Minor histocompatibility antigens

The existence of transplantation antigens, in addition to those encoded by genes in the MHC, has been known for over half a century. The molecular identification of these additional minor histocompatibility (H) antigens lagged behind that of their MHC counterparts, largely because minor H antigens are recognised by T cells and not by antibodies. In the past year, however, new minor H antigens have been identified at both the genetic and protein level and include Uty, a second novel gene encoding a male-specific epitope in mice, a novel autosomal gene encoding each of the H-13 alleles of mice, and a second male-specific epitope encoded by the SMCY gene.     

HA-1 and the SMCY-derived peptide FIDSYICQV (H-Y) are immunodominant minor histocompatibility antigens after bone marrow transplantation

BACKGROUND: Allogeneic bone marrow donors can be incompatible at different levels. Even HLA-identical pairs will be still incompatible for numerous minor histocompatibility antigens (mHag). Nevertheless, some incompatibilities are found to be associated with an increased risk of graft-versus-host disease (GVHD), which could be related to the way the immune system recognizes these antigens. METHODS: We determined the specificity of cytotoxic T-cell clones isolated during acute GVHD or during bone marrow graft rejection in patients (n=14) transplanted with marrow from donors who were histoincompatible for different minor and/or major histocompatibility antigens. RESULTS: We found a clear hierarchy among the different types of histoincompatibilities. In three combinations mismatched for a class I allele, all 27 clones isolated during GVHD were specific for the incompatible HLA molecule. In the 11 class I-identical combinations, 14 different mHags were recognized. The mHag HA-1, known to have a significant impact on the development of GVHD, was recognized in the two HA-1-incompatible combinations. In one of these combinations, which was sex mismatched, all 56 clones analyzed were directed against HA-1, demonstrating the dominance of this mHag. In the four HA-1-compatible, sex-mismatched combinations, the anti-H-Y response was directed against one immunodominant epitope rather than against multiple Y-chromosome-encoded epitopes. All male specific cytotoxic T lymphocytes (n=15) recognized the same high-performance liquid chromatography-purified peptide fraction presented by T2 cells. Moreover, all cytotoxic T lymphocytes tested (n=6) were specific for the SMCY-derived peptide FIDSYICQV, originally described as being the H-Y epitope recognized in the context of HLA-A*0201. CONCLUSIONS: Some histocompatibility antigens are recognized in an immunodominant fashion and will therefore be recognized in the majority of mismatched combinations. Only for such antigens, correlations between mismatches and the occurrence of GVHD or graft rejections will be found.     

Reimmunization after allogeneic bone marrow transplantation

BACKGROUND/AIMS: Patients with cirrhosis and ascites show high plasma concentrations of endothelin. The aim of the current study was to investigate whether this feature is a compensatory response to effective hypovolemia or a consequence of systemic endotoxemia. METHODS: Protocols 1 and 2 assess the effect of acute changes in effective blood volume on plasma endothelin, and protocol 3 investigates the relationship between plasma endotoxin and endothelin in patients with cirrhosis and ascites. Protocol 1 included nine healthy subjects and 26 patients with cirrhosis studied during supine rest, upright tilt (which decreases effective blood volume) and cycloergometric exercise (which activates vasoactive systems by a baroreceptor independent mechanism). Protocol 2 included six patients studied before and 1 and 3 h after the intravenous administration of a plasma expander. In protocol 3, the plasma levels of endothelin and endotoxin were measured in 17 non-infected patients with cirrhosis and also in four patients with spontaneous bacterial peritonitis at diagnosis and following resolution of infection. RESULTS: Plasma endothelin was 3-5 times higher in patients with cirrhosis than in healthy volunteers. In healthy subjects, upright tilt and exercise were associated with a significant activation of the renin-aldosterone and sympathetic nervous systems and an increase in plasma endothelin. In patients with cirrhosis, upright tilt and exercise were associated with a significant increase and plasma volume expansion with a marked suppression of the renin-aldosterone and sympathetic nervous systems. However, in these patients none of these maneuvers affected plasma endothelin levels. In the patients with cirrhosis in protocol 3, there was no correlation between plasma endotoxin and endothelin. Resolution of peritonitis was associated with a marked fall in plasma endotoxin and no changes in plasma endothelin. CONCLUSIONS: These findings suggest that mechanisms other than effective hypovolemia or systemic endotoxemia are involved in the increased plasma endothelin of cirrhosis with ascites.     

