Obesity and cancer: focus on leptin

Over the past decades, obesity has grown to epidemic proportions worldwide. It has been associated with an increased risk for different types of cancer. In addition, obesity has been associated with a poor prognosis, an increased risk of metastasis and mortality, and resistance to anti-cancer therapies. The pathophysiological mechanisms underlying the obesity-cancer connection have not yet been fully elucidated. However, this connection could result, at least in part, from the action of adipokines, whose levels are increased in obesity. Among these adipokines, evidence suggests leptin's critical role in linking obesity to cancer. In this review, we first summarize the current state of the literature regarding the implication of leptin in tumorigenic processes. Next, we focus on the effects of leptin on the anti-tumor immune response. Then, we discuss the influence of leptin on the efficiency of antineoplastic treatments and the development of tumor resistance. Finally, we highlight the use of leptin as a potential target for the prevention and treatment of cancer.

Significant association of MCP1 rs1024611 and CCR2 rs1799864 polymorphisms with colorectal cancer and liver metastases susceptibility and aggressiveness: A case-control study

BACKGROUND

The MCP-1/CCR2 axis is one of the major chemokine signaling pathways that play a crucial role in the tumor microenvironment and has been involved in triggering various tumor progression mechanisms, such as increasing the immunosuppressive cells recruitment and promoting tumor cell proliferation and invasiveness.

AIM

The current study investigated the association of MCP1 (rs1024611) and CCR2 (rs1799864) genes variants with the risk as well as prognosis of colorectal cancer (CRC) and colorectal liver metastases (CRLM).

SUBJECTS AND METHODS

A retrospective cohort study involved 408 patients (284 CRC and 124 CRLM), and 284 healthy control was conducted. Genotyping of selected polymorphisms was performed by PCR-RFLP assays and confirmed by microchip and capillary electrophoresis.

RESULTS

The results highlighted a positive association between MCP1 rs1024611 (non-AA) and CCR2 rs1799864 (GA) genotypes with increased CRC and CRLM risk. Correlation between SNPs and clinicopathological characteristics revealed a positive association between MCP1 rs1024611 and CCR2 rs1799864 (dominant model) and CRC poor prognosis features. Kaplan-Meier survival analysis revealed a significant association between MCP1 rs1024611 non-AA carriers and decreased survival rate. Neoadjuvant treatment showed an improvement in CRC and CRLM survival rates among carriers of MCP1 and CCR2 wild-type genotype. FOLFIRI chemotherapy exhibits reduced survival rates for patients who carried mutated genotypes of MCP1 and CCR2 polymorphisms.

CONCLUSION

Considering our results, we suggest That both MCP1 and CCR2 polymorphisms may constitute independent factors for CRC and CRLM occurrence and can be helpful targets for an efficient therapeutic approach.

Leptin Promotes Prostate Cancer Proliferation and Migration by Stimulating STAT3 Pathway

To better understand the link between obesity and prostate cancer (PC) aggressiveness, we investigate the role of leptin, an obesity associated adipokine, and its receptor (Ob-R) in PC cells migration. The migration assay (Wound-healing) was used to study the leptin impact on DU-145 and PC3 cells lines. STAT3 activation was performed by Western Blot. E-cadherin expression was studied using fluorescence microscopy and Ob-R expression in PC and benign prostatic Hyperplasia (BPH) biopsies was assessed by RT-PCR. In this study we demonstrate that high dose of leptin promotes PC cells migration and EMT transition via the stimulation of STAT3 pathway. In addition, we report that although Ob-R mRNA is expressed by ADK and BPH resections biopsies, significant higher levels were observed for ADK patients. Finally, we found a positive association between Ob-R mRNA expression and worse PC prognosis. A better understanding of the molecular processes of leptin signaling is crucial for identifying appropriate approaches for treatment of obesity-related PC patients.

Hypertension artérielle pulmonaire au cours de la drépanocytose : complication aiguë ou chronique ?

Introduction : Au cours de la drépanocytose (DPC), l’hypertension artérielle pulmonaire (HTAP) est fréquente et aggrave le pronostic. Son diagnostic précoce revêt un intérêt capital sur ce terrain.

