The Opportunistic Tumors of Immune Deficiency

TNFRSF13B is a potential contributor to prostate cancer

Background

Immunodeficiencies are genetic diseases known to predispose an individual to cancer owing to defective immunity towards malignant cells. However, the link between immunodeficiency and prostate cancer progression remains unclear. Therefore, the aim of this study was to evaluate the effects of common genetic variants among eight immunodeficiency pathway-related genes on disease recurrence in prostate cancer patients treated with radical prostatectomy.

Methods

Genetic and bioinformatic analyses on 19 haplotype-tagging single-nucleotide polymorphisms in eight immunodeficiency pathway-related genes were conducted in 458 patients with prostate cancer after receiving radical prostatectomy. Furthermore, the TNFRSF13B was knocked down in 22Rv1 and PC-3 human prostate cancer cell lines via transfecting short hairpin RNAs and cell proliferation and colony formation assays were performed. The molecular mechanisms underlying the effects of TNFRSF13B were further explored by microarray gene expression profiling.

Results

TNFRSF13B rs4792800 was found to be significantly associated with biochemical recurrence even after adjustment for clinical predictors and false discovery rate correction (adjusted hazard ratio 1.78, 95% confidence interval 1.16–2.71, p = 0.008), and the G allele was associated with higher TNFRSF13B expression (p = 0.038). Increased TNFRSF13B expression suggested poor prognosis in four independent prostate cancer datasets. Furthermore, silencing TNFRSF13B expression resulted in decreased colony formation of 22Rv1 and PC-3 cells through modulating the cell cycle and p53 signalling pathways.

Conclusions

The present study suggests the potential role of immunodeficiency pathway-related genes, primarily TNFRSF13B, in prostate cancer progression.

Supplementary information

The online version contains supplementary material available at 10.1186/s12935-022-02590-2.

Optimized nonclinical safety assessment strategies supporting clinical development of therapeutic monoclonal antibodies targeting inflammatory diseases

An increasing number of immunomodulatory monoclonal antibodies (mAbs) and IgG Fc fusion proteins are either approved or in early-to-late stage clinical trials for the treatment of chronic inflammatory conditions, autoimmune diseases and organ transplant rejection. The exquisite specificity of mAbs, in combination with their multi-functional properties, high potency, long half-life (permitting intermittent dosing and prolonged pharamcological effects), and general lack of off-target toxicity makes them ideal therapeutics. Dosing with mAbs for these severe and debilitating but often non life-threatening diseases is usually prolonged, for several months or years, and not only affects adults, including sensitive populations such as woman of child-bearing potential (WoCBP) and the elderly, but also children. Immunosuppression is usually a therapeutic goal of these mAbs and when administered to patients whose treatment program often involves other immunosuppressive therapies, there is an inherent risk for frank immunosuppression and reduced host defence which when prolonged increases the risk of infection and cancer. In addition when mAbs interact with the immune system they can induce other adverse immune-mediated drug reactions such as infusion reactions, cytokine release syndrome, anaphylaxis, immune-complex-mediated pathology and autoimmunity. An overview of the nonclinical safety assessment and risk mitigation strategies utilized to characterize these immunomodulatory mAbs and Fc fusion proteins to support first-in human (FIH) studies and futher clinical development in inflammatory disease indications is provided. Specific emphasis is placed on the design of studies to qualify animal species for toxicology studies, early studies to investigate safety and define PK/PD relationships, FIH-enabling and chronic toxicology studies, immunotoxicity, developmental, reproductive and juvenile toxicity studies and studies to determine the potential for immunosuppression and reduced host defence against infection and cancer. Nonclinical strategies to facilitate clinical and market entry in the most efficient timeframe are presented.

