Identification of a new MAGE gene with tumor-specific expression by representational difference analysis

Human genes expressed exclusively in tumors and male germ line cells, such as those of the MAGE, BAGE, and GAGE families, encode antigens recognized by T lymphocytes, which are potentially useful for antitumor immunotherapy. To identify new genes of this type, we generated cDNA populations enriched in sequences expressed only in testis and melanoma, using the representational difference analysis approach. A testis cDNA library enriched by subtraction with cDNA from four other normal tissues was hybridized with radiolabeled melanoma cDNA enriched by subtraction with normal skin cDNA. A cDNA fragment sharing significant homology with MAGE genes was identified, and a cosmid containing this new gene, named MAGE-C1, was isolated. MAGE-C1 is composed of four exons and encodes a putative protein of 1142 amino acids. It is about 800 residues longer than the other MAGE proteins due to the insertion of a large number of short repetitive sequences in front of the MAGE-homologous sequence. The MAGE-C1 gene appears to be located on band Xq26, whereas the MAGE-A and MAGE-B genes are located on Xq28 and Xp21, respectively. Like other MAGE genes, MAGE-C1 is expressed in a significant proportion of tumors of various histological types, whereas it is silent in normal tissues except testis. It is probable, therefore, that like other MAGE genes, MAGE-C1 encodes antigens that may constitute useful targets for cancer immunotherapy because of their strict tumoral specificity.

[Liposome encapsulation of cystostatic drugs and starch microspheres improve tumor targeting in locoregional therapy. An animal experiment study of CC 531 liver tumor]

Systemic adjuvant chemotherapy achieves unsatisfactory results for inoperable liver tumors and metastases. Various clinical studies have shown that locoregional chemotherapy increased the survival rate by a few months. The aim of this study was to investigate tumor targeting of the most frequently used cytostatic 5-fluouracil by modifying systemic and locoregional therapy by liposome encapsulation. The tumor concentration of 5-FU encapsulated in SUV-PEG liposomes increases by a factor of 27 in systemic therapy and a factor of 90 in locoregional therapy. The tumor concentration of 5-FU increases by a factor of 8000, if the blood flow is additionally slowed by starch microspheres (Spherex) during locoregional therapy with liposome-encapsulated 5-FU.

Identification of human testis-specific transcripts and analysis of their expression in tumor cells

Tumor-specific antigens recognized by autologous T lymphocytes are encoded by genes, including those of the MAGE, BAGE, and GAGE gene families, that are expressed in a significant fraction of tumors of various types, but not in normal adult tissues, except for testis where they appear to be expressed in germ cells. Because male germ cells are known to express many genes that are not expressed in other normal adult tissues, we wished to determine whether most of these genes are occasionally activated in tumor cells. Representational difference analysis was used to obtain testis-specific transcripts. The expression of 15 testis-specific cDNA sequences was tested by RT-PCR in a series of tumor cell lines. Only one cDNA sequence showed a significant level of expression in some tumor cell lines. Remarkably, this cDNA clone proved to be a new gene of the MAGE family. These results suggest that MAGE, BAGE, and GAGE genes belong to a minor subset of testis-specific genes that is often activated in tumors of various types, whereas most testis-specific genes are either never or very rarely activated in tumors.

Comparison of bacillary indexes in slit-skin smears, skin and nerve biopsies; a study from Malawi

Data analyzed in this paper were collected within the framework of the Lepra Evaluation Project, an epidemiological study of leprosy in Karonga District, northern Malawi. For 212 patients information on the number of skin lesions, slit-skin smear and skin biopsy results were available. Among 61 patients with a single lesion none were slit-skin-smear positive and two had bacilli detected in skin biopsies. In contrast, among 119 patients with four or more lesions 34 (28.6%) versus 59 (49.6%) had bacilli detectable in slit-skin smears or skin biopsies, respectively. In a further 47 patients skin biopsy results could be compared with split-nerve biopsy results. In 20 of 47 patients the bacterial indexes (BIs) were identical in skin and nerve biopsies, while in 26 of 47 patients the BIs were higher in nerve than in skin biopsies. This difference, which is consistent with several other studies in the literature, provides an insight into the pathogenesis of leprosy.

A negative role for phosphoinositide 3-kinase in T-cell antigen receptor function

BACKGROUND

A delicate balance between positive and negative regulatory mechanisms during T-cell activation determines the specificity and magnitude of an immune response. Phosphoinositide 3-kinase (PI 3-kinase) is activated by a diverse set of receptors that determine T-cell function, including the T-cell antigen receptor (TCR), the costimulatory receptor CD28, and negative regulators of T-cell activation such as CTLA-4. PI 3-kinase is also regulated by the haematopoietic cytokines that determine T-cell differentiation and lymphocyte proliferation. PI 3-kinase can thus dynamically influence the outcome of the immune reactions at various stages. In this study, we investigated the importance of PI 3-kinase in TCR-directed T-cell activation using activated or inhibitory versions of PI 3-kinase.