Observations : Le premier cas est celui d’un patient avec HTAP chronique et retentissement fonctionnel respiratoire, suspectée à l’occasion d’un épisode aigu et confirmée à distance. Le second cas rapporte une HTAP aiguë au cours d’un syndrome thoracique aigu ; spontanément réversible après résolution de la crise.

Conclusion : L’HTAP découverte lors d’une exacerbation de la DPC peut être aiguë et réversible ou chronique et permanente. À distance de cet épisode aigu, une exploration de la fonction cardiaque droite est nécessaire pour étiqueter la forme clinique de l’HTAP et préconiser la surveillance adéquate.

[Therapeutic and diagnostic difficulties of abdominal actinomycosis: about one case in a Tunisian female patient]

The Abdominal Actinomycosis (AA) is a rare and often unrecognised suppurative chronic illness. The diagnosis is difficult. It can have a variety of clinical manifestations and can mimic a malignancy. It's established by histology of surgical biopsy. We report a case of a 58 years old woman admitted to our institution for a pain of the right iliac fossa with a mass. The diagnosis was established after surgical intervention and histological examination. The treatment was surgical resection and antibiotherapy by amoxcillin during 6 months. The primary diagnosis of abdominal pelvic actinomycosis is difficult. All organs and anatomic structures of the abdomen can be involved. Even with extensive infection, combined operative and antibiotic therapy allows cure in most cases.

Y402H polymorphism in complement factor H and age-related macular degeneration in the Tunisian population

To evaluate a possible association between the complement factor H (CFH) Y402H polymorphism and susceptibility to age-related macular degeneration (AMD) in the Tunisian population, as well as the impact of the genotype distribution among different phenotypes and the response to treatment with intravitreal bevacizumab, exon 9 of CFH was analyzed for the Y402H polymorphism by direct sequencing in 135 healthy controls and 127 sporadic unrelated AMD patients classified into the following groups: 12 atrophic AMD (group G1), 115 exudative AMD (G2) and 10 AMD patients who had fibrovascular scarring (G3) that did not allow a precise grading of the phenotype. Seventy patients in G2 were treated with 1.25 mg intravitreal bevacizumab at 6-week intervals until choroidal neovascularization (CNV) was no longer active. The frequency of the CFH 402H allele was significantly higher in AMD patients than in controls (p = 2.62 × 10(-16)). However, subgroup analysis does not reveal any association between the variant allele H and phenotypes of AMD or CNV. Also, there was no significant difference in response to bevacizumab treatment according to Y402H CFH genotype (p = 0.59). A strong association of the 402H allele with susceptibility to AMD in the Tunisian population was confirmed; however, this variant does not appear to be involved in the clinical progression of this disease or in the postintravitreal bevacizumab response.

Genetic polymorphisms of inflammatory molecules in Tunisian kidney transplantation

As chemokines and adhesion molecules play major roles in the process by which leukocytes are recruited from the bloodstream into sites of inflammation, genetic variations in the production or activity of molecules may influence susceptibility to acute rejection episodes. This study sought to determine the impact of recipient monocyte chemoattractant protein-1 (MCP-1), chemokine receptor (CCR2, CCR5), and adhesion molecule (ICAM-1, PECAM-1 and L/E selectin) polymorphisms on acute rejection after renal transplantation. We selected 169 healthy blood donors and 173 renal transplant recipients for analysis according to the presence or absence of graft rejection in the first 30 days after transplantation. Using molecular methods DNA was genotyped for 11 polymorphisms of these inflammatory molecules genes. Results were stratified by the incidence of rejection episodes and by human leukocyte antigen (HLA) mismatching. No association was detected between adhesion molecule polymorphisms and the incidence of acute rejection episodes. However, a significant risk of acute renal loss was observed among HLA-identical recipients who possessed the CCR2-64I allele (odds ratio 0.24, 95% confidence interval, 0.05 to 1.06; P=.035). In conclusion, the observed association of CCR2-64I with acute rejection episodes should be added to the spectrum of immunogenetic factors known to be involved in renal allograft rejection.

