Reduced Incidence of Cytomegalovirus Infection in Kidney Transplant Recipients Receiving Everolimus and Reduced Tacrolimus Doses

This study compared the incidence of CMV infection/disease in de novo kidney transplant recipients receiving everolimus or mycophenolate and no CMV pharmacological prophylaxis. We randomized 288 patients to receive a single 3 mg/kg dose of antithymocyte globulin, tacrolimus, everolimus, and prednisone (r-ATG/EVR, n = 85); basiliximab, tacrolimus, everolimus, and prednisone (BAS/EVR, n = 102); or basiliximab, tacrolimus, mycophenolate, and prednisone (BAS/MPS, n = 101). The primary end-point was the incidence of first CMV infection/disease in the intention-to-treat population at 12 months. Patients treated with r-ATG/EVR showed a 90% proportional reduction (4.7% vs. 37.6%, HR 0.10, 95% CI 0.037-0.29; p < 0.001), while those treated with BAS/EVR showed a 75% proportional reduction (10.8% vs. 37.6%, HR 0.25, 95% CI 0.13-0.48; p < 0.001) in the incidence of CMV infection/disease compared to BAS/MPS. There were no differences in the incidence of acute rejection (9.4 vs. 18.6 vs. 15.8%, p = 0.403), wound-healing complications, delayed graft function, and proteinuria. Mean estimated glomerular filtration rate was lower in BAS/EVR (65.7 ± 21.8 vs. 60.6 ± 20.9 vs. 69.5 ± 21.5 ml/min, p = 0.021). In de novo kidney transplant recipients receiving no pharmacological CMV prophylaxis, reduced-dose tacrolimus and everolimus was associated with a significant reduction in the incidence of CMV infection/disease compared to standard tacrolimus dose and mycophenolate (ClinicalTrials.gov NCT01354301).

The HLA-A*02:481 allele was identified in unrelated Brazilians sharing HLA-B*15:17, C*07:01P, DRB1*13:02 and DQB1*06:04

HLA-A*02:481 differs from HLA-A*02:01:01:01 by one nucleotide and was found in four unrelated Brazilians.

Algorithms for the determination of unacceptable HLA antigen mismatches in kidney transplant recipients

One of the major tasks of human leukocyte antigen (HLA) laboratories is the pretransplant determination of unacceptable HLA antigen mismatches (UAM) in organ transplant recipients. HLA antigen specificities are determined against which the patient has circulating alloantibodies that are expected to harm the transplanted organ. Using the information on UAM, negative crossmatch (XM) prediction or 'virtual XM' is possible when a potential donor's complete HLA typing is available. Before the introduction of solid-phase antibody detection assays, UAM were determined using the complement-dependent cytotoxicity methodology. After the introduction of the single antigen bead technique, however, various UAM determination algorithms have emerged. In this report, six different laboratories worldwide present how they determine UAM in their collective of kidney transplant recipients in the pretransplant phase and proceed thereafter to transplantation.

HLA class II alleles and chronic hepatitis C virus infection

The aim of this study was to investigate association of human leucocyte antigens (HLA)-DRB1 and DQB1 polymorphisms with hepatitis C virus (HCV) infection and with the occurrence of severe liver fibrosis/cirrhosis in chronically infected patients. Ninety-nine white patients, from southeast Brazil, with confirmed HCV chronic infection were included in the study. Severe fibrosis/cirrhosis (METAVIR scores F3-F4) was present in 49 patients. HLA-DRB1 specificities and DRB1*11 and DQB1* alleles were determined by PCR-SSP, and their frequencies were compared between patients and a control group of 103 healthy white Brazilian individuals. The results confirmed previous reports of the association of DRB1*11 and DQB1*03 with protection from chronic HCV infection, but did not confirm their association with protection from severe fibrosis/cirrhosis. Furthermore, the results suggested that the polymorphic sites on HLA molecules responsible for protection from chronic HCV infection are encoded not only by the DRB1*1101 and DQB1*0301, as suggested in the literature, but also by other DRB1*11 and DQB1*03 alleles. Thus, we hypothesized that the common polymorphic residues shared by different DRB1*11 and/or DQB1*03 alleles might be responsible for selection of viral epitopes for presentation to CD4(+) T cells, leading to an efficient immune response against the virus.

