MHC non -HLA gene polymorphisms in transplantation

Despite many studies on non-HLA genetic polymorphism its role in transplantation is still not well understood. The NK cell receptor gene, MICA gene and Minor histocompatibility (mHag) system makes the puzzle still more intriguingly complex. Studies on cytokine gene polymorphism have enlightened some interesting associations such as the effect of donor IL-6 genotype on acute rejection in renal transplantation. In the bone marrow transplant where each polymorphism is taken as a risk factor for GVHD necessitates prospective testing of non-HLA gene polymorphism and hence, transplant outcome. Various typing methods are now available to identify the non-HLA genetic polymorphisms. A scenario can be envisaged where polymorphisms associated with transplant outcome are tested prior to transplantation at the same time as HLA typing.

Differentiation of Nijmegen breakage syndrome from Fanconi anemia

Nijmegen breakage syndrome (NBS) is a rare auto-somal recessive condition with chromosomal instability. Clinical and biological overlap between Fanconi anemia and ataxia telangiectasia has been reported. We report two cases of NBS born to consanguineous parents. Case one had NBS and Falconi anemia clinical features but relatively little chromosome breakage. The second case had mild NBS features, while cytogenetic evaluation with mitomycin C induction showed chromosome damage. Chromosomal analysis of bone marrow cells revealed tetraploidy, which indicates progression towards leukemia. On the basis of clinical and cytogenetic evaluation, these two cases were confirmed as NBS. However, detailed molecular studies are essential for accurate diagnosis and management of this disease.

Increased prevalence of antimitochondrial antibodies in first-degree relatives of patients with primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disorder that can progress to cirrhosis, shortening life expectancy. PBC patients are often asymptomatic, present with biochemical cholestasis, and test positive (>or=90%) for antimitochondrial antibodies (AMAs) in serum. Although AMA positivity without biochemical cholestasis may indicate increased risk of future PBC development, the contribution of these antibodies to pathogenesis remains enigmatic. Environmental risks and genetic determinants are likely implicated in PBC etiology. Given the familial aggregation of PBC, we hypothesized that AMAs also aggregate among relatives of PBC probands. We investigated the prevalence of AMAs in first-degree relatives (FDRs) of PBC probands to examine whether AMAs aggregate in such pedigrees. Using a PBC family registry, we prospectively screened for AMAs in the serum of 306 FDRs in 145 pedigrees, 350 PBC probands, and 196 controls who were age-matched, sex-matched, race-matched, and residence-matched to probands. The prevalence of AMA in FDRs and controls was 13.1% and 1%, respectively. Greater prevalence of AMA was found in female FDRs of PBC probands [sisters (20.7%), mothers (15.1%), and daughters (9.8%)] than in male FDRs [brothers (7.8%), fathers (3.7%), and sons (0%)].

CONCLUSIONS

AMAs aggregate among FDRs of PBC probands. Our data have clinical implications for FDRs of PBC probands because AMA positivity may suggest susceptibility to PBC. Thus, the identification and follow-up of these relatives may lead to earlier disease diagnosis and treatment. Furthermore, if AMA development is heritable, this trait will provide a basis to dissect the genetic predisposition to PBC.

Varied distribution of RhD epitopes in the Indian population

BACKGROUND

Inhabited by more than 4000 caste and tribal groups, India has an extremely heterogenous population. For thousands of years many tribal groups have practised endogamy and are practically genetically isolated. Traditionally, polyclonal anti-D reagent has been used for RhD typing; though monoclonal antibodies are increasingly being used. As a result, blood banks find it difficult to assign the RhD status to an increasing number of people. As monoclonal anti-D typing reagents may not detect all RhD antigen epitopes, we studied the RhD antigen epitope heterogeneity in different population groups in India.

METHODS

Red cells of 5315 RhD-positive individuals belonging to different castes and tribes of India were tested with 30 different epitope-specific monoclonal anti-D antibodies.

RESULTS

No single monoclonal antibody could detect all RhD-positive red cells detected by polyclonal antisera. The highest proportion of D antigen was detected by LHM 76/55 and BRAD-8 (98%) monoclonal antibodies.

CONCLUSION

We need to determine the correct mix of monoclonal antibodies that will detect nearly all RhD antigens detected by polyclonal anti-D sera. Similarly, before accepting monoclonal anti-D for therapeutic use, it would be necessary to determine the appropriate ones for use in the Indian population.