Femoral head osteonecrosis after bone marrow transplantation

Thirty-five patients with bilateral osteonecrosis of the femoral head after bone marrow transplantation were reviewed retrospectively. The median age at the time of transplantation was 26 years. The first symptoms occurred within 2 years of transplantation. At presentation, 18 of the patients reported pain in both hips, 17 had symmetric radiographic lesions, and 39 of the hips had collapsed. Medical treatment was indicated initially. At the final examination before surgery (median, 3.5 years), 31 patients had bilateral hip pain, 22 patients had symmetric radiographic lesions, and 56 of the hips had collapsed. Fifty-seven of the hips required surgery, including one open drainage, four core decompressions, six cup arthroplasties, and 46 primary total hip replacements. Six hips (four core decompressions; two cups) later underwent total hip replacement revision, and a deep infection developed in one. By considering the requirement of a total hip replacement as a failure of conservative treatment, the rate of survival of the femoral head was 30% 5 years after the transplant. There was no significant difference between the Ficat grades, except for Grade 0, which showed a higher survival rate. The study of the specific features of the osteonecrosis may lead to the recommendation of primary total hip arthroplasty after failure of the medical treatment.     

Antithymocyte globulin as conditioning regimen for bone marrow transplantation

Bone marrow transplantation was performed with a conditioning regimen including antithymocyte globulin (ATG) for 8 patients with HLA-compatible unrelated donors or HLA mismatched donor. Administration of ATG was halted due to side effects in only 1 case, but the other cases were had no adverse reaction. During administration of ATG, platelet counts did not decrease rapidly, but platelet infusion was not effective in some cases. As compared between patients with conventional allogeneic BMT, autologous BMT or peripheral blood stem cell transplantation and those with ATG administration, no obvious difference was seen between the two groups in lymphocyte counts, CD3, CD4, CD8 and CD20 positive cells. No patient with ATG saffered graft failure or acute GVHD. However, cytomegalovirus infection was observed more frequently than in patients without ATG. In hematological malignancy, relapse was more frequent than in patients without ATG.     

Donor leukocyte transfusion as treatment for relapsed chronic myelogenous leukemia after allogeneic bone marrow transplantation

We reviewed 4 cases of high-grade transitional-cell carcinoma (TCC) of the urinary tract with solitary pulmonary metastases that were studied by transthoracic needle aspiration biopsy cytology. There were two grade II and two grade III TCCs. The two grade II tumors yielded, in needle aspirates, syncytial tumor-cell clusters showing ill-defined, granular cytoplasm and slightly pleomorphic nuclei with inconspicuous nucleoli. In one case the tumor-cell cluster showed a focal acinar arrangement, mimicking cells of an adenocarcinoma. In both cases the electron microscopy (EM) study of aspirated tumor cells revealed epithelial cells with well-formed cell junctions, intracytoplasmic vesicles, apical short microvilli, and focal interdigitation of lateral cell membranes, suggesting a urothelial neoplasm. The two grade III TCCs yielded, in needle aspirates, pleomorphic malignant cells singly and in small clusters, showing well-defined, granular cytoplasm and pleomorphic nuclei containing prominent nucleoli, suggesting a poorly differentiated adenocarcinoma or an anaplastic large-cell carcinoma. By EM examination the aspirated tumor cells from one case revealed well-formed cell junctions, intracytoplasmic vesicles, poorly formed microvilli, and focal interdigitation of lateral cell membranes, suggesting a urothelial differentiation. In the other case the tumor cells were pleomorphic cells with occasional cell junctions and no ultrastructural features as seen in the other 3 cases of TCC. The tumor cells from the two grade II TCCs showed strong immunopositive reaction with keratin 7 antibody and weakly positive reaction with carcinoembryonic antigen antibody (CEAA), while those of the two grade III TCCs displayed only a weak and focal immunopositive staining with keratin 7 antibody and strong reaction with CEAA.     

Chronic progressive radiation myelopathy after bone marrow transplantation

CAPL is a cancer-related gene shown to be overexpressed during tumor metastasis formation. A CAPL antisense oligodeoxynucleotide (ODN), GX-1, and a random control ODN (CTRL1) were 3'-conjugated to MAG3, labeled with technetium-99m, purified, and the biodistribution of the radiolabeled conjugates in normal mice was studied. A 99mTc-MAG3-GX-1 complex of >97% radiochemical purity was obtained and the product was stable for >6 h as determined by reversed phase high performance liquid chromatography (HPLC). Biodistribution studies of the 99mTc-MAG3-ODNs in groups of four normal mice, sacrificed 5 min and 60 min after injection, demonstrated that the radiolabeled ODNs were distributed in an unspecific manner. The excretion route was mainly urinary. At 60 min, 55.2% of the injected dose of 99mTc-MAG3-GX-1 and 72.4% of 99mTc-MAG3-CTRL1 was found in the urine. This finding is clearly different from previously reported data on tritiated 20-mer phosphodiester ODNs, as well as the unconjugated 99mTc-MAG3 chelate, suggesting that 99mTc-MAG3 coupled to the 3'-end of ODNs has an influence on the biodistribution of the oligo, and possibly has a protective function to enzymatic degradation in vivo.     