Porcine Melanotic Cutaneous Lesions and Lymph Nodes

Porcine melanomas have proven interesting in a wider biological perspective due to a common phenomenon of spontaneous regression, which is characterized by infiltration of macrophages, among others. Separation of neoplastic melanocytes from pigment-laden macrophages may, however, be challenging as the morphology of melanocytes varies considerably and sometimes resembles macrophages. The aim of this study was correspondingly to characterize and differentiate the cells in 20 porcine melanocytomas and regional lymph nodes by histologic examination and immunohistochemistry for melan A, PNL2, S100, lysozyme, alpha-1-antitrypsin, and ionized calcium binding adaptor molecule 1 (Iba1). Grossly, the melanocytomas were divided into 2 distinct types: pigmented maculae ( n = 7) and raised tumors ( n = 13). In the maculae, the pigmented cells were mainly melanocytes reactive for melan A, PNL2 and S100. In contrast, the majority of the cells in the raised tumors were melanophages, which expressed Iba1, alpha-1-antitrypsin, and lysozyme. Yet, cells histomorphologically indistinguishable from the melanophages expressed melan A and PNL2. These cells were Iba1 and S100 negative, and ultrastructurally, they were devoid of lysosomal bodies and filled with stage III and IV melanosomes. In the regional lymph nodes, melanocytes were present in the trabecular sinuses. In focally or diffusely black lymph nodes, pigmentation was, however, mainly due to aggregates of melanophages, which were confined to the trabeculae, deep cortex, and peripheral lymphoreticular tissue. Normal and neoplastic porcine melanocytes express melan A and PNL2, and immunohistochemical staining for melan A, PNL2, and Iba1 was found useful to identify and distinguish melanocytes and melanophages in porcine melanotic lesions.

Tumor inhibitory T cell immunity may be largely a transplantation artifact not necessarily dependent upon a lack of Tregs

There exists a very large literature suggesting that T cells come in a variety of species and that without the action of Tregs tumors would seldom survive inhibition by T cell effectors. We believe that much of the evidence supporting the role of Tregs in cancer is compatible with a perhaps simpler hypothesis based upon the demonstration that that small quantities of effector T cells tend to stimulate tumors while larger quantities of seemingly the same cells are inhibitory (an hormesis-like effect). This possibility seems to destroy much of the need to postulate a role for T cell suppressors (Tregs) in cancer, but the exposure of effector T cells to antigen may convert them into Tregs (Tregs do exist). Furthermore, many other data suggest the possibility that immune inhibition of cancer could be a laboratory artifact seldom if ever seen in unmodified nature.

A new kink in an old theory of carcinogenesis

According to Berenblum’s two-stage hypothesis, the first stage in carcinogenesis is the production of benign premalignant lesions. Between this initiation stage and the formation of a malignant tumor there is often a long lag phase. We propose that this lag is caused by the delay in the formation of a new and rare tumor-specific antigen, which induces an immune response that stimulates tumor growth. Such tumor-specific antigens could arise as a result of a mutator-like phenotype, which is supposedly present in the benign initial stage of carcinogenesis. According to this hypothesis, the first stage lesion provides a weakly mutagenic environment conducive to the formation of the new antigen(s). If no such new antigens appear so there is no consequent immune response, it is argued that carcinogenesis would seldom if ever ensue.

Acquired melanosis caused by acorn ingestion in the Nero Siciliano pig

In this study, an acquired pigmentation in Nero Siciliano pigs is reported and evaluated by a multidisciplinary approach to support the hypothesis it is caused by an ingested material. A total of 18 pigs were studied. Fourteen conventionally slaughtered animals showed black discoloration of lymph nodes. The lymph nodes were normal in size and shape but showed diffuse black discoloration of the cortex and medulla. Melanosis of fat was observed in 2 animals and was limited to the back. Histochemical tests performed on tissues enabled identification and differentiation of the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Stains for human melanoma, as well as S-100 protein, did not show any reaction. Histochemical methods for tyrosinase showed colorimetric patterns that confirmed the presence of the enzyme in acorns. The activity was mostly latent. A high tannin content was demonstrated, reaching about 76% of the total phenolic compounds. Our data, and the well-known steps on melanin formation, permit us to hypothesize that swine tyrosinase could act on phenolic substances found in acorns. Tyrosinase activation could take place in genetically predisposed swine after acorns are eaten, and this event could increase the biosynthesis and the anomalous storage of melanin.

