A mobile telehealth program for behavioral treatment of urinary incontinence in women veterans: Development and pilot evaluation of MyHealtheBladder

AIM

To develop and pilot test an interactive mobile telehealth program (mHealth) for behavioral treatment of women veterans with urinary incontinence (UI).

METHODS

We developed an evidence-based 8-week behavioral mHealth program, MyHealtheBladder, with input from women veterans, behavioral medicine and health education experts, and clinical providers treating UI in the VA system. The program was story-based and included pelvic floor muscle exercises, bladder control strategies, fluid management, risk factor reduction, and self-monitoring. Participants were women veterans seeking outpatient treatment for UI occurring at least twice weekly. The primary efficacy estimate was the change in UI frequency, volume and impact on the quality of life as measured by the validated International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF; range: 0-21, 2.5 points for minimal clinically important difference [MCID]).

RESULTS

We enrolled 29 women veterans (ages 29-77 years; mean = 54.4 ± 10.4), including 15 (52%) African-American women, 13 (45%) women with high school education, and 16 (55%) with a college degree. Twenty of 29 women (69%) completed all 8 weeks of the intervention with a 97% adherence rate to the daily sessions among completers. We found reductions in ICIQ-SF scores from a mean 12.6 ± 3.9 at baseline to 10.4 ± 4.11 at 5 weeks, to 8.7 ± 4.0 at the end of the 8-week intervention.

CONCLUSIONS

Women veterans using an 8-week behavioral mHealth program for the treatment of UI had symptom improvements that exceeded the MCID for the ICIQ-SF. Our next step involves comparing the effectiveness of MyHealtheBladder to usual care in a larger clinical trial.

Simultaneous measurement of the HT and DT fusion burn histories in inertial fusion implosions

Measuring the thermonuclear burn history is an important way to diagnose inertial fusion implosions. Using the gas Cherenkov detectors at the OMEGA laser facility, we measure the HT fusion burn in a H₂+T₂ gas-fueled implosion for the first time. Using multiple detectors with varied Cherenkov thresholds, we demonstrate a technique for simultaneously measuring both the HT and DT burn histories from an implosion where the total reaction yields are comparable. This new technique will be used to study material mixing and kinetic phenomena in implosions.

Using Inertial Fusion Implosions to Measure the T+^{3}He Fusion Cross Section at Nucleosynthesis-Relevant Energies

Light nuclei were created during big-bang nucleosynthesis (BBN). Standard BBN theory, using rates inferred from accelerator-beam data, cannot explain high levels of ^{6}Li in low-metallicity stars. Using high-energy-density plasmas we measure the T(^{3}He,γ)^{6}Li reaction rate, a candidate for anomalously high ^{6}Li production; we find that the rate is too low to explain the observations, and different than values used in common BBN models. This is the first data directly relevant to BBN, and also the first use of laboratory plasmas, at comparable conditions to astrophysical systems, to address a problem in nuclear astrophysics.

A pilot study of combination anti-cytokine and anti-lymphocyte biological therapy in rheumatoid arthritis

BACKGROUND

Immunological tolerance in humans using anti-T-cell monoclonal antibodies (mAbs) may be hampered by a pro-inflammatory microenvironment. All clinical trials of such therapies in rheumatoid arthritis (RA), however, have selected patients with active disease at baseline. Concurrent neutralization of inflammation with a TNFalpha antagonist should maximize the potential of anti-T-cell mAbs to induce tolerance in RA.

AIM

To evaluate the safety of combining a TNFalpha antagonist and CD4 mAb in RA.

DESIGN

An iterative pilot study focused on the safety of such combination therapy.

METHODS

Eight poor prognosis, seropositive RA patients were treated with combined CD4 and TNFalpha blockade. Prolonged CD4 blockade was achieved with a humanized mAb, and TNFalpha blockade with a p55 TNF receptor fusion protein.

RESULTS

There was a low incidence of classical first-dose reactions to the CD4 mAb, possibly reflecting concomitant TNFalpha blockade. An unusual anaphylactoid reaction was seen, however, and one patient developed a probable allergic reaction after several infusions. Skin rashes were common, as previously reported with CD4 mAb monotherapy. No serious infections were documented during follow-up, despite CD4+ lymphopenia in some patients. Most patients appeared to demonstrate improved RA disease control after the study. After 17-49 months after therapy, one patient was in remission, one remained off disease modifying anti-rheumatic drugs and five had stable disease, three on previously ineffective doses of methotrexate.

CONCLUSION

We report, for the first time in man, immunotherapy with a combination of an anti-cytokine and an anti-T-cell reagent. We witnessed an unusual first-dose reaction but there were no significant infectious complications.

High nitrogen during growth reduced glucoraphanin and flavonol content in broccoli (Brassica oleracea var. italica) heads

Broccoli (Brassica oleracea var. italica) heads are commonly consumed in the Western diet and frequent consumption is thought to help protect against certain cancers and cardiovascular disease. Broccoli heads contain relatively high levels of glucosinolates and flavonols, thought to be the key phytochemicals that contribute to the health benefits gained upon consumption. In this study, we investigated the effect of applied nitrogen (N) at either 0, 15, 30 or 60 kg/ha, or 30, 60, 90 or 150 kg/ha with applied sulfur (S) at 50 or 100 kg/ha on the glucosinolates glucoraphanin, glucobrassicin and progoitrin, and the flavonols quercetin and kaempferol in broccoli cv. Marathon florets. Trials were conducted in two sites in either heavy clay or sandy loam to also assess the effect of soil type on phytochemical content. Application rates were based around recommended N and S applications for this crop in south-east Australia. N applications over 30 kg/ha caused a decrease in the content of glucoraphanin (18–34%) and both flavonols (20–38%). Progoitrin content was not affected while glucobrassicin increased by up to 44% with N applications >30 kg/ha. S applications of 50 or 100 kg/ha had no significant effect on either glucosinolates or flavonols. Crop yield (fresh weight), however, was significantly depressed (up to 40%) by N applications below 60 kg/ha. Fresh weight was also significantly depressed in plants grown in heavy clay compared with plants grown in a sandy loam, and phytochemical content increased, possibly due to a concentration effect. Therefore, low N applications to optimise phytochemicals may be only commercially useful if growers are producing mini-broccoli heads, as levels required to optimise phytochemical content (<30 kg/ha) also caused a significant decline in yield.

