[Kala azar - Lethal course of visceral leishmaniasis. Synchronous infection with Leishmania donovani/infantum complex and Leishmania major in a patient after Mediterranean vacation]. / Kala Azar - letaler Verlauf einer viszeralen Leishmaniose. Synchrone Infektion mit Leishmania-donovani/infantum -Komplex und Leishmania major bei einem Patienten nach Mittelmeeraufenthalt.

BACKGROUND: Infections with Leishmania spp. are endemic in areas of the tropics and subtropics. An increased incidence of human infections has been reported in southern Europe, where zoonotic leishmaniasis is common. The systemic, visceral infection is caused by the Leishmania donovani/infantum complex and may be fatal when untreated. PATIENT AND METHODS: A 42-year-old man presented with a 6 week history of erythroderma, pancytopenia, hepatosplenomegaly and recurrent fever after a sojourn in Croatia. The patient's past history revealed a 10-year history of psoriasis and chronic obstructive pulmonary disease treated with methotrexate and prednisolone. Pathology was assessed by histology and molecular biologic analyses. RESULTS AND COURSE: A repeated bone marrow biopsy revealed multiple intracellular particles which were identified as Leishmania amastigotes. Indirect immunofluorescence as well as enzyme-linked immunosorbent assay (ELISA) of patient's serum showed specific anti-Leishmania antibodies. Despite rapid initiation of systemic therapy, the patient died of a secondary infection. Post mortem, PCR and sequencing revealed synchronous infection with Leishmania donovani/infantum complex and Leishmania major. CONCLUSIONS: Diagnosis of patients with complex clinical features is challenging even for experienced clinicians. Critical interpretation of findings and, if necessary, repetition of invasive examinations may be necessary for proper diagnosis. Increasing numbers of immunocompromised patients (iatrogenic, HIV) will expand the spectrum of rare infectious diseases including visceral leishmaniasis.

Non-suppressible TSH in a patient thyroidectomized due to follicular thyroid carcinoma.

Poor compliance or drug malabsorption are the most common reasons why an adequate TSH suppression is not achieved with oral levothyroxin in patients with hypothyroidism or thyroid carcinoma. When these conditions are excluded rare causes have to be considered. We report a female patient with follicular thyroid carcinoma in whom, under intended levothyroxin suppression therapy, a TSH-PRL-producing pituitary adenoma manifested by failure to achieve adequate TSH suppression, subtle signs of hyperthyroidism,and finally symptoms of elevated PRL.

[Corneal infiltrates and ulcers. A retrospective study of 239 eyes]. / Hornhautinfiltrate und Hornhautgeschwüre. Eine retrospektive Analyse von 239 Augen.

PURPOSE: In our outpatient service the number of corneal infiltrates and ulcers associated with contact lens wear in young patients increased during the last years. Therefore we evaluated all patients with keratitis regarding to the reason. PATIENTS AND METHODS: From January 1999 to August 2000 the medical charts of 210 consecutive patients and 239 eyes were reviewed. We evaluated the percentage of contact lens wearers. Patient age, localisation and number of infiltrates, bacteria and healing results were also evaluated. RESULTS: In 134 of 239 eyes (56%) keratitis was caused by contact lenses, 127 eyes (53%) with soft lenses. The mean age of soft contact lens wearing patients was 28,2 +/-13,0 years. Mean age in other reasons was 46,0 +/-22,5 years. 71% (170 eyes) had single central infiltrates, 19% (45 eyes) multiple peripheral infiltrates and 10% (24 eyes) corneal ulcers. Bacteria were found in 33% (78 eyes). The most frequent isolated bacteria in non contact lens induced keratitis was staphylococcus aureus (22 eyes). In those eyes with soft contact lenses we found mostly gram negative bacteria such as serratia spp. (6 eyes), pseudomonas spp. (6 eyes), stenotrophomonas maltophilia (6 eyes) and klebsiella oxytoca (5 eyes). 20% (26 of 127 eyes) of contact lens induced corneal infection healed with a scar. CONCLUSION: Our analysis shows, that the major part of keratitis was induced by soft contact lenses. One fifth of these very young patients retained a corneal scar. There is a higher risk to suffer a keratitis when using soft contact lenses. This should influence especially patients information regarding choice and use of soft contact lenses.

Intra-abdominal sequestration of the lung and elevated serum levels of CA 19-9: a diagnostic pitfall.