RESULTS

Certain aspects of TCR responses such as the induction of transcriptional activity of AP1 and serum response factor were not affected by expression of the mutant forms of PI 3-kinase. We found, however, that PI 3-kinase profoundly influenced the transactivation capacity of 'nuclear factor of activated T cells' (NF-AT) elicited by the TCR: expression of an activated form of PI 3-kinase inhibited TCR-mediated NF-AT responses, whereas expression of a dominant negative mutant of PI 3-kinase potently enhanced TCR-controlled NF-AT induction. These effects of PI 3-kinase were not mediated by previously identified PI 3-kinase effectors, such as protein kinase B, a positive regulator of PI 3-kinase, or the GTPase Rac, and are therefore likely to involve a novel, as yet unknown, effector molecule.

CONCLUSIONS

Our results establish that PI 3-kinase can both positively and negatively regulate T-cell function, and uncover a previously unrecognized function for PI 3-kinase in T cells as a selective negative regulator of TCR-signalling events and therefore as a determinant of T-cell homeostasis.

Incidence of anti-mouse antibodies in thrombocytopenic patients with autoimmune disorders

Idiopathic thrombotycopenic purpura (ITP) is an autoimmune disorder in which circulating autoantibodies react with target antigens on the platelet membrane. In order to identify the autoimmune response in ITP, two MAIPA (Monoclonal Antibody (MAb) Immobilization of Platelet Antigen) assays (MAIPA I and MAIPA II) were performed on sera from thrombocytopenic patients. In the classic MAIPA assay (MAIPA I), control platelets were incubated simultaneously with human serum and a mouse MAb to a platelet glycoprotein. In MAIPA II, the control platelets were incubated first with the human serum and then, after washing, with the selected mouse MAb. A positive MAIPA I test but a negative MAIPA II has been shown to result from the presence of serum antibodies recognizing mouse MAb to platelet glycoproteins used in the assay. We compared the frequency of such 'anti-mouse' antibodies in patients with thrombocytopenia associated or not with other autoimmune states and in healthy donors with a normal platelet count. Statistically significant differences were found in the incidence of anti-mouse antibodies between patients and healthy donors. Furthermore, the identity of the targeted mouse MAbs varied in sera from the patients. The detected anti-mouse antibodies may include anti-idiotypic antibodies produced against cross-reactive idiotypes shared by human and mouse anti-platelet antibodies.

Erythema nodosum leprosum is associated with up-regulation of polyclonal IgG1 antibody synthesis

Erythema nodosum leprosum (ENL) is a serious complication of lepromatous (L) disease in leprosy. We have previously shown that of the four IgG subclasses, IgG1 and IgG3 Mycobacterium leprae-specific antibodies are significantly lower in leprosy patients during ENL reaction compared with untreated L patients. To see if this decrease results from a down-regulation of antibody synthesis during ENL, the frequency of antibody-secreting B cells (ABSC) in the blood compartment was determined by ELISPOT and related to serum immunoglobulin concentrations (microgram/ABSC). Control groups consisted of 16 patients with stable L disease and 32 healthy endemic controls (EC). Paired samples were analysed during acute ENLS (n = 13) and after the reaction had subsided to identify changes associated with ENL. Polyclonal (PC) IgG1 was elevated in L patients compared with EC (325 micrograms versus 180 micrograms). Interestingly, patients during acute ENL showed concentrations higher than L patients (419 micrograms), which decreased after the reaction had subsided (260 micrograms), indicating the transient nature of the antibody response. IgG2 antibodies showed the reverse trend and were lower during ENL and increased after the reaction had subsided. The mean concentrations for PC IgG3 and IgG4 antibodies were similar during ENL and after the reaction had subsided. Thus, decrease in M. leprae-specific IgG1 and IgG3 antibodies is not related to down-regulation of B cell responses. Identification of factors which regulate PC IgG1 antibody synthesis may provide additional insights into determinants of ENL reactions.

Prevalence and characteristics of brittle diabetes in Britain

We investigated the prevalence and characteristics of 'brittle diabetes', defined as insulin-dependent diabetes mellitus associated with glycaemic instability of any type, leading to life disruption with recurrent and/or prolonged hospitalizations. A questionnaire was sent to all physicians and paediatricians running diabetic clinics in the UK, from lists held at the British Diabetic Association. A total of 414 brittle patients were reported (72% questionnaire return). Most were young (mean age +/- SD was 26 +/- 15 years), though there was a small peak at ages 60-70 years. There was an excess of females (66%) and overall clinic prevalence was 1.2 per 1000 diabetic patients and 2.9 per 1000 insulin-treated diabetic patients. On average, there was 1.0 brittle patient per diabetic clinic. The most common form of brittleness was recurrent ketoacidosis (59%), with 17% having predominant hypoglycaemia, and 24% mixed instability. Female excess was highest and mean age lowest in the recurrent ketoacidosis group, whilst the reverse was true for those with recurrent hypoglycaemia. Causes of brittleness were offered by 58% of consultants, and most (93%) considered various psychosocial problems as likely underlying factors. We conclude that brittle diabetes is a small but significant problem, currently affecting about 1 per 1000 diabetic patients. Most, but by no means all, are young females--often with recurrent ketoacidosis. Older age groups are more likely to have recurrent hypoglycaemic or mixed types of brittleness. Perceived causes of brittleness are usually psychosocial.

