Changes in interleukin-2 and interleukin-4 production in asymptomatic, human immunodeficiency virus-seropositive individuals.

Infection with HIV results in an incremental loss of T helper cell (TH) function, which can occur years before CD4 cell numbers are critically reduced and AIDS is diagnosed. All TH function is not affected, however, because B cell activation and hypergammaglobulinema are also characteristic of this period. Recently, in a murine model of AIDS an early loss in production of the CD4 cytokines IL-2 and IFN-gamma was correlated with an increase in the B cell stimulatory cytokines IL-4, IL-5, and IL-10. We therefore assessed the production of IL-4 generated by PBL from HIV-seropositive (HIV+) individuals who did not have AIDS, yet who exhibited different TH functional categories based on their IL-2 production profiles. We observed that the decreases in recall antigen-stimulated IL-2 production were accompanied by an increase in IL-4 production. The loss of recall antigen-stimulated responses in HIV+ individuals could be reversed in vitro by anti-IL-4 antibody. Our results suggest that the TH functions assessed by IL-4 production replace the normally dominant TH function of antigen-stimulated IL-2 production in the progression toward AIDS, and raise the possibility of cytokine cross-regulation in AIDS therapy.

Novel targets in the treatment of chronic graft-versus-host disease.

Despite advances that have improved survival after allogeneic hematopoietic stem cell transplantation (HCT), chronic graft-versus-host disease (GVHD) remains a leading cause of late morbidity and mortality after transplant. Current treatment options show limited efficacy in steroid-refractory disease, and there exists a paucity of robust data to guide management decisions. Lack of United States Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved agents in GVHD underscore the importance of developing novel therapies. Better understanding of the biology of chronic GVHD has provided novel targets for treatment, and structured guidelines in diagnosis and in clinical trial design have provided a common language and pathways for research in this area. These, combined with the surge of drug development in Oncology and Immunology, are factors that have contributed to the accelerating field of drug development and clinical research in chronic GVHD. In these exciting times, it is possible to foresee long awaited advances in the treatment of this devastating complication of HCT. This review will summarize the ongoing clinical development for novel therapies in chronic GVHD.

Phase I and pharmacokinetic study of farnesyl protein transferase inhibitor R115777 in advanced cancer.

PURPOSE: To determine the maximum-tolerated dose, toxicities, and pharmacokinetic profile of the farnesyl protein transferase inhibitor R115777 when administered orally bid for 5 days every 2 weeks. PATIENTS AND METHODS: Twenty-seven patients with a median age of 58 years received 85 cycles of R115777 using an intrapatient and interpatient dose escalation schema. Drug was administered orally at escalating doses as a solution (25 to 850 mg bid) or as pellet capsules (500 to 1300 mg bid). Pharmacokinetics were assessed after the first dose and the last dose administered during cycle 1. RESULTS: Dose-limiting toxicity of grade 3 neuropathy was observed in one patient and grade 2 fatigue (decrease in two performance status levels) was seen in four of six patients treated with 1,300 mg bid. The most frequent clinical grade 2 or 3 adverse events in any cycle included nausea, vomiting, headache, fatigue, anemia, and hypotension. Myelosuppression was mild and infrequent. Peak plasma concentrations of R115777 were achieved within 0.5 to 4 hours after oral drug administration. The elimination of R115777 from plasma was biphasic, with sequential half-lives of about 5 hours and 16 hours. There was little drug accumulation after bid dosing, and steady-state concentrations were achieved within 2 to 3 days. The pharmacokinetics were dose proportional in the 25 to 325 mg/dose range for the oral solution. Urinary excretion of unchanged R115777 was less than 0.1% of the oral dose. One patient with metastatic colon cancer treated at the 500-mg bid dose had a 46% decrease in carcinoembryonic antigen levels, improvement in cough, and radiographically stable disease for 5 months. CONCLUSION: R115777 is bioavailable after oral administration and has an acceptable toxicity profile. Based upon pharmacokinetic data, the recommended dose for phase II trials is 500 mg orally bid (total daily dose, 1, 000 mg) for 5 consecutive days followed by 9 days of rest. Studies of continuous dosing and studies of R115777 in combination with chemotherapy are ongoing.

Alterations in T cell-derived colony-stimulating factors associated with GVH-induced immune deficiency.