(AT) repeat in the 3' untranslated region of the CTLA-4 gene and susceptibility to acute allograft rejection in Tunisian renal transplantation

Allograft rejection is an immune response relying on the proliferation and the differentiation of T cells. CTLA-4 is a co-stimulatory molecule, expressed on activated T lymphocytes, which has been shown to play a crucial role in the down-regulation of T-cell activation. Herein, we have examined the impart of a genetic marker in the CTLA-4 gene on renal transplant outcomes. A cohort of 144 renal recipients and 100 healthy subjects were genotyped by the fragments analysis method using an automated sequencer. Patients were classified into two groups: Group I included 31 HLA-identical haplotype allograft recipients and Group II, 113 showing one or more HLA haplotype mismatches. Forty patients (27.78%) developed at least one acute rejection episode (ARE): 9 in Group I and 31 in Group II. Before transplantation, 20 patients were lymphocytotoxic antibodies (LCT) positive: 4 Group I, 2 of whom developed an ARE, and sixty in Group II, including 8 with an ARE. The occurrence of an ARE was associated with the presence of LCT before transplantation among the entire cohort of patients (P = .032) and among Group II (P = .037). The allelic frequencies of (AT)n polymorphism did not reveal significant differences between patients and controls. The most prevalent alleles were the 88 bp (51% in controls and 44.44% in patients) and the 106 bp (8% and 10.76%, respectively). We noticed an increase of the 120 bp allele frequency among patients who had undergone an ARE compared with those who did not display this complication (8.75% vs 3.85%). Likewise, among LCT-negative Group I, recipients the incidence of the 120 bp allele was higher in ARE than non-ARE patients. Although the differences were not statistically significant, we propose that the 120 bp allele of the CTLA-4 gene (AT)n microsatellite a predisposes to acute rejection episodes in renal transplantation.

Allograft renal rejection and chemokine polymorphism

Chemokines play a major role in the process by which leukocytes are recruited from the bloodstream into the sites of inflammation. Genes for the chemokine receptors CCR5, CCR2 and MCP-1 are characterized by functional polymorphisms implicated in transplant rejection. To investigate this association, we analyzed polymorphisms of CCR5-∆32, CCR5-59029-A/G, CCR2-V64I and MCP-1 G/A (-2518) in 173 renal transplant recipients and 169 healthy blood donors. The patients were classified in two groups: Group-1 (G-1) included 33 HLA-identical recipients and Group-2 (G-2) included 140 (one or more) mismatched graft recipients. Forty-two patients had developed acute rejection episodes (ARs): seven in G-1 and 35 in G-2. Thirteen G-2 patients developed chronic allograft dysfunction (CAD). The genotypic and allelic frequencies of all polymorphisms studied did not reveal significant differences between patients and controls and among G-1 and G-2 recipients. However, a significant risk of acute renal transplant rejection was found in G-1 patients who possessed the CCR2-64I allele (odds ratio 0.24, 95% confidence inter-val [CI], 0.05-1.06; P = 0.035). There was no significant association of this polymorphism and CAD. In conclusion, the observed association of CCR2-64I with AR should be added to the spectrum of immunogenetic factors known to be involved in allograft renal loss.

Association of chemokine and chemokine receptor polymorphisms with activity degree of IBD in Tunisian patients