BACKGROUND: Extralobar pulmonary sequestration is an uncommon congenital abnormality that is rarely diagnosed after the age of 40 years. We describe a 64-year-old woman with an intra-abdominal sequestration of the lung and elevated carbohydrate antigen (CA) 19-9 serum levels. CASE OUTLINE: On abdominal ultrasound a semi-solid cystic tumour was demonstrated that showed tight connection to the tail of the pancreas according to computed tomography. Cytological examination of the percutaneous biopsy did not lead to a definitive diagnosis. CA 19-9 serum levels were repeatedly elevated >250 IU/ml. With a tentative diagnosis of a tumour of the tail of pancreas the semi-solid cystic mass was resected. Frozen section histology suggested the diagnosis of pulmonary sequestration, which was confirmed by definitive histological examination. Immunohistochemical staining of the specimen with a specific monoclonal antibody against CA 19-9 showed strong immunoreactivity. Three months later the elevated CA 19-9 serum levels returned to normal. DISCUSSION: Elevated CA 19-9 serum levels have been described in benign pulmonary and mediastinal cystic lesions and in one case of extralobar intrathoracic lung sequestration. Although there is evidence that malignancies may arise in congenital lung cysts, CA 19-9 serum levels have not been investigated in such cases. Based on our results elevated serum values of CA 19-9 in combination with a cystic semi-solid mass in the left subphrenic space should include the differential diagnosis of extralobar pulmonary sequestration.

Surgical anatomy of the puboprostatic complex with special reference to radical perineal prostatectomy.

OBJECTIVE: To investigate the retropubic space and attachments of the prostate and urethra, with special reference to radical perineal prostatectomy. MATERIALS AND METHODS: Anatomical relationships were assessed intraoperatively in 60 patients, and in five cadavers after preparing the dorsal vein complex with coloured latex. Cross-sections of the area of interest were evaluated by microscopy. RESULTS: The puboprostatic (pubovesical) ligaments could be clearly distinguished from the median part of the puboprostatic complex continuous with the urethral suspensory mechanism. The dorsal vein complex is integrated into this fibromuscular attachment of the prostate and male urethra. During the perineal approach, dissection in this region follows the so-called avascular plane. CONCLUSION: With this new insight into the anatomical relationships the nomenclature derived from radical retropubic prostatectomy could be mirrored. In radical perineal prostatectomy, both the urethral suspensory mechanism and the dorsal vein complex can be preserved.

Heat shock protein expression in the transplanted human kidney.

Heat shock proteins (HSPs) have been shown to represent potential target molecules for T-cell-mediated allograft rejection in heart and kidney transplants. In the present study, we therefore investigated the expression of HSP subtypes 60, 72, and 73 in normal kidneys and qualitative and/or quantitative changes in rejected renal allografts. Six normal kidney tissue specimens, three biopsies from patients with minimal change nephritis, as well as 37 biopsies and eight transplant nephrectomy specimens of patients with renal allograft rejection were studied. Type and severity of rejection were assessed according to the Banff classification. Immunohistochemical demonstration of HSP expression was performed using specific monoclonal antibodies after wet autoclave antigen retrieval on sections from either Carnoy-fixed (biopsies) or formalin-fixed (transplant nephrectomies) and paraffin-embedded tissue. The expression was scored in a semiquantitative manner. All three subtypes were found to be constitutively expressed in normal kidney tissue and in noninflammatory minimal change nephritis, albeit with a characteristic compartmental and cellular distribution. Rejection resulted in a higher immunohistochemical scoring for all three HSP subtypes in compartments in which they were normally present; in addition, a de novo expression of HSP60 was found in the vascular compartment and, moreover, infiltrating mononuclear cells were strongly immunoreactive for HSP60 and HSP73. Only quantitative differences were observed for HSP72 immunoreactivity. These results indicate that rejection episodes are paralleled by an increased but differential expression of HSPs in the glomerular, tubular, and vascular compartments of the kidney. This enhancement as well as the de novo appearance of HSP60 on vascular endothelial cells might explain the presence of HSP-reactive T lymphocytes in rejected allografts.

Epstein-Barr virus-associated multicentric leiomyosarcoma in an adult patient after heart transplantation: case report and review of the literature.