Autoantibodies and anti-mouse antibodies in thrombocytopenic patients as assessed by different MAIPA assays

Two MAIPA (monoclonal antibody [MAb] immobilization of platelet antigen) assays were performed to determine (a) autoantibodies to platelet glycoproteins (GP) and (b) serum antibodies recognizing mouse MAbs used in the assay. In MAIPA I, control platelets were incubated simultaneously with human serum and a mouse MAb to a platelet glycoprotein (GP IIb-IIIa, Ib-IX, Ia-IIa, IV and p24). In MAIPA II, the control platelets were incubated first with the human serum and then, after washing, with the selected mouse MAb. A series of 25 patients with autoimmune thrombocytopenic purpura (ATP) associated or not with other autoimmune states were examined. Autoantibodies (both MAIPA I and MAIPA II positive) or anti-mouse Abs (MAIPA I positive and MAIPA II negative) were frequent in both groups of patients. Statistically significant differences existed in the incidence of anti-mouse Abs between patients (56.5%) and healthy donors (10%). This suggests that their production may be related to thrombocytopenias associated with autoimmune disease. We speculate that the presence of anti-mouse antibodies could reflect an abnormality in the immunological modulation of the idiotypic network.

The haemolytic uraemic syndrome in patients with AIDS

OBJECTIVE

Thrombotic microangiopathies have been increasingly recognised in HIV infection. The contribution of haemolytic uraemic syndrome (HUS) has not received as much emphasis as other members of the thrombotic microangiopathies. We describe the clinical features and prognosis of HUS in a group of patients with AIDS.

SETTING

St Bartholomew's and The Middlesex Hospitals, London.

PATIENTS

Five HIV seropositive individuals with clinical and histological features consistent with HUS.

INTERVENTIONS

Blood transfusion, fresh frozen plasma, haemodialysis, renal biopsy, autopsy.

CONCLUSIONS

HUS occurs in advanced HIV infection. Hypertension was a prominent clinical feature in HUS in this patient group. Measures to limit renovascular damage were unsuccessful and haemodialysis was usually needed to support renal function. The prognosis is poor, no patient achieved clinical remission and all died.

Acquired immunodeficiency syndrome and ocular calcification

We report the presence of peculiar nonbanded calcification of the cornea in three patients with acquired immunodeficiency syndrome, discovered on postmortem histological examination of the globes. In one patient, multiple calcium salt precipitates also affected other ocular and orbital structures. Calcium deposits were present in the corneal stroma but spared Bowman's layer, as is usually seen in primary and secondary corneal calcification. The calcified areas were positive to von Kossa, alizarin red, alcian blue, and colloidal iron stains. Electron probe analysis of the three cases showed the presence of calcium and phosphorus in a ratio characteristic for hydroxyapatite. No predisposing factors could be found. The possible role of associated alterations in the mucopolysaccharide content or composition in the calcified areas is unclear.

The protein interactions of the immunoglobulin receptor family tyrosine-based activation motifs present in the T cell receptor zeta subunits and the CD3 gamma, delta and epsilon chains

Immunoglobulin family tyrosine-based activation motifs (ITAM), which define the conserved signaling sequence EX2YX2L/IX7YX2L/I, couple the T cell antigen receptor (TCR) to cellular proteins including protein tyrosine kinases (PTK) and adapter molecules. The TCR is a multichain complex with four invariant chains CD3 gamma, delta and epsilon that each contain a single ITAM and the TCR zeta chain that contains three ITAM. The present study explores the protein interactions of the doubly phosphorylated CD3 gamma, delta, epsilon ITAM to determine whether they have common or unique biochemical properties. The data show that the doubly phosphorylated ITAM all bind the PTK ZAP-70, but the ITAM also variably bind the PTK p59fyn and the adapters Shc, Grb-2 and the p85 regulatory subunit of phosphoinositol 3' kinase. The CD3 and zeta ITAM display a hierarchy of ZAP-70 binding: zeta 1 = gamma = delta > zeta 3 > zeta 2 = epsilon. Shc, Grb-2 and p85 could bind the zeta ITAM and the CD3 gamma and delta ITAM, but not the CD3 epsilon ITAM. There were also subtle differences in the hierarchy of reactivity of these adapters for the CD3 gamma, delta and zeta ITAM that show that the zeta, CD3 gamma, delta and epsilon ITAM have different binding properties. The present study thus shows that the different ITAM of the TCR/CD3 complex can interact with different cytosolic effectors, indicating that differential ITAM phosphorylation during T cell activation could be a mechanism to generate signaling diversity by the TCR complex.