Crohn's disease (CD) and ulcerative colitis (UC) have complex genetic background that is characterised by more than one susceptibility locus. To detect a possible association between the functional polymorphisms of the chemokine receptors CCR5, CCR2 and MCP-1 genes and susceptibility to CD and UC in Tunisian population, polymorphisms of CCR5-delta32, CCR5-59029-A/G, CCR2-V641 and MCP-1-2518-G/A were analysed in 194 Inflammatory bowel disease (IBD) patients and 169 healthy blood donors using PCR-RFLP and PCR-SSP methods. The patients were classified in 126 patients with CD and 68 patients with UC. The genotypic and allelic frequencies of all polymorphisms studied, did not reveal significant differences between patients and conrols and among CD and UC patients. However, analysis of CD patients revealed that those without homozygosous G/G genotype are more frequently in remission compared to those with this genotype (OR: 0.4, 95% CI: [0.174-0.928]; p = 0.03). Also, the frequency of the CCR2-641 muted allele was statistically higher in CD patients in remission disease than those in active form (OR: 0.267 95% CI: [0.09-0.78]; p = 0.01). Adjustment for known covariates factors (age, gender and immunosuppressive regimen) confirmed these univariate findings and revealed that the CCR5-59029-A/G and CCR2-V64I genotype were associated to remission form of CD (OR: 263; 95% CI: [1.01-6.80]; p = 0.047 and OR: 4.64; 95% CI: [1.01-21.31]; p = 0.049 respectively). In conclusion, the present study supports the involvement of chemokine receptor (CCR2 and CCR5) polymorphisms in activity degree of the IBD disease in Tunisian patients.

Association of specific amino acid sequence (QRRAA) of HLA-DRB1*0405 with rheumatoid arthritis in a Tunisian population

This study aimed to investigate HLA-DRB1 alleles in rheumatoid arthritis (RA) patients from Tunisia and to examine the effect of these alleles on disease severity. HLA-DRBI alleles and sub-typing of DRBI*04 and *01 were determined in 90 patients and 100 healthy controls, by PCR-SSP. HLA-DRB1*04 was significantly higher in patients (51.1%) than in controls (27%) [OR=2.83, p=0.00066]. DRBJ*0405 was found to be the unique DR4 allele associated with RA (28.88% vs 6%) [OR=6.36, p=0.000059]. A significant decrease in the frequency of HLA-DRB1*0701 was observed in RA patients (16.66%) compared to controls (36%) [p=0.0026]. However, the frequency of patients carrying the shared epitope (SE) QRRAA, was slightly increased compared with controls (37.8% vs 23%) [OR=2.03, p=0.039]. We found that the presence of rheumatoid factor, HLA-DR4 and HLA-DRBI*0405 were not significantly associated with bone erosions or the presence of extra-joint involvement. In our population, the SE (QRRAA) expressed in DRBI*04 alleles is related to the susceptibility to RA but it is not involved in RA severity in Tunisia, while DRBI*0701 might protect against this disease.

The PTPN22 C1858T (R620W) functional polymorphism in kidney transplantation

To investigate the association between kidney transplant rejection and PTPN22 (protein tyrosine phosphatase non-receptor 22) polymorphism, genomic DNA of 175 renal transplant recipients and 100 healthy blood donors were genotyped by restriction fragment length polymorphism-polymerase chain reaction. The patients were classified in two groups: G1 included 33 HLA-identical recipients and G2 included 142 with one or more HLA mismatches. Forty-nine patients developed an acute rejection episode (ARE): 8 in G1 and 41 in G2. The allelic frequencies of PTPN22 R620W revealed a significant difference between patients and controls. In fact, the W-allele was significantly more frequent in graft recipients than in blood donors (0.05 vs 0.01, P < .05). Furthermore, the frequency of this allele was increased in G1 patients with an ARE (0.188) compared with those without an ARE (0.040), but the difference was not statistically significant. Thus, we concluded that the PTPN22 W-variant allele could be involved in the susceptibility to acute allograft rejection in Tunisian kidney transplant patients.