Epstein-Barr virus (EBV)-associated smooth muscle tumors following solid organ transplantation are extremely rare, with only 12 cases reported in the literature thus far. The exact pathogenetic role of EBV infection in the oncogenesis of these soft tissue tumors in immunodeficient patients and the biologic behavior of such tumors is still unclear. We report a 26-year-old man in whom multiple smooth muscle tumors developed 36 to 51 months after heart transplantation. All tumors, two synchronous liver nodules, two subsequently occurring paravertebral tumors, and a single tumor in a vein at the left ankle were surgically resected. The tumor tissue was processed for routine histology and immunohistochemical (IHC) stains. Additionally, competitive polymerase-chain-reaction (PCR), reverse-transcriptase PCR (RT-PCR), as well as in situ hybridization (ISH) were used for EBV particle quantification and gene transcription analysis. The histologic features and immunohistochemical profiles were consistent with leiomyosarcoma in all tumor nodules. EBV infection was detected in >95% of tumor cell nuclei by EBER 1/2 ISH. Competitive PCR revealed 3105 EBV particles per milligram of tumor tissue. The EBV gene expression pattern analyzed by RT-PCR and IHC corresponded to the latency type III with specific expression of EBNA1, EBNA2, LMP1, and LMP2A genes. Under continuous antiviral therapy (famcyclovir) the patient currently shows no evidence of disease. Our data indicate that EBV infection plays a causal role in the development of smooth muscle tumors following organ transplantation. A latency type III, identical to EBV-associated posttransplant lymphoproliferative disorders, was identified and suggests a common pathogenetic mechanism in the development of these histogenetically distinct neoplasms. The fact that the patient currently shows no evidence of disease may be the result of the continuous administration of antiviral therapy because the soft tissue recurrences of the leiomyosarcoma occurred while the patient was not receiving antiviral prophylaxis.

New approaches in the management of choroidal neovascular membrane in age-related macular degeneration.

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly population. The prevalence is reported to be 1.2-1.4% in several population-based epidemiological studies. Currently 25-30 million people worldwide are blind due to AMD. With the aging world population it is bound to increase significantly, and could become a significant public health problem in next two decades, with serious socio-economic implications. Several strategies are today available to treat the wet form of AMD, which is responsible for significant visual loss. These were until recently confined to laser photocoagulation, and subretinal surgery, but today two other modalities, namely, radiation and photodynamic therapy, are available. These treatment modalities however, are aimed at preservation of vision only, and not at reversing the process of the disease. Further research on antiangiogenic drugs and gene therapy could significantly help AMD patients.

Thymic Hodgkin's disease--a histological and immunohistochemical study of three cases.

Thymic Hodgkin's disease (HD) shows some peculiar histological features different from nodal disease which are a result of the interaction with the specific thymic microenvironment. We describe the histological and immunohistochemical findings in three cases presenting as a primary thymic neoplasm both clinically and radiologically. Histological hallmarks were the prominent formation of epithelium-lined cysts, inflammatory changes, a marked proliferation of thymic epithelium in association with Hodgkin- and Reed-Sternberg (RS) cells and the occurrence of the nodular sclerosing subtype in all cases. The immunophenotype of the neoplastic cells was that of classical HD. They expressed CD30, CD15 and lacked CD45. In two cases CD20 expression was observed. All cases were negative for the latent membrane protein (LMP) of the Epstein-Barr virus (EBV). The accompanying inflammatory infiltrate was rich in mature T-cells, but also showed a significant number of B-cells with frequent formation of follicles and proliferation of follicular dendritic cells. Thymic HD develops in a microenvironment with features of thymic medulla as defined by the morphology and pattern of the proliferating epithelial cells and the mature immunophenotype of the admixed thymocytes. These findings, especially the CD20 positivity in Hodgkin and RS-cells, may point to the possible origin of thymic HD from medullary B-cells.

Familial clustering of infantile cirrhosis in Northern Germany: A clue to the etiology of idiopathic copper toxicosis.

Two cases of infantile liver cirrhosis of unknown origin occurred in a circumscribed rural area of Northern Germany. Both children had increased dietary copper exposure. The search for additional cases of what appeared to be idiopathic copper toxicosis (ICT) revealed a cluster of affected infants in this region, raising questions about the relative importance of genetic and environmental factors that are considered to be etiologic. We gathered clinical and pathologic data concerning the patients, analyzed the pedigrees of affected families, and searched for possible environmental factors contributing to the pathologic process. We encountered 8 cases of infantile liver cirrhosis in 5 families in Emsland, a circumscribed and predominantly rural area of Northern Germany; ICT was definitely proven in 2 cases. Clinical presentation and liver pathology in 6 additional cases were consistent with the diagnosis of ICT. Pedigrees of affected families revealed complex relationships with occasional consanguinity of parents, suggesting autosomal recessive inheritance. The households were served by private wells with water of low pH flowing through copper pipes, suggesting the possibility of increased alimentary copper exposure. These findings support earlier conclusions that ICT develops when an infant with a genetic predisposition is exposed to a copper-enriched diet.