Injection of parental C57BL/10 spleen cells into unirradiated immune-competent (B10 x B10.BR)F1 hosts has been demonstrated to produce a graft-vs.-host-induced immune deficiency in T cell-mediated functions, including mitogen or alloantigen stimulated proliferation or cytotoxic T cell generation. The production of T cell-derived lymphokines affecting hematopoiesis was also altered during GVH. During the first two weeks of GVH, IL-3 and particularly GM-CSF were produced spontaneously; in subsequent weeks, the spontaneous production dropped to normal or subnormal levels. CSF content in concanavalin A-stimulated splenic supernatants was reduced at weeks 1-2, and declined to less than 5% of normal levels by 3-4 weeks of GVH. This decline in CSF content was correlated with a decrease in immune function as assessed by concanavalin A-stimulated IL-2 production and by generation of cytotoxic T lymphocytes. Concurrent with the recovery of immune function during GVH weeks 8-15, mitogen-stimulated production of CSF returned to normal levels. In addition to the decrease in CSF production identified in acute suppressive GVH, CSF content in concanavalin A-stimulated splenic supernatants was also decreased in chronic stimulatory GVH, generated in the strain combination (B6 x B6bm1)F1----(B6bm1 x B6bm12)F1. This decrease in CSF production correlated with a decrease in self-restricted T helper cell function. Finally, a decrease in both immune function and CSF production capacity was observed in the acute GVH following allogeneic (minor histocompatibility loci) bone marrow transplantation into irradiated hosts.

Factors contributing to the decrease in concanavalin A-induced colony-stimulating factors in acute suppressive graft-versus-host disorder.

We have recently demonstrated that IL-3 and GM-CSF content in concanavalin A--stimulated splenic cultures was severely depressed for several weeks in mice undergoing an acute graft-vs.-host reaction (GVHR). Several factors contributed to this decrease in CSF levels at different points in the first 10 weeks of GVH. Myeloid lineage cells, both GM-CFU and Mac-1+ cells, increased in the spleen during GVH weeks 3-6, and (125I)-GM-CSF binding by spleen cells increased 10 fold--hence CSF content in supernatants was probably reduced by local consumption during these weeks. During GVH weeks 3-12, levels of all T cells--and of L3T4+ T cells, in particular--were reduced, limiting production of T cell derived lymphokines. Finally, during the first six weeks of GVH, immune suppression was found in cocultures of normal F1 and GVH spleens. Furthermore, during weeks 3-5, nonspecific suppression was found, affecting CSF production not only by normal host spleens but also by parental donor or unrelated spleen cells as well.

Comparative analysis of FoxP3(+) regulatory T cells in the target tissues and blood in chronic graft versus host disease.

Activation and migration of regulatory T cells (Treg) into tissue is critical in control of inflammation, but has not been examined extensively in chronic graft versus host disease (cGVHD). In parallel studies of tissues and blood, we determined that FoxP3(+) T cells increased in proportion to T effectors (Teff) in tissue infiltrates in oral and cutaneous lichenoid cGVHD. These FoxP3(+) cells expressed distinguishing phenotypic and functional markers of Treg (CD3(+), CD4(+), CD27(+), ICOS(+) and CD39(+)), not found on FoxP3(-) Teff. Both Teff and FoxP3(+) Treg expressed T-bet and the chemokine receptor CXCR3, however, consistent with a common mechanism of chemokine-mediated migration into tissue. Furthermore, functional markers (ICOS and CD39) and chemokine receptors (CXCR3) were both present in a higher proportion of FoxP3(+) cells in tissues than in peripheral blood, consistent with recruitment and activation of Treg in cGVHD target tissues. Finally, the 'activated' CD45RA(-)FoxP3(hi) subset of Treg cells, which highly express functional markers, were found in comparable frequencies in cGVHD patients and normal controls, despite a significant deficit in naive 'resting' Treg. These findings are consistent with Treg capacity to upregulate functional markers and traffick into tissue in cGVHD.

Clinical laboratory markers of inflammation as determinants of chronic graft-versus-host disease activity and NIH global severity.