Kidney transplantation: Charles Nicolle Hospital experience

The aim of our retrospective study was to analyze the short- and long-term follow-up of 298 renal transplantations performed between June 1986 and May 2005. All were first transplantations except 4 cases, with 54 from cadaveric and 244 from living donors. The recipients included 196 males and 102 females of overall mean age of 31.21 +/- 8.9 years (range, 16-61 years). A combination of prednisolone and azathioprine was presented for 212 patients or mycophenolate mofetil for 86 patients. Polyclonal or monoclonal antibodies were used as induction therapy in 183 cases. Cyclosporine was administered to 188 cases and tacrolimus only to 16. HLA matching was 0 mismatches (MM) in 65 cases; 1 or 2 MM in 113; 3 MM in 99; and > or =4 MM in 21. Acute tubular necrosis occurred in 45 cases. One hundred eighteen patients experienced at least 1 acute rejection episode: 102 cases (41.8%) among living and 16 (29.6%) among cadaveric kidneys donor (P = .0007). The actuarial patient and graft survival rates at 1, 5, 10, 15, and 20 years were 95.9%, 87.4%, 77.5%, 65.6%, and 60.8%, and 94.9%, 84.5%, 75.4%, 65.4%, and 53%, respectively. Sixty-three patients died and 72 patients returned to dialysis. Our results were comparable to experienced centers. However, the member of kidney transplantations does not match the increased number of patients on renal replacement therapy. It is advisable to promote obtaining organs from brain-dead donors.

Mannose binding lectin (+54) exon 1 gene polymorphism in Tunisian kidney transplant patients

Mannose-binding lectin (MBL), a collagen-like serum protein, is a key component of innate immunity. MBL binding to carbohydrates present on pathogens mediates lectin-dependent activation of the complement pathway. There is growing interest in the importance of innate immunity in host defense, particularly when adaptive immunity is compromised. Three single nucleotide polymorphisms (SNPs) of the MBL gene have been described in the first exon to be associated with low MBL serum concentrations as well as impaired MBL structure and function. Clinical studies have shown that these MBL SNPs are associated with increased susceptibility to infections, especially in immunocompromised patients. To investigate the association between acute kidney transplant rejection and polymorphism at codon 54 of the MBL gene, the DNA genomic of 133 renal transplant recipients and 117 healthy blood donors was analyzed by restriction fragment length polymorphism-polymerase chain reaction. The patients were classified into two groups: group 1 included 32 HLA-identical recipients and group 2, 101 one haplo-identical recipients. Forty-eight (36.1%) subjects had developed one or more acute rejection episodes (AREs) within the first 6 months after transplantation: 9 in group 1 (28.12%) and 39 in group 2 (38.61%). The genotype and allele frequencies of (+54) MBL gene polymorphism among patients and controls did not reveal a significant difference. However, the frequency of MBL-B mutant allele was increased among patients with AREs compared with those without AREs: group 1 (0.167 vs 0.065) versus group 2 (0.205 vs 0.105). Although the difference was not significant, perhaps because of the small number of patients, the MBL at codon (+54) polymorphism could be involved in the susceptibility of Tunisian kidney transplant recipients to acute allograft rejection episodes.

Prevalence of autoantibodies in a Tunisian cohort of hepatitis C virus infected dialysis patients

The hepatitis C virus (HCV) is the principal agent of viral chronic hepatitis. Cirrhosis and hepatocellular carcinoma are the major complications of this chronic infection. In haemodialysis, HCV infection remains a very frequent problem. Several autoimmune phenomena have been described during this infection. Two hundred haemodialysis patients, all of them anti-HCV (+), were included in this study to evaluate the frequency of Anti-Nuclear Autoantibodies (ANA), anti-cardiolipine antibodies (ACL), anti-smooth muscle antibodies (ASMA), anti-mitochondria antibodies (AMA), anti-thyroperoxydase antibodies (ATPO) and Rheumatoid Factor (RF) comparing them to healthy controls. Sixty eight serums (34%) patients were positive to at least one of the auto-antibodies tested. The difference between patients and controls was statistically significant. These markers were dominated by RF of the IgM isotype and ACL of the IgG isotype. Nevertheless, the positivity of ANA, ASMA, AMA and ATPO was not statistically different comparing to the controls. In addition, an association between the presence of the auto-antibodies and the viral replication was found suggesting that HCV is responsible for inducing these autoimmune phenomena.