Identification of a lipocalin in mucosal glands of the human tracheobronchial tree and its enhanced secretion in cystic fibrosis.

Members of the lipocalin protein family are characterized by their ability to bind small hydrophobic molecules. Some of them are known to be produced by various glands and secretory cells. Under certain conditions, these proteins would be ideally suited for clearance of lipophilic, potentially harmful substances and might also act as protection factors in airway secretions. We therefore used RT-PCR analysis with a set of oligonucleotide primers deduced from conserved regions of lipocalin members to identify specific RNA isolated from human trachea. With two of these oligonucleotide primers, a positive result was obtained. Sequencing of the RT-PCR products revealed that the DNA fragments were identical to the lipocalin 1 (LCN1) encoding cDNA. LCN1 is an unusual lipocalin member that binds a variety of lipophilic compounds and exhibits cysteine proteinase inhibitor and antimicrobial activities. The local production and topographic distribution of LCN1 in the human tracheobronchial tree was then investigated by immunoperoxidase staining on thin-layer sections using a specific antiserum. LCN1 was detectable in the acini of serous mucosal glands and sometimes within the glandular lumen, suggesting excretion of the protein. The latter finding was tested and verified by Western blot analysis of bronchial secretions of healthy individuals. Furthermore, the results of SDS-PAGE and Western blot analysis of bronchial secretions from patients with cystic fibrosis (CF), which are usually characterized by an increase of airway lipids, suggested that LCN1 secretion was enhanced. Northern blot analysis of RNA from normal trachea and RNA isolated from tracheal biopsies of patients with CF indicated that induced secretion was due to an up-regulated expression of the LCN1 gene. Thus, our investigations present the first clear evidence that LCN1 is induced in infection or inflammation and support the idea that this lipocalin functions as a physiologic protection factor of epithelia in vivo.

[Urothelial tumors and preneoplasias. Diagnostic problems and their clinical consequences]. / Urotheliale Tumoren und Präneoplasien. Diagnostische Probleme und deren klinische Konsequenzen.

The surgical pathology of biopsies or electroresection specimens taken from clinically suspicious or overt tumors in the urinary bladder encompasses the evaluation of a few parameters. This should allow the segregation of bladder tumor patients into subgroups with distinct clinical features and biological behavior, thus providing a rationale for choosing the best available therapy. In essence, the pathologist's role entails a careful morphologic assessment of the primary tumor, including evaluation of the histologic type, the growth pattern, the tumor grade, the tumor stage, and finally the presence and type of primary or tumor-associated flat intraurothelial lesions. Whereas the growth pattern of a lesion can be readily recognized, the correct grading and staging of papillary tumors are often more dependent on the complexity of the individual case and the experience of the pathologist due to the inherent subjectivity of the field and a lack of standardized criteria. These problems of intra- and interobserver variability are intimately coupled with the characteristics of the material, that is, bad orientation and tangential sectioning, thermal injury, crush and fixation artifacts, and limitations of the size of the samples. The correct evaluation and interpretation of flat intrauorothelial lesions suffer from similar difficulties and are further complicated by a confusing categorization and terminology. Although new modalities and molecular approaches have been introduced in recent years in an effort to overcome some of these obstacles, morphology still remains the most effective means to assess the biological behavior and prognosis of urothelial bladder cancer. The present article therefore addresses some of the diagnostically and clinically most relevant controversies and aims to give some useful hints for the evaluation of the above-mentioned morphological parameters. In addition, it adds some remarks on the morphological basis and diagnostic validity of urinary cytology in primary diagnosis and, more importantly, monitoring of bladder cancer patients.

The incidence of hyperthyroidism in Austria from 1987 to 1995 before and after an increase in salt iodization in 1990.