Congenital and hereditary tumours in domestic animals. 2. pigs. A review

The literature on congenital and hereditary tumours in pigs was reviewed. One hitherto unreported own case was added. Sporadic cases of congenital tumours included several types found in newborn piglets. Embryonic tumours (nephroblastoma, rhabdomyosarcoma) occurred either in newborn or in juvenile animals. Cardiac rhabdomyomas were provisionally classified as hamartomas. The hereditary tumours, melanomas and lymphomas, were reproducible by experimental matings. These tumours are particularly interesting as models to elucidate genetic and immunologic mechanisms of tumour diseases. Striking is the high degree of regression in porcine melanomas and the associated melanosis.

Human-SCID mouse chimeric models for the evaluation of anti-cancer therapies

The ability to engraft human tumors and human immunocompetent cells successfully in severe combined immunodeficient (SCID) mice has spawned the development and use of human-mouse chimeric models to evaluate anti-cancer therapies. The lack of standardization and many other potential pitfalls have contributed to the current controversy surrounding the reliability of these different models. Five frequently used SCID mouse models and their specific applications are summarized with the specific aim of providing an objective discussion of the strengths and limitations of each model, together with suggestions for overcoming some of the variabilities and for improving the design and use of future models.

Activated macrophages migrate to the subcutaneous tumor site via the peritoneum: a novel route of cell trafficking

Spontaneous regression of AK-5 tumor in syngeneic hosts reported earlier involves the interplay of Th1-type cytokines and cell-mediated immunity. Upon subcutaneous transplantation of AK-5 cells, there was accumulation of immune cells in the peritoneum, of which macrophages were the predominant type and were found to be in a hyperactive state. They released macrophage-derived tumoricidal mediators like NO, O2(-), and ONOO(-) which exhibited potent cytotoxic activity against AK-5 cells in vitro. Interestingly, there was a dramatic disappearance of these hyperactive cells from the peritoneal cavity which correlated well with the onset of tumor regression at the subcutaneous site. Direct labeling of these cells in the peritoneum by the tracking dye PKH26 showed their migration to the tumor site. Similarly, frozen tumor sections when scanned under confocal microscope clearly exhibited fluorescent macrophages embedded into the tumor. Immunohistochemical sections of these intratumoral macrophages showed nitrotyrosine residues, indicating their contribution in the free-radical-mediated AK-5 cell death, thereby leading to successful tumor remission. These observations suggest a directional migration of the hyperactivated peritoneal population to the tumor site. We have also confirmed the influx of macrophages and other immune cells into the peritoneum after sc transplantation of Meth A tumor cells in Balb/c mice. Our studies suggest a role for the peritoneal compartment in imparting appropriate stimulus to the immune cells prior to their participation in the antitumor immune response. These studies suggest a novel route of macrophage trafficking via the peritoneum.

Neopterin production in SCID mice injected with human peripheral blood mononuclear cells

Intraperitoneal transfer of peripheral blood mononuclear cells (PBMC) from human EBV+ donors into severe combined immunodeficiency (SCID) mice is a suitable model for studying some aspects of lymphomagenesis and immune activation. Neopterin is a soluble immune marker which was found to be a useful indicator for immune activation processes in humans, e.g. to monitor immunological complications in allograft recipients or to predict prognosis in HIV-infected individuals. In contrast, this pteridine compound is normally synthesized in murine organism in only very low amounts. The measurement of neopterin concentrations in serum and urine should be feasible in SCID mice reconstituted with human PBMC. In this study, we examined the usability of this experimental model for monitoring human T cell activation by neopterin measurements. The production of neopterin by SCID mice after injection of freshly isolated human PBMC, purified B or T cells and cultured Epstein-Barr virus (EBV)+ lymphoblastoid cells (LCL) was determined. It was found that neopterin can be detected early after injecting SCID mice with PBMC, whereas injection of purified human T or B cells did not result in neopterin production. Highest neopterin levels were detected in mice treated with LCL cells when developing lymphoma. We discuss the possible sources of neopterin along this process and its usefulness in this model.