Functional polymorphisms of PTPN22 and FcgR genes in Tunisian patients with rheumatoid arthritis

To investigate a possible association between functional polymorphisms of the protein tyrosine phosphatase nonreceptor type 22 (PTPN22-R620W) and receptors for the Fc fragment of IgG (FcgRIIa-H131R, FcgRIIIa-F158V FcgRIIIb-NA1/NA2), and rheumatoid arthritis (RA), 133 Tunisian patients with RA and 100 controls were genotyped. We found strong evidence of an association of PTPN22 620W allele and RA. However, analysis does not detect an association between auto-antibodies seropositivity, presence of nodules or erosions and this allele. No significant skewing of any of the three FcgR polymorphisms was seen in this RA group. Nevertheless, we identified FcgRIIIa-V/V158 as the most important FcgR genotype for severe disease subset with joint erosions and observed that patients with FcgRIIIb-NA2/NA2 genotype had an earlier incidence of clinical symptoms. In conclusion, we have confirmed that PTPN22 620W allele is associated with Tunisian RA but does not constitute a factor influencing clinical manifestations. Conversely, this study supports that the FcgRIIa/IIIa and IIIb polymorphisms could influence the course and the severity of this disease. A large number of samples are required to provide independent confirmation of these findings.

Pustular Psoriasis After Renal Transplantation

Cutaneous manifestations in renal transplant recipients are frequently represented by infections and cancerous lesions. However, dermatologic lesions secondary to autoimmune diseases are rare. We report a case of pustular psoriasis occurring after renal transplantation in a 31-year-old woman with a history of vitiligo. The patient was on hemodialysis for 2 years for undetermined chronic nephropathy. She received an HLA identical live related transplant from her brother. She was maintained on an immunosuppressive regimen of corticosteroids, azathioprine, and cyclosporine, which was replaced with mycophenolate mofetil because of neurotoxicity and azathioprine was stopped. Thirty-one months after renal transplantation, she developed pustular psoriasis which was treated with retinoids; she experienced a relapse and resistance to treatment despite the reintroduction of cyclosporine.

CTLA-4 Exon 1 (+49) and Promoter (−318) Gene Polymorphisms in Kidney Transplantation

To investigate the association between kidney transplant rejection and the polymorphisms of CTLA-4 gene exon 1(+49) and promoter (-318), genomic DNA of 70 renal transplant recipients and 110 healthy blood donors were genotyped by PCR-RFLP and PCR-SSP, respectively. The patients were classified in two groups: G1 included 33 HLA-identical recipients and G2, 37 one haplo-identical recipients. Thirty-one recipients experienced an acute rejection episode: 10 in G1 and 21 in G2. Ten G2 patients developed chronic allograft dysfunction (CAD). Allelic frequencies and genotype distribution were similar among patients and controls. CTLA-4 exon 1 genotype A/A and CTLA-4 promoter genotype C/C were significantly higher among G2 patients with CAD than without CAD (P < .01). The distribution of CTLA-4 exon 1-promoter genes did not reach significance between graft recipients and controls. The genotype frequency of (G/G-C/C) was increased among controls (42.72%) compared with graft recipients (G1 and G2; 35.71%). CTLA-4 polymorphisms gene were associated with susceptibility to chronic allograft dysfunction.

Plasma Levels of Soluble CD30 in Kidney Graft Recipients as Predictors of Acute Allograft Rejection

In renal transplant recipients elevated soluble serum CD30 levels are associated with increased rejection and graft loss. We sought to determine the sCD30 plasma levels before and after kidney transplantation and to assess whether sCD30 was a predictive factor of immunological risk. sCD30 plasma levels were determined by an enzyme-linked immunosorbent assay assay in 52 kidney graft recipients before as well as 7, 15, and 21 days after transplantation. Eighteen patients developed acute allograft rejection (group I) and 34 patients showed uneventful courses (group II). Before transplantation sCD30 plasma levels were elevated in both groups (mean: 162.6 +/- 89.5 U/mL). After transplantation, group I recipients with acute rejection showed higher relative levels of plasma sCD30 on days 7 and 15 (120.8 +/- 74.6 U/mL and 210.6 +/- 108.7 U/mL respectively) compared with group II patients without rejection (95 +/- 45 U/mL and 59.4 +/- 31.6 U/mL), a difference that was significant for group I (P = .0003) and not significant for group II (P = .09). On day 21, sCD30 decreased in the two groups but remained higher among group I patients (120.6 +/- 92.7 U/mL). HLA antibodies were positive in 18 patients (34.6%) with 9 (50%) experiencing at last one episode of acute rejection. Among 34 patients negative for anti-HLA antibodies, nine displayed acute rejection only (26.4%), a difference that was not significant (P > .05). If we consider 100 U/mL as the minimum predictive level for allograft rejection, our results suggested that levels of sCD30 should be taken into consideration with the presence of HLA-antibodies detectable before and after transplantation, especially in patients with more than three HLA mismatches [RR = 3.20 (0.94 < RR < 10.91)]. These data suggested that measurement of plasma sCD30 is a useful procedure for the recognition of rejection in its earliest stages.