Mechanisms of Antibody Immunotherapy on Clonal Islet Reactive T Cells

Clinical intervention trials evaluating the efficacy of antibody immunotherapy in type 1 diabetes are in progress. We tested effects on prediabetic islet antigen-specific autoreactive T cells of antithymocyte globulin (ATG) and humanized monoclonal antibodies against CD3 (ChAglyCD3) or CD25 (daclizumab) with regard to downmodulation of the target protein, proliferation, cytokine production, complement-dependent cytotoxicity (CDC), antibody-dependent cell cytotoxicity (ADCC), and survival. ATG leads to depletion of autoreactive CD4+ T cells by ADCC, CDC, and apoptosis, whereas anti-CD3 and anti-CD25 inhibited T-cell autoreactivity in a nondepleting fashion. ATG treatment led to a cytokine burst of Th1- and Th2-associated cytokines. Modulation of cytokine release through humanized monoclonal antibodies was moderate and selective: anti-CD25 led to increased release of IL-2 and reduced production of TNFalpha, whereas anti-CD3 decreased release of interferon-y and IL-5 and increased secretion of IL-10. ATG and the humanized monoclonal antibodies displayed contrasting mechanisms of action.

Different glycoforms of the human GPI-anchored antigen CD52 associate differently with lipid microdomains in leukocytes and sperm membranes

CD52 is a human GPI-anchored antigen, expressed exclusively in the immune system and part of the reproductive system (epididymal cells). Sperm cells acquire the antigen from the epididymal secretions when transiting in the epididymal corpus and cauda. The peptide backbone of CD52, consisting of only 12 aminoacids, is generally considered no more than a scaffold for post-translational modifications, such as GPI-anchor and especially N-glycosylation which occur at the third asparagine. The latter modification is highly heterogeneous, especially in the reproductive system, giving rise to many different glycoforms, some of which are tissue specific. A peculiar O-glycan-containing glycoform is also found in reproductive and immune systems. We determined to locate CD52 in microdomains of leukocytes and sperm membranes using two antibodies: (1) CAMPATH-1G, the epitope of which includes the last three aminoacids and part of the GPI-anchor of glycoforms present in leukocytes and sperm cells; (2) anti-gp20, the epitope of which belongs to the unique O-glycan-bearing glycoform also present in both cell types. Using a Brij 98 solubilization protocol and sucrose gradient partition we demonstrated that the CD52 glycoforms recognized by both antibodies are markers of typical raft microdomains in leukocytes, whereas in capacitated sperm the O-glycoform is included in GM3-rich microdomains different from the cholesterol and GM1-rich lipid rafts with which CAMPATH antigen is stably associated. The importance of the association between GM3 and O-glycans for formation of specialized microdomains was confirmed by heterologous CD52 insertion experiments. When prostasomes from human seminal fluid were incubated with rat sperm from different epididymal regions, the CD52 glycoform recognized by anti-gp20 decorated rat epididymal corpus and cauda sperm, associated with the same low-cholesterol GM3-rich sperm membrane fractions as in human sperm. The glycoforms recognized by CAMPATH-1G were not found in rat sperm. The relationship between this differential insertion and differences in glycosylation of rat and human CD52 is discussed.

Myeloablative conditioning is well tolerated by older patients receiving T-cell-depleted grafts

Older age has been linked to increased transplant-related mortality from graft-versus-host disease (GvHD). Depletion of T cells from stem cell grafts seems to protect from complications of GvHD particularly in older patients. After myeloablative conditioning, patients with haematological malignancies received allogeneic grafts from HLA identical siblings. For GvHD prophylaxis, PBPC grafts were treated ex vivo with anti-CD52, and therapeutic doses of cyclosporin until day +90. Survival of patients younger or older than the population age median was analysed. In all, 62 consecutive patients with a median age of 42.5 years were studied. Death was procedure related in 17% and from relapse of malignancy in five. At a median, follow-up is 662 (7-2316) days, 74% survive disease free. The rate of haematopoietic recovery and treatment-related mortality was similar in both groups. A total of 73% of 30 individuals in the younger group and 75% (P=0.8) in the older cohort survive at a median follow-up of 444 and 806 days (P=0.4). GvHD occurred in 13% and was the only adverse factor for survival (P<0.04). Myeloablative conditioning is well tolerated up to the age of 59 in patients receiving T-cell-depleted grafts. This information is useful to more precisely select patients who would benefit most from reduced intensity conditioning schedules.

Epitope analysis of immunoglobulins against gp20, a GPI-anchored protein of the human sperm surface homologous to leukocyte antigen CD52

Gp20 is a sialylglycoprotein of the human sperm surface related to maturation and capacitation and is homologous to CD52, a glycosyl- phosphatidyl-inositol (GPI)-anchored protein highly expressed in lymphocytes, monocytes, eosinophils, and epididymal cells, described by the monoclonal antibody family CAMPATH. The CAMPATH antigen is characterized by a very short peptide (12 amino acids) and an N-linked oligosaccharide chain bound to the asparagine located in the third position and a GPI anchor bound to the C-terminal serine. The CAMPATH epitope includes three amino acids at the C-terminus and part of the GPI anchor. It has been suggested that anti-gp20 interacts with the same peptide recognized by CAMPATH antibodies but with a different epitope, since it describes the corresponding antigen in a different way. For example, it localizes the corresponding antigen in the equatorial region of the sperm head when sperm are capacitated, whereas CAMPATH antibodies bind all over the sperm surface. Our results indicate that the anti-gp20 epitope does not include the peptide backbone, the GPI anchor, or the N-glycans but consists of O-linked oligosaccharide chains bound to a unique CD52 glycoform present both in sperm and leukocytes. This is suggested by results obtained using many different approaches, such as immunoblot analysis of gp20 after removal of N- and O-glycans and after jacalin (Artocarpus integrifolia agglutinin)-affinity chromatography.

Encephalopathy in pediatric patients after allogeneic hematopoietic stem cell transplantation is associated with a poor prognosis

Encephalopathy is a poorly characterized complication of hematopoietic stem cell transplantation (HSCT). No comprehensive report of encephalopathy exists for children, and the literature contains only a few for adults. We analyzed a large cohort of 405 pediatric patients who underwent allogeneic HSCT during a 10-year period and identified 26 patients (6.4%) who experienced encephalopathy. Identifiable causes of encephalopathy included infection (n=5), single or multiorgan failure (n=4), medication-related complications (n=3), nonconvulsive seizures (n=4), acute disseminated encephalomyelitis (n=2), thrombotic thrombocytopenic purpura (n=2), and stroke (n=1). We were unable to identify the etiology of encephalopathy in five (19%) patients. The prognosis for pediatric patients with encephalopathy was poor: only four (15%) experienced complete neurologic recovery, and 10 (38%) patients experienced partial recovery with residual neurologic deficits. Nine (35%) patients with complete or partial recovery survive long term. A total of 17 patients died; one died of progressive encephalopathy, and 16 died of either relapse of primary disease or toxicity. MRI, CSF analysis including molecular testing for infectious pathogens, and brain biopsy were helpful in obtaining a diagnosis in most of our patients. However, a standardized approach to accurate and timely diagnosis and treatment is needed to improve outcome in these patients.

