The need for paradigm shift: prognostic significance and implications of standard therapy-related systemic immunosuppression in glioblastoma for immunotherapy and oncolytic virotherapy

Despite significant advances in our knowledge regarding the genetics and molecular biology of gliomas over the past two decades and hundreds of clinical trials, no effective therapeutic approach has been identified for adult patients with newly diagnosed glioblastoma, and overall survival remains dismal. Great hopes are now placed on combination immunotherapy. In clinical trials, immunotherapeutics are generally tested after standard therapy (radiation, temozolomide, and steroid dexamethasone) or concurrently with temozolomide and/or steroids. Only a minor subset of patients with progressive/recurrent glioblastoma have benefited from immunotherapies. In this review, we comprehensively discuss standard therapy-related systemic immunosuppression and lymphopenia, their prognostic significance, and the implications for immunotherapy/oncolytic virotherapy. The effectiveness of immunotherapy and oncolytic virotherapy (viro-immunotherapy) critically depends on the activity of the host immune cells. The absolute counts, ratios, and functional states of different circulating and tumor-infiltrating immune cell subsets determine the net immune fitness of patients with cancer and may have various effects on tumor progression, therapeutic response, and survival outcomes. Although different immunosuppressive mechanisms operate in patients with glioblastoma/gliomas at presentation, the immunological competence of patients may be significantly compromised by standard therapy, exacerbating tumor-related systemic immunosuppression. Standard therapy affects diverse immune cell subsets, including dendritic, CD4+, CD8+, natural killer (NK), NKT, macrophage, neutrophil, and myeloid-derived suppressor cell (MDSC). Systemic immunosuppression and lymphopenia limit the immune system's ability to target glioblastoma. Changes in the standard therapy are required to increase the success of immunotherapies. Steroid use, high neutrophil-to-lymphocyte ratio (NLR), and low post-treatment total lymphocyte count (TLC) are significant prognostic factors for shorter survival in patients with glioblastoma in retrospective studies; however, these clinically relevant variables are rarely reported and correlated with response and survival in immunotherapy studies (e.g., immune checkpoint inhibitors, vaccines, and oncolytic viruses). Our analysis should help in the development of a more rational clinical trial design and decision-making regarding the treatment to potentially improve the efficacy of immunotherapy or oncolytic virotherapy.

Results of phase 2 randomized multi-center study to evaluate the safety and efficacy of infusion of memory T cells as adoptive therapy in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia and/or lymphopenia (RELEASE NCT04578210)

BACKGROUND AIMS

There are currently no effective anti-viral treatments for coronavirus disease 2019 (COVID-19)-hospitalized patients with hypoxemia. Lymphopenia is a biomarker of disease severity usually present in patients who are hospitalized. Approaches to increasing lymphocytes exerting an anti-viral effect must be considered to treat these patients. Following our phase 1 study, we performed a phase 2 randomized multicenter clinical trial in which we evaluated the efficacy of the infusion of allogeneic off-the-shelf CD45RA- memory T cells containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells from convalescent donors plus the standard of care (SoC) versus just the SoC treatment.

METHODS

Eighty-four patients were enrolled in three Spanish centers. The patients were randomized into the infusion of 1 × 106/kg CD45RA- memory T cells or the SoC. We selected four unvaccinated donors based on the expression of interferon gamma SARS-CoV-2-specific response within the CD45RA- memory T cells and the most frequent human leukocyte antigen typing in the Spanish population.

RESULTS

We analyzed data from 81 patients. The primary outcome for recovery, defined as the proportion of participants in each group with normalization of fever, oxygen saturation sustained for at least 24 hours and lymphopenia recovery through day 14 or at discharge, was met for the experimental arm. We also observed faster lymphocyte recovery in the experimental group. We did not observe any treatment-related adverse events.

CONCLUSIONS

Adoptive cell therapy with off-the-shelf CD45RA- memory T cells containing SAR-CoV-2-specific T cells is safe, effective and accelerates lymphocyte recovery of patients with COVID-19 pneumonia and/or lymphopenia.

TRIAL REGISTRATION

NCT04578210.

A phase I/II dose-escalation multi-center study to evaluate the safety of infusion of natural killer cells or memory T cells as adoptive therapy in coronavirus pneumonia and/or lymphopenia: RELEASE study protocol

BACKGROUND

Moderate/severe cases of COVID-19 present a dysregulated immune system with T cell lymphopenia and a hyper-inflammatory state. This is a study protocol of an open-label, multi-center, double-arm, randomized, dose-finding phase I/II clinical trial to evaluate the safety, tolerability, alloreactivity, and efficacy of the administration of allogeneic memory T cells and natural killer (NK) cells in COVID-19 patients with lymphopenia and/or pneumonia. The aim of the study is to determine the safety and the efficacy of the recommended phase 2 dose (RP2D) of this treatment for patients with moderate/severe COVID-19.

METHODS

In the phase I trial, 18 patients with COVID-19-related pneumonia and/or lymphopenia with no oxygen requirement or with an oxygen need of ≤ 2.5 liters per minute (lpm) in nasal cannula will be assigned to two arms, based on the biology of the donor and the patient. Treatment of arm A consists of the administration of escalating doses of memory T cells, plus standard of care (SoC). Treatment of arm B consists of the administration of escalating doses of NK cells, plus SoC. In the phase II trial, a total of 182 patients with COVID-19-related pneumonia and/or lymphopenia requiring or not oxygen supplementation but without mechanical ventilation will be allocated to arm A or B, considering HLA typing. Within each arm, they will be randomized in a 1:1 ratio. In arm A, patients will receive SoC or RP2D for memory T cells plus the SoC. In arm B, patients will receive SoC or RP2D for NK cells plus the SoC.

DISCUSSION

We hypothesized that SARS-CoV-2-specific memory T-lymphocytes obtained from convalescent donors recovered from COVID-19 can be used as a passive cell immunotherapy to treat pneumonia and lymphopenia in moderate/severe patients. The lymphopenia induced by COVID-19 constitutes a therapeutic window that may facilitate donor engraftment and viral protection until recovery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04578210 . First Posted : October 8, 2020.

Advances in Adoptive Cell Therapy Using Induced Pluripotent Stem Cell-Derived T Cells

Adoptive cell therapy (ACT) using chimeric antigen receptor (CAR) T cells holds impressive clinical outcomes especially in patients who are refractory to other kinds of therapy. However, many challenges hinder its clinical applications. For example, patients who undergo chemotherapy usually have an insufficient number of autologous T cells due to lymphopenia. Long-term ex vivo expansion can result in T cell exhaustion, which reduces the effector function. There is also a batch-to-batch variation during the manufacturing process, making it difficult to standardize and validate the cell products. In addition, the process is labor-intensive and costly. Generation of universal off-the-shelf CAR T cells, which can be broadly given to any patient, prepared in advance and ready to use, would be ideal and more cost-effective. Human induced pluripotent stem cells (iPSCs) provide a renewable source of cells that can be genetically engineered and differentiated into immune cells with enhanced anti-tumor cytotoxicity. This review describes basic knowledge of T cell biology, applications in ACT, the use of iPSCs as a new source of T cells and current differentiation strategies used to generate T cells as well as recent advances in genome engineering to produce next-generation off-the-shelf T cells with improved effector functions. We also discuss challenges in the field and future perspectives toward the final universal off-the-shelf immunotherapeutic products.