First-trimester prenatal diagnosis of pyruvate kinase deficiency in an Indian family with the pyruvate kinase-Amish mutation

Pyruvate kinase (PK) deficiency is a rare red cell glycolytic enzymopathy. The purpose of the present investigation was to offer prenatal diagnosis for PK deficiency to a couple who had a previous child with severe enzyme deficiency and congenital non-spherocytic hemolytic anemia. PK deficiency was identified in the family by assaying the enzyme activity in red cells. Chorionic villus sampling was performed in an 11-week gestation and the mutation was located in exon 10 of the PKLR gene characterized by polymerase chain reaction and using restriction endonuclease digestion with the MspI enzyme, which was confirmed by DNA sequencing on the ABI 310 DNA sequencer. Both the parents were heterozygous for the 1436G-->A [479 Arg-->His] mutation in exon 10 and the proband was homozygous for this mutation. The fetus was also heterozygous for this mutation and the pregnancy was continued. Prenatal diagnosis allowed the parents with a severely affected child with PK deficiency to have the reproductive choice of having the fetus tested in a subsequent pregnancy.

Mammographic breast density as a general marker of breast cancer risk

Mammographic breast density is a strong risk factor for breast cancer but whether breast density is a general marker of susceptibility or is specific to the location of the eventual cancer is unknown. A study of 372 incident breast cancer cases and 713 matched controls was conducted within the Mayo Clinic mammography screening practice. Mammograms on average 7 years before breast cancer were digitized, and quantitative measures of percentage density and dense area from each side and view were estimated. A regional density estimate accounting for overall percentage density was calculated from both mammogram views. Location of breast cancer and potential confounders were abstracted from medical records. Conditional logistic regression was used to estimate associations, and C-statistics were used to evaluate the strength of risk prediction. There were increasing trends in breast cancer risk with increasing quartiles of percentage density and dense area, irrespective of the side of the breast with cancer (P(trends) < 0.001). Percentage density from the ipsilateral side [craniocaudal (CC): odds ratios (ORs), 1.0 (ref), 1.7, 3.1, and 3.1; mediolateral oblique (MLO): ORs, 1.0 (ref), 1.5, 2.2, and 2.8] and the contralateral side [CC: ORs, 1.0 (ref), 1.8, 2.2, and 3.7; MLO: ORs, 1.0 (ref), 1.6, 1.9, and 2.5] similarly predicted case-control status (C-statistics, 0.64-65). Accounting for overall percentage density, density in the region where the cancer subsequently developed was not a significant risk factor [CC: 1.0 (ref), 1.3, 1.0, and 1.2; MLO: 1.0 (ref), 1.1, 1.0, and 1.1 for increasing quartiles]. Results did not change when examining mammograms 3 years on average before the cancer. Overall mammographic density seems to represent a general marker of breast cancer risk that is not specific to breast side or location of the eventual cancer.

Stratification of breast cancer risk in women with atypia: a Mayo cohort study

PURPOSE

Atypical hyperplasia is a well-recognized risk factor for breast cancer, conveying an approximately four-fold increased risk. Data regarding long-term absolute risk and factors for risk stratification are needed.

PATIENTS AND METHODS

Women with atypical hyperplasia in the Mayo Benign Breast Disease Cohort were identified through pathology review. Subsequent breast cancers were identified via medical records and a questionnaire. Relative risks (RRs) were estimated using standardized incidence ratios, comparing the observed number of breast cancers with those expected based on Iowa Surveillance, Epidemiology, and End Results (SEER) data. Age, histologic factors, and family history were evaluated as risk modifiers. Plots of cumulative breast cancer incidence provided estimates of risk over time.

RESULTS

With mean follow-up of 13.7 years, 66 breast cancers (19.9%) occurred among 331 women with atypia. RR of breast cancer with atypia was 3.88 (95% CI, 3.00 to 4.94). Marked elevations in risk were seen with multifocal atypia (eg, three or more foci with calcifications [RR, 10.35; 95% CI, 6.13 to 16.4]). RR was higher for younger women (< 45; RR, 6.76; 95% CI, 3.24 to 12.4). Risk was similar for atypical ductal and atypical lobular hyperplasia, and family history added no significant risk. Breast cancer risk remained elevated over 20 years, and the cumulative incidence approached 35% at 30 years.