Chronic graft-versus-host disease (cGVHD) remains a major cause of non-relapse morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Currently there are no accepted measures of cGVHD activity to aid in clinical management and disease staging. We analyzed clinical markers of inflammation in the sera of patients with established cGVHD and correlated those with definitions of disease activity. In all, 189 adults with cGVHD (33% moderate and 66% severe according to National Institutes of Health (NIH) global scoring) were consecutively enrolled onto a cross-sectional prospective cGVHD natural history study. At the time of evaluation, 80% were receiving systemic immunosuppression and failed a median of four prior systemic therapies (PST) for their cGVHD. Lower albumin (P<0.0001), higher C-reactive protein (P = 0.043), higher platelets (P = 0.030) and higher number of PST (P<0.0001) were associated with active disease defined as clinician's intention to intensify or alter systemic therapy due to the lack of response. Higher platelet count (P = 0.021) and higher number of PST (P<0.0001) were associated with more severe diseased defined by NIH global score. This study identified common laboratory indicators of inflammation that can serve as markers of cGVHD activity and severity.

Oral chronic graft-vs.-host disease characterization using the NIH scale.

Chronic graft-vs.-host disease (cGVHD) is a complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). Oral cGVHD is manifested by mucosal, salivary, and/or sclerotic changes that have been linked to pain and poor quality of life. Our aim was to describe the demographic, clinical, and laboratory markers of oral cGVHD in alloHSCT patients (N = 187) enrolled in a cGVHD cross-sectional study at the NIH (#NCT00331968). We propose a meaningful and reproducible measure of disease defined by a cut-off point reflecting clinical minimally detectable change (0-2 = no oral cGVHD, 3-15 = oral cGVHD) on the 15-point NIH cGVHD clinician assessment scale. Forty-four patients had oral cGVHD. Oral cGVHD was associated with a quiescent or de novo type of cGVHD onset (p = 0.05), higher cGVHD severity (p = 0.033), lower albumin (p = 0.0008), higher total complement (p = 0.012), greater bother from foods or oral ulcers and greater mouth pain, and sensitivity (p < 0.0001). Multivariable logistic regression modeling with albumin, mouth pain, and total complement was 74.3% predictive of oral cGVHD and 80.2% predictive of non-oral cGVHD. We propose the use of >2 points on the NIH scale as a reproducible definition of clinically significant oral cGVHD, which may be useful in clinical settings or as eligibility criterion or as an endpoint in clinical trials.

Immunosenescence: deficits in adaptive immunity in the elderly.

Aging is associated clinically with increases in the frequency and severity of infectious diseases and an increased incidence of cancer, chronic inflammatory disorders and autoimmunity. These age-associated immune dysfunctions are the consequence of declines in both the generation of new naïve T and B lymphocytes and the functional competence of memory populations. These alterations collectively are termed immunosenescence.

Abrogation of hybrid resistance to bone marrow engraftment by graft-vs-host-induced immune deficiency.

Lethally irradiated F1 mice, heterozygous at the hematopoietic histocompatibility locus Hh-1, which is linked with H-2Db, reject bone marrow grafts from H-2b parents. This hybrid resistance (HR) is reduced by prior injection of H-2b parental spleen cells. Because injection of parental spleen cells produces a profound suppression of F1 immune functions, we investigated whether parental-induced abrogation of HR was due to graft-vs-host-induced immune deficiency (GVHID). HR was assessed by quantifying engraftment of H-2b bone marrow in F1 mice with the use of splenic [125I]IUdR uptake; GVHID, by the ability of F1 spleen cells to generate cytotoxic T lymphocytes (CTL) in vitro. We observed a correlation in the time course and spleen cell dose dependence between loss of HR and GVHID. Both GVHID and loss of HR were dependent on injection of parental T cells; nude or T-depleted spleen cells were ineffective. The injection of B10 recombinant congenic spleens into (B10 X B10.A)F1 mice, before grafting with B10 marrow, demonstrated that only those disparities in major histocompatibility antigens that generated GVH would result in loss of HR. Thus, spleens from (B10 X B10.A(2R]F1 mice (Class I disparity only) did not induce GVHID or affect HR, whereas (B10 X B10.A(5R))F1 spleens (Class I and II disparity) abrogated CTL generation and HR completely. GVHID produced by a class II only disparity, as in (B10 X B10.A(5R))F1 spleens injected into (B6bm12 X B10.A(5R))F1 mice, was also sufficient to markedly reduce HR to B10 bone marrow. This evidence that GVHID can modulate hematopoietic graft rejection may be relevant to the mechanisms of natural resistance to marrow grafts in man.

