A novel HLA-B*39 allele (HLA-B*3916) due to a rare mutation causing cryptic splice site activation

A novel HLA-B*39 variant, found in an African patient with sickle cell anemia undergoing bone marrow transplantation is described. Initially suspected by inconsistent serological typing (B-blank, Bw6), then recognized by PCR-SSP, and finally characterized by nucleotide sequencing, this novel allele is designated HLA-B*3916. It differs from HLA-B*3910 by a point mutation (G to C) at position 17 of exon 3 causing glutamine to histidine change at codon 96 of alpha(2) domain, a conserved position among HLA class I alleles. cDNA sequence analysis further revealed the presence of both normally and abnormally spliced mRNA species in established cell lines. The abnormal species correspond to partial truncation of exon 3 presumably due to the nucleotide change in exon 3, which constitutes a new consensus acceptor splice site within this exon. We postulate that the observed blank is essentially the consequence of qualitative change in a critical region of this novel antigen as abnormal mRNA species are relatively less abundant than normal species. Because the residue 96 of the HLA class I heavy chain is directly involved in interaction with alpha(2)m, another interesting possibility is that an aminoacid change in this position would perturb such interaction and consequently could affect the serological specificity of B*3916, or its expression or both.     

Sequencing-based typing reveals six novel MHC class I chain-related gene B (MICB) alleles

Abstract: The MHC class I chain-related gene A (MICA) is highly polymorphic. In this paper we demonstrate polymorphism in the other expressing member of the MIC family of genes: MICB. Using a sequencing-based typing approach on cDNA, analysis of exons 2 through 6 revealed eight polymorphic sites resulting in six unique MICB sequences. Although MICB has high nucleotide homology with MICA, its polymorphism is restricted and at different sites compared to those in MICA.     

Infectious complications in sickle cell disease are influenced by HLA class II alleles

Despite systematic antibiotic therapy, severe infections (septicemia, meningitis, or osteomyelitis) are a major cause of mortality and morbidity in children with sickle cell disease (SCD). In this study, we explored the possibility that polymorphism at the human leukocyte antigen (HLA) locus might constitute an immunogenetic modifying factor to the intrinsic susceptibility to infection in patients with SCD. A cohort of 80 SCD patients living in Paris, 43 with at least one major infectious complication and 37 without infections, were typed for HLA class II loci by polymerase chain reaction-sequence-specific primers (PCR-SSP). We found that significantly more patients without infections carry the HLA class II DRB1*15 specificity than did patients with infections (21.6% in the first group, versus 4.7% in the second group; chi(2) = 10.47, p(c) = 0.01), supporting a protective effect of this allele. Conversely, significantly more patients were found to carry the DQB1*03 specificity within the group of severe infections, supporting a negative effect (34.9% versus 12.2%, chi(2) = 9.41, p(c) = 0.01). These findings suggest a direct involvement of HLA polymorphism in the development of major infections in SCD. Together with previous data on polymorphism of the Fc receptor and of the mannose-binding lectin, they provide evidence for a polygenic immunomodulation of the constitutively increased infectious risk in SCD.     

Conservative Management of Rectal Adenocarcinoma by Radiotherapy

Purpose: The aim of this study was to analyze the experience of Centre GF Leclerc for conservative and curative treatment by radiotherapy of low rectal cancer.

Patients and Methods: A total of 151 patients received radiotherapy alone for rectal adenocarcinoma with curative intent. They were clinically staged according to size (T1 < 3 cm, and T2 > 3 cm) and depth of infiltration (A = superficial, and B = impaired mobility and T3 fixed). Over the past 6 years, rectal ultrasound (US) has been used systematically, compared with computed tomographic scan and magnetic resonance imaging when needed. Intracavitary contact X ray was given to 129 patients (69%), and brachytherapy in 45 of 151. External radiotherapy was used in 34 cases (22.5%).

Results: Complete response was obtained in 93%. Local failures were observed in 50 cases (28%); two occurred in pelvic nodes after intracavitary X rays. Size (tumors > 3 cm) and alteration of mobility significantly influenced the rate of local failure (p = 0.009 and 0.007). The addition of external radiotherapy in patients with poor prognostic factors improved the local control rate. A total of 39 patients with recurrence were amenable to salvage surgery. After salvage treatment, the local control rate was 82% with unlimited follow-up. The 5-year actuarial survival rate was 57%, with a specific survival of 66%. There was no difference in local control or survival according to differentiation of the tumors and distance between anal margin and the inferior level of the lesion. Severe late effect (grade 3) was 3.8%. The sphincter preservation was obtained in 104 of 124 cases (84%). The sphincter function was judged to normal in 102 of 104 patients (98%).

Conclusion: Intracavitary contact X ray is the treatment of choice for clinical Stage T1A rectal tumors. External radiotherapy significantly improved the results of treatment of tumors > 3 cm. Clinical staging and transrectal ultrasound allows a safe selection of indications. Radiotherapy alone may be proposed for selected cases as an alternative to mutilating surgery for small rectal adenocarcinoma.     