CONCLUSION

Among women with atypical hyperplasia, multiple foci of atypia and the presence of histologic calcifications may indicate "very high risk" status (> 50% risk at 20 years). A positive family history does not further increase risk in women with atypia.

Longitudinal Trends in Mammographic Percent Density and Breast Cancer Risk

BACKGROUND

Mammographic density is a strong risk factor for breast cancer. However, whether changes in mammographic density are associated with risk remains unclear.

MATERIALS AND METHODS

A study of 372 incident breast cancer cases and 713 matched controls was conducted within the Mayo Clinic mammography screening practice. Controls were matched on age, exam date, residence, menopause, interval between, and number of mammograms. All serial craniocaudal mammograms 10 years before ascertainment were digitized, and quantitative measures of percent density (PD) were estimated using a thresholding method. Data on potential confounders were abstracted from medical records. Logistic regression models with generalized estimating equations were used to evaluate the interactions among PD at earliest mammogram, time from earliest to each serial mammogram, and absolute change in PD between the earliest and subsequent mammograms. Analyses were done separately for PD measures from the ipsilateral and contralateral breast and also by use of hormone therapy (HT).

RESULTS

Subjects had an average of five mammograms available, were primarily postmenopausal (83%), and averaged 61 years at the earliest mammogram. Mean PD at earliest mammogram was higher for cases (31%) than controls (27%; ipsilateral side). There was no evidence of an association between change in PD and breast cancer risk by time. Compared with no change, an overall reduction of 10% PD (lowest quartile of change) was associated with an odds ratio of 0.9997 and an increase of 6.5% PD (highest quartile of change) with an odds ratio of 1.002. The same results held within the group of 220 cases and 340 controls never using HT. Among the 124 cases and 337 controls known to use HT during the interval, there was a statistically significant interaction between change in PD and time since the earliest mammogram (P = 0.01). However, in all groups, the risk associated with the earliest PD remained a stronger predictor of risk than change in PD.

CONCLUSION

We observed no association between change in PD with breast cancer risk among all women and those never using HT. However, the interaction between change in PD and time should be evaluated in other populations.

14th International HLA and Immunogenetics Workshop: Report from the reproductive immunology component

The aim of the study was to investigate whether human leukocyte antigen (HLA) allele sharing between partners or the maternal killer immunoglobulin-like receptor (KIR) repertoire is associated with recurrent spontaneous abortion (RSA) and repeated implantation failure after in vitro fertilization (IVF)/embryo transfer. From a total population of 158 RSA couples, 40 couples with repeated implantation failures (IVF) and 81 control couples, reported by five different laboratories, analysis was performed for (a) HLA sharing in 50 RSA, 31 IVF and 31 control couples, (b) DQA1*0505 sharing/homozygosity among partners in 108 RSA, 40 IVF and 36 control couples, and (c) the women's KIR repertoire in 46 RSA, 26 IVF and 36 control wives. RSA couples were divided into alloimmune aborter (RSAallo) and autoimmune aborter (RSAauto). The results oppose to the suggestion that increased HLA sharing per se or a limited maternal KIR repertoire predisposes to RSA or IVF failure. However, the observation of a slightly higher percentage of DQA1*0505 sharing in the RSAauto and the IVF group needs further investigation. The ratio of inhibitory to activating KIR (actKIR) was slightly lower in RSAallo and IVF women (1.9 vs 2.6 in controls), while in a high percentage of these women, the standard receptors of the KIR A haplotype were combined with actKIR/s of the haplotype B (66.6% and 45.4% vs 20% and 15.3% in RSAauto and control groups). This may suggest a possible involvement of actKIRs in embryo implantation and the maintenance of pregnancy and also requires further investigation.

Robustness of factor assays following cordocentesis in the prenatal diagnosis of haemophilia and other bleeding disorders