Purification of antigenic peptide from murine hepatoma cells recognized by Class-I major histocompatibility complex molecule-restricted cytotoxic T-lymphocytes induced with B7-1-gene-transfected hepatoma cells

BACKGROUND/AIM

It has been reported that expression of costimulatory molecules, such as B7, on tumors is essential for priming tumor-specific cytotoxic T-lymphocytes (CTLs). Here, we have attempted to induce murine hepatoma-specific CTLs by immunizing with the B7-1-gene-expressing hepatoma cells, and to identify the epitope(s) presented on the hepatoma cells.

METHODS

The B7-1-gene encoding plasmid was transferred into the murine hepatoma cell line, Hepa1-6. Syngeneic C57BL/6 mice were immunized with the B7-1-transfected cells via various routes to prime CTLs. The mild acid elution method was used to isolate antigenic fractions from the class-I major histocompatibility complex (MHC) molecules on the Hepa1-6 cells. Cytotoxicity was measured by standard 51Cr-releasing assay. The effect of the CTLs on hepatoma growth was evaluated in hepatoma-bearing SCID mice to which the cells were preadministered.

RESULTS

A clone, termed L1, highly expressing the B7-1-gene, has been established. Killer cells generated from mice immunized intraperitoneally with L1 cells eliminated both L1 and Hepa1-6 cells, and also another syngeneic hepatoma cell line, Hepa1-clc7. The killer cells were CD8+ and the class-I MHC molecule-restricted CTLs which might recognize hepatoma-specific antigenic peptide(s) in association with the D(b)class-I MHC molecules. A functional peptide fraction was obtained from eluted fluid of the Hepa1-6 cells. In addition, intravenous preadministration of the CTLs inhibited the hepatoma growth in SCID mice.

CONCLUSIONS

The hepatoma epitope-specific CTLs which suppressed hepatoma growth in vivo could be generated with the B7-1-gene-transfected hepatoma cells. These results will be useful in establishing immunotherapy against hepatocellular carcinoma.

Lymphoproliferative Disease in Human Peripheral Blood Mononuclear Cell-Injected SCID Mice. IV. Differential Activation of Human Th1 and Th2 Lymphocytes and Influence of the Atopic Status on Lymphoma Development

Intraperitoneal transfer of PBMC from EBV+ donors into SCID mice leads to high human Ig levels in mouse serum and B cell lymphoproliferative disease. As these events depend on the activation of coinjected human T cells, we addressed the behavior of the Th1 and Th2 subsets in this model. Production of IFN-γ, but not of Th2 cytokines such as IL-4, was detected in culture supernatants of PBMC stimulated in vitro with mouse splenocytes. Moreover, anti-CD3 stimulation of the human cells recovered from mice brought about IFN-γ, but not IL-4, synthesis; on the other hand, PCR and in situ hybridization analysis of ex vivo-recovered cells disclosed the presence of mRNA for both cytokines following in vitro restimulation, thus suggesting post-transcriptional regulation of IL-4 gene expression. When SCID mice were inoculated with PBMC from atopic donors, whose Th1/Th2 profile displays an imbalance toward Th2 cells, tumor development rates were lower, and tumor latency was higher, compared with those in mice injected with PBMC from normal donors. Isotypic analysis of human Ig in mouse serum showed the exclusive presence of IFN-γ-driven IgG subclasses; in addition, human IgE were low or undetectable in most cases. These findings indicate that following transfer into SCID mice, human Th1 lymphocytes undergo preferential activation, whereas Th2 function is down-regulated. Th1 lymphocytes probably are a major component in promoting EBV+ B cell expansion and tumor development; the individual Th1/Th2 profile could in part account for the as yet unexplained donor variability in tumor generation in this experimental model.