Identification of a novel HLA-B*52 allele in a Brazilian individual: B*52:21

HLA-B*52:21 differs from the closest, HLA-B*52:01:02, by two nucleotides (CTG → TGG), leading to an amino acid substitution from Leu to Trp at codon 156.

Post-transplant anti-HLA class II antibodies as risk factor for late kidney allograft failure

The purpose of this study was to prospectively analyze the relationship between the post-transplant anti-HLA class I and/or class II panel reactive antibodies and graft failure due to chronic allograft nephropathy (CAN). We studied 512 first kidney recipients transplanted at a single center, with a graft functioning for at least 3 years. A single blood sample was collected from each patient for antibody evaluation. The median posttransplant time after blood collection was 4.4 years and did not differ between patients with (n = 91) or without anti-HLA antibodies (n = 421). Female gender, pregnancies and blood transfusions were associated with the presence of anti-HLA class I antibodies. Graft function deterioration was associated with anti-HLA class II antibodies. Multivariate analysis showed independent association for creatinine levels (RR = 7.5), acute rejection (RR = 2.6), recipient male gender (RR = 3.6) and anti-HLA class II antibodies (RR = 2.9) and CAN-associated graft loss. In conclusion, the presence of anti-HLA class II antibodies conferred a risk for graft loss before a decline in renal function and increased the risk of graft failure in patients who already had a decline in graft function. Thus, anti-HLA class II antibody monitoring is a useful tool for the management of long-term kidney recipients.

Expression of Fas, FasL, and Soluble Fas mRNA in Endomyocardial Biopsies of Human Cardiac Allografts

Apoptosis mediated by the Fas/Fas ligand (FasL) has been implicated in rejection of solid organ allografts and it has been recently proposed that soluble forms of Fas could interfere with this interaction, blocking apoptosis. The purpose of this study was to analyze intragraft Fas, FasL, and soluble Fas mRNA levels in relation to acute rejection in cardiac allografts in humans. mRNA levels were determined by quantitative reverse transcriptase-polymerase chain reaction in 42 samples of endomyocardial biopsies obtained from 18 cardiac transplant recipients within the first 6 months after transplantation. FasL and Fas mRNA levels were higher in biopsies with rejection than in biopsies without rejection, and no difference was observed in soluble Fas mRNA. During rejection, there was a positive correlation between the mRNA levels of Fas-FasL, Fas-soluble Fas, and FasL-soluble Fas. During quiescent periods, however, the only correlation observed was between Fas and soluble Fas mRNA levels. In conclusion, our findings do not suggest a role for soluble Fas, confirm the heightened expression of FasL, and indicate, for the first time, an increased expression of Fas in acute rejection of cardiac allografts.

Interleukin-2 gene polymorphism is associated with renal but not cardiac transplant outcome

It was recently shown that IL-2 gene single nucleotide polymorphism (SNP) at position -330 (G-->T) is related to in vitro cytokine production levels, with the T/T and T/G genotypes being associated with low production and the G/G genotype associated with high production. The objective of this study was to investigate a possible influence of this polymorphism on renal and cardiac allograft outcomes. IL-2 SNP G-T (-330) was determined by PCR-RFLP in 67 recipients of heart allografts and in 63 recipients of renal grafts from HLA-haplo-identical, related donors. A higher frequency of the T/T genotype was observed in renal transplant patients who experienced at least one acute rejection episode during the first 3 months after transplantation than in those without rejection during this period (80% vs 49%, respectively, P <.05). Accordingly, the same genotype tended to be more frequent in renal recipients with a 6-month serum creatinine level above 1.5 mg/dL (median value for the whole group of kidney recipients) than in patients with lower creatinine levels (79% vs 45%, P <.08). Regarding cardiac transplant recipients, no associations were observed concerning acute rejection or graft survival. The finding of the association of T/T but not T/G genotype with acute kidney rejection was unexpected considering that both genotypes were shown to be associated with equal (low) IL-2 in vitro production. Further studies are necessary not only to dissect the nature of IL-2 T/T genotype association with kidney rejection, but also to explain why this genotype does not apparently influence cardiac allograft outcome.