Prenatal diagnosis is the generally accepted option for genetic disorders including haemophilias and other bleeding disorders. Cord blood analysis between 17.4 and 20.6 weeks of gestation was performed in 172 confirmed carriers belonging to families of haemophilia A, haemophilia B, von Willebrand disease (VWD), factor VII and X deficiency; 133 were carriers for haemophilia A, 30 for haemophilia B, six for type 3 VWD, two for FX deficiency and one for FVII deficiency. The approach to the cord was either transabdominal or transamniotic. The volume of blood collected varied between 1 and 2 mL. In case of haemophilias, the diagnosis was offered by factor VIII/IX:C activity and antigen assays wherever required. In case of VWD, the diagnosis was based on von Willebrand factor antigen assays as detected by ELISA along with FVIII:C assay while in cases of FVII and FX deficiency, the diagnosis was based on FVII:C and FX:C respectively. The factor levels were compared with the normal range established in the laboratory for different coagulation factors between 18 and 21 weeks of gestation in women tested for other haematological disorders. Only in two cases, the procedure had to be repeated for reasons of extensive maternal contamination. All the deliveries have been followed up and the diagnoses reconfirmed by repeat clotting factor assays and DNA analysis whenever informative. Simple precautions like collection of fetal blood samples in smaller volumes in separate tubes, assaying multiple coagulation factors in the fetal blood samples helped us to offer diagnoses in all the women analysed. No fetal death or abortion was reported following the procedure. We suggest that accurate fetal blood sampling is a safe technique for the diagnosis of many of the bleeding disorders in places where genetic diagnostic services are not available.

Iatrogenic duodenal perforations caused by endoscopic biliary stenting and stent migration: an update

Endoscopic biliary stenting is the preferred method of decompression in obstructive jaundice. Duodenal perforations caused during stenting and stent migration are rare but life-threatening complications, and require judicious management. With the increasing use of therapeutic endoscopy, an awareness of these complications is becoming important in our surgical practice. Advances in interventional radiology, endoscopy, and laparoscopy have enhanced the scope and reduced the morbidity of both conservative and surgical treatments of these perforations. This article presents an update on the current state of our knowledge on the science and the management of this complication.

Extreme Rank Selections for Linkage Analysis of Quantitative Trait Loci Using Selected Sib-Pairs

It is well known that linkage analysis using simple random sib-pairs has relatively low power for detecting quantitative trait loci with small genetic effects. The power can be substantially increased by using samples selected based on their trait values. Usually, samples that are obtained by truncation selection consist of random samples from a truncated trait distribution. In this article we propose an alternative method using extreme ranks for linkage analysis with selected sib-pairs. This approach approximates the truncation selection. With similar screening sizes and the same sample size of selected sib-pairs, the extreme rank selection and truncation method have similar power performance, both of which are substantially more powerful than when using random sib-pairs. Simulation results on the comparison of powers between the truncation selection and the extreme rank selection and/or random selection for linkage analysis are reported.

Paget’s disease of the breast: accuracy of preoperative assessment

BACKGROUND

Routine preoperative assessment may not accurately assess the extent of underlying cancer in patients with Paget's disease (PD) of the breast. We performed this study to correlate findings on clinical examination and mammography with pathologic results and outcomes in women with PD.

METHODS

An IRB-approved retrospective review identified all patients with PD between 1975 and 2000. Clinical exam and mammographic findings were recorded, and information on recurrence and survival was obtained from medical records.

RESULTS

Univariate analyses identified palpable mass and suspicious mammogram as risk factors significantly associated with a worse outcome. Patients were therefore categorized by combinations of these two preoperative factors. All patients with a palpable mass and a suspicious mammogram had invasive cancer. In the subgroup of 40 women with a benign mammogram and no palpable mass, invasive cancer occurred in 5% and the majority (68%) had ductal carcinoma in situ which extended beyond the nipple. Women with a palpable mass and a suspicious mammogram had significantly worse survival compared to those with a benign mammogram and no palpable mass (P = 0.008). With a median follow-up of 6.4 years, five local recurrences occurred in patients with invasive cancer who underwent mastectomy.

CONCLUSION

In women with PD, a palpable mass or suspicious mammogram portends a high likelihood of invasive cancer. Underlying cancer is common even in women with a benign mammogram and no palpable mass. Although breast conservation is an attractive option in patients with PD, mammography and physical exam may significantly underestimate the presence and extent of underlying disease.

Clinical approach to breast disorders: A primer for internists

Women with breast disorders often present first to their internists for evaluation. A delay in accurate diagnosis could often result in worsening of prognosis for the patient. Common diagnostic problems include evaluation of a breast lump, nipple discharge and breast pain. Internist now has a choice of several diagnostic modalities to evaluate breast disorders. An evidence-based approach to common breast symptoms and advances in breast diagnostic techniques has been described to enable early diagnosis of breast cancer, thereby reducing the need for intensive treatments and improve patient satisfaction and clinical outcome.