Intracerebral HIV glycoprotein (gp120) enhances tumor metastasis via centrally released interleukin-1

Infection with the human immunodeficiency virus (HIV) is associated with a high incidence of cancers. This relationship does not appear to be due to a direct effect of the virus, and may be mediated by neuroimmune interactions since the HIV glycoprotein, gp120, enters the brain soon after infection with HIV, and intracerebroventricular (i.c.v.) infusion of gp120 suppresses aspects of cellular and tumor immunity. It has been speculated that this suppression may be attributed to the release of interleukin-1 (IL-1) in the brain induced by gp120. Using an in vivo tumor model, we examined the effect of centrally administered gp120 on tumor metastasis and lung clearance of mammary adenocarcinoma (MADB106) tumor cells in rats, and the role played by brain IL-1 in mediating these effects. We demonstrate that central administration of gp120 (4 microg) significantly (p<0.05) increased the retention of tumor cells in the lungs and significantly (p<0.02) enhanced the development of tumor metastases. Central administration of IL-1beta (10 ng) also significantly (p<0.05) increased retention of tumor cells in the lungs. The effect of gp120 on lung retention of tumor cells was blocked by co-administration of alpha-melanocyte stimulating hormone (alpha-MSH, 20 ng), a hormone that blocks many of the biological effects of IL-1, or the IL-1 receptor antagonist (50 microg). Given that systemic administration of gp120 or IL-1beta had no effect on the retention of tumor cells in the lungs, these findings indicate that gp120-induced secretion of IL-1 within the brain most likely mediates the effects of gp120 on tumor metastasis. These findings suggest a possible neuroimmune mechanism to account for the increased incidence and aggressiveness of tumors in HIV-infected patients.

EBV-associated anorectal lymphomas in patients with acquired immune deficiency syndrome

Primary lymphomas of the gastrointestinal tract represent 9% of all non-Hodgkin lymphomas, and of these only 3% arise in the rectum or anus. In contrast to their rare occurrence in the general population, the incidence of anorectal lymphomas in patients with acquired immune deficiency syndrome (AIDS), particularly homosexual patients, may be as high as 26% as reported in our own series of AIDS-associated lymphomas. To determine the characteristics of this entity, we studied 15 cases of primary anorectal lymphoma in AIDS patients and compared them with four cases of anorectal lymphoma unrelated to AIDS. The cases in our study were also compared with the reports of rectal lymphoma in the medical literature over the past 30 years. In the present series, the AIDS patients were all male with a median age of 34 years, human immunodeficiency virus (HIV)-positive, with homosexuality as the main risk factor. The four non-AIDS patients included a woman and had a median age of 66.5 years. Histologically, the anorectal lymphomas in AIDS patients were all high grade, predominantly immunoblastic, and polymorphous. In the non-AIDS patients, only two of four lymphomas were high grade, including one Burkitt type. All tumors were of B-cell phenotype. In the AIDS-associated anorectal lymphomas, the presence of Epstein-Barr virus (EBV) in a latent form was demonstrated by an abundance of Epstein-Barr-encoded RNA (EBER) in 14 of 15 cases and latent membrane protein (LMP) in four cases. All anorectal lymphomas unrelated to AIDS were negative for EBV. The unusual anorectal location of AIDS-associated lymphomas is explainable by the high incidence of preceding traumatic lesions and chronic infections in the area. As a result, EBV-carrying B cells may be attracted to the field providing the cell population that, under the conditions of immune deficiency, is able to give rise to high-grade lymphomas.

Malignant B-cell lymphoma in an infant with severe combined immunodeficiency with short-limbed skeletal dysplasia

In an infant with skeletal anomalies and haemolytic disease, intestinal perforation was caused by necrosis of an as yet undetected B-cell lymphoma. Severe combined immunodeficiency with short-limbed skeletal dysplasia was diagnosed. This is the first published report of a patient with this syndrome in combination with haemolytic disease and B-cell-lymphoma.