Successful Cord Blood Transplantation for Idiopathic CD4+ Lymphocytopenia

Idiopathic CD4+ lymphocytopenia (ICL) is the depletion of CD4+ lymphocytes to <300 cells/mm3 without human immunodeficiency virus infection or other causes of lymphocytopenia. ICL causes fatal infections; its etiology remains unclear and it lacks consensus regarding therapeutic options. We report the first patient with ICL who had a successful clinical course following a cord blood transplant (CBT). A 45-year-old woman was diagnosed with ICL and underwent partial hepatectomy for an abscess caused by the Mycobacterium avium complex. No specific gene alterations were detected through next generation sequencing-based evaluation. Following a reduced-intensity conditioning (RIC) regimen consisting of fludarabine, busulfan, and 4 Gy total body irradiation, a single-unit CBT was performed. Neutrophils were engrafted on day +14. CD4+ lymphocyte counts increased to over 300 cells/mm3 on day +436. After 75 months, she was alive without any sequelae. CBT with an RIC regimen could be a curable treatment option for ICL.

Three Cases of Pediatric Multisystem Inflammatory Syndrome Associated with COVID-19 Due to SARS-CoV-2

BACKGROUND Coronavirus disease 2019 (COVID-19) infection commonly presents as fever, cough, and shortness of breath in adults. Children are thought to have milder respiratory symptoms and to recover more quickly. We describe a new presentation of COVID-19 infection in children consisting of multisystem inflammation with decreased left ventricular function and evidence of lung disease. CASE REPORT Three children presented with fever, conjunctivitis, dry and cracked lips, rash, and/or cervical lymphadenopathy for at least 5 days. Two of these children required mechanical ventilation, and 1 of the 2 needed extracorporeal membrane oxygenation (ECMO) to support cardiorespiratory function. All of these children had moderate to severe hyponatremia and lymphopenia, which is usually seen in COVID-19. They were treated with intravenous immunoglobulin and high-dose aspirin. All of the children recovered. CONCLUSIONS Early recognition of children with multisystem inflammation is important because they are at increased risk for deterioration. Treatment with intravenous immunoglobulin and aspirin was used because this regimen has been shown to be beneficial in vasculitis of Kawasaki disease. The development of shock due to cardiac involvement may require ECMO.

Coronavirus Disease 2019 (COVID-19): A Haematologist's Perspective

Coronavirus disease 2019 (COVID-19) is affecting millions of patients worldwide. It is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which belongs to the family Coronaviridae, with 80% genomic similarities to SARS-CoV. Lymphopenia was commonly seen in infected patients and has a correlation to disease severity. Thrombocytopenia, coagulation abnormalities, and disseminated intravascular coagulation were observed in COVID-19 patients, especially those with critical illness and non-survivors. This pandemic has caused disruption in communities and hospital services, as well as straining blood product supply, affecting chemotherapy treatment and haematopoietic stem cell transplantation schedule. In this article, we review the haematological manifestations of the disease and its implication on the management of patients with haematological disorders.

The many faces of the anti-COVID immune response

The novel 2019 strain of coronavirus is a source of profound morbidity and mortality worldwide. Compared with recent viral outbreaks, COVID-19 infection has a relatively high mortality rate, the reasons for which are not entirely clear. Furthermore, treatment options for COVID-19 infection are currently limited. In this Perspective, we explore the contributions of the innate and adaptive immune systems to both viral control as well as toxicity during COVID-19 infections and offer suggestions to both understand and therapeutically modulate anti-COVID immunity.

Multiple Myeloma in the Time of COVID-19

We provide our recommendations (not evidence based) for managing multiple myeloma patients during the pandemic of COVID-19. We do not recommend therapy for smoldering myeloma patients (standard or high risk). Screening for COVID-19 should be done in all patients before therapy. For standard-risk patients, we recommend the following: ixazomib, lenalidomide, and dexamethasone (IRd) (preferred), cyclophosphamide lenalidomide and dexamethasone (CRd), daratumumab lenalidomide and dexamethasone (DRd), lenalidomide, bortezomib, and dexamethasone (RVd), or cyclophosphamide, bortezomib, and dexamethasone (CyBorD). For high-risk patients we recommend carfilzomib, lenalidomide, and dexamethasone (KRd) (preferred) or RVd. Decreasing the dose of dexamethasone to 20 mg and giving bortezomib subcutaneously once a week is recommended. We recommend delaying autologous stem cell transplant (ASCT), unless the patient has high-risk disease that is not responding well, or if the patient has plasma cell leukemia (PCL). Testing for COVID-19 should be done before ASCT. If a patient achieves a very good partial response or better, doses and frequency of drug administration can be modified. After 10–12 cycles, lenalidomide maintenance is recommended for standard-risk patients and bortezomib or ixazomib are recommended for high-risk patients. Daratumumab-based regimens are recommended for relapsed patients. Routine ASCT is not recommended for relapse during the epidemic unless the patient has an aggressive relapse or secondary PCL. Patients on current maintenance should continue their therapy.

Primary intestinal lymphangiectasia in an elderly female patient: A case report on a rare cause of secondary immunodeficiency

Protein loss via the gut can be caused by a number of gastrointestinal disorders, among which intestinal lymphangiectasia has been described to not only lead to a loss of proteins but also to a loss of lymphocytes, resembling secondary immunodeficiency. We are reporting on a 75-year-old female patient who came to our hospital because of a minor stroke. She had no history of serious infections. During the diagnostic work-up, we detected an apparent immunodeficiency syndrome associated with primary intestinal lymphangiectasia. Trying to characterize the alterations of the immune system, we not only found hypogammaglobulinemia and lymphopenia primarily affecting CD4+, and also CD8+ T cells, but also marked hypocomplementemia affecting levels of complement C4, C2, and C3. The loss of components of the immune system most likely was due to a chronic loss of immune cells and proteins via the intestinal lymphangiectasia, with levels of complement components following the pattern of protein electrophoresis. Thus, intestinal lymphangiectasia should not only be considered as a potential cause of secondary immune defects in an elderly patient, but can also be associated with additional hypocomplementemia.