Between 1963 and 1990, Austria had iodized salt prophylaxis of endemic goitre with 10 mg KI (7.5 mg I) per kg. This was obviously insufficient, as urinary iodine excretion ranged from 42 to 78 microg I per g of creatinine and goitre in adults remained in the endemic range of 15%-30%. Therefore salt iodization was doubled in 1990. The aim of this study was to assess the annual incidence of different types of hyperthyroidism (HT) before and after this increase in salt iodization. The incidence of HT was recorded in 14 nuclear medicine centres from 1987 to 1995. In five additional centres data were available from 1992 onwards. Data prior to 1992 were documented retrospectively, while those after 1992 were recorded prospectively. The 14 centres drew patients from an area with a population of approximately 4.23 million while all 19 institutes were estimated to cover an area with a population of 5.4 million (the total population of Austria is 7.86 million). A total of 414232 persons were examined for the first time in the participating centres. HT and the type of HT were defined by clinical examination, serum TSH, thyroid hormone levels in blood, ultrasonography, scintigraphy and serum autoantibody titres. HT was classified into immunogenic HT (Graves' or Basedow's disease, GD) and HT with intrinsic thyroid autonomy (uni-, multinodular or disseminated Plummers' disease, PD). HT was also divided into overt (o) or subclinical (sc) disease. The following data were calculated: annual incidence per 100000 and the relative risk (RR) for HT with 95% confidence intervals (CI). In addition, linear trends were calculated for each type of HT by means of logistic regressions. In the 19 centres a total of 47834 patients with HT were registered from 1987 to 1995. PD accounted for 75% of all cases of HT and GD for 19%, while other types of HT were present in 6%. From 1987 to 1989 (time period T0), the annual incidence of oPD was 30.5 (95% CI 29.6-31.5) per 100000. The RR compared to the baseline period T0 was highest in 1992 (1.37; 1.3-1.45) and decreased to 1.17 (1.1-1.24) in 1995. The annual incidence of scPD in T0 was 27.4 (26.5-28.3) per 100000. The RR was highest in 1991 (1.64; 1.56-1.73) and was 1.60 (1. 51-1.69) in 1995. In oPD and scPD a higher RR was observed in persons older than 50 years of age, particularly in men. The incidence of oGD in T0 was 10.4 (9.8-10.9) per 100000; the maximum RR increased to 2.19 (2.01-2.38) in 1993 and decreased to 1.95 (1.78-2.13) in 1995. The incidence of scGD was 1.9 (1.6-2.1) in T0. The maximum RR was observed in 1994 (2.47; 2.04-3.0) and it was still 2.26 (1.85-2.77) in 1995. The increased incidence of oGD and scGD was evenly distributed in all ages and both sexes. The time course of different types of HT following the increase in salt iodization could be divided into two phases: an increase in the incidences of HT with peaks after 1-4 years and a subsequent decrease, the only exception being scGD. The effect was more pronounced in GD than in PD. PD showed an age and gender dependency over time, while GD did not.

Production of trophoblastic hormones by transitional cell carcinoma of the bladder: association to tumor stage and grade.

Cancer registration statistics of economically advanced countries indicate that bladder carcinoma incidence ranks fourth in men and eighth in women, but a reliable tumor marker for predicting the disease course is still lacking. We designed an immunohistochemical study to comprehensively assess the trophoblastic hormone production profile of transitional cell carcinoma (TCC) of the bladder. Moreover, we correlated histological differentiation and tumor stages with marker expression and, finally, evaluated a potential tumor origin of hCGbeta core-fragment (hCGbetacf). To this end, formalin-fixed, paraffin-embedded tumor tissues from 104 patients with urothelial neoplasms of various histological grades (23 GI, 24 GII, and 38 GIII) and stage (19pTis, 21pTa, 29pT1, and 35pT2-T4) were analyzed by the immunoperoxidase technique using our own well-characterized monoclonal antibodies against the glycoprotein hormones human chorionic gonadotropin (hCG) and its derivatives hCGalpha, hCGbeta, hCGbetacf, luteinizing hormone (LH, LHbeta), follicle-stimulating hormone (FSH, FSHbeta), and the protein hormones placental lactogen (hPL) and growth hormone (hGH-V/N). Overall, trophoblastic hormone immunoreactivity was found in 36% of TCC. Detailed analysis showed 35% hCGbeta, 17% hCGbetacf, 9% hCGalpha, 4% hCG, and 2% hPL-positive cases. The tumors produced neither GH-N, placental GH-V, nor the pituitary gonadotropins FSH/FSHbeta and LH/LHbeta. Marker positivity significantly increased with high-grade lesions (26% GI- v 55% GIII-TCC) and advanced tumor stages (24% pTa v 63% > or = pT2). Hormone immunoreactivity was frequently observed in highly proliferating areas. Our findings, together with recent structural and clinical studies, strongly suggest that these hormones, or derivates thereof, might act as local tumor growth factors. Normal urothelium, urothelial papillomas, and carcinoma in situ showed no positive reactions. All tumors producing hCG-derived molecules were negative for the concommitantly analyzed neuroendocrine markers chromogranin A, synaptophysin, and neuron-specific enolase (NSE). In summary, one third of TCC ectopically produce trophoblastic hormones, which is specifically correlated with stage and grade. Apart from hCGbeta (97% of the marker-positive cases), the intracellular occurrence of hCGbetacf, apparently the second most frequently produced marker, was surprising, and there was also a lesser degree free hCGalpha and intact holo-hormone expression. The placental protein hormones PL and GH-V are not appropriate tumor marker candidates. Finally, our histogenetic findings support a metaplastic origin of the hCG producing choriocarcinomatous phenotype of some TCC.