Design and manufacture of monoclonal antibodies for radioimmunotherapy

antibodies is fundamental to their use for radioimmunotherapy. Besides the right selection of antibody specificity and affinity, recombinant antibodies can be designed to simplify manufacture and minimise unwanted side effects. Although many innovative new technologies have been developed in recent years, antibodies are still most commonly produced from mammalian cells and purified by column chromatography. Purification methods have to be designed and validated to remove potential contaminants, especially retroviruses, which in principle might be present in mammalian cell lines. Adherence to relevant ''Good Manufacturing Practices'' is mandatory in the production of any medicinal product and there are numerous guidelines regarding the manufacture of antibodies. This article outlines some methods used for fermentation, purification and quality control of antibodies intended for radiolabelling.

Radiotherapy-based conditioning is effective immunosuppression for patients undergoing transplantation with T-cell depleted stem cell grafts for severe aplasia

BACKGROUND

We studied the outcome of individuals with aplastic anemia conditioned with a radiation-containing regimen followed by an infusion of stem cell grafts that had been depleted of lymphocytes with CAMPATH-1H (antiCD52; humanised).

METHODS

The conditioning regime consisted of fractionated (f) TBI 8 Gy followed by f total nodal irradiation (TNI) 6 Gy. In addition, patients received CY 60 mg/kg on 2 consecutive days. Cytokine-mobilized peripheral blood grafts from HLA-identical siblings were T-cell depleted with CAMPATH-1H 'in the bag'. CsA was commenced on day -1 and continued until day +90.

RESULTS

Seventeen heavily transfused patients with aplastic anemia, median age 18 years (range 14-56 years), were studied. The median time from diagnosis to transplantation was 172 days (range 34-443 days). The median CD34(+) cell number infused was 3.47 x 10(6)/kg (range 1.03-18.4 x 10(6)/kg). All patients engrafted. Recovery was fast and patients reached 0.5 x 10(9)/L polymorphs by median day 11 (range 9-17 days). Toxicity from the conditioning included grade 4 hematologic toxicity in all patients. Another major toxicity was gastrointestinal mucosal damage, which exceeded grade 2 in two instances. One patient developed thrombotic thrombocytopenic purpura, which responded to substitution of CsA with tacrolimus and plasmapheresis. Another patient, who had normal blood counts, died of infection on day 241. Chimerism studies at 6 months post-transplantation confirmed the donor origin of hematopoiesis in all seven patients tested. None of the patients developed acute or chronic GvHD. There was no delayed graft failure and 94% of patients had survived disease free at a median of 1303.5 days (range 216-2615 days) from graft infusion.

DISCUSSION

In this cohort of multiply transfused patients, the radiation-containing schedules described in this study led to universal engraftment with limited toxicity despite T-cell depletion. No patient developed GvHD or late graft failure. Lower doses of radiation-containing conditioning should be explored further.

Alemtuzumab (Campath-1H) in allogeneic stem cell transplantation: where do we go from here?

Alemtuzumab (Campath-1H) has been widely used for T-cell depletion following both conventional and reduced-intensity conditioning allografts. We studied the impact of alemtuzumab used in vivo and in vitro on infections, immune reconstitution, and allograft outcome. The use of alemtuzumab in vivo following reduced-intensity conditioning and unrelated donor conventional transplantation was associated with durable engraftment and significant reduction in graft-versus-host disease (GVHD) but at the cost of impaired immune reconstitution and increased infectious complications. Alemtuzumab exposure in vitro was associated with durable engraftment and reduced GVHD following conventional transplants without affecting immune recovery to the same extent. Improved results were obtained following a further reduction in the alemtuzumab dose in vitro from 20 mg to 10 mg. Subsequent pharmacokinetic studies on alemtuzumab demonstrated that the antibody persisted at a higher concentration at the time of transplant and for at least 2 months thereafter when used in vivo compared to persistence for less than 30 days when used at 20 mg in vitro. In this context; an antibody with a shorter half-life, like the original rat CD52 antibody Campath-1G, would be preferable. Otherwise, our cumulative experience with alemtuzumab suggests that better results might be achieved by tailoring the dose and mode of antibody use to match the clinical situation. Further studies are needed to optimize the dose of alemtuzumab in vivo and in vitro, determined by the type of conditioning and the graft.

Campath-1 Abs ‘in the bag’ for hematological malignancies: the Cape Town experience

BACKGROUND

We examined the strategy of T-cell depletion of HLA-identical sibling grafts for the prevention of GvHD, as well as disease control and overall survival.

PATIENTS AND METHODS

The myeloablative conditioning was radiation based. The source of stem cells was BM in 62, and cytokine-mobilized PBPC in 68 patients. GvHD prophylaxis was by ex vivo incubation of the stem-cell concentrates with Campath-1G (anti-CD52; n=76) or Campath-1H (n=54).

RESULTS

Patients receiving PBPC grafts were older (median 38.5) than those undergoing BMT (median 31; P=0.002). More patients in the PBPC group developed chronic GvHD (p<0.01). While no post-transplant GvHD prophylaxis was given to BMT recipients, prednisone 30 mg daily was prescribed to 12 and CYA for 90 days to a further 32 patients who had received PBPC grafts. Median follow-up was 1055 (range 28-4867) days. Although there was no difference in the survival between patients who received BMT or PBPC, death was from disease recurrence in 16 and nine (p=0.03; chi(2) test) subjects, respectively. Multivariate analysis showed that outcome was particularly favorable in those who were given<20 mg Campath-1 (survival: 28/39 versus 12/29; P=0.01), and in the subgroup of 30 patients who received Campath-1H and post-transplantation CYA.

DISCUSSION

In patients receiving BMT, Campath-1 Abs effectively prevent GvHD. For those treated with PBPC grafts, the combination of T-cell depletion and post-transplantation CYA is equally effective, without an obvious increase in disease recurrence.

Effective donor lymphohematopoietic reconstitution after haploidentical CD34+-selected hematopoietic stem cell transplantation in children with refractory severe aplastic anemia

Peritransplant toxicity and a delay in effective immune reconstitution have limited the utility of alternate donor transplantation for children with refractory severe aplastic anemia. We have assessed the effectiveness of infusing large numbers of highly purified haploidentical CD34+ cells after immunoablative conditioning in three patients who had failed intensive immunosuppression, lacked unrelated donors, and had active or recent serious infections. One patient rejected the first infusion, but engrafted after a second infusion from the same donor. This patient died 4 months after hematopoietic stem cell transplantation with no evidence of lymphoid reconstitution. Two patients experienced mixed chimerism requiring treatment with antibodies and/or donor lymphocyte infusion. Both currently survive more than 1 year after transplantation with normal blood counts, 100% donor engraftment, effective lymphoid reconstitution, and no chronic graft-versus-host disease. We observed functional thymopoiesis as measured by lymphocyte immunophenotyping, T cell receptor excision circles and T cell receptor Vbeta spectratyping complexity analysis. Further study is required to validate the initial promise of these preliminary observations.