Overall cancer incidence not increased after prosthetic knee replacement: 14,551 patients followed for 66,622 person-years

It is unknown whether patients as a consequence of prosthetic joint replacement are at a higher risk of developing cancer. We therefore analyzed cancer incidence following prosthetic knee replacement (TKR). The observed cancer incidence in 14,551 patients from the population-based Swedish Knee Arthroplasty Register who have undergone TKR because of osteoarthrosis (OA, n = 10,120) or rheumatoid arthritis (RA, n = 4431) were compared with the expected cancer incidence for a Swedish reference population. The cohort was followed for a total of 66,622 person-years. We followed 33% of the patients with OA and 59% of those with RA for more than 5 years. All patients who underwent TKR, whether for OA or for RA, had lower than expected total cancer incidence. We found a markedly low incidence of colorectal carcinoma, especially in patients with RA. Our results do not indicate an increased incidence of cancer following TKR.

FNB diagnosis of breast carcinoma associated with HIV infection: a case report and review of HIV associated malignancy

A 48 yr old HIV seropositive female presented with a right breast mass and bilateral axillary lymphadenopathy. Fine needle biopsy (FNB) revealed an adenocarcinoma with abundant mucin production and features suggestive of a cribriform and micropapillary ductal carcinoma in situ (DCIS). Histopathological examination of the tumor confirmed an invasive mixed colloid carcinoma with extensive DCIS. There have been 4 previous reports in the literature of breast carcinoma associated with HIV seropositivity. This case initially diagnosed by FNB is the first case reported in Australia. In spite of the somewhat more favourable histological type of breast carcinoma, this tumor shows numerous unfavourable prognostic factors and has had an aggressive clinical course with relapse of disease in the contralateral breast and distant metastases within 4 wks of surgery, probably related to the patient's immunodeficiency.

Historical origins of current concepts of carcinogenesis

The first attempts to understand the causes of cancer were based on generalizations of what might now be termed a "holistic" nature, and hereditary influences were recognized at an early stage; these views survive principally through a supposed positive connection between psychological factors such as stress and diminished ability to combat the progressive development of tumors through some form of immunologically mediated rejection of potentially cancerous cells. While evidence for immunosurveillance is generally accepted, it is now widely regarded as almost wholly confined to instances where tumor viruses are involved as causative agents. The earliest theorists drew an analogy between the processes of carcinogenesis and of evolution; the cancer cells acquired the ability to outstrip their normal counterparts in their capacity for proliferation. This was even before evolution had been interpreted as involving a continuous succession of mutations. Evidence was already to hand before the end of the 18th century that exogenous agents, notably soot, a product of the "industrial revolution," could cause skin cancer. Somewhat over 100 years later, another industrial innovation, the manufacture of synthetic dyestuffs, implicated specific chemical compounds that could act systemically to cause bladder cancer. Meanwhile, the 19th century saw the establishment of the fundamentals of modern medical science; of particular relevance to cancer was the demonstration that it involved abnormalities in the process of cell division. The commencement of the 20th century was marked by a rediscovery of the concept of mutation; and it was proposed that cancer originated through uncontrolled division of somatically mutated cells. At around this time, two further important exogenous causative agents were discovered: X-rays and tumor viruses. In the late 1920s, x-radiation became the first established exogenous cause of mutagenesis. The discoverer of this phenomenon, H. J. Muller, suggested that while mutation in a single cell was the primary causative mechanism in carcinogenesis, its generally observed logarithmic increase in incidence with age reflected a "multihit" process, and that multiple successive mutations were required in the progeny of the original mutants. He also recognized that the rate of proliferation of potentially cancerous cells would markedly influence the probability of their subsequent mutation. These considerations are essentially the foundation of the generally accepted view of carcinogenesis that now seems unlikely to be superseded. However, this acceptance did not come about unopposed. The analogy between carcinogenesis and evolution was disliked by many biologists because it embodied the concept that cancer was an inevitable consequence of our evolutionary origins.(ABSTRACT TRUNCATED AT 400 WORDS)

T-cell based cancer immunotherapy: direct or redirected tumor-cell recognition?