Intragraft activation of genes encoding cytotoxic T lymphocyte effector molecules precedes the histological evidence of rejection in human cardiac transplantation

BACKGROUND

The purpose of the present study was to investigate transcripts of perforin, granzyme B, and Fas ligand (FasL) in heart transplants undergoing rejection.

METHODS

Quantitative reverse transcriptase-polymerase chain reaction was applied for mRNA detection in 29 endomyocardial biopsy specimens from 11 cardiac allograft recipients.

RESULTS

The mRNA levels of granzyme B, perforin, and FasL were higher (P<0.05) in biopsy specimens with rejection than in biopsy specimens without rejection (granzyme B, 0.53 vs. 0.09; perforin, 0.34 vs. 0; FasL, 0.57 vs. 0.36). In prerejection biopsy specimens, granzyme B and FasL levels were significantly higher than in biopsy specimens without rejection. Any two of the three transcripts were increased in 100% of prerejection, in 92% of rejection, and in 36% of no rejection biopsy specimens (P<0.04).

CONCLUSIONS

The assessment of intragraft levels of cytotoxic T lymphocyte effector molecule mRNA represents a valuable tool in the monitoring of cardiac allograft rejection, especially considering the predictive value for warning of impending acute rejection.

Monitoring of intragraft and peripheral blood TIRC7 expression as a diagnostic tool for acute cardiac rejection in humans

T-cell immune response cDNA 7 (TIRC7) is a recently described T-cell costimulatory molecule that exhibits a central role in T-cell activation in vitro and in vivo. The present study was undertaken to investigate association between intragraft and peripheral blood mononuclear cell (PBMC) TIRC7 mRNA levels and cardiac allograft rejection in humans. TIRC7 gene expression levels were determined by a quantitative-competitive reverse transcriptase-polymerase chain reaction (QC-RT-PCR) in endomyocardial biopsies and in PBMC from cardiac transplant recipients. Biopsies collected during rejection or up to 15 days before rejection showed heightened TIRC7 mRNA expression in comparison with biopsies without rejection. All prerejection and rejection biopsies showed TIRC7 mRNA upregulation, while this was present in only 30% of the biopsies without rejection. Regarding TIRC7 mRNA in PBMC, transplant recipients showed lower levels than healthy individuals and, in contrast to the results obtained in biopsies, the levels were lower during rejection than in rejection-free periods. In summary, TIRC7 mRNA expression levels increase in biopsies and decrease in peripheral blood during acute cardiac rejection. We conclude that intragraft detection of TIRC7 transcripts is a useful tool not only for the diagnosis but also for the prediction of acute heart allograft rejection episodes.

Tumor necrosis factor during pregnancy and at the onset of labor and spontaneous abortion

OBJECTIVE

The aim of this study was to evaluate the production of tumor necrosis factor (TNF) by peripheral blood cells during pregnancy, at the onset of labor and of spontaneous abortion (SA), as well as in non-pregnant women with and without a history of recurrent spontaneous abortions (RSA).

STUDY DESIGN

The peripheral blood cells TNF production was evaluated in 28 women in the 1st trimester of pregnancy, 21 in the 2nd, and 30 in the 3rd, 47 at term labor; 43, at the onset of SA; 19 healthy and 19 RSA non-pregnant women. The statistical method used was the Mann-Whitney test.

RESULTS

We observed (1) lack of TNF detection in the 1st gestational trimester; (2) increase of TNF production with gestational age, with the highest values being observed at labor (P<0.05); (3) high TNF production at the onset of SA; (4) no difference in the TNF production by healthy and RSA non-pregnant women.

CONCLUSIONS

The suppression of TNF production during the 1st trimester of pregnancy seems to favor the normal development of pregnancy. It remains to be investigated whether the assessment of TNF production is a valuable prognostic parameter for the occurrence of abortion.