Idiopathic copper toxicosis.

Liver diseases of infancy and childhood are generally rare and within the spectrum of these disorders, only a few subtypes are related to abnormal hepatic copper accumulation. Idiopathic copper toxicosis has been defined as such a subtype; although this disease is characterized by distinct clinical and pathologic features, its exact etiology is still controversial. On the basis of a review of the literature, supplemented by our own observations of 138 cases endemic to western Austria, we hypothesize that idiopathic copper toxicosis is caused by a synergy of an autosomal-recessive inherited defect in copper metabolism and excess dietary copper. Increased awareness of the disease should enable early diagnosis and lead to successful treatment, thereby improving the overall poor prognosis of affected patients.

Endemic Tyrolean infantile cirrhosis is not an allelic variant of Wilson's disease.

Recently, 138 cases of infantile cirrhosis originating in several families in the Austrian province of the Tyrol were reported. This endemic Tyrolean infantile cirrhosis (ETIC) is indistinguishable from Indian childhood cirrhosis (ICC), idiopathic copper toxicosis (ICT), and resembles the early forms of Wilson's disease (WND). It has been argued that ETIC might represent an allelic variant of the WND gene, which is a copper transporting P-type ATPase (ATP7B). Assuming that ETIC results from a founder effect, a possible role for ATP7B in ETIC was investigated by association studies and haplotype sharing. Because of its lethality, the mapping of ETIC was focused on obligate gene carriers, i.e. the patients' parents. Our data indicate that ETIC is a separate genetic entity, distinct from WND.

Induction of apoptosis in Kaposi's sarcoma spindle cell cultures by the subunits of human chorionic gonadotropin.

OBJECTIVES: Elucidation of the mechanisms of the previously shown growth-inhibitory action of human chorionic gonadotropin (hCG) on Kaposi's sarcoma (KS) cells and the role of the luteinizing hormone/hCG receptor (hCGR). DESIGN AND METHODS: Analysis of KS tissues and cultured spindle-type KS cells for the presence of the hCGR using 125I-hCG binding and reverse transcriptase-polymerase chain reaction; analysis of several hCG preparations (urinary, recombinant, isolated alpha and beta subunits); analysis of apoptosis mechanisms by several assays including using z-Val-Ala-Asp-fluoromethylketone (zVAD-FMK), a known apoptosis-inhibitory drug. RESULTS: First, we found that some urinary preparations of hCG (e.g., CG-10, Steris Profasi) were indeed KS-killing but others (such as Pregnyl, Choragon, Serono Profasi) were not. Secondly, recombinant subunits (alpha as well as beta) of hCG were KS cell-killing but recombinant intact hCG was not. Thirdly, the hCGR message and protein were undetectable in KS. Fourthly, CG10-induced cell death occurred by apoptosis and KS cells could be rescued by preincubation with zVAD-FMK. Finally, we also found that normal peripheral blood lymphocytes (PBL) were killed by CG-10. CONCLUSION: It is proposed that the action of subunits or subunit fragments of hCG, mediated by a putative orphan receptor (as opposed to the hCGR) and executed by interleukin-1-converting enzyme (ICE)-like protease(s), constitutes a novel apoptosis mechanism effective towards KS cells, but PBLs and possibly other cells as well. These results provide a basis for testing in vitro the therapeutic efficacy of hCG preparations which, in turn, should improve current clinical trials with 'hCG' in patients who have KS.