Cytokine gene expression after allogeneic bone marrow transplantation

Cytokines produced by T lymphocytes, monocytes/macrophages, and fibroblasts play a central role in the immune response and in the development of graft-versus-host disease (GVHD). Also, it has been reported that dysregulated production of cytokines maybe the primary mediator of clinical manifestation of acute GVHD. Regarding cytokine gene expression after human allogeneic bone marrow transplantation (allo BMT), we have demonstrated increased IL-1 beta, IL-6, and TNF-alpha mRNA expression in peripheral blood mononuclear cells during the development of acute and chronic GVHD and that the degree of the increase was dependent on the severity of the disease. Furthermore, overexpression of these cytokine mRNAs could be detected before the clinical manifestations of GVHD developed. In contrast, IL-2 mRNA expression was not detected in peripheral blood mononuclear cells in GVHD patients. On the other hand, we have reported that increased mRNA expression and protein product of IL-2 and IFN-gamma were evident in the mixed lymphocyte culture of the cases who developed severe lethal transplantation-related complications. Therefore, the detection of increased IL-2 and IFN-gamma gene expression in MLC appeared to be useful for predicting transplantation-related complications in BMT patients. Furthermore, we found increased IL-2 receptor alpha subunit mRNA expression in the peripheral blood mononuclear cells during GVHD. These findings may indicate the important role of inflammatory cytokines such as IL-1 beta, IL-6 and TNF-alpha in the development of the clinical manifestation of GVHD and also may be indicative of the important role of IL-2 and the IL-2 receptor in allo response perhaps mainly as an autocrine effect.(ABSTRACT TRUNCATED AT 250 WORDS)     

Multiple autoimmune events after autologous bone marrow transplantation

A 36-year-old woman with RAEB-t and severe bone marrow fibrosis undergoing autologous BMT, developed a histologically documented GVHD-like skin rash. Thereafter, autoimmune thyroiditis, autoimmune thrombocytopenic purpura and autoimmune hemolytic anemia and a lupus anti-coagulant (LAC) were diagnosed. The patient is still alive, symptom-free and in first complete remission (CR); however, all of the autoantibodies are still detectable, with the exception being the anti-erythrocyte antibody. The most outstanding feature of the present case is the polymorphism of the autoimmune events, in the absence of a coexisting systemic autoimmune disease. This patient has achieved long-term disease-free survival (DFS) in first CR despite high-risk MDS and the repeated immunosuppressant therapy required because of the complications described above; a GVL reaction somewhat similar to the autoimmune events may have contributed towards maintaining disease control.     

Varicella vaccination in children after bone marrow transplantation

Herpes zoster (HZ) is one of the most common complications after bone marrow transplantation (BMT) in children. Apart from treatment with antiviral drugs, effective prevention by active immunization with varicella-zoster virus (VZV) appears to be possible. In this study 15 patients were vaccinated with a live attenuated VZV vaccine (Varilrix) 12-23 months after BMT. The vaccine was well tolerated without adverse reactions. Chickenpox or HZ were not observed for up to 2 years after immunization. Eight out of nine seronegative patients seroconverted and in six virus-specific IgG could still be demonstrated 2 years later. The incidence of VZV diseases in 133 non-immunized children after BMT was 26.3%. Infections usually occurred within 18 months after BMT.     

Phimosis as a manifestation of chronic graft-versus-host disease after allogeneic bone marrow transplantation

Chronic GVHD is one of the major complications of BMT, involving a variety of organs, but rarely involving the genitourinary system. We report a patient who simultaneously developed extensive chronic GVHD and phimosis after BMT. From the clinical course and pathological findings, chronic GVHD was considered to be responsible for the phimosis. Despite intensive immunosuppressive therapy, the phimosis persisted. Phimosis is a rare complication after BMT, which may often remain neglected. Possibility of this complication should be considered in patients with chronic GVHD.     