In development of strategies for immunotherapy of cancer a new emphasis is emerging, termed T-cell retargeting, which involves artificial redirection of cytotoxic T lymphocytes (CTL) against cancer cells, using bispecific reagents. In this article, Gideon Beun, Cornelis van de Velde and Gert Jan Fleuren evaluate this potential strategy for cellular immunotherapy, and propose how the gap between in vitro results and clinical application might be bridged.

Cancer morbidity in blood recipients--results of a cohort study

Blood transfusions involve the transfer of relatively large volumes of body fluids and cellular material between individuals. A variety of pathogens like viruses, some of which are associated with development of certain tumours, are known to be transmitted by this route. Blood recipients were identified during 1981-1982 in the register of the hospital blood centre, and in-patients by the in-patient and discharge register of the hospital. Tumour occurrence and vital status were determined by means of the population-based regional tumour register. Age, gender and calendar-year specific rates from the general population were used to calculate expected values. In a cohort study of 3177 blood recipients, increased numbers of malignant lymphomas [13 vs. 4.8 expected, standard morbidity ratio (SMR) 2.70 95% confidence interval (CI) 1.44-4.62] and skin cancers [12 vs. 5.2 expected, SMR 2.29, 95% CI 1.19-4.01] were seen 3 to 9 years after transfusion. In a second cohort study of 29,910 hospitalised patients, a total of 37 (29.8 expected) malignant lymphomas was found in 28,338 patients with no transfusion and 10 (2.73 expected) in 1572 patients with a transfusion, 3 to 9 years after the hospitalisation. The incidence rate ratio between these groups was 3.11 (95% CI 1.56-6.20) using a Mantel-Haenszel estimator with age stratification. Non-melanomatous skin cancers had an incidence ratio of 2.74 (95% CI 1.25-6.00). We conclude that, in the cohorts discussed here, malignant lymphomas and skin cancer occur more often in blood recipients than in controls. It remains to be established whether this is due to factors covariating with transfusion or by the transfusion itself. Further studies on these putative associations are warranted, as are analytical studies of the epidemiology of malignant lymphomas, especially non-Hodgkin's lymphoma, whose aetiology is still poorly understood.

Immunosuppression and cancer: the ciclosporin case

Experimental and clinical data relevant for the evaluation of the carcinogenic potential of the immunosuppressant ciclosporin are reviewed. Ciclosporin binds reversibly to the cytosolic receptor protein ciclophilin. Ciclophilin is likely involved in the blockade of lymphocyte activation-induced gene transcription of various growth factors, especially interleukin-2. The drug has no effect on the transcription of housekeeping genes nor does it activate any gene. Ciclosporin may inhibit tumor cell growth, notably those which are growth factor dependent. At high concentration virus-transformed cells, especially Epstein-Barr-infected B-lymphocytes, may escape the control of specific cytotoxic T-lymphocytes. Ciclosporin has no genotoxic activity, and has no DNA-binding property. In experimental studies ciclosporin did not cause cancer in the absence of an initiating event (e.g. chemical mutagen). However, by its immunosuppressive property, the drug may allow the growth of initiated tumor cells in vivo, an effect which is dose-dependent. In clinical use ciclosporin immunosuppression is associated with an increased incidence of lymphoproliferative disorders and other malignancies particularly of the skin when compared with a normal, not immunosuppressed population. Conventional immunosuppression (azathioprine, antilymphocyte globulin, prednisone) also demonstrates comparable risks to develop tumors. Lymphoproliferative lesions regress after dose reduction or cessation of treatment. Furthermore, combinations of various immunosuppressants with associated 'over-immunosuppression' may result in a higher incidence of viral infection and malignancy. In summary, chemical immunosuppression carries the intrinsic risk of tumor growth. In the case of ciclosporin this effect is dose dependent. Thus, the risk may be reduced by low dosage and by avoiding combination therapies with additional immunosuppressants.