A peptide recognized by human cytolytic T lymphocytes on HLA-A2 melanomas is encoded by an intron sequence of the N-acetylglucosaminyltransferase V gene

A cytolytic T lymphocyte (CTL) clone that lyses many HLA-A2 melanomas was derived from a population of tumor-infiltrating lymphocytes of an HLA-A2 melanoma patient. The gene coding for the antigen recognized by this CTL was identified by transfection of a cDNA library. It is the gene which has been reported to code for N-acetylglucosaminyltransferase V (GnT-V). Remarkably, the antigenic peptide recognized by the CTL is encoded by a sequence located in an intron. In contrast to the fully spliced GnT-V mRNA, which was found in a wide range of normal and tumoral tissues, the mRNA containing the intron region coding for the antigen was not found at a significant level in normal tissues. This mRNA was observed to be present in about 50% of melanomas. Our results suggest that a promoter located near the end of the relevant intron is activated in melanoma cells, resulting in the production of an mRNA coding for the antigen.

A patient with autoimmune thrombocytopenic purpura demonstrating serum antibodies reactive with mouse cross-reactive idiotypes

Autoimmune thrombocytopenic purpura (ATP) is a syndrome of destructive thrombocytopenia due to platelet-binding antibodies. We report the case of a young woman (C.V.) who has a history of chronic ATP with severe but transient bouts of thrombocytopenia. Using the classic monoclonal antibody (MAb) immobilization of platelet antigens (MAIPA) assay to screen serum antibody specificity, results were strongly positive with MAbs to glycoproteins (GPs) Ib-IX, Ia-IIa, IV, and p24, but weakly positive or negative for GP IIb-IIIa. In contrast, a two-step incubation assay (MAIPA II), in which platelets were incubated sequentially with C.V. serum and the murine MAb, gave negative results for all GPs. Affinity chromatography performed using Bx-1, a MAb to GP Ib, showed that the patient's serum contained antibodies to determinants expressed by mouse immunoglobulins. These were present on Fab fragments on Bx-1. A survey of sera from other patients with thrombocytopenia of immune origin revealed that antibodies reactive with selected idiotypes of mouse MAbs were not infrequent and raises the question of their role in the thrombocytopenia.

Histological study of oxalosis in the eye and adnexa of AIDS patients

Review of a series of 98 eyes removed at autopsy from 86 AIDS patients identified 12 cases (14%) showing varying degrees of microscopic calcium oxalate deposition. The oxalate crystals were birefringent using polarisation microscopy and were stained histochemically by the silver nitrate-rubeanic acid method (Yasue), a stain considered to be specific for calcium oxalate. In two cases, the deposition was extensive and involved the surface of the ciliary processes, ciliary body and pars plana of the retina, the retinal and optic nerve blood vessel wall, a few retinal pigment cells, and the anterior inner sclera. A lesser degree of intraocular involvement was observed in the remaining 10 cases. In all but two eyes, where a peripheral active area of cytomegalovirus retinitis was present, no other significant microscopical abnormality was found. Clinically, these patients were asymptomatic. At autopsy, oxalate deposits were found in the kidney and/or thyroid in seven of the patients.

Autopsy-proven causes of death in HIV-infected patients treated for tuberculosis in Abidjan, Côte d'Ivoire

OBJECTIVE

To determine autopsy-proven causes of death in HIV-infected patients treated for tuberculosis in Abidjan, Côte d'Ivoire.

METHODS

A computerized listing of 9523 patients diagnosed with tuberculosis and tested for HIV infection at Abidjan's two large tuberculosis treatment centers from July 1989 to December 1991 was matched against a listing of 496 patients who were autopsied in Abidjan's largest public hospital in 1991-1992.

RESULTS

Fifteen matching patients were identified including 11 adults with smear-positive pulmonary tuberculosis, three adults with extrapulmonary tuberculosis, and one child with smear-negative pulmonary tuberculosis. The autopsy-proven causes of death among the adults were tuberculosis (n = 4), bacterial infections (n = 3), cerebral toxoplasmosis (n = 2), pulmonary nocardiosis (n = 2), Pneumocystis carinii pneumonia (n = 1), atypical mycobacteriosis (n = 1), and wasting syndrome (n = 1). Tuberculosis was the primary cause of death in two of five smear-positive patients who had not completed therapy, in none of the six patients with smear-positive disease who had completed therapy, and in two of the three patients with extrapulmonary tuberculosis.

CONCLUSIONS

Chemoprophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) might have provided benefit to eight (57%) of the 14 adults in this series who died either of bacterial infections, toxoplasmosis, nocardiosis, or pneumocystosis. Prospective studies are required to elucidate further the causes of increased mortality, and to evaluate the benefits of TMP-SMX prophylaxis in HIV-infected African patients with tuberculosis.

