Low-Dose Heparin and Deep-Vein Thrombosis after Total Hip Replacement

The effect of subcutaneous low-dose heparin on postoperative deep-vein thrombosis (D. V. T.) (diagnosed by the 125I-labelled fibrinogen test) has been investigated in a trial of 143 patients undergoing the operation of total hip replacement. Two randomized studies were carried out: in one the scanning for D.V.T. was carried out daily for 7 days post operatively and in the other for 15 days. In both, the incidence of D.V.T. was significantly lower in the heparin-treated patients (P<0.005). Bilateral D.V.T. was also prevented (P<0.05), through the extension of D.V.T. to the distal veins of the thigh was not significantly reduced. Heparin treatment was, however, followed by a higher incidence of severe postoperative bleeding (P< 0.02) and wound haematoma formation (P< 0.005), and the postoperative haemoglobin was significantly lower than in the control group (P<0.005). A higher number of transfused blood units was also needed by the heparin treated patients (P<0.001).

Pre- and posttransplant monitoring of alloantibodies by complement-dependent cytotoxicity and luminex methodologies in liver transplantation

BACKGROUND

This study evaluated the influence of circulating anti-HLA antibodies on outcomes of 97 liver allografts from deceased donors.

METHODS

Human leukocyte antigen (HLA) antibody screening was performed by both complement-dependent cytotoxicity (CDC) and multiparameter Luminex microsphere-based assays (Luminex assay).

RESULTS

The agreements between T- and B- cell CDC and Luminex assays were 67% and 77% for pre- and posttransplant specimens, respectively. Graft dysfunction was not associated with either positive pretransplant CDC or Luminex panel-reactive antibody (PRA) values. Likewise, positive posttransplant T- or B- cell CDC PRA values were not associated with graft dysfunction. In contrast, posttransplant Luminex PRA values were significantly higher among patients with graft dysfunction compared with subjects with good outcomes (P = .017).

CONCLUSION

Posttransplant monitoring of HLA antibodies with Luminex methodology allowed identification of patients at high-risk for poor graft outcomes.

Microchimerism does not correlate with survival of murine cardiac allografts

The development of microchimerism was evaluated at different time points after infusion of a mixed population of bone marrow and spleen cells from (BALB/c x C57Bl/6)F1 mice in the presence or absence of a cardiac transplant. Microchimerism was observed in the spleen, bone marrow and thymus of transplanted BALB/c mice even after graft rejection. In the absence of transplantation, donor cells persisted especially in the thymus. The results show that despite augmentation of graft survival after donor cell infusion compared to nontreated controls, the development of microchimerism did not sustain cardiac semihistocompatible grafts. Moreover, the persistence of donor cells in the thymus in both situations suggests a role for this organ in the increased graft survival in our model.

Antibodies eluted from acutely rejected renal allografts bind to and activate human endothelial cells

This study was designed to investigate how antiendothelial antibodies (EAbs) are involved in acute irreversible renal graft rejection. Eluates from 25 renal allografts, lost by irreversible rejection (n = 22) and by renal vein thrombosis (controls n = 3), were tested against a panel of cultured human umbilical vein endothelial cells (HUVEC). All patients were under immunosuppression at the time of nephrectomy. EAbs binding and membrane expression of adhesion molecules ELAM-1 and VCAM-1 were analyzed by flow cytometry (FACS) and by semiquantitative RT-PCR for mRNAs coding for those molecules. The absence of anti-HLA antibodies against the donor was ascertained at transplant, and before and after nephrectomy by the negativity of specific crossmatches performed using the most sensitive techniques. EAbs eluted from eight rejected kidneys bound to HUVEC. They did not induce any cytotoxicity, but their incubation with HUVEC (4 h at 37 degrees C; 2.5 mg/ml) led to upregulation of mRNAs coding for VCAM-1 (35- to 60-fold increases) and ICAM-1 (8- to 12-fold increases) as compared with control EAbs. Membrane expression of adhesion molecules was also strikingly increased, with 80% of the cells expressing VCAM-1 and 65% expressing ELAM-1 upon incubation. EAbs were detected in eight out of nine (88.8%) eluates from kidneys lost from acute vascular rejection, but in none of the 13 (0.0%) kidneys lost from other types of rejection (p < 0.0001). We conclude that EAbs, capable of activating human endothelial cells, can be recovered from acutely rejected kidneys and may play a direct role in the pathogenesis of acute rejection.

