Impact of CTLA4 genotype and other immune response gene polymorphisms on outcomes after single umbilical cord blood transplantation.

We evaluated the impact of recipient and cord blood unit (CBU) genetic polymorphisms related to immune response on outcomes after unrelated cord blood transplantations (CBTs). Pretransplant DNA samples from 696 CBUs with malignant diseases were genotyped for NLRP1, NLRP2, NLRP3, TIRAP/Mal, IL10, REL, TNFRSF1B, and CTLA4. HLA compatibility was 6 of 6 in 10%, 5 of 6 in 39%, and ≥4 of 6 in 51% of transplants. Myeloablative conditioning was used in 80%, and in vivo T-cell depletion in 81%, of cases. The median number of total nucleated cells infused was 3.4 × 107/kg. In multivariable analysis, patients receiving CBUs with GG-CTLA4 genotype had poorer neutrophil recovery (hazard ratio [HR], 1.33; P = .02), increased nonrelapse mortality (NRM) (HR, 1.50; P < .01), and inferior disease-free survival (HR, 1.41; P = .02). We performed the same analysis in a more homogeneous subset of cohort 1 (cohort 2, n = 305) of patients who received transplants for acute leukemia, all given a myeloablative conditioning regimen, and with available allele HLA typing (HLA-A, -B, -C, and -DRB1). In this more homogeneous but smaller cohort, we were able to demonstrate that GG-CTLA4-CBU was associated with increased NRM (HR, 1.85; P = .01). Use of GG-CTLA4-CBU was associated with higher mortality after CBT, which may be a useful criterion for CBU selection, when multiple CBUs are available.

Prevalence of hereditary risk factors for thrombophilia in Belém, Brazilian Amazon

Different risk factors for venous thromboembolism (VTE) have been identified, including hereditary abnormalities in the mechanisms of coagulation and fibrinolysis. We investigated five genetic polymorphisms (FVL G1691A, FII G20210A, MTHFR C677T, TAFI A152G and TAFI T1053C) associated with VTE in individuals from the city of Belém in the Brazilian Amazon who had no history of VTE. No significant difference was found between the observed and expected genotype frequencies for the loci analyzed. We found high frequencies of MTHFR C677T (33.9 percent) and TAFI T1053C (74 percent) and low frequencies of FVL (1.6 percent), FII G20210A (0.8 percent) and TAFI A152G (0.8 percent). The FVL G1691A, FII G20210A and MTHFR C677T frequencies were similar to those for European populations and populations of European descent living in the city of Ribeirão Preto in the Brazilian state of São Paulo. The frequency of the two TAFI mutations in the Belém individuals was not significantly different from that described for individuals from Ribeirão Preto. We suggest that the risks for VTE in the population of Belém are of the same magnitude as that observed in European populations and in populations with an expressive European contribution.

Hereditary hemochromatosis in a Brazilian university hospital in São Paulo State (1990-2000).

Hereditary hemochromatosis (HH) is the most common genetic disease among individuals of European descent. Two mutations (845G-->A, C282Y and 187C-->G, H63D) in the hemochromatosis gene (HFE gene) are associated with HH. About 85-90% of patients of northern European descent with HH are C282Y homozygous. The prevalence of HH in the Brazilian population, which has a very high level of racial admixture, is unknown. The aims of the present study were to identify individuals with diagnostic criteria for HH among patients with a body iron overload attended at the university hospital of the Faculty of Medicine of Ribeirao Preto from 1990 to 2000, and to evaluate the prevalence of HFE mutations. We screened first-degree relatives for HFE mutations. Four of 72 patients (three men and one woman, mean age 47 years) fulfilled the criteria for HH. HFE mutations were studied in three patients [two C282Y homozygotes (patients 1 and 2) and one H63D heterozygote]. Patient 1 had four children (all C282Y heterozygotes with no iron overload) and seven brothers and sisters: two sisters (66 and 76 years old) were C282Y homozygotes and both had an iron overload (a liver biopsy in one showed severe iron deposits), one sister (79 years old) was a compound heterozygote with no iron overload, one brother (78 years old) was a C282Y heterozygote with no iron overload, two individuals were H63D heterozygotes (one brother, 49 years old, obese, with a body iron overload and abnormal liver enzymes - a biopsy showed non-alcoholic steatohepatitis, and one 70-year-old sister with no iron overload). Patient 2 had two children (22 and 24 years old who were C282Y heterozygotes with no iron overload) but no brothers or sisters. These results showed that HH was uncommon among individuals attended at our hospital, although HFE mutations were found in all patients. Familial screening is valuable for the early diagnosis of individuals at risk since it allows treatment to be initiated before the onset of the clinical manifestations of organ damage associated with HH.