Remission induction in Behçet's disease following lymphocyte depletion by the anti-CD52 antibody CAMPATH 1-H

OBJECTIVE

Behçet's disease (BD) is a multisystem vasculopathy of unknown cause with variable clinical presentation and the outcome of current treatments is often unsatisfactory. There is evidence for T-cell autoreactivity in BD and this study explores the therapeutic response to lymphocyte depletion with a humanized anti-CD52 antibody, CAMPATH-1H.

METHODS

Eighteen patients with active BD received a single course of 134 mg of CAMPATH-1H. Immunosuppressives were withdrawn and prednisolone reduced according to clinical status. Treatment response was assessed by remission of clinical features of disease activity, erythrocyte sedimentation rate, C-reactive protein, prednisolone dose, the need for subsequent immunosuppressives and disease relapse.

RESULTS

By 6 months, 13/18 (72%) had entered remission and average, daily prednisolone dose was reduced from 17.7 to 6.7 mg/day (P < 0.005). At patient follow-up after 37 (6-60) months, seven had relapsed after an average of 25 months, five had required the introduction of an immunosuppressive drug and two had been retreated with CAMPATH-1H; 10 were in stable remission and six were receiving no therapy. Moderate infusion-related adverse effects occurred in five and two developed hypothyroidism. Circulating CD4+ T cells fell to low levels after CAMPATH-1H and remained depressed for at least 1 yr; no opportunistic infections were seen.

CONCLUSIONS

The therapeutic response to CAMPATH-1H suggests a central role for autoreactive lymphocytes in BD. The potential of CAMPATH-1H to induce sustained treatment-free remission in BD poorly controlled by conventional therapy requires further evaluation.

Intensive chemotherapy with hematopoietic stem-cell support for children with recurrent or refractory NHL

BACKGROUND

Children with refractory or recurrent NHL are generally thought to have a poor prognosis. Those with chemosensitive disease are usually considered for an intensification phase, with either autologous or allogeneic hematopoietic stem-cell transplantation (HSCT).

METHODS

From 1990 to 2001 we performed 24 HSCTs in 22 children with refractory (n = 8), recurrent (n = 13), or high-risk in first CR (n = 1) NHL. Among the HSCTs, 19 were autologous and five were allogeneic.

RESULTS

In two children, allogeneic HSCT was performed after failing autologous HSCT. The histologic subtypes comprised large cell, (n = 13), Burkitt's lymphoma (n = 5) and lymphoblastic (n = 4). Among the cases of primary relapse, 10 occurred during therapy and three occurred after completing initial therapy. Among the 22 children in this series, two died of transplant-related toxicity and nine died of progressive disease or relapse after transplant. Among the 11 children who are alive and disease-free, 10 had non-lymphoblastic histology and one had lymphoblastic disease; one relapsed after autologous HSCT, but was successfully salvaged with multi-agent chemotherapy and involved-field irradiation. Among the 22 initial transplanted cases, 10 of 19 children with chemosensitive disease before transplantation and one of three with chemoresistant disease are currently alive and disease-free.

DISCUSSION

Intensive chemotherapy followed by hematopoietic stem-cell support is an effective strategy for children with chemosensitive recurrent non-lymphoblastic NHL.

Impact on T-cell depletion and CD34+ cell recovery using humanised CD52 monoclonal antibody (CAMPATH-1H) in BM and PSBC collections; comparison with CAMPATH-1M and CAMPATH-1G

BACKGROUND

Ex vivo T-cell depletion of allogeneic BM (BM) grafts can effectively reduce graft versus host disease (GvHD) and may also apply to transplantation of allogeneic peripheral blood stem cell (PBSC) transplants.

METHODS

Here we have evaluated T-cell depletion and progenitor cell recovery by antibody-mediated cells lysis using three CD52 monoclonal antibodies (MAbs) at different concentrations and cell densities.

RESULTS

CAMPATH-1M was superior to CAMPATH-1H for T-cell depletion of BM samples. Treatment with CAMPATH-1M resulted in up to 2.55 log depletion of CD3+ cells, with recoveries of >or=45% CD34+ cells, >or=67% CFU-GM and >or=65% BFU-E. CAMPATH-1H treatment resulted in up to 1.64 log depletion of CD3+ cells and similar recoveries of CD34+ cells, CFU-GM and BFU-E as seen with CAMPATH-1M. Depletion of CD19+ cells was similar to that observed for CD3+ cells while natural killer (NK) cells were relatively spared compared with the T and B cell populations. Log depletions of T cells from PBSC, as determined by immunofluorescence studies and limiting dilution analyses, were similar using CAMPATH-1M, -1H, and -1G. There were also no differences in the depletion of CD19+ cells or NK cells using the three MAbs. Similar results were obtained for recoveries of CD34+ cells, CFU-GM and BFU-E using all three MAbs, although the recovery of CD34+ cells using the highest concentration of MAbs was significantly greater in CAMPATH-1H treated samples. Increasing the number of PBSC treated with CAMPATH-1H and -1M had no effect on the log depletion of T, B or NK cells and there were no major differences in the log depletions achieved with CAMPATH-1H or -1M. Likewise, the higher PBSC density had no effect on the recoveries of CD34+ cells or committed progenitors and once again CAMPATH-1H gave similar recoveries to those obtained using CAMPATH-1M.

DISCUSSION

Although CAMPATH-1M resulted in greater ex vivo T-cell depletion of BM than CAMPATH-1H, in all other respects, the humanised CAMPATH-1H was just as effective as CAMPATH-1M and -1G.

In vivo CAMPATH-1H prevents GvHD following nonmyeloablative stem-cell transplantation

BACKGROUND

We have investigated a novel nonmyeloablative conditioning regimen in 44 patients with hematological malignancies. The median patient age was 41 years. Many of the patients had high-risk features, including 19 patients with a previous failed transplant.

METHODS

Recipient conditioning consisted of CAMPATH-1H 20 mg/day on Days -8 to -4, fludarabine 30 mg/m(2) on Days -7 to -3 and melphalan 140 mg/m(2) on Day -2. Thirty-six recipients received unmanipulated G-CSF mobilized PBSC from HLA identical siblings and eight received unmanipulated BM from MUD. GvHD prophylaxis was with CYA alone for 38 patients and CYA plus MTX for six sibling recipients.