AT1 receptor blockade prevents the decrease in conduit artery flow-mediated dilatation during NOS inhibition in humans

Whether AT(1) (angiotenin II type 1) receptor blockade can prevent the decrease in conduit artery FMD (flow-mediated dilatation) during NOS (nitric oxide synthase) inhibition by alternative endothelial pathways has not been explored previously in humans. In 12 healthy subjects, we measured radial artery diameter (echotracking) and flow (Doppler) during FMD induced by sustained reactive hyperaemia during a control period and following NOS inhibition [1.5 mg.min(-1).l(-1) L-NMMA (N(G)-monomethyl-L-arginine)], after a single oral administration of telmisartan (80 mg) or placebo, using a randomized double-blind cross-over design. In six volunteers, we also assessed the roles of prostacyclin and EDHF (endothelium-derived hyperpolarizing factor) during radial FMD after AT(1) receptor blockade by oral administration of aspirin (500 mg) alone, aspirin+L-NMMA or aspirin+L-NMMA+fluconazole (a cytochrome epoxygenases inhibitor; 0.37 mg.min(-1).l(-1)). Telmisartan did not affect radial artery FMD in the control period (10.9+/-0.6% with placebo compared with 9.9+/-0.7% with telmisartan), but prevented its decrease after L-NMMA (9.3+/-0.8% with placebo compared with 12.6+/-1.2% with telmisartan; P<0.05) with no modification in baseline parameters, hyperaemia and radial artery endothelium-independent dilatation to sodium nitroprusside. Moreover, in telmisartan-treated subjects, radial artery FMD, compared with control (9.0+/-1.0%), was not modified by aspirin alone (9.4+/-0.7%) or associated with L-NMMA (9.5+/-0.5%), but was reduced by the combination of aspirin, L-NMMA and fluconazole (7.5+/-0.6%; P<0.05). These results demonstrate that AT(1) receptor blockade prevents the decrease in conduit artery FMD during NOS inhibition in humans, suggesting the development of a compensatory endothelial mechanism. This mechanism appears to be independent of prostacyclin and could possibly be related to an EDHF release.     

HLA Association with hematopoietic stem cell transplantation outcome: the number of mismatches at HLA-A, -B, -C, -DRB1, or -DQB1 is strongly associated with overall survival.

HLA matching between the donor and recipient improves the success of unrelated hematopoietic stem cell transplantation (HSCT). Because many patients in need of an unrelated transplant have only donors with mismatch, information is needed to evaluate the limits of HLA mismatching. We examined the association of survival, acute graft-versus-host disease (aGVHD) and relapse with HLA-A, -B, -C, -DRB, -DQB1, and -DPB1 mismatching in 334 patients coming from 12 French transplant centers and who received a non-T cell-depleted bone marrow graft from an unrelated donor. All patients were prepared with the use of myeloablative conditioning regimens. Our analyses demonstrate negative effects of HLA mismatching for either HLA-A, -B, -C, -DRB1, or -DQB1 loci on survival. Multivariate Cox analyses showed that a single mismatch was associated with a significant decrement in survival (P=.046, hazard ratio [HR]=1.41, confidence interval [CI] 95% 1.1-1.98). The presence of multiple mismatches was worse for survival (P=.003, HR=1.91, CI 95% 1.26-2.91) and severe aGVHD (grade III-IV) (P=.002, HR=2.51, CI95% 1.41-4.46). The cumulative incidences of aGVHD and relapse in those HLA-A, -B, -C, -DRB1, and -DQB1 identical pairs with 2, 1, or 0 DPB1 incompatibilities were 63%, 50%, and 51%, and 12%, 27%, and 20%, respectively, but these differences were not statistically significant. Similar differences of aGVHD and relapse, but not statistically significant, were observed in those HLA-A, -B, -C, -DRB1, and -DQB1 identical pairs with DPB1 disparities classified into permissive or nonpermissive mismatches according to Zino's classification based on a hierarchy of the immunogenicity of the HLA-DP molecules. "Missing killer cell immunoglobulin-like receptor (KIR) ligand" evaluated on the presence of HLA-C1, -C2, and Bw4 groups in the recipients was not associated with aGVHD, survival, and relapse in this cohort of non-T cell-depleted HSCT.     

Homozygous status for HLA-E*0103 confers protection from acute graft-versus-host disease and transplant-related mortality in HLA-matched sibling hematopoietic stem cell transplantation

BACKGROUND: The posttransplant period following hematopoietic stem cell transplantation (HSCT) is potentially high risk for developing survival-compromising complications, many of which are known to be under the control of immunogenetic factors. Given the dual role of human leukocyte antigen (HLA)-E molecules in innate and adaptive immune processes, we analyzed the impact of HLA-E polymorphism in genoidentical HSCT setting. METHODS: We analyzed 187 HLA-genoidentical sibling pairs for HLA-E polymorphism. To explore its potential association with the incidence of acute and chronic graft versus host disease (aGVHD, cGVHD), severe infections, risk for transplant-related mortality (TRM), and overall survival, HLA-E locus was genotyped by a polymerase chain-reaction-sequence-specific primer (PCR-SSP) strategy. RESULTS: Multivariate analysis, taking into account the patient-, donor- and transplant-related factors, showed that the incidence of aGVHD and TRM at day 180 were low when the genotype was HLA-E*0103/E*0103, either in the donor or in the recipient, the pairs being identical for HLA-E alleles (hazard ratio [HR]=0.71, P=0.009; and HR=0.42, P=0.04, respectively). We also found a trend towards association between E*0103 homozygosity and improved survival (P=0.05). There was no association between HLA-E polymorphism and incidence of severe infections. CONCLUSIONS: These data suggest that the homozygous state for HLA-E*0103 allele behaves as a protective genetic factor against aGVHD and TRM and likely contributes to improved survival in HLA-genoidentical bone marrow transplantation.