The role of tyrosine phosphorylation in the interaction of cellular tyrosine kinases with the T cell receptor zeta chain tyrosine-based activation motif

Immunoglobulin receptor family tyrosine-based activation motifs (ITAM) define a conserved signaling sequence, EX2YX2L/IX7YX2L/I, that mediates coupling of the T cell antigen receptor (TCR) to protein tyrosine kinases (PTK). In the present study, we explored the role of phosphorylation of the two ITAM tyrosine residues in the interactions of the motif with the PTK ZAP-70 and p59fyn. The data show that the phosphorylation of a single tyrosine within the motif enables binding of p59fyn, whereas phosphorylation of both tyrosines within the motif is required for maximal binding of the PTK ZAP-70. Quantitative binding experiments show that nanomolar concentrations of the doubly phosphorylated zeta 1-ITAM are sufficient for ZAP-70 recruitment, whereas micromolar levels of singly phosphorylated ITAM are necessary for p59fyn binding. ZAP-70 binds with low efficiency to a singly phosphorylated ITAM, but shows preferential binding to the C-terminal phosphotyrosine in the ITAM, whereas p59fyn binds selectively to the N-terminal phosphotyrosine. The present data thus show that there is the potential for a singly phosphorylated ITAM to couple to cellular PTK. Moreover, the data suggest a mechanism for heterogeneity in signal transduction responses by the TCR, since ITAM could differentially couple the TCR to downstream signaling events depending on their phosphorylation state.

A new family of genes coding for an antigen recognized by autologous cytolytic T lymphocytes on a human melanoma

Human melanoma MZ2-MEL expresses several distinct antigens that are recognized by autologous cytolytic T lymphocytes (CTL). Some of these antigens are encoded by genes MAGE-1, MAGE-3, and BAGE, which are expressed in a large fraction of tumors of various histological types but are silent in normal adult tissues with the exception of testis. We report here the identification of the gene coding for MZ2-F, another antigen recognized by autologous CTL on MZ2-MEL cells. This gene, which was named GAGE-1, is not related to any presently known gene. It belongs to a family of genes that are expressed in a variety of tumors but not in normal tissues, except for the testis. Antigenic peptide YRPRPRRY, which is encoded by GAGE-1, is recognized by anti-MZ2-F CTL on class I molecule HLA-Cw6. The two genes of the GAGE family that code for this peptide, namely GAGE-1 and GAGE-2, are expressed in a significant proportion of melanomas (24%), sarcomas (25%), non-small cell lung cancers (19%), head and neck tumors (19%), and bladder tumors (12%). About 50% of melanoma patients carry on their tumor at least one of the presently defined antigens encoded by the MAGE, BAGE, and GAGE genes.

Individual differences in the orientation of the cytolytic T cell response against mouse tumor P815

We reported previously that the mouse tumor P815 expresses four distinct antigens (A, B, C, D) recognized by syngeneic cytolytic T lymphocytes (CTL). A fifth P815 antigen (E) was identified by means of a CTL clone derived from tumor-infiltrating lymphocytes. We compared a number of mice for the orientation of their CTL response with respect to the various P815 antigens. Lymphocytes from mice inoculated subcutaneously with living P815 cells were stimulated in vitro with tumor cells and the resulting CTL were tested against targets expressing either antigens A and B or antigens C, D and E. Many mice had an asymmetrical response, some producing CTL directed almost exclusively against antigens A, B and others producing CTL directed almost exclusively against C, D. E. When mice were inoculated into two separate sites, different orientations in the responses of the two local lymph nodes were often observed, suggesting that individual differences in the orientation of the anti-P815 CTL response do not result from preexisting differences between the animals. Asymmetrical CTL responses persisted in mice that were given a second injection of tumor cells. A possible interpretation of our results is that the major component of the CTL response is made of the progeny of a very small number of CTL precursors that happen to be the first to be stimulated by the tumor antigens.

[Autopsy findings in 70 AIDS patients who died in a department of pneumology in Ivory Coast: impact of tuberculosis]

Based on autopsy findings in 70 patients infected by human immunodeficiency virus (HIV) who died in the Pulmonology Department of the Treichville University Hospital Center in Abidjan, Ivory Coast. the authors assess the incidence of tuberculosis as the cause of death and analyze the clinical, bacteriologic, and histologic features of the disease. in this population. Pulmonary tuberculosis was the first cause of death in this series accounting for 31 cases (44.2%). In 12 cases (38.7%), microscopic identification failed during hospitalization and the disease had been misdiagnosed as common bacterial pneumonia. In 29 cases (93.5%) pulmonary tuberculosis was associated with abdominal involvement. In 17 cases (54.8%) involvement of more than two organs was observed. Of the 60 abdominal sites detected during the autopsy of the 31 patients with pulmonary tuberculosis, there were 19 (31.3%) in lymph nodes, 18 (30%) in the liver, 14 (23.3%) in the spleen, and 9 (14.9%) in the kidneys. Histologic features were remarkable by the absence of typical tuberculous granulomas. The findings of this study confirm the high incidence of disseminated tuberculosis in patient infected by HIV as noted in a number of previous studies.

Pulmonary cryptococcosis associated with HIV-1 infection in Rwanda: a retrospective study of 37 cases

OBJECTIVES

To study the demographic, clinical, radiographic and diagnostic features, the clinical course and therapeutic response of pulmonary cryptococcosis in HIV-1-infected patients.

DESIGN

Retrospective review.

SETTING

The Department of Medicine of an urban reference hospital in Central Africa.

METHODS

All the records of HIV-1-infected patients with pulmonary cryptococcosis were reviewed retrospectively with regard to the parameters described above.