Human leukocyte antigens and malignant essential hypertension

The purpose of this study was to investigate an association between human leukocyte antigens (HLA) and the susceptibility to malignant hypertension. The presence of HLA-A, -B, -DR, and -DQ was determined in 33 white and in 23 mulatto Brazilian patients with malignant essential hypertension. No statistically significant differences were detected between patients and control subjects. It is nevertheless important to note that we have observed an increased frequency of DR3 in the mulatto patients (34.8% v 21.4%). We consider that this finding supports the existence of an HLA-DR3 association with hypertension in the black population, as has been claimed by other authors.

Idiopathic focal segmental glomerulosclerosis and HLA antigens

The objective of the present study was to investigate a possible association between HLA class II antigens and idiopathic focal segmental glomerulosclerosis (FSGS). HLA-A, -B, -DR and -DQ antigens were determined in 19 Brazilian patients (16 white subjects and three subjects of Japanese origin) with biopsy-proven FSGS. Comparison of the HLA antigen frequencies between white patients and white local controls showed a significant increase in HLA-DR4 frequency among FSGS patients (37.7 vs 17.2%, P < 0.05). In addition, the three patients of Japanese extraction, not included in the statistical analysis, also presented HLA-DR4. In conclusion, our data confirm the association of FSGS with HLA-DR4 previously reported by others, thus providing further evidence for a role of genes of the HLA complex in the susceptibility to this disease.

HLA antigens in asthmatic children

The purpose of the present study was to analyze the frequency of HLA-DR and DQ antigens in Brazilian asthmatic children with skin-test and RAST positivity to Dermatophagoides pteronyssinus. The comparison of HLA-DR and DQ antigenic frequencies between patients (n = 30) and controls disclosed a significantly higher HLA-DQ2 frequency in the patients (60% versus 34%, p = 0.013; R. R. = 2.8).

C2 deficiency in blood donors and lupus patients: prevalence, clinical characteristics and HLA-associations in the Brazilian population

The objective of the present study was to investigate the prevalence, clinical characteristics, and HLA association of C2 deficiency in the Brazilian population. The frequency of C2 deficiency profile (C2Q degree profile) was 2.2% among 1503 blood donors and 6.6% among 166 patients with systemic lupus erythematosus (SLE). A higher incidence of clinical manifestations possibly related to immune complex disease was observed among blood donors with C2Q degree profile and their relatives with C2Q degree profile when compared to the normal C2 relatives. The comparison of clinical and laboratory features between SLE patients with C2Q degree profile and those with normal C2 revealed earlier disease onset, higher frequency of oral ulcerations and lower frequency of anti-native DNA antibodies in the first group. The HLA study conducted on 18 individuals with C2Q degree profile (11 blood donors and 7 SLE patients) confirmed the previously reported association with the antigens HLA-A25, B18 and DR2, supporting the concept that probably most C2 deficiency cases, throughout the world, are due to a single mutation in the C2 gene in linkage disequilibrium with the A25B18DR2 haplotype.

Conditioned immunosuppression in orally immunized mice

Mice were given oral immunization after pretreatment with a regimen (cyclophosphamide and a novel taste in the drinking water, chocolate milk (CHM), which leads to suppression of the antibody response to intravenously administered antigens given concurrently with CHM. Following this treatment mice were reexposed to CHM and IgM and IgA antibody forming cells (AFC) were measured in spleen and Peyer's patch cells. Conditioned immunosuppression of AFC production was most marked (> fivefold) for IgA-AFC in Peyer's patch, with effects of lesser magnitude for IgM-AFC in Peyer's patch (twofold) and both IgM- and IgA-AFC in spleen. Analysis of cytokine production from stimulated Peyer's patch and splenic T cells in vitro showed significant decreased production of both IL-2 and IL-4, with the latter being the predominant cytokine produced in Peyer's patch cells of control animals.

Rheumatic fever and the HLA complex. A cosegregation study

BACKGROUND

Considering the controversial results published in the literature concerning associations between human leukocyte antigens (HLA) and rheumatic fever (RF), the purpose of the present study was to investigate by means of cosegregation analysis the participation of HLA genes in susceptibility to RF.