The carcinogenicity of ciclosporin

Experimental data relevant for the evaluation of the carcinogenic potential of the immunosuppressant ciclosporin are reviewed: Firstly, the mode of action of ciclosporin at the level of lymphocyte gene transcription, secondly, the main adverse effects especially nephrotoxicity and thirdly, the results of the chronic bioassays. The experimental data are discussed together with the clinical evidence of increased incidence of tumors, especially lymphoproliferative disorders under ciclosporin immunosuppression. Conventional immunosuppression (azathioprine, anti-lymphocyte globulin, prednisone) also demonstrates comparable risks to develop tumors. Lympho-proliferative lesions regress after dose reduction or cessation of treatment. Furthermore, combinations of various immunosuppressants may result in a higher incidence of viral infection and malignancy. In summary, chemical immunosuppression carries the intrinsic risk of tumor growth. In the case of ciclosporin, which has no direct genotoxic effect, tumor promotion is probably dose-dependent. Thus, the risk may be reduced by low dosage and by avoiding combination therapies with additional immunosuppressants.

Acquired immunodeficiency syndrome-associated lymphomas: clinical, pathologic, immunologic, and viral characteristics of 111 cases

The incidence of lymphomas in individuals infected with the human immunodeficiency virus has increased progressively since the beginning of the acquired immunodeficiency syndrome (AIDS) epidemic. The present series includes 111 patients, all diagnosed and studied at one hospital in New York City. There were 108 men and three women; the average age was 39 years and male homosexuality was the predominant risk factor. The materials examined originated from 138 surgical specimens and 24 autopsies. There were 11 cases of Hodgkin's lymphoma and 100 cases of non-Hodgkin's lymphomas (NHL), a proportion strongly skewed in favor of the latter. Hodgkin's lymphoma in AIDS patients was characterized by advanced clinical stage, high histologic grade, and frequent bone marrow involvement. Non-Hodgkin's lymphoma in AIDS patients, in contrast to the general population, originated predominantly in extranodal locations (61 cases) versus locations in which the lymph nodes were the site of the primary tumors (39 cases). In the digestive tract, the unusual oral and anal primary locations were often noted and were possibly related to specific risk factors. There were 15 cases of NHL of the central nervous system, an incidence 14 times greater than that recorded in the general population. The majority of NHLs were of high histologic grade, Burkitt's and large cell immunoblastic, representing most of the cerebral and gastrointestinal tumors. All NHLs were of B-cell immunophenotype. Lymphadenopathies with the histologic features of human immunodeficiency virus infection, particularly of the late stage (type C), often preceded NHL. Probing for Epstein-Barr virus genome was more frequently positive in Hodgkin's lymphoma than in NHL. Immunologic evaluations showed severely depressed T cell counts and CD4 to CD8 cell ratios as well as markedly increased levels of antilymphocyte antibodies. Reflecting the background of profound immune deficiency, the AIDS-associated lymphomas were characterized by high aggressiveness, early tendency to generalization, frequent post-treatment relapse, and short periods of survival.

Current status of immunotherapy of patients with HIV-infection

Immunotherapy is receiving increasing attention as an approach to managing HIV-infection and its complications. As the immune response to HIV becomes better understood, new approaches to HIV immunotherapy are possible. Approaches under development include, first and foremost, the use of vaccines, not only for prophylaxis but also for therapy of established disease. Other approaches being studied include passive serotherapy, use of synthetic HIV-binding molecules such as CD4, immunorestoration and immunomodulation with immunomodulatory drugs, thymic hormones, cytokines and anti-infective immunotherapy directed against the opportunistic infecting organisms of HIV. The current role of these modalities as single agents and in combination and their potential role in the future is discussed.