RESULTS

Forty-two of the 43 evaluable patients had sustained engraftment. Results of chimerism analysis using microsatellite PCR indicate that 18 of 31 patients studied were full donor chimeras, while the other patients were mixed chimeras in one or more lineages. At a median follow-up of 9 months (range, 3-29 months) 33 patients remain alive in CR, or with no evidence of disease progression. Seven patients relapsed or progressed post-transplant and four of them subsequently died. Four patients died from regimen-related complications. There were no cases of Grades III-IV acute GvHD. Only two patients developed Grade II acute GvHD and only one had chronic GvHD. The estimated probability of non-relapse mortality at 1 year was 11%.Results: Although longer follow-up is needed to establish the long-term remission rates, this study demonstrates that this nonmyeloablative preparative regimen is associated with durable engraftment, minimal toxicity and low incidence of GvHD.

CAMPATH-1 antibodies in stem-cell transplantation

BACKGROUND

CAMPATH-1 (CD52) Abs have been used in stem-cell transplants for the prevention of GvHD and graft rejection. These complications can effectively be prevented by depletion of T lymphocytes from both donor and recipient. However, donor lymphocytes might contribute an anti-leukemia effect and lymphocyte depletion may exacerbate problems with immune reconstitution. There is a fine balance between the risks of GvHD and host-versus-graft reactions, relapse and infection.

METHODS

Clinical outcomes for 4264 patients were reported to a central registry and analyzed by univariate and multivariate methods to determine the superior protocols. Various protocols of lymphocyte depletion were tested, using either CAMPATH-1M (IgM) plus complement or CAMPATH-1G (IgG2b) to treat the donor BM ex vivo and CAMPATH-1G in vivo to treat the recipient. The humanized antibody CAMPATH-1H has recently replaced CAMPATH-1G. A meeting of the clinical collaborators was convened to discuss the results and to review the experiences of individual centers.

RESULTS

Interest focused on the use of mobilized PBSC for transplantation and on the use of reduced-intensity conditioning regimens ('mini' or 'non-Correspondence myeloablative' transplants). These approaches are likely to become increasingly important in the future and will allow transplant procedures to be used for relatively older patients. The use of CAMPATH-1G or CAMPATH-1H was associated with a low incidence of GvHD or rejection, though there were some differences that might be related to the longer half-life of the humanized antibody. An unexpected and apparently paradoxical effect of post-transplant CYA was observed - it appeared to reduce the risk of dying from infection after 6 months. Although part of the benefit could be explained by a reduction in GvHD, the effect was still evident when patients with GvHD or graft rejection were excluded from analysis.

DISCUSSION

CAMPATH-1H appears to have a useful role in the prevention of graft rejection and GvHD, particularly in patients who are at high risk of these complications. It can equally well be used by admixture with the infused stem cells, or by administration to the patient prior to the transplant. Future studies will seek to understand the mechanism of the CYA effect and to improve the quality of immune reconstitution.

Manufacture and quality control of CAMPATH-1 antibodies for clinical trials

BACKGROUND

CAMPATH-1 Abs have been used for T-cell depletion in stem-cell transplantation since the early 1980s. During that time there has been substantial progress in manufacturing techniques and quality control procedures. This article summarizes the methods used to produce the Abs for clinical use and describes results of quality control tests on representative batches.

METHODS

Rat hybridoma and recombinant CHO cells were cultured in hollow-fiber fermentors. Antibodies were purified from the culture supernatant by fractionation with ammonium sulphate, or by column chromatography. Additional steps were added to assure the removal of DNA and viruses. A range of analytical methods was used to characterize the antibodies. Samples were stored frozen at -70 degrees C and re-analyzed many years later to assess the long-term stability.

RESULTS

Hollow-fiber fermentors provided a simple and reliable means for antibody production, with yields between 3-10 mg/h and a convenient concentration for further processing (0.6-2.0 mg/mL). All of the CAMPATH-1 Abs (rat IgM, rat IgG2b and human IgG1) could be purified by affinity chromatography on Protein A, but the low pH required for elution caused unacceptable aggregation of the IgM. CAMPATH-1H contained approx. 20% dimeric IgG, which could be removed by size exclusion chromatography. Antibodies were stable for at least 6 years at -70 degrees C, but there was unacceptable aggregation of CAMPATH-1M in one batch stored for 9 years.

DISCUSSION

Pilot-scale production of MAbs for clinical studies is feasible in a small academic center, but regulatory requirements now demand that great attention is paid to all aspects of manufacturing and quality assurance. Although the underlying principles of cell culture and protein chemistry remain the same, the level of documentation, validation and quality control has increased greatly over the last 20 years.

Alemtuzumab (Campath-1H) for treatment of lymphoid malignancies in the age of nonmyeloablative conditioning?

The anti-CD52 (Campath-1) monoclonal antibodies (Mabs) have a substantial history of use for controlling graft-versus-host disease in allogeneic bone marrow transplantation. Now, with the availability of a humanised form, alemtuzumab (Campath-1H), and the demonstration that this agent can reduce the tumour burden in B-CLL, a new niche may be found - as a potentially curative agent in which its tumour purging ability in vivo combines with its role as a conditioning agent in nonmyeloablative transplantation. Review of the literature shows that alemtuzumab has unique advantages as a method of depleting malignant lymphocytes, including those in patients resistant to conventional chemotherapy. Alemtuzumab can also be used in BMT for depletion of normal T and B lymphocytes of both the recipient and donor for prevention of graft rejection and GVHD. It allows good stem cell recovery with resultant rapid engraftment, has a low risk of EBV-triggered secondary malignancy and does not interfere with blood stem cell mobilisation. As a method of eliminating the malignant clone in B-CLL, alemtuzumab has shown remarkable efficacy in heavily pre-treated patients, a number of whom have progressed to autologous or allogeneic transplantation. Efficacy data are shown within the context of other transplantation data for B-CLL. These results indicate that the combination of tumour-depleting and immunosuppressive properties of alemtuzumab should be explored, with the hope of providing improved treatment options for elderly patients with advanced B-CLL or indolent lymphoma whose prognosis is too poor currently to allow treatment with traditional regimens of high-dose myeloablative chemotherapy.

Pharmacokinetics of CAMPATH-1H in BMT patients

BACKGROUND

CAMPATH-1 (CD52)Abs are used in stem-cell transplantation for prevention of GvHD and rejection. The humanized Ab CAMPATH1H has recently replaced the rat Ab CAMPATH-1G. There was a concern whether it might have a longer half-life in vivo and, possibly, cause prolonged immunosuppression post-transplant.