Pretreatment Lymphopenia, Poor Performance Status, and Early Courses of Therapy Are Risk Factors for Severe Bacterial Infection in Patients with Multiple Myeloma during Treatment with Bortezomib-based Regimens

The aim of this study was to identify the risk factors associated with severe bacterial infection (SBI) in multiple myeloma (MM) patients during treatment with bortezomib-based regimens. A total of 98 patients with MM were evaluated during 427 treatment courses. SBI occurred in 57.1% (56/98) of the patients and during 19.0% (81/427) of the treatment courses. In the multivariate analysis for the factors associated with the development of SBI in each treatment course, poor performance status (Eastern Cooperative Oncology Group ≥ 2, P < 0.001), early course of therapy (≤ 2 courses, P < 0.001), and pretreatment lymphopenia (absolute lymphocyte count < 1.0 × 10(9)/L, P = 0.043) were confirmed as independent risk factors. The probability of developing SBI were 5.1%, 14.9%, 23.9% and 59.5% in courses with 0, 1, 2, and 3 risk factors, respectively (P < 0.001). In conclusion, we identified three pretreatment risk factors associated with SBI in each course of bortezomib treatment. Therefore, MM patients with these risk factors should be more closely monitored for the development of SBI during bortezomib-based treatment.

Understanding the biology of ex vivo-expanded CD8 T cells for adoptive cell therapy: role of CD62L

CD62L governs the circulation of CD8(+) T cells between lymph nodes and peripheral tissues, whereby the expression of CD62L by CD8(+) T cells promotes their recirculation through lymph nodes. As such, CD62L participates in the fate of adoptively transferred CD8(+) T cells and may control their effectiveness for cancer immunotherapy, including settings in which host preconditioning results in the acute lymphopenia-induced proliferation of the transferred cells. Indeed, previous studies correlated CD62L expression by donor CD8(+) cells with the success rate of adoptive cell therapy (ACT). Here, we analyzed the functions and fate of ex vivo-activated, tumor-specific CD62L(-/-) CD8(+) T cells in a mouse melanoma model for ACT. Unexpectedly, we observed that CD62L(-/-) CD8(+) T cells were functionally indistinguishable from CD62L(+/+) CD8(+) T cells, i.e., both greatly expanded in cyclophosphamide preconditioned animals, controlled subcutaneously and hematogenously spreading tumors, and generated anti-tumor-specific CD8(+) T cell memory. Moreover, even in hosts with rudimentary secondary lymphoid organs (LT(-/-) animals), CD8(+) T cells with and without CD62L expanded equivalently to those adoptively transferred into wild-type animals. These results put into question the utility of CD62L as a predictive biomarker for the efficacy of ex vivo-expanded T cells after ACT in lymphopenic conditions and also offer new insights into the homing, engraftment, and memory generation of adoptively transferred ex vivo-activated CD8(+) T cells.

The prognostic significance of lymphopenia in peripheral T-cell and natural killer/T-cell lymphomas: a study of 826 cases from the International Peripheral T-cell Lymphoma Project

Lymphopenia is a marker of inferior survival in patients with various malignancies. However, the prognostic significance of lymphopenia in peripheral T-cell lymphoma (PTCL) is unclear. We analyzed the prognostic significance of lymphopenia in 826 patients with different types of PTCL and natural killer/T-cell lymphoma (NKTCL) from the International Peripheral T-cell Lymphoma Project. Lymphopenia was defined as an absolute lymphocyte count of less than 1,000 cells per microliter. The overall frequency of lymphopenia was 35.3%, ranging from 21.1% in ALK(+) anaplastic large cell lymphoma (ALCL) to 47.5% in angioimmunoblastic T-cell lymphoma (AITL). Lymphopenia was independently associated with an inferior overall survival (OS) in patients with the lymphoma type of adult T-cell leukemia/lymphoma (ATLL), with a 2-year OS of 15% versus 40% for those without lymphopenia (P < 0.001). Lymphopenia was also an adverse predictor of survival in PTCL, not otherwise specified, but was associated with other unfavorable prognostic factors. A trend toward inferior survival for lymphopenic patients was also observed in AITL, ALK(-) ALCL and extranasal NKTCL lymphoma, whereas no difference in survival was found in nasal NKTCL, ALK(+) ALCL, or enteropathy-associated T-cell lymphoma. In this study, lymphopenia was identified as a new adverse prognostic factor in the lymphoma type of ATLL.

A glycosylphosphatidylinositol-based treatment alleviates trypanosomiasis-associated immunopathology

The GPI-anchored trypanosome variant surface glycoprotein (VSG) triggers macrophages to produce TNF, involved in trypanosomiasis-associated inflammation and the clinical manifestation of sleeping sickness. Aiming at inhibiting immunopathology during experimental Trypanosoma brucei infections, a VSG-derived GPI-based treatment approach was developed. To achieve this, mice were exposed to the GPI before an infectious trypanosome challenge. This GPI-based strategy resulted in a significant prolonged survival and a substantial protection against infection-associated weight loss, liver damage, acidosis, and anemia; the latter was shown to be Ab-independent and correlated with reduced macrophage-mediated RBC clearance. In addition, GPI-based treatment resulted in reduced circulating serum levels of the inflammatory cytokines TNF and IL-6, abrogation of infection-induced LPS hypersensitivity, and an increase in circulating IL-10. At the level of trypanosomiasis-associated macrophage activation, the GPI-based treatment resulted in an impaired secretion of TNF by VSG and LPS pulsed macrophages, a reduced expression of the inflammatory cytokine genes TNF, IL-6, and IL-12, and an increased expression of the anti-inflammatory cytokine gene IL-10. In addition, this change in cytokine pattern upon GPI-based treatment was associated with the expression of alternatively activated macrophage markers. Finally, the GPI-based treatment also reduced the infection-associated pathology in Trypanosoma congolense and Trypanosoma evansi model systems as well as in tsetse fly challenge experiments, indicating potential field applicability for this intervention strategy.

Transplant conditions determine the contribution of homeostatically expanded donor CD8 memory cells to host lymphoid reconstitution following syngeneic HCT

OBJECTIVE

To investigate the ability of donor CD8 memory (CD8 TM) cells to expand in recipients following syngeneic hematopoietic stem cell transplants (HCT). The influence of clinically important transplant parameters--conditioning level, delayed infusion and dose--on the homeostatic expansion and overall contribution of donor CD8 TM to host CD8 reconstitution was determined.

MATERIALS AND METHODS

Lymphopenia-induced CD8 TM homeostatic expansion was examined in a syngeneic murine HCT model. Antigen specific CD8 TM included both T-cell receptor transgenic and nontransgenic populations. An ex vivo technique using antigen, interleukin (IL)-2, and IL-15 was used to generate homogenous transgenic CD8 TM (i.e., central memory) and was adapted to enrich the heterogeneous nontransgenic CD8 population specific for a nonameric epitope.

RESULTS

Both transgenic and naturally occurring CD8 memory populations, derived in vivo or generated ex vivo, underwent a similar kinetic pattern of homeostatic expansion following transplantation into ablatively conditioned syngeneic recipients. Transplant parameters, i.e., lower conditioning, delayed infusion, and lower donor CD8 cell numbers shortened the period of expansion and lowered the steady-state numbers.

