. Rituximab (RTX), for which CD20 molecule is the target, proved to be less efficient in CLL than in lymphoma. This is accounted for by a lower CD20 level in the former than in the latter B lymphocytes. CD20 transcription is mediated by four transcription factors, of which only purine‐rich box‐1 (PU.1) is reduced in CLL. We thus examined the effects of LPS, CpG, tumor necrosis factor‐alpha, interferon‐alpha, interleukin (IL)‐3, IL‐4, IL‐21, granulocyte macrophage‐colony stimulating factor (CSF), and granulocyte‐CSF on the transcription of PU.1, and the subsequent expression of CD20. It appeared that CpG was unique in that it raised the membrane expression of CD20 on malignant B cells, owing to a PU.1 independent increase in its gene transcription. Moreover, RTX‐induced complement‐mediated lysis was also ameliorated. Thus, CpG accelerates the transcription of CD20 independently of PU.1, and thereby improves the efficacy of RTX in CLL.

Performance of anti-deamidated gliadin peptides antibodies in celiac disease diagnosis.

OBJECTIVES To assess the usefulness of anti-deamidated gliadin peptides antibodies (a-DGP), in the diagnostic of celiac disease (CD). PATIENTS AND METHODS One hundred and three untreated CD patients (67 children and 36 adults) and 36 celiac patients under gluten-free diet were studied. Two hundred and seventy-four subjects served as controls (114 healthy blood donors, 80 healthy children and 80 patients with primary biliary cirrhosis). a-DGP (IgG and IgA) and anti-tissue transglutaminase antibodies (AtTG) were detected by enzyme-linked immunosorbent assay (Elisa). Anti-endomysium antibodies (AEA) were detected by indirect immunofluorescence on human umbilical cord. RESULTS The sensitivitiy of IgG and IgA a-DGP were 94% and 97% respectively, compared to 96% for AEA and AtTG. The specificity of a-DGP was 93.6% for IgG and 92% for IgA. The specificity of AEA and AtTG were 100%. The frequency of IgG and IgA a-DGP was significantly higher in patients with CD than in control group (94% vs. 4.4%, P<10(-7); 97% vs. 8%, P<10(-7)). The frequency of IgG a-DGP was the same in children and adult (94%). The frequency of IgA a-DGP were similar in children and adults (95.5% vs. 100%). CONCLUSION Our study shows that a-DGP increases neither the sensitivity nor the specificity of AEA and AtTG.

IgA anti-actin antibodies in celiac disease

AIMS The purpose of this study was to determine the sensitivity and specificity of IgA anti-actin antibodies (IgA-AAA) for celiac disease (CD), to investigate their usefulness as a marker of compliance in CD patients to the gluten-free diet (GFD), and to assess the relationship between their presence in the sera of CD patients and severity of intestinal mucosal damage. PATIENTS AND METHODS A total of 182 patients with CD were studied: 63 patients were untreated; 50 patients were following a strict GFD; and 69 patients were non-compliant with a GFD. IgA-AAA was detected using a homemade enzyme-linked immunosorbent assay (ELISA). RESULTS IgA-AAA showed a sensitivity of 41.3% and a specificity of 71.4% for a diagnosis of CD. In children, the frequency of IgA-AAA detection was lower in those following a strict GFD (23.1%) compared with untreated patients (39.4%) and those not complying with a GFD (32.5%). In patients following a strict GFD, IgA-AAA detection was significantly less frequent in children than in adults (23.1% vs. 58.3%, respectively; P<0.001). IgA-AAA was found in 17 out of 52 CD patients with total villous atrophy (32.7%), and in one out of 11 patients with subtotal villous atrophy (9%). CONCLUSION IgA-AAA cannot replace anti-endomysium and anti-tissue transglutaminase antibodies in the diagnosis algorithm of CD, but it can serve as a reliable marker of severe intestinal mucosal damage in CD patients.

High Frequency of Antiphospholipid Antibodies in Primary Biliary Cirrhosis

To evaluate, retrospectively, the frequency of autoantibodies of antiphospholipid syndrome (APLS) in Tunisian patients with primary biliary cirrhosis (PBC).