Regulation of graft-versus-host-reaction by Mlsa-reactive donor T cells.

Injection of A/J splenocytes (H-2Dd, Mlsc) into unirradiated (A/J x CBA)F1 (BAF1) host mice (H-2Dd/k, Mlsd) results in an acute suppressive graft-vs.-host reaction (GVHR), characterized by immune dysfunction and appreciable donor cell engraftment; injection of the CBA/J parent (H-2Dk, Mlsd), which recognizes no Mls disparity in the host, results in little or no GVHR. Furthermore, the Mlsa-reactive V beta 6 and V beta 8.1 T cell subsets in A/J T cells expand significantly in the GVHR host. Finally, depletion of V beta 6+ and V beta 8.1+ from the A/J population abrogates the proliferative response to BAF1 in vitro and the development of GVHR in vivo. Thus, the response to Mls determinants can contribute to the generation of a GVHR.

Murine cytomegalovirus infection can enhance hybrid resistance through modulation of host natural killer activity.

Studies were undertaken to assess the effect of murine cytomegalovirus (MCMV) in two different models involving injection of parental cells into F1 hosts. In both of these systems, MCMV-induced enhancement of hybrid resistance was found. In the first model, parent-into-F1 graft-vs-host reaction, MCMV infection of (C57BL/6 x C3H)F1 (B6C3F1) hosts was found to prevent the GVHR normally induced by injection of B6 parental splenocytes into the F1 hosts. The second model involved injection of parental bone marrow into lethally irradiated B6C3F1 and (C57BL/6 x DBA/2)F1 (B6D2F1) hosts. These irradiated hosts are known to exhibit resistance to engraftment by parental C57BL/6 (B6) bone marrow. This resistance was found to be markedly enhanced by injection of the hosts with MCMV 3 days before irradiation and bone marrow injection. In contrast, engraftment into B6C3F1 hosts of syngeneic marrow, or bone marrow from the C3H parent, was not affected by MCMV infection. Engraftment of DBA/2 marrow into B6D2F1 hosts was reduced at lower doses of injected marrow, suggesting enhanced resistance against the minor Hh Ag Hh-DBA. To test whether the MCMV-induced enhancement of resistance was mediated by NK cells, splenic NK activity (YAC-1 killing) and frequency (NK1.1 staining) were assessed. Both parameters were found to be elevated at 3 days after MCMV infection but to return to normal levels by 9 days. B6 bone marrow engraftment was in fact found to be normal when the marrow was administered to F1 mice 9 days after MCMV infection. Furthermore, anti-asialoGM1 administration prevented MCMV-induced enhancement of resistance to marrow engraftment. Thus, the NK enhancement resulting from MCMV infection appears to play a major role in the enhanced HR observed in the marrow engraftment model. This effect may be of importance in clinical bone marrow transplantation, a situation in which patients are susceptible to viral infection.

Recovery of T cell populations after acute graft-vs-host reaction.

We previously have observed that T dependent immune functions were deficient for several months after induction of acute suppressive graft-vs-host-reaction (GVHR) by injection of parental C57BL/10 donor spleen cells into unirradiated (B10 x B10.BR) F, hosts. We therefore investigated whether new T cells matured after acute GVHR, and whether these were tolerant of host Ag. By 8 to 17 mo after GVHR, the frequencies of splenic CD4 and CD8 T cells were found to be comparable to age-matched untreated hosts, although the lymphoid organ size and hence the total number of T cells was significantly reduced. When GVHR was induced with a combination of C57BL/6 (Thy-1.2) mature lymphocytes and B6.PL (Thy-1.1) bone marrow stem cells, the mature donor Thy-1.2 T cells initially predominated during the acute GVHR. After several months, however, 75% of the CD4 and 50% of the CD8 T cell population was derived from donor Thy-1.1% pre-T cells that had matured in the host. Long term GVHR spleen cells were unresponsive to host Ag in CTL assays, but did not suppress anti-host CTL responses. Finally, host-reactive V beta 11 TCR expressing cells were found to be clonally deleted from splenic CD4 and CD8 populations, consistent with intrathymic negative selection. This evidence suggests that the post-GVHR thymus has the capacity to produce and negatively select phenotypically mature CD4 and CD8 T cells and that a failure to clonally delete self-reactive populations is not a contributing factor to the development of chronic GVHR in this system.