CONCLUSIONS

The pattern of CD8 TM expansion was dependent on conditioning levels, time of infusion, and dose. Transplantation of varying donor CD8 TM numbers demonstrated there was a maximal donor cell contribution to host CD8 reconstitution. The application of multiple well-defined memory CD8 populations supports the notion that these findings are characteristic of memory CD8 cells in general.

Lymphopenic mice reconstituted with limited repertoire T cells develop severe, multiorgan, Th2-associated inflammatory disease

Lymphopenia and restricted T cell repertoires in humans are often associated with severe eosinophilic disease and a T cell Th2 bias. To examine the pathogenesis of this phenomenon, C57BL/6 Rag2-/- mice received limited (3 x 10(4)) or large (2 x 10(6)) numbers of CD4 T cells. Three to 5 months after transfer, mice that had received 3 x 10(4) T cells, but not those that received 2 x 10(6), developed fulminant macrophage pneumonia with eosinophilia, Ym1 deposition, and methacholine-induced airway hyperresponsiveness, as well as eosinophilic gastritis; esophagitis and other organ damage occurred in some cases. Donor cells were enriched for IL-4, IL-5, and IL-13 producers. When 3 x 10(4) cells were transferred into CD3epsilon-/- hosts, the mice developed strikingly elevated serum IgE. Prior transfer of 3 x 10(5) CD25+ CD4 T cells into Rag2-/- recipients prevented disease upon subsequent transfer of CD25- CD4 T cells, whereas 3 x 10(4) regulatory T cells (Tregs) did not, despite the fact that there were equal total numbers of Tregs in the host at the time of transfer of CD25- CD4 T cells. Limited repertoire complexity of Tregs may lead to a failure to control induction of immunopathologic responses, and limitation in repertoire complexity of conventional cells may be responsible for the Th2 phenotype.

Use of hot water bottles can improve lymphocytopenia

We observed that patients with lymphocytopenia have a cold external body temperature-especially the abdomen, hips and extremities-as recognized by palpation. Such patients were recommended to use a hot water bottle especially for cold extremities for the purpose of improving "chill". Six cases of lymphocytopenia diagnosed by previous medical doctors within two weeks before consulting our clinic are described in this study. The patients warmed their trunks and extremities by hot water bottles for as long as possible not only while sleeping but also during the daytime. There was no remarkable change in leukocyte count, but granulocytes significantly decreased in number (from 6,716 +/- 4,032 to 5,467 +/- 2,660) (p=0.013), and lymphocytes significantly increased from 718 +/- 211 to 1,845 +/- 406 (p=0.0017). It is important for clinicians to recognize that such an easy method can improve lymphocytopenia.

Cytokine signals in T-cell homeostasis

Thymic production of T cells declines rapidly with age, and therefore homeostatic cycling (HC) of mature lymphocytes plays an important role in maintaining stable numbers of mature T lymphocytes bearing sufficient repertoire diversity. Following lymphocyte depletion, HC changes in quality and magnitude, resulting in homeostatic peripheral expansion (HPE), a state of widespread T-cell cycling that serves to increase T-cell number and to maintain T-cell repertoire diversity to the greatest extent possible. Recent studies delineating the requirements for HC and HPE have shown that naive CD4+ cells and naive CD8+ cells require both IL7 and TCR engagement for survival, cycling, and homeostatic expansion, whereas CD8+ memory cells are maintained and expanded by cytokine signals alone, independent of TCR engagement. While basal levels of IL15 are sufficient for HC and HPE of CD8+ memory cells, supranormal levels of IL7 will also suffice. The requirements for memory CD4+ cells remain unclear, but current models hypothesize that either IL7 or TCR triggering may be sufficient. Thus, the changes in immune physiology that are present in lymphopenic hosts can be largely accounted for by cytokine-driven signals, especially those rendered by IL7 or IL15. As the alterations in immune physiology present in lymphopenic hosts may be conducive to stronger antitumor immune responsiveness, careful delineation of the factors responsible may be expected to give rise to approaches to augment the effectiveness of current antitumor immunotherapies.

Restoration of immunity in lymphopenic individuals with cancer by vaccination and adoptive T-cell transfer

Immunodeficiency is a barrier to successful vaccination in individuals with cancer and chronic infection. We performed a randomized phase 1/2 study in lymphopenic individuals after high-dose chemotherapy and autologous hematopoietic stem cell transplantation for myeloma. Combination immunotherapy consisting of a single early post-transplant infusion of in vivo vaccine-primed and ex vivo costimulated autologous T cells followed by post-transplant booster immunizations improved the severe immunodeficiency associated with high-dose chemotherapy and led to the induction of clinically relevant immunity in adults within a month after transplantation. Immune assays showed accelerated restoration of CD4 T-cell numbers and function. Early T-cell infusions also resulted in significantly improved T-cell proliferation in response to antigens that were not contained in the vaccine, as assessed by responses to staphylococcal enterotoxin B and cytomegalovirus antigens (P < 0.05). In the setting of lymphopenia, combined vaccine therapy and adoptive T-cell transfer fosters the development of enhanced memory T-cell responses.

[New strategy of cancer immunotherapy: irradiation or chemotherapeutics-induced lymphopenia combined with immune reconstitution and tumor vaccine]

OBJECTIVE

To test whether vaccination performed during irradiation or chemotherapeutics-induced lymphopenia-driven T cell proliferation could augment the antitumor immunity.

METHODS

The study composed of two parts, investigating the anti-tumor efficacy of performing tumor vaccination during early immune reconstitution period following sublethal total body irradiation and cyclophosphamide (Cy)-induced lymphopenia, respectively. Mice were subsequently reconstituted with naïve splenocytes from syngeneic mice and were named RLM (Reconstituted lymphopenic mice). Immunization/vaccination (F10) and adoptive immunotherapy (D5-G6) were used to explore anti-tumor immune responses in vaccinated irradiation/RLM and vaccinated Cy/RLM, respectively. Both normal C57BL/6 mice and RLM were vaccinated with irradiated, weakly immunogenic F10 melanoma cells and subsequently challenged with F10 cells. In addition, to determine the role of CD4(+) and CD8(+) T cells in the protective anti-tumor immune response, irradiation/RLM were depleted of these subpopulations by administration of the appropriate mAb around challenge. In the second part, adoptive immunotherapy was used to evaluate the anti-tumor immune responses under chemotherapeutics-induced lymphopenic condition. Both normal mice and RLM (Cy-treated) were vaccinated with GM-CSF-modified D5 melanoma cells (D5-G6) and tumor vaccine draining lymph nodes (TVDLN) were harvested 9-10 days later. Effector T cells were generated in vitro from TVDLN cells and adoptively transferred to mice bearing 3-day pre-established pulmonary metastases (D5). Recipient mice were sacrificed 2 weeks later after tumor inoculation and pulmonary metastases were enumerated.