Liver iron deposits in hepatitis B patients: association with severity of liver disease but not with hemochromatosis gene mutations.

BACKGROUND AND AIMS: Iron deposits in the liver and abnormalities in serum iron biochemistry are frequently observed in patients with chronic liver diseases, but data for patients with hepatitis B virus (HBV) infection are scarce. Moreover, the role of HFE mutations in iron deposits in this condition remains unknown. The aim of the present study was to determine the prevalence of serum iron biochemical abnormalities and iron deposits in the liver of chronic HBV patients, and to evaluate the consequences for the activity and severity of liver disease. Additionally, we studied the role of HFE gene mutations in iron deposits. METHODS: Eighty-one male non-cirrhotic HBV patients were studied. Serum iron biochemistry, liver enzymes and C282Y/H63D mutations were investigated. Liver biopsies were scored for necroinflammatory activity (histological activity index [HAI]), fibrosis and iron deposits. RESULTS: Elevated transferrin saturation (TS) was found in 27.1% of patients and liver iron deposits in 48.7%; these deposits were mild in 68.4% and moderate in 31.6%. Patients with liver iron deposits exhibited significantly higher scores for HAI and fibrosis than those without iron deposits. HFE mutations were identified in 23.4% of patients (14 H63D heterozygotes, four H63D homozygotes, one compound mutation). No difference in the prevalence of C282Y and H63D mutations was observed between HBV patients (1.2% and 23.4%, respectively) and the general population (4.1% and 27.8%, respectively). No association was detected between HFE mutations and elevated TS or liver iron deposits. CONCLUSIONS: Elevated TS and liver iron deposits were frequent in non-cirrhotic HBV patients. Iron deposits were mainly mild and associated with higher activity and severity of liver disease, but not with HFE mutations.

Heterogeneous ethnic distribution of the factor V leiden mutation

Inherited resistance to activated protein C caused by the factor V Leiden (FVL) mutation is the most common genetic cause of venous thrombosis yet described, being found in 20-60 per cent of patients with venous thrombophilia. A relationship between the FVL mutation and an increased predisposition to arterial thrombosis in young women was recently reported. We assessed the prevalence of the FVL mutation in 440 individuals (880 chromosomes) belonging to four different ethnic groups: Caucasians, African Blacks, Asians and Amerindians. PCR amplification followed by MnlI digestion was employed to define the genotype. The FVL mutation was found in a heterozygous state in four out of 152 Whites (2.6 per cent), one out of 151 Amerindians (0.6 per cent), and was absent among 97 African Blacks and 40 Asians. Our results confirm that FVL has a heterogeneous distribution in different human populations, a fact that may contribute to geographic and ethnic differences in the prevalence of thrombotic diseases. In addition, these data may be helpful in decisions regarding the usefulness of screening for the FVL mutation in subjects at risk for thrombosis.

Absence of the E2 allele of apolipoprotein in Amerindians

A determinaçäo da distribuiçäo do alelo ApoE em cinco tribos de índios sulamericanos revelou ausência do alelo ApoE2, acompanhada por freqüência alta do alelo ApoE3 e baixa do alelo ApoE4 na maioria das tribos, uma distribuiçäo previamente relatada apenas para os esquimós Inuit da Groenlândia.