RESULTS

Over a 3-year period, pulmonary cryptococcosis was diagnosed in 37 HIV-1-infected Rwandan patients (21 men, 16 women; mean age, 35 years; range, 26-55 years). Twenty-nine patients (78%) had primary pulmonary cryptococcosis. Cough (94%), weight loss (65%), fever (51%), dyspnoea (46%), thoracic pain (30%), headache (13%) and haemoptysis (8%) were the predominant clinical findings. A diffuse interstitial infiltrate on chest radiograph was observed in 76% of the patients, an alveolar pattern in 19%, mediastinal and/or hilar adenopathy in 11%, nodules and pleural effusion each in 5%. Bronchoalveolar lavage, with a yield of 82%, was found to be the most sensitive diagnostic procedure. Screening of cryptococcal antigen in the serum failed to detect cases of primary pulmonary cryptococcosis. Twelve patients with primary pulmonary cryptococcosis treated with itraconazole as acute and maintenance therapy were all protected against disseminated cryptococcal disease; seven out of 10 (70%) of those who did not receive a specific anticryptococcal drug developed disseminated cryptococcal disease.

CONCLUSION

Pulmonary cryptococcosis is not a rare complication of HIV-1 infection in Rwanda. Its clinical and radiographic patterns are non-specific and bronchoalveolar lavage is the procedure of choice for its diagnosis. The natural history of untreated primary pulmonary cryptococcosis is disseminated cryptococcal disease. Itraconazole is highly effective in the prevention of disseminated cryptococcal disease in patients with primary pulmonary cryptococcosis.

Pulmonary disease associated with the human immunodeficiency virus in Kigali, Rwanda. A fiberoptic bronchoscopic study of 111 cases of undetermined etiology

All human immunodeficiency virus type 1 (HIV-1) infected adult patients referred to the Division of Pulmonary Diseases of the Centre Hospitalier de Kigali, Rwanda for evaluation of a pulmonary disease of undetermined etiology (PDUE) were investigated by fiberoptic bronchoscopy using both bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB). During a 10-mo period 111 HIV-1 infected patients with PDUE were examined, of whom 47 (42%) fulfilled the World Health Organization (WHO) clinical case definition for acquired immunodeficiency syndrome (AIDS) and seven (6%) had an AIDS-defining illness. Nonspecific interstitial pneumonitis was diagnosed in 42 (38%) patients, tuberculosis in 25 (23%), cryptococcosis in 14 (13%), Kaposi's sarcoma (KS) in 10 (9%), Pneumocystis carinii pneumonia (PCP) in five (5%). The diagnosis remained undetermined in 18 (16%) patients. Chest radiograph patterns were generally nonspecific. TBB and BAL had diagnostic yields of 82 and 26% of all final diagnoses, respectively. Our study on Rwandese HIV-1-infected patients with PDUE provides evidence for a large spectrum of pulmonary diseases with relative frequencies differing strikingly from those in developed countries. Detailed investigations confirm the rarity of PCP in Africa and highlight nonspecific interstitial pneumonitis as the predominant diagnosis of PDUE. Empiric antituberculosis treatment is justified in the absence of clinical manifestations suggestive of a specific diagnosis and while awaiting the results of the diagnostic procedures. Primary prophylaxis for PCP would not be appropriate in Africa.

Episodic brainstem compression masquerading as electrodecremental seizures

An 8-year-old boy developed generalized tonic spasms lasting minutes accompanied by an electrodecremental event on electroencephalogram in association with increased intracranial pressure caused by shunt malfunction. The electroencephalographic abnormalities and clinical attacks occurred despite an otherwise normal neurologic examination, normal initial opening pressure on lumbar puncture and shunt tap, and only mild ventricular dilation revealed by brain imaging. There was no improvement with antiepileptic drugs. Further signs of uncal herniation led to repeat tap of the shunt, revealing a pressure of 800 mm of water. After revision of the shunt "seizures" stopped and the electroencephalogram returned to normal. Antiepileptic drugs were discontinued, with no recurrence of events.

[Prevalence of pneumocystosis in HIV infected patients in a pneumology unit. Autopsy study performed in Abidjan (Côte d'Ivoire)]

Autopsies were performed in the Pathology Department of the Treichville University Hospital, Abidjan, Ivory Coast in 70 HIV infected subjects who had died in the Department of Pneumophtisiology. The prevalence of Pneumocystis carinii pneumonia was determined. None of the patients had received prophylaxis against P. carinii and none had bee treated for pneumocystosis. Autopsies were performed within 6 to 48 hours after death and the diagnosis of pneumocystosis was confirmed with the Gomori-Grocott staining technique on lung specimens. Among the 70 autopsies Pneumocystis carinii pneumonia was observed in 6. Thus the prevalence of P. carinii pneumonia in these patients infected with HIV was 8.57%.

The genomic region encoding toxin gamma from the scorpion Tityus serrulatus contains an intron

The gene encoding toxin gamma from the scorpion, Tityus serrulatus, was amplified by PCR from genomic DNA employing synthetic oligonucleotides designed from the reported cDNA sequence. The nucleotide sequence of this gene reveals the presence of an intron of 475 base pairs (bp) which interrupts the region that encodes the signal peptide of the precursor toxin. A comparison of the intron boundary sequences of the gamma toxin gene with ones from other arachnid genes is also presented.