RESULTS

Significantly greater protection was induced in vaccinated irradiation/RLM, compared to vaccinated normal mice (63.2% vs 16.7%). Protective immunity in RLM depended on CD8(+) T cells. Increase in the interval between reconstitution and vaccination significantly decrease the protection. Effector T cells generated from vaccinated Cy-treated RLM demonstrated significantly higher in vivo anti-tumor efficacy over those of vaccinated normal mice.

CONCLUSION

This study suggests that vaccination of RLM could elicit augmented antitumor immunity compared to normal hosts, highlighting the potential clinical benefit of performing tumor vaccination during irradiation or chemotherapeutics-induced lymphopenia in cancer patients.

Less is more: lymphodepletion followed by hematopoietic stem cell transplant augments adoptive T-cell-based anti-tumor immunotherapy

Adoptive T-cell immunotherapy combined with non-myeloablative lymphodepletion has emerged as the most effective immunotherapy treatment for patients with metastatic melanoma (objective response rates of 50%). The mechanisms underlying this major advance in the field of immunotherapy include the elimination of regulatory elements and increased access to activating cytokines. This results in the activation of low-affinity T cells, enabling them to destroy tumors. We propose that a more complete depletion of the patient's immune system followed by transplantation with hematopoietic stem cells, which can be genetically modified, would be more effective in the treatment of metastatic cancer.

Reversible acute gastrointestinal syndrome associated with active systemic lupus erythematosus in patients admitted to hospital

Patients with systemic lupus erythematosus (SLE) frequently have gastrointestinal (GI) symptoms. These are usually self-limiting and related to treatment side-effects or concurrent illness. However, abdominal pain may be due to bowel ischaemia which can lead to infarction and perforation. The likelihood of these serious events is increased in individuals with pain severe enough to require assessment in hospital or a SLEDAI score > 5. This paper describes a group of patients with active SLE and GI symptoms severe enough to require admission to hospital using a retrospective review of 52 SLE patients admitted to hospital with acute abdominal symptoms. The results showed that abdominal pain (87%), vomiting (82%) and diarrhoea (67%) had been present for a mean of 4.4 +/- 6.5 days and SLEDAI score was > or = 4 in 83% of patients. CT scanning showed evidence of serositis and bowel involvement in 63% of patients who underwent this investigation. Intravenous (iv) fluids were used in 87%, parenteral steroids in 90% and iv cyclophosphamide in 31%. Most (n = 51) were discharged well. Recurrence of GI symptoms occurred in 12 patients. The conclusions are that active SLE may manifest as an acute gastrointestinal syndrome. Early diagnosis, bowel rest, supportive medical therapy and treatment with corticosteroids and/or immunosupressives can result in a good outcome.

Potentiation of immunological tolerance induction in adult mice by co-administration of pooled normal IgG and oral tolerogens: a potential therapeutic approach for autoimmune diseases

Oral tolerance can be defined as the inability of an adult animal to produce specific antibodies or cellular immune responses upon conventional immunization, after oral antigenic administration. Recently, the oral administration of antigens has gained renewed interest because of the possibility of inducing tolerance in nonimmunized adult animals and, consequently, opening up the theoretical possibility of preventing or treating diseases caused by malfunction of the immune system. This strategy has been proven to be useful in the prevention of allergic and autoimmune diseases in rodents, as well as in the amelioration of certain autoimmune diseases in humans. Although there is experimental and clinical evidence for the usefulness of oral tolerance in medical practice, the mechanisms responsible for this phenomenon are still poorly understood, and the results obtained are not always satisfactory. Herein, we show that the thymus is required for the induction and maintenance of oral tolerance, providing evidence that it is not a pure form of clonal deletion-based peripheral tolerance. Oral tolerance could therefore depend on the formation and release to the periphery of regulatory T cells, such as gammadelta or alphabeta T cells, by the thymus. This finding may have profound implications for the treatment of autoimmune diseases, since most of them are associated with thymic hypofunction. On the other hand, due to so far unknown mechanisms, the intraperitoneal co-administration of normal IgG to mice orally treated with tolerogen leads to a sustained and intense immunological tolerance, both in euthymic and thymectomized mice, including those of the lupus erythematosus-prone NZB x NZW lineage. This approach for inducing and maintaining tolerance in thymus-deficient conditions is discussed and put forth herein as a new evidence-based proposition for the therapy of autoimmune diseases.

Growth hormone (GH)-induced reconstitution of CD8+ CD28+ T lymphocytes in a rare case of severe lymphopenia associated with Juvenile Haemochromatosis and Turner's syndrome

This paper describes a rare case of Turner's syndrome associated with Juvenile Haemochromatosis and severe lymphopenia, followed-up for a period of 5 years. Because of the indication for treatment with growth hormone (GH), this case was observed as a model to analyse the effects of GH on growth, iron mobilization and lymphocyte reconstitution. For this purpose, a serial study of the T lymphocyte subpopulations CD4+, CD8+, CD8+ CD28+ and CD8+ CD28- was performed by immunophenotyping during the follow-up period. Besides the impact of both phlebotomy treatment and GH on the rapid growth and mobilization of 20.8 g of iron in 136 weeks, the most relevant observation was the finding of a significant expansion of CD8+ T lymphocytes expressing the costimulatory marker CD28 in the setting of the severe lymphopenia. These findings constitute new clinical evidence supporting the notion that the GH/IGF-1 system has an important role on the maintenance of T cell homeostasis in vivo, and that GH may be regarded as a putative therapeutic agent in T lymphocyte reconstitution.

Transplantation of a combination of CD133+ and CD34+ selected progenitor cells from alternative donors

Positive selected haematopoietic stem cells are increasingly used for allogeneic transplantation with the CD34 antigen employed in most separation techniques. However, the recently described pentaspan molecule CD133 appears to be a marker of more primitive haematopoietic progenitors. Here we report our experience with a new CD133-based selection method in 10 paediatric patients with matched unrelated (n = 2) or mismatched-related donors (n = 8). These patients received a combination of stem cells (median = 29.3 x 10(6)/kg), selected with either anti-CD34 or anti-CD133 coated microbeads. The proportion of CD133+ selected cells was gradually increased from patient to patient from 10% to 100%. Comparison of CD133+ and CD34+ separation procedures revealed similar purity and recovery of target populations but a lower depletion of T cells by CD133+ selection (3.7 log vs. 4.1 log, P < 0.001). Both separation procedures produced >90% CD34+/CD133+ double positive target cells. Engraftment occurred in all patients (sustained primary, n = 8; after reconditioning, n = 2). No primary acute graft versus host disease (GvHD) >/= grade II or chronic GvHD was observed. The patients showed a rapid platelet recovery (median time to independence from substitution = 13.5 d), whereas T cell regeneration was variable. Five patients are alive with a median follow-up of 10 months. Our data demonstrates the feasibility of CD133+ selection for transplantation from alternative donors and encourages further trials with total CD133+ separated grafts.