METHODS

Serum samples were collected pre- and post-transplant from patients receiving CAMPATH-1H at 10 mg/day according to two protocols: (A) from Day -5 to Day +4 (total dose, 100 mg), (B) from Day -10 to Day -6 (total dose, 50 mg). The Ab concentrations were measured using an immunofluorescence assay.

RESULTS

Lymphocytes were substantially depleted by the second day of treatment and were below 0.1 x 10(9)/L by the day of transplant and for at least 1 month post-transplant. By Day 90 there was a greater recovery in Group B, to a median of 0.32 x 10(9)/L compared with 0.25 x 10(9)/L in Group A. By Day 180, both groups had recovered to approx 0.52 x 10(9)/L. Serum concentrations of CAMPATH-1H on the day of transplant were well above the level necessary for opsonization of lymphocytes. The peak Ab concentration was 6.1 micro g/mL in Group A and 2.5 micro g/mL in Group B. CAMPATH-1H could be detected in Group A for 23 days post-transplant, significantly longer than in Group B (11 days). The terminal half-life in the two groups was similar (range 15-21 days) and contrasts with the half-life of < 1 day previously estimated for CAMPATH-1G. There were no cases of graft failure and the incidence of GvHD was similar in the two groups.

DISCUSSION

The humanized Ab CAMPATH-1H appears to persist in the circulation for longer than the original rat Ab CAMPATH-1G. This might contribute to delayed lymphocyte recovery and prohibit the use of early donor-lymphocyte infusions. A short course of treatment given early pre-transplant is likely to be preferable to the extended course given both pre- and post-transplant.

Excessive T cell depletion of peripheral blood stem cells has an adverse effect upon outcome following allogeneic stem cell transplantation

We evaluated the outcome of two modes of T cell depletion for HLA-identical sibling stem cell transplants in 34 consecutive adult patients: group A (n = 11) received PBSC post CliniMACs immuno-magnetic enrichment of CD34(+) cells and group B (n = 23) received bone marrow following in vitro incubation with CAMPATH-1M and complement. All patients received an identical conditioning regimen which consisted of in vivoCAMPATH-1H 20 mg over 5 days, thiotepa 10 mg/kg, cyclophosphamide 120 mg/kg and 14.4 Gy TBI. No additional graft-versus-host disease prophylaxis was given. The mean T cell dose administered was 0.02 +/- 0.05 x 10(6)/kg for group A and 2.8 +/- 2.8 10(6)/kg for group B (P < 0.001). With a median follow-up of 28 months overall survival was 36.4% for group A at 12 months compared to 78.3% for group B (P = 0.001). Transplant-related mortality in group A at 12 months was 63.6% as compared to 18.0% in group B (P = 0.003). Most of the procedure-related deaths in group A occurred secondary to infection. These results suggest that extensive in vitro T cell depletion of peripheral blood stem cells in combination with in vivo T cell depletion may have profound effects upon the incidence of infections following allogeneic stem cell transplantation and this may adversely effect transplant-related mortality.

Respiratory virus infections in adult T cell-depleted transplant recipients: the role of cellular immunity

BACKGROUND

Little is known about the role of cellular immunity in respiratory virus infections after bone marrow transplantation.

METHODS

Forty allograft recipients T-cell depleted with Campath antibodies were evaluated for respiratory virus infections in an active surveillance program with early initiation of antiviral therapy.

RESULTS

Eighteen episodes of respiratory virus infection were detected in nine patients (22%) at a median of 95 days, with lower respiratory involvement in 44%. Fourteen episodes were treated with antiviral therapy for 7 to 46 days, with 11% mortality. Respiratory virus infections were more common in patients receiving Campath 100 mg in vivo, but delayed CD4+ recovery was the most significant risk factor.

CONCLUSIONS

Respiratory virus infections are common and often recurrent in patients with severe CD4+ T lymphopenia. However, the mortality was low, which may have been due to early institution of antiviral treatment or reduced inflammatory damage to the lungs due to severe lymphopenia.

Appropriate targets for monoclonal antibodies in the induction of transplantation tolerance

There are many routes to exploiting tolerance processes to ensure long-term graft survival. Complete tolerance although attractive as a goal, may not be the most practical in the clinic. Instead simple and low-impact procedures that harness tolerance processes used in conjunction with low doses of immunosuppressive drugs may prove the most reliable and user-friendly of approaches.

Morbidity and mortality in rheumatoid arthritis patients with prolonged and profound therapy-induced lymphopenia

OBJECTIVE

Therapies that deplete lymphocytes often improve symptoms in patients with otherwise refractory autoimmune disease but may result in long-term lymphopenia, the consequences of which are uncertain. To assess the impact of prolonged lymphopenia on morbidity and mortality, we studied patients who had previously received lymphocytotoxic monoclonal antibody (mAb) therapy for rheumatoid arthritis (RA).

METHODS

Fifty-three patients who received the lymphocytotoxic mAb CAMPATH-1H between 1991 and 1994 in the United Kingdom were assessed for mortality and infectious and malignant morbidity, by interview and case-note review. In addition, patients were monitored via the National Health Service Central Registry, to verify notification of death. Peripheral blood lymphocyte subsets were analyzed by flow cytometry. A retrospective, matched-cohort study of mortality was also performed with 102 control subjects selected from the European League Against Rheumatism database, which comprises patients with rheumatic disorders who have received immunosuppressive drugs.

RESULTS

There was profound and persistent peripheral blood lymphopenia in the mAb-treated patients, affecting predominantly the CD4+ subset. Median CD4+, CD8+, and CD19+ peripheral blood lymphocyte counts at 73-84 months after therapy were 185 cells/microl, 95 cells/microl, and 115 cells/microl, respectively. At a median followup of 71 months (range 14-90), 13 patients had died (24.5%), compared with 18% of the matched controls, providing a mortality rate ratio of 1.45 (95% confidence interval 0.65-3.13). During 283 patient-years of followup, there were 36 infections classified as major (12.7 per 100 patient-years). The causes of death and the spectrum of infections documented were similar to those expected in a hospital-based RA cohort. Patients who received more than 1 course of therapy had more severe lymphopenia than did patients who received a single course, but this did not have an impact on mortality or morbidity.

CONCLUSION

Despite the occurrence of profound and long-lasting lymphopenia following treatment with antilymphocyte mAb therapy for RA, this therapy is not associated with a large excess of mortality nor with an unusual spectrum of infections, at least during a medium-term period of followup. These data are also relevant to patients receiving lymphocytotoxic mAb therapy for other indications, and to patients receiving other lymphodepleting therapies such as autologous stem cell transplantation.