HLA class-I and HLA class-II phenotypic, gene and haplotypic frequencies in Tunisians by using molecular typing data

The aim of this study is to define a reliable reckoning of gene frequencies and six-locus haplotypic frequencies of HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DQA1, HLA-DQB1 and HLA-DPB1 in the Tunisian population. One hundred unrelated random, healthy people originating from various parts of Tunisia were typed for the alleles of the loci mentioned above by using the molecular techniques polymerase chain reaction--hybridization with oligonucleotide probe (PCR-SSO) and sequence specific primers (SSP). The population studied appeared to be in Hardy-Weinberg equilibrium. Allelic frequency distributions were observed at each locus. The most frequent HLA-A alleles were HLA-A*02 (39%) HLA-A*0101 (25%), HLA-A*30 (21%) and HLA-A*2301 (18%). Moreover, HLA-3A*3601, HLA-1A*6601, HLA-1A*3402 and HLA-2A*8001 were found; however, no HLA-A*4301 was detected. For the HLA-B locus, the most common in descending order were HLA-B*44 (22%), HLA-B*5001 (19%), HLA-B*51 (16%) and HLA-B*18 (15%). Among the 28 alleles HLA-Cw detected, HLA-Cw*6 and HLA-Cw*7 were highly predominant with the frequencies of 33 and 30%, respectively. For the HLA class-II loci, HLA-DRB1*0701, HLA-DRB1*11, HLA-DRB1*13 and HLA-DRB1*03 were the most frequent DR alleles. For the HLA-DPB1, HLA-DPB1*0401, HLA-DPB1*0301 and HLA-DPB1*0201 were the most frequent DP alleles. Many haplotypes were in a strong positive-linkage disequilibrium. The most frequent haplotypes for HLA-A, HLA-B, HLA-C and HLA-DRDQ were HLA-A*3301, HLA-B*1402, HLA-Cw*0802, HLA-DRB1*0102, HLA-DQA1*0101 and HLA-DQB1*0501; HLA-A*2402, HLA-B*0801, HLA-Cw*0702, HLA-DRB1*0301, HLA-DQA1*0501 and HLA-DQB1*0201; HLA-A*2902, HLA-B*4403.1, HLA-Cw*1601, HLA-DRB1*0701, HLA-DQA1*0201 and HLA-DQB1*0202; HLA-A*3002, HLA-B*1801, HLA-Cw*0501, HLA-DRB1*0301, HLA-DQA1*0501 and HLA-DQB1*0201, with frequencies between 0.025 and 0.015. These data can be used as control data for HLA disease associations and paternity studies, but they are also important for the evaluation of the probability rate of success in determining the optimal matched donor in unrelated stem transplantation for Tunisian patients or patients of Tunisian origin.