Rapid recovery from T lymphopenia by CD28 superagonist therapy

Slow recovery of T-cell numbers and function contributes to the high incidence of life-threatening infections after cytotoxic cancer therapies. We have tested the therapeutic potential of a novel class of superagonistic CD28-specific antibodies that induce polyclonal T-cell proliferation without T-cell receptor engagement in an experimental rat model of T lymphopenia. We show that in lethally irradiated, bone marrow-reconstituted hosts, CD28 superagonist is able to dramatically accelerate repopulation by a small inoculum of mature, allotype-marked T cells. CD28-driven recovery of CD4 cells was superior to that of CD8 T cells. CD28 superagonist- expanded CD4 T cells had maintained repertoire diversity and were functional both in vitro and in vivo, suggesting that treatment with a human CD28-specific superagonist will protect T-lymphopenic patients from opportunistic infections.

Tumour cell contamination of autologous stem cells grafts in high-risk neuroblastoma: the good news?

We analysed the effect of graft-contaminating tumour cells on the long-term survival of 24 patients with high-risk neuroblastoma and found that patients whose grafts contained detectable neuroblastoma cells had a significantly higher probability of survival than did patients with no detectable tumour cells. Estimated contamination of the graft by more than 2000 tumour cells was associated with a significantly higher probability of survival than contamination with fewer tumour cells. We hypothesise that the presence of a critical number of graft-contaminating neuroblastoma cells can elicit a protective antitumour immune response after autologous transplantation.

IL-2 therapy and thymic production of naive CD4 T cells in HIV-infected patients with severe CD4 lymphopenia

OBJECTIVES

IL-2 therapy increases memory and naive CD4 T cells in HIV-infected patients, but its effect on thymopoiesis is unknown. To investigate this effect, we quantified T-cell receptor rearrangement excision circles (TREC) in CD4 T cells from lymphopenic AIDS patients treated with highly active antiretroviral therapy and IL-2.

METHODS

CD4 cell subsets were evaluated by flow cytometry using anti-CD45RO/RA, CD62L, Ki67 and CD95 monoclonal antibodies. The proportion of recent thymic emigrant had been quantified by a real-time polymerase chain reaction assay for signal joint TREC in peripheral blood mononuclear and purified CD4 T cells.

RESULTS

At initiation of IL-2, TREC copies/microl of blood were correlated with naive T cell numbers and age. Both naive and TREC numbers/microl significantly increased over time in all patients, with a wide range of TREC increases. Higher percentages of CD4+CD45RO-negative cells positive for the Ki67 cell-cycle marker were found in patients with a low TREC increase, but remained stable under IL-2. TREC and naive cell recovery were correlated; they also correlated with the numbers of TREC and naive cells at the start of IL-2, and with age, suggesting a thymic origin for naive T-cell recovery. A mathematical model showing the linear recovery of naive cells and TREC under IL-2 also strongly suggested that a naive T-cell increase reflects thymic export and involves little net death and proliferation.

CONCLUSION

Although we cannot rule out a mechanism of altered proliferation or death rate, the thymus plays an important role in the long-term recovery of naive T cells under IL-2 therapy.

Idiopathic CD4+ T cell lymphocytopenia with the absence of B cells and CD8+28+ cells in peripheral blood

The absence of B cells and a severe decrease in CD8+28+ cells were observed in two female children with CD4+ T cell lymphocytopenia. Idiopathic (primary) CD4+ lymphocytopenia is a rare entity and its pathogenesis and genetics are not yet known. The literature was reviewed, in particular for severe alterations in B and CD8+28+ cells and for the role of NF-kappa B and p56 (lck) in the immunopathogenesis. Whether the underlying mechanism in idiopathic CD4+ lymphocytopenia is found or not, these patients who present with severe symptoms of a combined immunodeficiency must be treated with intravenous immunoglobin regularly until they have a compatible donor for bone marrow transplantation.

Transient lymphopenia in acutely unwell young infants

The clinical outcome of 42 acutely unwell infants <3 months old with lymphopenia was retrospectively compared with that of 42 controls. Lymphopenic infants were significantly more likely to require active resuscitation and intensive care, independent of total leucocyte count, gender, degree of prematurity, and diagnosis.

Neonatal ingestion of IgG-containing milk increases the survival of adoptively transferred B-lineage cells in B cell-deficient mice

This study shows that neonatal ingestion of immunoglobulin-containing milk increases the survival of adoptively transferred B-lineage cells in non-irradiated B cell-deficient (mu-/-) mice. Neonatal mu-/- mice were either transferred to lactating mu+/+ foster dams, allowing them to suckle IgG-containing milk, or were kept with their mu-) dams, without IgG in the milk. After adoptive transfer of spleen cells as adults, serum-IgG levels, numbers of plasma cells, T and B cells in spleen and bone marrow were determined. The results showed that the mice which had received milk-IgG had significantly higher levels of serum-IgG and splenic B cells, as well as a higher number of Ig-secreting cells in spleen and bone marrow. This indicates that the mice might have been tolerised against IgG as neonates, if allowed to ingest Ig-containing milk. There is, however, a possibility that B cells in the milk may also contribute to the observed tolerising effect. In summary, the results suggest that 'cross-fostering' could be a suitable method to facilitate the long-term reconstitution of B- and plasma cell numbers in non-irradiated B cell-deficient mice.

Signal via lymphotoxin-beta R on bone marrow stromal cells is required for an early checkpoint of NK cell development

NK cells play an important role in the immune system but the cellular and molecular requirements for their early development are poorly understood. Lymphotoxin-alpha (LTalpha)(-/-) and LTbetaR(-/-) mice show a severe systemic reduction of NK cells, which provides an excellent model to study NK cell development. In this study, we show that the bone marrow (BM) or fetal liver cells from LTalpha(-/-) or LTbetaR(-/-) mice efficiently develop into mature NK cells in the presence of stromal cells from wild-type mice but not from LTalpha(-/-) or LTbetaR(-/-) mice. Direct activation of LTbetaR-expressing BM stromal cells is shown to promote to early NK cell development in vitro. Furthermore, the blockade of the interaction between LT and LTbetaR in adult wild-type mice by administration of LTbetaR-Ig impairs the development of NK cells in vivo. Together, these results indicate that the signal via LTbetaR on BM stromal cells by membrane LT is an important pathway for early NK cell development.