The effect of treatment with Campath-1H in patients with autoimmune cytopenias

We describe 21 patients with severe and life-threatening autoimmune cytopenias resistant to standard immunosuppression who were treated with the monoclonal antibody Campath-1H. Four patients had autoimmune neutropenia, four had autoimmune haemolytic anaemia, four had pure red cell aplasia, one had immune thrombocytopenia purpura (ITP), three had autoimmune haemolytic anaemia and ITP (Evan's syndrome), three had autoimmune pancytopenia (ITP, autoimmune neutropenia and autoimmune haemolytic anaemia), one had ITP (associated with acquired Glanzmann's disease) and autoimmune neutropenia, and one had ITP and red cell aplasia. Campath-1H was administered at a dose of 10 mg/d as an intravenous infusion for 10 d. Responses were seen in 15 patients, which were sustained in six. Relapse occurred in eight patients after Campath-1H treatment. Patients entering the study later, received cyclosporine after Campath-1H in an attempt to reduce the incidence of relapse. Three patients received a second course of Campath-1H; all responded but later relapsed. Fourteen patients are alive at a median of 12 months (range 4-61) after Campath-1H. Campath-1H represents an alternative therapeutic option for severe, refractory autoimmune cytopenias.

Quantitation of minimal disease levels in chronic lymphocytic leukemia using a sensitive flow cytometric assay improves the prediction of outcome and can be used to optimize therapy

Previous studies have suggested that the level of residual disease at the end of therapy predicts outcome in chronic lymphocytic leukemia (CLL). However, available methods for detecting CLL cells are either insensitive or not routinely applicable. A flow cytometric assay was developed that can differentiate CLL cells from normal B cells on the basis of their CD19/CD5/CD20/CD79b expression. The assay is rapid and can detect one CLL cell in 10(4) to 10(5) leukocytes in all patients. We have compared this assay to conventional assessment in 104 patients treated with CAMPATH-1H and/or autologous transplant. During CAMPATH-1H therapy, circulating CLL cells were rapidly depleted in responding patients, but remained detectable in nonresponders. Patients with more than 0.01 x 10(9)/L circulating CLL cells always had significant (> 5%) marrow disease, and blood monitoring could be used to time marrow assessments. In 25 out of 104 patients achieving complete remission by National Cancer Institute (NCI) criteria, the detection of residual bone marrow disease at more than 0.05% of leukocytes in 6 out of 25 patients predicted significantly poorer event-free (P =.0001) and overall survival (P =.007). CLL cells are detectable at a median of 15.8 months (range, 5.5-41.8) posttreatment in 9 out of 18 evaluable patients with less than 0.05% CLL cells at end of treatment. All patients with detectable disease have progressively increasing disease levels on follow-up. The use of sensitive techniques, such as the flow assay described here, allow accurate quantitation of disease levels and provide an accurate method for guiding therapy and predicting outcome. These results suggest that the eradication of detectable disease may lead to improved survival and should be tested in future studies.

Allogeneic bone marrow transplantation for infants with acute leukemia or myelodysplastic syndrome

The objective of this study is to investigate the outcome of children 24 months of age or younger (infants) at the time of allogeneic bone marrow transplantation (BMT) for acute leukemia or myelodysplasia. We analyzed the survival rate, prognostic factors, incidences of late sequelae, and immune reconstitution in 22 infants who underwent allogeneic BMT. The 5-year event-free survival estimate was 45.5% (95% confidence interval (CI), 24.4% to 63.3%). Six patients died of transplant-related complications and six died of disease relapse. Remission status at the time of BMT was the most important prognostic factor (P = 0.005): no patient who received a transplant while their disease was not in remission survived, whereas the 5-year survival estimate for infants who underwent BMT during remission was 56% (95% CI, 31% to 75%). Long-term outcomes in the 10 infant survivors were compared with those of 10 older controls matched for diagnosis, disease status at the time of BMT, calendar year at the time of BMT, and source of stem cells. Immune function 1 year after transplantation and the incidences and spectra of late sequelae were similar for both groups during a median of 3.5 years (range, 1.5 to 7.2 years) of follow-up.

Comparison of allogeneic T cell-depleted peripheral blood stem cell and bone marrow transplantation: effect of stem cell source on short- and long-term outcome

We report the results of a retrospective single-center study comparing engraftment, acute and chronic GVHD, relapse and survival in patients with malignant hematological disorders transplanted with allogeneic peripheral blood stem cells (alloPBSCT, n = 40) or bone marrow cells (alloBMT, n = 42). All transplants were T cell depleted by in vitro incubation with the Campath-1 monoclonal antibody. Primary graft failure occurred in none of the patients receiving an alloPBSCT compared with 3/42 of the recipients of an alloBMT. In addition, two patients in the alloBMT group showed no platelet engraftment. Recipients of PBSC had a more rapid recovery of neutrophils (median 14 days) compared to BM transplant recipients (median 32 days). Platelet recovery was also accelerated in PBSC recipients compared to BM recipients (11 vs 38 days). There was an increase in the incidence of grade II acute GVHD and chronic GVHD in patients after alloPBSCT (18% and 23%, respectively) compared to patients receiving alloBMT (5% and 8%, respectively). The 2-year cumulative incidence of relapse was similar in both groups (47%). At 6 months after transplantation, transplant-related mortality (TRM) was lower in PBSCT recipients than in BMT recipients. However, at a follow-up of 3 years TRM was similar in both groups. The disease-free survival rate at 3 years after transplantation did not differ between the groups (42% for PBSCT and 41% for BMT recipients). Our results indicate that T cell-depleted alloPBSCT compared to alloBMT is associated with a more rapid hematopoietic reconstitution and a decreased TRM at 6 months follow-up after transplantation. However, at a follow-up of 3 years, no sustained survival benefits were observed.

Effect of HLA class I or class II incompatibility in pediatric marrow transplantation from unrelated and related donors

The degree of histoincompatibility that can be tolerated, and the relative importance of matching at individual HLA class I and class II locus in bone marrow transplantation (BMT) has not been established. We hypothesized that matching for HLA-DR may not be more important than matching for HLA-A or HLA-B in selection of a donor for successful BMT. We retrospectively analyzed the outcomes of 248 consecutive pediatric patients who received allogeneic BMT from related donors (RD, n = 119) or unrelated donors (URD, n = 129). HLA-A and HLA-B were serologically matched, and HLA-DRB1 were identical by DNA typing in 69% of donor-recipient pairs. Most patients (89%) had hematologic malignancies; the rest had aplastic anemia or a congenital disorder. One HLA-A antigen mismatch was associated with a decrease in survival (p = 0.003) and a delay in granulocyte engraftment (p = 0.02) in recipients of RD marrow; as well as a decrease in survival (p = 0.02) and the development of severe acute graft-versus-host disease (GVHD) (p = 0.03) in recipients of URD marrow. One HLA-B antigen mismatch was associated with a decrease in the survival (p = 0.05) and the development of severe GVHD (p = 0.0007) in recipients of RD marrow. One HLA-DRB1 allele mismatch was associated only with a decrease in the survival (p = 0.0003) of recipients of RD marrow. Results of this study suggest that disparity in HLA-A and HLA-B antigens may not be better tolerated than disparity in HLA-DR allele in allogeneic BMT. Further studies are warranted to confirm our results.