Cytomegalovirus infection amplifies class I major histocompatibility complex expression on cultured human endothelial cells

Cytomegalovirus infection, a common complication in immunosuppressed graft recipients, bears an adverse impact on graft survival. Cytomegalovirus enhances the expression of the monotypic determinants of the class I major histocompatibility complex molecule by the endothelium, possibly rendering the endothelial cells more immunogenic and prone to attack by the allogeneic lymphocytes. In the present study, we focused on the effect of cytomegalovirus on the endothelial cell expression of different class I genes, on the relation between the extent of endothelial cell infection and the class I effect, and on the time course of the class I changes induced by the cytomegalovirus infection. Cytomegalovirus infection of primary cultures of human umbilical vein endothelial cells augmented the expression of the A2, A3, and B7 class I major histocompatibility complex genes when compared with uninfected cells. beta 2 microglobulin upregulation by the infected cells paralleled the changes in specific class I expression; this effect was significant only after 7 days after infection. Double immunocytochemical staining and fluorescence-activated cell sorter analysis revealed that the class I enhancement was uniform throughout the umbilical vein endothelial cell monolayer and not restricted to the cells that expressed cytomegalovirus early or late antigens. Ultraviolet-inactivated supernatants from infected umbilical vein endothelial cell did not increase class I expression on uninfected cells. In conclusion, cytomegalovirus might affect graft survival by amplifying the changes in class I expression beyond the sites of viral replication.

HLA typing in 67 Italian patients with idiopathic hemochromatosis and their relatives

The frequency of HLA A3 and B7 antigens was significantly higher in 67 unrelated patients with idiopathic hemochromatosis (IH) than in 700 controls (62.7% vs 22.5%, p less than 10(-8) and 26.9% vs 9.3%, p less than 10(-3), respectively). A3 B7, A3 B35 and A3 B5 were significantly more frequent in 72 haplotypes linked to IH gene than in 278 control haplotypes. The prevalence of B35 and A3 B35 was significantly higher in IH patients from North-Eastern Italy than from other regions (60% vs 21%, p less than .05 and 54.5% vs 8.2%, p less than 0.0001, respectively). All 15 siblings HLA identical to the respective proband were homozygous for IH with variable expression of the disease, whereas minor abnormalities of iron-related indexes were present in 23% of heterozygous relatives. Homozygous-heterozygous mating probably occurred in three of 40 families, accounting for the overt disease in three offspring and in one HLA semi-identical sibling; however, in this last case the possibility of a recombination event cannot be excluded.

Association of hereditary spherocytosis and idiopathic hemochromatosis. A synergistic effect in determining iron overload

Two siblings, both splenectomized at an early age for hereditary spherocytosis, had a severe hemochromatosis develop. The human leukocyte antigen (HLA) system typing showed that they were half HLA identical. All the other members of the family who did not have evidence of hereditary spherocytosis, including those who displayed identical HLA haplotypes with the two patients, did not have any increase in iron stores. These results suggest that the two siblings are heterozygous for idiopathic hemochromatosis and that the coexistence of this condition with hereditary spherocytosis can cause a severe iron overload.

Low-dose heparin and deep-vein thrombosis after total hip replacement

The effect of subcutaneous low-dose heparin on postoperative deep-vein thrombosis (D.V.T.) (diagnosed by the 125I-labelled fibrinogen test) has been investigated in a trial of 143 patients undergoing the operation of total hip replacement. Two randomized studies were carried out: in one the scanning for D.V.T. was carried out daily for 7 days postoperatively andin the other for 15 days. In both, the incidence of D.V.T. was significantly lower in the heparin-treated patients (P less than 0.005). Bilateral D.V.T. was also prevented (P less than 0.05), through the extension of D.V.T. to the distal veins of the thigh was not significantly reduced. Heparin treatment was, however, followed by a higher incidence of severe postoperative bleeding (P less than 0.02) and wound haematoma formation (P less than 0.005), and the postoperative haemoglobin was significantly lower than in the control group (P less than 0.005). A higher number of transfused blood units was also needed by the heparin treated patients (P less than 0.001).