The use of enzyme therapy to regulate the metabolic and phenotypic consequences of adenosine deaminase deficiency in mice. Differential impact on pulmonary and immunologic abnormalities

Adenosine deaminase (ADA) deficiency results in a combined immunodeficiency brought about by the immunotoxic properties of elevated ADA substrates. Additional non-lymphoid abnormalities are associated with ADA deficiency, however, little is known about how these relate to the metabolic consequences of ADA deficiency. ADA-deficient mice develop a combined immunodeficiency as well as severe pulmonary insufficiency. ADA enzyme therapy was used to examine the relative impact of ADA substrate elevations on these phenotypes. A "low-dose" enzyme therapy protocol prevented the pulmonary phenotype seen in ADA-deficient mice, but did little to improve their immune status. This treatment protocol reduced metabolic disturbances in the circulation and lung, but not in the thymus and spleen. A "high-dose" enzyme therapy protocol resulted in decreased metabolic disturbances in the thymus and spleen and was associated with improvement in immune status. These findings suggest that the pulmonary and immune phenotypes are separable and are related to the severity of metabolic disturbances in these tissues. This model will be useful in examining the efficacy of ADA enzyme therapy and studying the mechanisms underlying the immunodeficiency and pulmonary phenotypes associated with ADA deficiency.

Treatment of idiopathic CD4 T lymphocytopenia with IL-2

Idiopathic CD4 T lymphocytopenia (ICL) is an unusual immune defect in which there is an unexplained deficit of CD4 T cells, leading to fungal, parasitic or other serious opportunistic infections. Current treatment efforts are directed at eliminating infections. Here we describe the use of a novel treatment, subcutaneous polyethylene glycol (PEG)-IL-2 injections, in a woman with this disorder, who had chronic severe mycobacterial disease which led to repeated hospitalizations, and advancing respiratory insufficiency. For this patient, PEG-IL-2, 50 000 U/m2, has been given by weekly subcutaneous injections for 5.5 years. This treatment has resulted in marked (and still continuing) long-term immunological improvement with normalized T cell functions and increased CD4 cell numbers. She has had substantial clinical improvement with clearing of mycobacterial disease, reducing hospitalizations and improved lung functions. The improvement seen in this patient suggests that low-dose IL-2 is a safe and practical therapy, which might be useful in other subjects with this potentially serious immune defect.

Haematological response of patients with myelodysplastic syndrome to antithymocyte globulin is associated with a loss of lymphocyte-mediated inhibition of CFU-GM and alterations in T-cell receptor Vbeta profiles

We have demonstrated that 44% of myelodysplastic syndrome (MDS) patients with cytopenia have a haematological response to antithymocyte globulin (ATG). Three ATG responders and two non-responders with refractory anaemia were further studied for lymphocyte-mediated inhibition of bone marrow using a standard CFU-GM assay. In responders, peripheral blood lymphocytes (PBL) added at a 5:1 ratio suppressed CFU-GM by 54+/-9% (P=0.04) and was reversed by ATG treatment. Pre-treatment marrow depleted of CD3 lymphocytes, increased CFU-GM by 32% (P=0.02) in an ATG responder, but not in a non-responder. CD3 lymphocytes from 6-month post-treatment marrow did not inhibit pre-treatment CFU-GM, indicating ATG had affected the T cells. Pre-treatment marrow depleted of CD8 lymphocytes, increased CFU-GM by 60% (P=0.01) and 49% (P=0.03) in two ATG responders, but not in a non-responder. Inhibition required cell-cell interaction through MHCI. TCRVbeta families, analysed by SSCP, changed from clonal to polyclonal in one ATG responder after 6 months, but clones persisted in a non-responder. These results indicate patients with refractory anaemia who respond to ATG have CD8 T-cell clones that mediate MHCI-restricted suppression of CFU-GM which are replaced by polyclonal T cells that do not suppress CFU-GM after ATG treatment.

Lung injury induced by alloreactive Th1 cells is characterized by host-derived mononuclear cell inflammation and activation of alveolar macrophages

We have investigated a murine model of acute lung injury caused by i.v. administration of a T cell clone (CD4+, Th1 phenotype) that recognizes Ly5, a polymorphic cell surface glycoprotein expressed on hemopoietic cells. Alloreactive cloned T cells, specific for host Ly5 Ag, cause a mononuclear cell pulmonary vasculitis and interstitial pneumonitis. In further studies of the cellular mechanisms involved in this model, we found that mature host T cells or B cells are not required, since lung injury was comparable in transgenic host mice that lack these cells (RAG-1 knockout). Cloned T cells labeled in vitro with bromodeoxyuridine were localized in inflammation foci in lung, but the majority of cells in the foci were not labeled. Using transgenic mice that constitutively express lacZ, we determined that the mononuclear cell vasculitis is of host cell origin. Alveolar macrophages (AM) from T cell-treated mice spontaneously secreted TNF-alpha in culture, whereas TNF-alpha was not detected in AM cultures from control mice. TNF-alpha production in response to LPS stimulation was significantly higher in AM cultures derived from T cell-treated mice than in those from control mice. Challenge with sublethal doses of LPS resulted in 50% mortality in T cell-treated mice and was associated with augmented AM TNF-alpha production and protein in bronchoalveolar lavage fluid. We conclude that immune activation of T cells of the Th1 phenotype can initiate lung injury characterized by a host-derived mononuclear cell inflammation and activation of AM.

[Agammaglobulinemia with the absence of circulating B-lymphocytes. 9 cases]

OBJECTIVES

Agammaglobulinemia with absence of circulating B lymphocytes is a rare genetically transmitted immunodeficiency that appears in early childhood and affect mainly boys. The clinical manifestations of the disease are rather heterogeneous.

PATIENTS AND METHODS

Nine patients (7 boys and 2 girls) were diagnosed as suffering from agammaglobulinemia with absence of circulating B lymphocytes, over a period of 6 years. Quantitation of immunoglobulins and search for circulating B lymphocytes were respectively performed by the Mancini method and immunofluorescence using T specific (anti-CD3, anti-CD4 and anti-CD8) and B (anti-CD19) monoclonal antibody.

RESULTS

The disease started to manifest clinically at the mean age of 8.7 months (4-16 months). The mean age at diagnosis is 4 years (1-11 years). The clinical manifestations were essentially recurrent infections of the lung and the gastrointestinal tract. However, bacterial meningitidis was observed in 3 patients. Severe complications such as an echovirus 27 meningoencephalitis and a chronic active hepatitis (1 patient) and a pericarditis (1 patient) were observed. All of our patients lacked circulating B lymphocytes and had low or null immunoglobulin levels. Five patients were treated by intravenous immunoglobulin (Ig) and 3 were treated by intramuscular immunoglobulin with a residual IgG level respectively of 5.5 g/l and 3.3 g/l.

CONCLUSION

Recurrent infections are the principal manifestation of the agammaglobulinemia, early Ig treatment is the only therapy allowing improved.