Restoration of T-cell homeostasis after T-cell depletion.

T-cell homeostasis appears to be maintained throughout much of normal adult life independent of de-novo production from hematopoietic stem cells via thymopoiesis. Instead, peripheral mechanisms are generally sufficient to maintain normal T-cell number, function and adequate TCR repertoire diversity in healthy hosts. Studies of T-cell regeneration in animals, however, have shown that full restoration of T-cell homeostasis after profound T-cell depletion is primarily dependent upon thymopoiesis. In this setting, thymic-deficient hosts have prolonged reductions in total T-cell number, restricted TCR repertoire diversity, and limited immunocompetence. In humans, age-related reductions in thymic regenerative capacity as early as young adulthood result in incomplete restoration of T-cell homeostasis after T-cell depletion.

Hereditary joint disorder in progressive ankylosis (ank/ank) mice. II. Effect of high-dose hydrocortisone treatment on inflammation and intraarticular calcium hydroxyapatite deposits.

Mice homozygous for the progressive ankylosis trait develop an inflammatory joint disorder associated with the intraarticular deposition of calcium hydroxyapatite. When affected (ank/ank) mice were treated with high doses of hydrocortisone, synovitis receded, development of cartilaginous and bony osteophytes halted, and calcium hydroxyapatite accumulated in and distended the synovial spaces. No changes, however, occurred in the joint morphology of hydrocortisone-treated normal (ank/+) mice. Since inhibition of inflammation by hydrocortisone treatment did not block apatite accumulation, intraarticular deposition of hydroxyapatite occurs independent of inflammation in progressive ankylosis.

Acute graft-versus-host reaction can be aborted by blockade of costimulatory molecules.

Injection of parental lymphocytes into an unirradiated adult F1 host results in an acute GVH reaction characterized by immune deficiency, attack on host lymphohematopoietic tissues, and repopulation with donor-derived cells. All of these events result from the initial activation of donor lymphocytes by host alloantigens. Interaction of pairs of host and donor costimulatory molecules, in particular CD28/CTLA4 and B7-1/B7-2, play a crucial role in this initial activation of donor T cells. We demonstrate here that in vivo treatment of the host with high doses of CTLA4-Ig solely during the initial period of donor alloactivation can completely abort the subsequent development of GVH reaction. Although donor T cells are retained, CTLA4-Ig treatment reduces the initial endogenous cytokine production and arrests the subsequent expansion of donor T cells, the differentiation of anti-host effectors, and the development of severe immune deficiency. This result is consistent with the establishment of host-specific tolerance in the donor population, while maintaining host immune competence.

Synergistic role of CD4+ and CD8+ T lymphocytes in IFN-gamma production and protective immunity induced by an attenuated Toxoplasma gondii vaccine.

BALB/c mice vaccinated with a temperature-sensitive mutant (TS-4) of Toxoplasma gondii develop complete resistance to lethal challenge with a highly virulent toxoplasma strain (RH). This immunity is known to be dependent on IFN-gamma synthesis. In vitro and in vivo T cell depletions were performed in order to identify the subsets responsible for both protective immunity and IFN-gamma production. When stimulated with crude tachyzoite Ag in vitro, CD4+ cells from vaccinated mice produced high levels of TH1 cytokines (IL-2 and IFN-gamma) but not TH2 cytokines (IL-4 and IL-5). CD8+ cells, in contrast, produced less IFN-gamma and no detectable IL-2. Nevertheless, they could be induced to synthesize IFN-gamma when exposed in culture to exogenous IL-2. In vivo treatment with anti-CD4 plus anti-CD8 or anti-IFN-gamma antibodies during challenge infection completely abrogated resistance to T. gondii. In contrast, treatment with anti-CD4 alone failed to reduce immunity, whereas anti-CD8 treatment partially decreased vaccine-induced resistance. These results suggest that although IFN-gamma and IL-2-producing CD4+ lymphocytes are induced by vaccination, IFN-gamma-producing CD8+ T cells are the major effectors of immunity in vivo. Nevertheless, CD4+ lymphocytes appear to play a synergistic role in vaccine-induced immunity, probably through the augmentation of IFN-gamma synthesis by the CD8+ effector cells. This hypothesis is supported by the observation that when giving during vaccination, as opposed to after challenge, anti-CD4 antibodies are capable of blocking protective immunity.