Reconstitution of the T-cell compartment after bone marrow transplantation: restoration of the repertoire by thymic emigrants

We have studied the reconstitution of the T-cell compartment after bone marrow transplantation (BMT) in five patients who received a graft-versus-host disease (GVHD) prophylaxis consisting of methotrexate, cyclosporin, and 10 daily injections (day -4 to day +5) of Campath-1G. This treatment eliminated virtually all T cells (7 +/- 8 T cells/microL at day 14) which facilitated the analysis of the thymus-dependent and independent pathways of T-cell regeneration. During the first 6 months, the peripheral T-cell pool was repopulated exclusively through expansion of residual T cells with all CD4(+) T cells expressing the CD45RO-memory marker. In two patients, the expansion was extensive and within 2 months, the total number of T cells (CD8>CD4) exceeded 1,000/microL. In the other three patients, T cells remained low (87 +/- 64 T cells/microL at 6 months) and remained below normal values during the 2 years of the study. In all patients, the first CD4(+)CD45RA+RO- T cells appeared after 6 months and accumulated thereafter. In the youngest patient (age 13), the increase was relatively fast and naive CD4(+) T cells reached normal levels (600 T cells/microL) 1 year later. In the four adult patients (age 25 +/- 5), the levels reached at that time-point were significantly lower (71 +/- 50 T cells/microL). In all patients, the T-cell repertoire that had been very limited, diversified with the advent of the CD4(+)CD45RA+RO- T cells. Cell sorting experiments showed that this could be attributed to the complexity of the T-cell repertoire of the CD4(+)CD45RA+RO- T cells that was comparable to that of a normal individual and that, therefore, it is likely that these cells are thymic emigrants. We conclude that after BMT, the thymus is essential for the restoration of the T-cell repertoire. Because the thymic activity is restored with a lag time of approximately 6 months, this might explain why, in particular in recipients of a T-cell-depleted graft, immune recovery is delayed.     

Donor helper T-cell frequencies as predictors of acute graft-versus-host disease in bone marrow transplantation between HLA-identical siblings

BACKGROUND: Despite the current level of sophistication of molecular typing for class I and class II alleles, a significant proportion (20-40%) of recipients of HLA-identical sibling marrow develop severe, acute graft-versus-host disease (GVHD) after bone marrow transplantation. It has been suggested that the frequency of patient-specific helper T lymphocyte precursors (HTLp) detected in the HLA-identical sibling donor correlates with the incidence and severity of acute GVHD after transplantation. METHODS: This study group consisted of 42 patients who all received bone marrow from HLA-identical sibling donors from January 1990 to December 1996. Using a limiting dilution analysis, donor HTLp frequencies were determined on samples collected before transplantation. The HTLp assay used the cytotoxic T-cell line, CTLL-2, which proliferates in the presence of interleukin-2. The reliability and reproducibility of this assay was established by using cryopreserved batches of CTLL-2 cells of known sensitivity. RESULTS: The recipient-directed HTLp frequencies detected in the donor before transplantation were correlated with the incidence and severity of acute GVHD experienced by the recipient after transplantation. Statistical analysis revealed an extremely significant correlation between donor precursor frequencies and the development of acute GVHD in the patient after transplantation (P<0.0001). CONCLUSIONS: This study suggests that together with molecular typing the HTLp frequency should be considered when selecting the most suitable sibling donor for bone marrow transplantation.     

Filgrastim for the treatment of leukemia relapse after bone marrow transplantation

The absence of an effective therapy for most patients with leukemia who relapse after allogeneic BMT has generated interest in new strategies. We present our experience on the use of filgrastim 5 micrograms/kg/day s.c., in four patients with leukemia (three with AML and one with CLL) who relapsed after allogeneic transplantation. One patient with AML achieved CR after 55 days of treatment. No response was observed in the remaining three. The patient who responded developed extensive chronic GVHD but relapsed 10 months later. In one of the unresponsive patients a dramatic increase in bone marrow infiltration and WBC count followed administration of filgrastim. We conclude that filgrastim can occasionally induce CR in leukemic patients who relapse after BMT.     

Hypercalcemia as the first manifestation of bone marrow T-cell lymphoma

The authors describe the case of a 20-year-old patient where the first leading symptom was hypercalcaemia. A similar case was not published so far in the Czech literature. The disease took a fulminant course and proved fatal nine days after the first symptoms of the disease. The correct diagnosis was established only by necropsy. The adverse course of the disease could not be influenced by repeated haemodialysis nor by the administration of disodium pamidronate (Aredia) and calcitonin. The authors discuss differential diagnostic problems of hypercalcaemias and the pathogenesis of hypercalcaemia in malignant diseases of the haematopoietic system.