[Congenital heart block associated with maternal anti SSA/SSB antibodies :a report of four cases]

Congenital heart block (CHB) associated with maternal anti-SSA/SSB antibodies: a report of four cases. CHB detected in utero is strongly associated with maternal antibodies to SSA (Ro) and SSB (La). Their pathogenic role in the development of CHB has been established in several studies. The mothers of affected infants frequently had autoimmune disease (systemic lupus erythematosus, Sjögren's syndrome) or were entirely asymptomatic. It is very difficult to identify pregnant asymptomatic mothers carrying anti-SSA/SSB antibodies. We report four cases of infants born to asymptomatic mothers with anti-SSA/SSB antibodies, three of them developed isolated congenital cardiac heart block and one with no evidence of CHB. All three CHB are detected during pregnancy between 16 and 24 weeks of gestation. All maternal sera contained antibodies to SSA alone or the both SSA and SSB. Three of four subsequent pregnancies were complicated by heart block. One child affected died in utero. While the two other newborns with CHB required pacemaker insertion during the first 3 months of life. Although the association of anti-SSA/SSB with CHB is widely accepted, the precise mechanism by which these antibodies cause cardiac conduction abnormalities remains to be defined. Antibodies to SSA/SSB have been proposed to be a serologic marker for neonatal lupus syndrome and CHB. Fetal and neonatal diseases are presumed to be due to the transplacental passage of these IgG autoantibodies from the mother into the fetal circulation. Since these antibodies may have a pathogenic role in CHB, screening of infants with isolated CHB or neonatal lupus and their mothers for the presence of anti-SSA and anti-SSB is strongly recommended.

Autoantibodies to ribosomal P proteins in systemic lupus erythematosus

Autoantibodies to ribosomal P proteins (anti-P) are directed against three ribosomal phosphoproteins (P0, P1, and P2) and are believed to be specific markers for systemic lupus erythematosus (SLE), particularly with neuropsychiatric manifestations. The objective of this study was to determine the rate of occurrence and clinical significance of anti-P in Tunisian patients.

METHODS

We included 100 Tunisian patients with SLE whose sera were received between January 1998 and December 2000 by the immunology laboratory of the Charles Nicolle Teaching Hospital in Tunis, Tunisia, and were tested for anti-P. An immunodot technique based on a synthetic protein shared by all ribosomal phosphoproteins was used.

RESULTS

Sera from 22 (22%) patients were positive for anti-P. This rate is consistent with the literature. We found no statistically significant associations between anti-P and specific manifestations of SLE. CONCLUSION. We found that anti-P were significantly associated with anti-Sm and anti-RNP, as reported previously. The significance of these associations remains debatable.

Association between HLA-A/-B antigens and -DRB1 alleles and nasopharyngeal carcinoma in Tunisia

Using serologic and molecular methods, 45 nasopharyngeal carcinoma (NPC) patients were typed for HLA class I and class II and were compared to 100 unrelated normal Tunisians. Our results showed that the antigen frequency of HLA-B13 and allelic frequencies of DRB1*03, DRB1*15 were significantly higher in the NPC patients than in the control group (15.5 vs. 4; 26.4 vs. 11.5, and 14.4 vs. 6.5%, respectively) probably indicating a positive association with NPC. Moreover, we observed that HLA-A23 was absent in our NPC sample and was present in 18% of normal controls, and HLA-DRB1*11 was less frequent among the patients compared to the controls (5.5 vs. 14%) suggesting a protective effect of this association with NPC.

[Evaluation of an immunoblotting technique for the detection of anti-SSA and anti-SSB antibodies]

Immunoblotting and ELISA methods are now employed for the detection of anti Ro/SSA and anti La/SSB antibodies sometimes more often than double immunodiffusion or counter-immunoelectrophoresis. We have developed an immunoblotting technique for the detection of anti Ro/SSA and anti-La/SSB antibodies. This assay named IB-Hela, which uses a Hela cell extract, was compared with the double immunodiffusion technique like two other commercial immunoassays (Elisa test from Sanofi-diagnostic Pasteur and Line immunoassay from Innogenetics). This evaluation shows a good agreement especially in the case of Ro/SSA antibodies detection. IB-Hela seems to be useful in the La/SSB detection with a better sensitivity than the double immunodiffusion technique. We conclude that the IB Hela is helpful for the search for anti-Ro/SSA and anti-La/SSB autoantibodies and that it can be used as an alternative method to the classical techniques of immunodiffusion and counter immunoelectrophoresis.