Macrophage nitric oxide synthase subunits. Purification, characterization, and role of prosthetic groups and substrate in regulating their association into a dimeric enzyme

The cytokine-induced nitric oxide synthase (NOS) of macrophages is a homodimeric enzyme that contains iron protoporphorin IX (heme), FAD, FMN, tetrahydrobiopterin, and calmodulin. To investigate how the enzyme's quaternary structure relates to its catalytic activity and binding of prosthetic groups, dimeric NOS and its subunits were purified separately and their composition and catalytic properties compared. In contrast to dimeric NOS, purified subunits did not synthesize NO or contain bound heme or tetrahydrobiopterin. However, the subunits did contain FAD, FMN, and calmodulin in amounts comparable with dimeric NOS, displayed the light absorbance spectrum of an FAD- and FMN-containing flavoprotein, and generated an air-stable flavin semiquinone radical upon reduction of their ferricyanide-oxidized form. Dimeric NOS and NOS subunits were equivalent in catalyzing electron transfer from NADPH to cytochrome c, dichlorophenolindophenol, or ferricyanide at rates that were 8-30-fold faster than the maximal rate of NO synthesis by dimeric NOS. Reconstitution of subunit NO synthesis required their incubation with L-arginine, tetrahydrobiopterin, and stoichiometric amounts of heme and correlated with formation of a proportional amount of dimeric NOS in all cases. The dimeric NOS reconstituted from its subunits contained 0.9 heme and 0.44 tetrahydrobiopterin bound per subunit and had the spectral and catalytic properties of native dimeric NOS. Thus, NOS subunits are NADPH-dependent reductases that acquire the capacity to synthesize NO only through their dimerization and binding of heme and tetrahydrobiopterin. The ability of heme, tetrahydrobiopterin, and L-arginine to promote subunit dimerization is unprecedented and suggests novel roles for these molecules in forming and stabilizing the active dimeric NOS.

Clinical research, prophylaxis, therapy, and care for HIV disease in Africa

By the end of the century, citizens of resource-poor countries will constitute 90% of the world's human immunodeficiency virus (HIV)-infected people. Clinical management of such persons in developing countries has been neglected; most AIDS research has concentrated on epidemiology, and donor agencies have generally invested in the prevention of HIV infection. The heavy burden of HIV disease in Africa requires that care for AIDS be addressed, and prevention and care should be seen as interrelated. Prevention and treatment of tuberculosis, the commonest severe infection in persons with AIDS in Africa, illustrate this interrelationship. We outline priorities for applied research on the management of HIV disease in a resource-poor environment, and discuss prophylaxis, therapy for opportunistic diseases, terminal care, and use of antiretroviral therapy. Research should define the standard of care that can realistically be demanded for HIV disease in a resource-poor environment. Research and public health programs for AIDS in developing countries must address AIDS care and attempt to reduce the widening gap between interventions available for HIV-infected persons in different parts of the world.

Human immunodeficiency virus and leprosy

In summary, clinical leprosy does not appear to be more frequent in HIV-positive than in HIV-negative people in areas where both infections are endemic. There is no evidence that the paucibacillary to multibacillary distribution of patients is altered by HIV infection. There are reports that neuritis is more severe in co-infected people, and that reversal reactions (or, at least, new lesions) may be more frequent after therapy; but these reports are either poorly documented or poorly controlled. In several ways, this lack of expected leprosy is similar to the patterns of other low-virulent infections in HIV-positive patients in the tropics, such as MAC infection, Pneumocystis carinii and cytomegalovirus infection. Despite the presence of the agents in the environment and/or in the human host, they are infrequently encountered clinicopathologically. This is in marked contrast to their importance in industrialized countries. One explanation, as yet unproven, is that HIV-positive patients in the tropics do not live long enough in states of severe immunosuppression to develop these infections. Perhaps the same applies to M. leprae infection, whose incubation period can be measured in decades and whose clinical course may evolve over years, in contrast to the common reactivation of latent, virulent M. tuberculosis infection with its high morbidity. There may also be an analogy between leprosy and infection with Plasmodium falciparum, Strongyloides stercoralis and Entamoeba histolytica: these infections are controlled (or at least influenced) by cell-mediated immunity and, theoretically, should be more frequent in HIV-positive people than HIV-negatives. In fact they are not, and leprosy may be regarded as another 'missing infection in AIDS'.(ABSTRACT TRUNCATED AT 250 WORDS)

Diarrhoea associated with cyanobacterium-like bodies: a new coccidian enteritis of man

Faecal excretion of cysts known as cyanobacterium-like bodies (CLB) is associated with a diarrhoeal illness, which is often prolonged and severe. It is seen mainly in travellers and immunocompromised patients. Recently these cysts have been shown to be coccidian oocysts. We describe three patients who developed diarrhoea while travelling abroad. Stool samples from all three patients contained CLB. Jejunal aspirates from two patients also yielded CLB. Conventional histology of jejunal biopsy specimens confirmed that two patients had enteritis. Electronmicroscopy of the same biopsy specimens revealed intraepithelial coccidia. These findings suggest that the small bowel is the site of infection of this new coccidian disease.