Repopulation of host lymphohematopoietic systems by donor cells during graft-versus-host reaction in unirradiated adult F1 mice injected with parental lymphocytes.

The graft-vs-host reaction (GVHR) generated by the injection of parental lymphocytes into unirradiated immune-competent F1 hosts is characterized by an acute loss of immune functions, an attack on host tissues, and a gradual recovery of function. Flow cytometric analysis of the donor- and host-derived splenic populations during the course of acute dysfunction and gradual recovery revealed a complex pattern of changes in lymphoid and myeloid populations that resulted in the repopulation of the host with donor-derived cells. Initially, donor-derived T cell populations expanded, particularly CD8+ T cells. Next, host T cell and B cell populations disappeared. Finally, donor-derived cells repopulated the lymphohematopoietic system in the sequence myeloid populations, B cells, and, after a protracted period, T cells. The recovery of immune functions following GVHR-induced immune deficiency was associated with this repopulation of the spleen by donor-derived cells. Donor repopulation of the host lymphohematopoietic system required the presence of both CD4 and CD8 cells in the original donor inoculum. Depletion of donor CD4 populations precluded development of GVHR or any donor engraftment; depletion of CD8 cells resulted in engraftment solely of donor CD4 populations.

CD8+ T cells from mice vaccinated against Toxoplasma gondii are cytotoxic for parasite-infected or antigen-pulsed host cells.

Mice vaccinated with a live temperature sensitive mutant (TS-4) of Toxoplasma gondii develop complete resistance to subsequent challenge with a highly virulent Toxoplasma strain (RH). Because CD8+ T cells have been demonstrated to be critical to this protective immunity in vivo, the involvement of cytotoxic T lymphocytes in the killing of infected cells in vaccinated mice was investigated. After restimulation in vitro, splenic T cells from vaccinated mice of either the BALB/c or C57BL/6 strains were found to kill syngeneic bone marrow-derived macrophages infected with TS-4 tachyzoites or preincubated with soluble T. gondii Ag. Unimmunized control mice or mice vaccinated with heat-killed TS-4 tachyzoites failed to generate significant CTL activity in vitro. Moreover, the observed lytic reaction was found to be target specific, not killing uninfected or unpulsed macrophages even when included as bystanders in the assay. Target lysis did not depend on the production by the effector cells of either a cytotoxic supernatant factor or IFN-gamma. Depletion of CD8+ cells from the splenic effector cell population, however, abrogated the cytotoxic activity, whereas depletion of CD4+ cells had little effect. The MHC restriction of the Toxoplasma-specific cytolytic reaction was confirmed in studies using effector cells from BALB/c mice and targets from congenic or mutant haplotype strains. These experiments indicated that target killing is primarily restricted by genes mapping within the H-2D/Ld loci. Together, these results establish MHC-restricted cytolysis as a major parameter of CD8+ effector function against T. gondii and indicate that, in the case of this protozoan, Ag presentation to CD8+ lymphocytes can occur as a result of either processing within infected cells or exogenous uptake of parasite Ag.

Hereditary joint disorder in progressive ankylosis (ank/ank) mice. I. Association of calcium hydroxyapatite deposition with inflammatory arthropathy.

Progressive ankylosis (ank), a murine autosomal recessive mutation, produces an inflammatory joint disorder associated with intraarticular calcium hydroxyapatite deposition and culminates in fusion of the joints. Joints in the feet become stiffened and swollen with milky white fluid containing polymorphonuclear leukocytes, large mononuclear macrophage-like cells, and calcium hydroxyapatite. The joints develop a proliferative synovitis, sometimes associated with marginal erosions of the articular cartilage and periosteal bone. Subsequently, cartilaginous osteophytes, extending outward from the subchondral bone, bridge the margins of the joint and undergo ossification. The progressive ankylosis mutation provides a useful system for investigating calcium hydroxyapatite-associated arthropathies.