METHODS AND RESULTS

The sample reported here was composed of 51 affected and 66 healthy individuals belonging to 22 genetically informative families. The comparison (chi 2 goodness-of-fit test) of the observed numbers of identical-by-descent (IBD) HLA haplotypes among all affected individuals (siblings, cousins, and uncle/nephew and grandparent/grandchild type of pairs) with the expected ones under the assumption of independent segregation of HLA alleles and the presumptive RF susceptibility gene gave a value of P = .088. Since the number of subjects studied was relatively small and the rejection level obtained was near the usual .05 significance level, we calculated the expected HLA IBD scores in the 13 pairs of affected sibs of our sample for all possible frequencies of the presumptive RF susceptibility gene. This analysis allowed clear rejection of a recessive mode, considering susceptibility gene frequencies lower than 20%, whereas the observed values fitted very well a dominant mode of inheritance, with penetrance (K) values varying between 0.5 and 0.9 and a frequency of the susceptibility gene of at least 1%.

CONCLUSIONS

The present data support the hypothesis of an RF susceptibility gene within or very near the HLA complex.

Essential hypertension and histocompatibility antigens. An association study

Data from a previous study concerning the distribution of human leukocyte antigen (HLA) haplotypes in siblings with essential hypertension suggested that at least one of the genes responsible for the genetic susceptibility to this disease is located in or near the HLA complex. The objective of the present study was to investigate if a given HLA-A, B, or DR gene could represent a marker for susceptibility to essential hypertension at the population level. Thus, the frequencies of HLA antigens were determined in Caucasian patients with essential hypertension (HLA-A and B antigens were determined in 89 cases, 85 of which were also typed for HLA-DR antigens). The results showed an increased frequency (p = 0.00064) of HLA-DR4, which was present in 34% of the patients and in 16% of local ethnically matched control subjects. We conclude that HLA-DR4 may represent a marker for susceptibility to essential hypertension in the Brazilian Caucasian population.

Essential hypertension and histocompatibility antigens. A linkage study

It is well established that genetic and environmental factors are involved in the etiology of essential hypertension. The presence of genes predisposing to essential hypertension in the human leukocyte antigen (HLA) complex is controversial because studies of an association between HLA antigens and essential hypertension have failed to yield consistent results. Our aim in the present study was to further investigate this issue through the method of linkage analysis. Analysis of 96 hypertensive siblings distributed in 31 families indicated a significant distortion (p = 0.0009) of the normal segregation pattern of inheritance of HLA haplotypes. Thus, our data indicate that at least one of the genes responsible for genetic predisposition to essential hypertension is located very near or within the HLA complex.

Age-related changes, including synergy and suppression, in the mixed lymphocyte reaction in long-lived mice

The mixed lymphocyte culture reaction represents the in vitro counterpart of the recognition phase of the graft-versus-host reaction, and of allograft rejection. The mixed lymphocyte culture reactivities of lymph node and spleen cells from all strains show a striking decline with advanced age. Furthermore, studies of "synergy" between subpopulations of T cells in the mixed lymphocyte culture reaction suggest that the cells of the recirculating lymphoid pool (T2 cells) in particular display a functional decline. Finally, spleen cells from old mice of appropriate strains inhibit or suppress the mixed lymphocyte culture reactivity of lymph node or spleen cells from young mice.

Immune function and survival in a long-lived mouse strain subjected to undernutrition

Functional immune changes were monitored in populations of the long-lived C57BL/6J strain of mice which were subjected to dietary restriction from time of weaning or subjected to such restriction both before and after weaning, along with the appropriate control populations. Responses to T and B cell mitogens (PHA, Con-A, pokeweed, bacterial lipopolysaccharide, and PPD), to injected sheep red blood cells, and measurement of skin allograft rejection rates were followed. Early in life, restricted mice appear immunosuppressed, as judged by all these parameters. Skin allograft rejection remained suppressed until relatively late in life. Other responses tended to reverse from the earlier pattern; by mid-life restricted mice responded better than controls. Dietary restriction profoundly affects the immune system. Mice on such regimes display anatomic and certain immune functional changes which suggest that the immune system may mature less rapidly and stay "younger" longer than in the controls. Furthermore, dietary restriction results in prolongation of life span.