Deficient CD4+ T cell proliferation in the class 1 MHC-restricted 2C TCR-transgenic mouse

A comparative study of immune function and marker expression of CD4+ T cells from MHC class 1-restricted 2C TCR-transgenic (2C+) and control transgene-negative littermate (2C-) mice was performed. While 2C+CD4+ T cells resembled memory T cells on the basis of CD44highCD45RBlow expression, the majority of 2C-CD4+ T cells were of the CD44lowCD45RBhigh naive phenotype. Slightly lower levels of TCR-beta and CD3 were found on 2C+CD4+ T cell than 2C-CD4+ T cells. Vigorous proliferation by 2C-CD4+ T cells was observed upon stimulation with 1) anti-CD3 mAb presented through the FcR of macrophages; 2) immobilized (plate-bound) anti-CD3 + anti-CD28 mAbs; and 3) PMA + ionomycin. In marked contrast, all three mitogenic stimuli stimulated highly deficient proliferative responses by 2C+CD4+ T cells. However, significant IL-2 production was detected both in anti-CD3 and in PMA + ionomycin-stimulated cultures of 2C+CD4+ T cells. While intracellular calcium in 2C-CD4+ T cells rapidly increased following anti-CD3 addition, no such increase was observed for similarly stimulated 2C+CD4+ T cells. Anti-CD28, PMA, and coculture with 2C-CD4+ T cells each failed to significantly correct the deficient 2C+CD4+ T cells proliferation as induced by anti-CD3. In addition, IL-2, IL-4, and IL-7 supplements also failed to reverse the deficient proliferation of 2C+CD4+ T cells despite expression of IL-2R component alpha-, beta-chains and the gamma-chain common also to IL-4R and IL-7R. Thymus CD4+8- T cells from the 2C-transgenic mouse were similarly deficient in proliferation as spleen CD4+ T cells. A small subpopulation of CD4+ T cell from the 2C-transgenic mouse expressed the transgenic TCR alpha:beta heterodimer as detected by the 1B2 anti-2C clonotypic mAb; both 1B2+ and 1B2- subpopulations proliferated poorly in response to anti-CD3 and to PMA + ionomycin. These results raise the possibility that TCR engagement with MHC class 1 molecules during early intrathymic development can result in the emergence of CD4+ T cells characterized by unusual marker expression and function.

Regulation of B cell survival in xid mice by the proto-oncogene bcl-2

CBA/N mice carry an X-linked immunodeficiency (xid) due to a point mutation in the Bruton's tyrosine kinase (btk) gene. xid mice have a smaller peripheral B cell pool than normal animals, lack CD5+ B cells (B1), and are hyporesponsive to mitogenic anti-Igs and thymus-independent type 2 Ags. The proto-oncogene bcl-2 affects B cell homeostasis by suppressing programmed cell death. We hypothesized that reduced bcl-2 expression could enhance programmed cell death in xid B cells, directly causing poor peripheral B cell survival and indirectly affecting Ag responsiveness. We measured and compared levels of endogenous Bcl-2 protein and spontaneous apoptosis in xid and normal B cells, and determined the effect of a human bcl-2/Ig minigene on B cell survival and Ag responsiveness in bcl-2 transgenics. The amount of endogenous Bcl-2 was reduced fivefold in freshly isolated xid B cells compared with that in normal cells, but was equal in xid and normal T cells. Attrition by spontaneous apoptosis was significantly higher in cultured xid B cells. Expression of the bcl-2 transgene suppressed apoptosis equally in normal and xid B cells, prolonged in vitro survival, and markedly expanded in vivo the follicular B cell population normally reduced in xid mice. However, most xid defects persisted; xid/bcl-2 mice remained deficient in B1 cells and hyporesponsive to anti-Igs, thymus-independent type 1 Ags, and thymus-independent type 2 Ags. The data suggest that signal transduction pathways using Btk independently regulate B cell survival and Ag responsiveness.

[Prevention of early inflammatory complications after transthoracic interventions and estimation of the degree of immunologic deficiency]

An analysis of the results of the examination and treatment of 379 patients undergoing transthoracic interventions showed that the use of the target-aimed selective immunomodulation, short-term antibacterial prophylaxis, inhibitors of arachidonic acid metabolites, active elimination of the circulating immune complexes and medium-weight molecular peptides and adequate local analgesia after the interventions providing normalization of the laryngeal reflex and early activation of the patients permitted the incidence of the pulmonary complications to be decreased by 2.5 times, pleural complications by 1.7 times, suppuration of the postoperative wound by 1.8 times and the total expenses by 25.6 per cent.

[Therapy-refractory primary intestinal lymphangiectasis]

A 20-year-old man with severe physical weakness (from which he soon recovered spontaneously) was found to have hypoproteinaemia and lymphocytopenia (768/microliters). Ten years later, after having been free of symptoms in the meantime, oedema, ascites and abdominal pain occurred, associated with loss of physical capacity. Enteric loss of protein (alpha 1-antitrypsin clearance increased about thirtyfold) with a total serum protein concentration of only 3.7 g/dl, as well as histological evidence of lymphangiectasia of the small and large intestines provided the diagnosis of primary intestinal lymphangiectasia. In the course of the disease cholelithiasis and (after treatment with tranexamic acid) thrombosis of the axillary vein occurred. No treatment has been of any avail and the patient has been unable to work for three years.

[Immunologic status and its correction in amebic liver abscess]

The author analyses the results of study of the immune status in 100 patients with amebic abscess of the liver, who were divided into 2 groups. In an uncomplicated course of the disease (50 patients, Group 1) there were no essential shifts in the immune status in the preoperative period. In the postoperative period (1st-3rd day), however, the percentage and absolute number of T- and B-lymphocytes reduced. Due to this, immunostimulation therapy (decaris, gamma-globulin, hyperimmune antistaphylococcal plasma, activin) had to be applied. In a complicated course of amebic abscess of the liver (50 patients, group 2) the water-electrolyte metabolism was disturbed and the blood erythrocyte-globular volume was reduced and the cellular and humoral links of immunity were markedly depressed in the preoperative period. Intensive transfusion-infusion therapy had to be conducted along with immunostimulation treatment (decaris, T-activin, gamma-globulin, hyperimmune antistaphylococcal plasma, direct transfusion of blood) and prescription of anabolic hormones (pentoxyl, retabolil).

[Correction of immunologic disorders in patients with burns]

Addition of immunomodulating therapy with Thymalin, a thymus agent, to the multimodality therapy of burnt patients contributes to a rapid normalization of immunological parameters. The most marked immune response was observed 7-10 days after a therapy course initiated in the early periods of burn disease in patients with severely depressed T-system immunity and a high sensitivity to the drug. Inclusion of a donor blood leukomass transfusion course activates the cellular link of the immune system just after the treatment course, but fails to favour a stable normalization of thymus-dependent lymphocyte ratios.

[Immunologic effect of hemosorption in patients with acute peritonitis]

An examination of 65 patients with acute diffuse peritonitis has shown that pronounced T-immune deficiency is observed in the postoperative period of acute peritonitis. Hemosorption was shown to be efficient in patients with high content of toxin which allows considering the method of extracorporeal detoxication as effective means of immune-correcting therapy in peritonitis patients with high level of toxinemia who make up a group of risk.