(-)-Spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin-2'-one], a conformationally restricted analogue of acetylcholine, is a highly selective full agonist at the alpha 7 nicotinic acetylcholine receptor

Neuronal nicotinic acetylcholine receptors are members of the ligand-gated ion channel receptor superfamily and may play important roles in modulating neurotransmission, cognition, sensory gating, and anxiety. Because of its distribution and abundance in the CNS, the alpha 7 nicotinic receptor is a strong candidate to be involved in some of these functions. In this paper we describe the synthesis and in vitro profile of AR-R17779, (-)-spiro[1-azabicyclo[2.2. 2]octane-3,5'-oxazolidin-2'-one] (4a), a potent full agonist at the rat alpha 7 nicotinic receptor, which is highly selective for the rat alpha 7 nicotinic receptor over the alpha 4 beta 2 subtype. Preliminary SAR of AR-R17779 presented here indicate that there is little scope for modification of this rigid molecule as even minor changes result in significant loss of the alpha 7 nicotinic receptor affinity.

In vivo CAMPATH-1H prevents graft-versus-host disease following nonmyeloablative stem cell transplantation

A novel nonmyeloablative conditioning regimen was investigated in 44 patients with hematologic malignancies. The median patient age was 41 years. Many of the patients had high-risk features, including 19 patients with a previous failed transplant. Recipient conditioning consisted of CAMPATH-1H, 20 mg/day on days -8 to -4; fludarabine, 30 mg/m(2) on days -7 to -3; and melphalan, 140 mg/m(2) on day -2. Thirty-six recipients received unmanipulated granculocyte colony-stimulating factor-mobilized peripheral blood stem cells from HLA-identical siblings, and 8 received unmanipulated marrow from matched unrelated donors. GVHD prophylaxis was with cyclosporine A alone for 38 patients and cyclosporine A plus methotrexate for 6 sibling recipients. Forty-two of the 43 evaluable patients had sustained engraftment. Results of chimerism analysis using microsatellite polymerase chain reaction indicate that 18 of 31 patients studied were full-donor chimeras while the other patients were mixed chimeras in one or more lineages. At a median follow-up of 9 months (range 3 to 29 months), 33 patients remain alive in complete remission or with no evidence of disease progression. Seven patients relapsed or progressed post-transplantation, and 4 of them subsequently died. Four patients died of regimen-related complications. There were no cases of grades III-IV acute GVHD. Only 2 patients developed grade II acute GVHD, and only 1 had chronic GVHD. The estimated probability of nonrelapse mortality was 11%. Although longer follow-up is needed to establish the long-term remission rates, this study demonstrates that this nonmyeloablative preparative regimen is associated with durable engraftment, minimal toxicity, and low incidence of GVHD.

Local bioactive tumour necrosis factor (TNF) in corneal allotransplantation

The aim of this study was to examine the kinetic profile of bioactive TNF levels in aqueous humour of rabbit eyes undergoing corneal allograft rejection and to investigate the effect of locally blocking TNF activity after corneal transplantation. In a rabbit corneal transplantation, endothelial allograft rejection was identified and correlated with increase in central graft thickness. Samples of aqueous humour obtained on alternate days following transplantation were tested for TNF mRNA and bioactive TNF protein. To investigate the effect of locally blocking TNF activity in allograft recipients, the fusion protein TNFR-Ig was administered by injections into the anterior chamber after transplantation. Pulsatile increases in levels of this cytokine were found in 14 of 15 allograft recipients. Peaks of TNF bioactivity preceded by varying intervals the observed onset of rejection in allograft recipients. TNF levels were not elevated in aqueous humour from corneal autograft recipient controls or in serum of allografted animals. mRNA levels were elevated before onset of and during clinically observed allograft rejection. In three of seven animals receiving TNFR-Ig injections on alternate days from day 8 to day 16 post-transplant, clear prolongation of corneal allograft survival was demonstrated. Bioactive TNF is present in aqueous humour following rabbit corneal allotransplantation. Rather than correlating directly with endothelial rejection onset, pulsatile peak levels of TNF precede and follow the observed onset of endothelial rejection. Blockade of TNF activity prolongs corneal allograft survival in some animals, indicating that this cytokine may be a suitable target in local therapy of corneal allograft rejection.

CD52 antibodies for prevention of graft-versus-host disease and graft rejection following transplantation of allogeneic peripheral blood stem cells

Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity after allogeneic bone marrow transplantation, but can be avoided by removing T lymphocytes from the donor bone marrow. However, T cell depletion increases the risk of graft rejection. In this study, two strategies are used to overcome rejection: (1) use of high doses of stem cells obtained from peripheral blood (PBSC), (2) admixture with a CD52 monoclonal antibody in order to deplete both donor and residual recipient lymphocytes. Two antibodies are compared: CAMPATH-1G (rat IgG2b) and its humanized equivalent CAMPATH-1H (human IgG1). A total of 187 consecutive patients at six centers received PBSC transplants from HLA-matched siblings between 1997 and 1999. A wide spectrum of diseases, both malignant and non-malignant, was included. The recovery of CD34+ cells after antibody treatment was close to 100%. The risk of acute GVHD (grade 2 to 4) was 11% in the CAMPATH-1G group and 4% in the CAMPATH-1H group (P = NS). The risk of chronic GVHD (any grade) was 11% in the CAMPATH-1G group and 24% in the CAMPATH-1H group (P = 0.03) but the risk of extensive chronic GVHD was only 2%. The overall risk of graft failure/rejection was 2%, not significantly different between the two antibodies. Antibody treatment was equally effective at concentrations between 10 microg/ml and 120 microg/ml and it made no significant difference to the outcome whether the patients received post-transplant immunosuppression or not (87% did not). Transplant-related mortality in this heterogenous group of patients (including high-risk and advanced disease) was 22% at 12 months. It is proposed that treatment of peripheral blood stem cells with CAMPATH-1H is a simple and effective method for depleting T cells which may be applicable to both autologous and allogeneic transplants from related or unrelated donors. Special advantages of this approach are the simultaneous depletion of donor B cells (which reduces the risk of EBV-associated lymphoproliferative disease) and the concomitant infusion of CAMPATH-1H to deplete residual recipient T cells and thus prevent graft rejection.