Multiple cerebral hemorrhages in HTLV-I-associated myelopathy

We describe a 66-year-old woman with long-standing HTLV-I-associated myelopathy who developed multiple parenchymal hemorrhages and whose angiogram suggested cerebral vasculitis. After cyclophosphamide and glucocorticoid therapy, both her acute deficits and chronic paraparesis improved. HTLV-I may be an etiologic agent in isolated angiitis of CNS.

Bcl-2 proto-oncogene expression in Epstein-Barr-virus-associated nasopharyngeal carcinoma

The bcl-2 proto-oncogene product inhibits apoptosis. Increased levels of bcl-2 protein are associated with prolonged B-cell survival and have been demonstrated in a high proportion of follicular B-cell lymphoma. Recent studies have shown that bcl-2 protein expression in B cells immortalized by Epstein-Barr virus (EBV) in vitro is up-regulated by the EBV-latency-associated antigen, latent membrane protein (LMP) 1. The epithelial malignancy, undifferentiated nasopharyngeal carcinoma (UNPC), has a well-established association with EBV and the tumour cells characteristically display a restricted latent viral phenotype including LMP 1. This study has investigated the relationship between the presence of EBV DNA, EBV phenotypic profiles and bcl-2 protein expression in conventionally processed and cryopreserved samples of NPC using in situ hybridization, immunocytochemical and immunoblotting techniques. bcl-2 was detected in most (80%) samples of UNPC as well as in 1/3 samples of keratinizing NPC and 2/2 samples of nasopharyngeal adenocarcinoma. However, no close correlation was found between the presence of EBV DNA, and profiles for LMP 1 and bcl-2 protein expression in 45 UNPC. In addition, bcl-2 protein was shown to be selectively expressed in the basal compartment of normal nasopharyngeal epithelia. bcl-2 protein expression has not been reported previously in malignant tumours of epithelial origin. The findings in this study implicate a role for bcl-2 both in normal keratinocyte differentiation and in the pathogenesis of epithelial malignancy.

[Pulmonary diseases and retrovirus infections. A pathological study in 70 cases]

A necroscopic study, conducted in the Pathology Department of the Centre Hospitalier Universitaire (CHU) de Treichville in Abidjan, included 70 seropositive subjects who died in the Pneumophtisiology Department. We attempted to determine the different pulmonary affections occurring during infection with the human immunodeficiency virus (HIV). This study demonstrated the predominant role of tuberculosis (44%) and bacterial pneumonia (30%) which remain the predominant aetiologies. Other opportunistic affections were rare including: Pneumocystises, Mycobacteriaceae, and Cytomegalovirus infection and the Kaposi sarcoma. The absence of pulmonary cryptococcosis and non-Hodgkin lymphoma were also noted. Necroscopic examinations do not necessarily provide evidence of the in vivo pathologies, the autopsy being able to identify only the causal diseases or those present at death.

The pathology of the posterior root ganglia in AIDS and its relationship to the pallor of the gracile tract

The spinal cord and the thoracic and lumbar posterior root ganglia (PRGs) of 14 HIV-positive men and 7 age- and sex-matched controls were studied by routine histology, morphometric analysis of the number of nodules of Nageotte (nN) and the diameters of sensory ganglion cells, immunohistochemistry and in situ hybridization. In 7 patients (2 of whom had evidence of cytomegalovirus ganglionitis) there were increased numbers of nN and diffuse, mild infiltration with CD45R+ T lymphocytes; no B lymphocytes were observed. Macrophages were increased in number in all cases. Whenever more than one ganglion was examined from the same patient, the appearances were similar in all. There was no alteration in the distribution of ganglion cell diameters. Changes in the spinal cord included vacuolar myelopathy (5 cases), HIV myelitis (1 case), microglial nodules (3 cases) and pallor of the gracile tracts (GTP) in 7 cases, in 6 of whom it co-existed with increased numbers of nN. Seven cases had no abnormalities, except the increase in number of macrophages in PRGs. In spite of a correlation between sensory nerve cell loss and GTP our findings suggest that other mechanisms, such as 'dying back' may contribute to the pathogenesis of GTP. Moreover, sensory disturbances were found most commonly in association with nerve cell loss; however, loss of sensory ganglion cells was not necessarily associated with evidence of sensory impairment.

Histoplasmosis of the central nervous system

Histoplasma capsulatum infection of the central nervous system is extremely rare in the United Kingdom partly because the organism is not endemic. However, because the organism can remain quiescent in the lungs or the adrenal glands for over 40 years before dissemination, it increasingly needs to be considered in unexplained neurological disease particularly in people who lived in endemic areas as children. In this paper a rapidly progressive fatal myelopathy in an English man brought up in India was shown at necropsy to be due to histoplasmosis. The neurological features of this infection are reviewed.