Human papillomavirus (HPV) viral load and HPV type in the clinical outcome of HIV-positive patients treated with imiquimod for anogenital warts and anal intraepithelial neoplasia

OBJECTIVE

To evaluate the efficacy of 5% imiquimod in HIV-positive male patients with anogenital warts or anal intraepithelial neoplasia (AIN), and to elucidate whether human papillomavirus (HPV) type and viral load were important for clinical outcome and recurrences.

METHODS

Thirty-seven patients with histologically proven anogenital warts or AIN were enrolled. Topical 5% imiquimod was applied three times per week for more than 8 h overnight for 16 weeks, although patients were allowed to continue therapy for 4 more weeks if they did not have complete clearance of lesions.

RESULTS

Mean age was 34 years. The perianal area was the main lesion location. Thirty-three patients had CD4 counts of < 500 cells/mm(3). Eighteen patients had a histopathological diagnosis of AIN-1. Main HPV types detected corresponded to low-risk HPV types. At 20 weeks of therapy, 46% patients achieved total clearance whereas 14 patients had > 50% clearance. Recurrence was observed in 5 of 17 patients who cleared. Clearance was not influenced by patients' CD4 counts, wart location, HIV viral load or HPV viral load.

CONCLUSIONS

The assumption that visible perianal warts are benign lesions in HIV-positive patients has to be reevaluated since an important number of such lesions could correspond to low-grade anal disease, which in turn could progress to high-grade anal disease or cancer. In addition, our results in this preliminary study indicate that imiquimod appears to be effective in treating AIN in HIV-positive patients. Further studies are needed to document its utility to prevent high-grade dysplasia and/or anal cancer.

Impact of Pregnancy on the Function of Transplanted Kidneys

INTRODUCTION

This study reviewed the course of pregnancies in terms of impact on renal function and delivery-related data among women who received kidney transplants in our unit.

METHODS

We reviewed the medical records of women transplanted between 1982 and 2002 who became pregnant. We recorded the data of medical, obstetrical, and transplant-related complications, plasma creatinine levels, and blood pressures at baseline, delivery, and 12 months after delivery.

RESULTS

Thirty women had 37 pregnancies. Immunosuppressive protocols included cyclosporine, ketoconazole, azathioprine, and prednisone in 22 patients or azathioprine and prednisone in 15. Renal function decreased significantly: mean creatinine levels at baseline, delivery, and after 1 year were: 1.19 +/- 0.38 mg/dL; 1.44 +/- 0.70 mg/dL; and 1.38 +/- 0.53 mg/dL, respectively (P = .023 and P = .004 vs baseline respectively). Systolic and diastolic blood pressures at delivery were higher than at baseline (134 +/- 19 and 86 +/- 14 mm Hg vs 126 +/- 21 and 79 +/- 13 mm Hg (P = .029 and P = .053, respectively). These values normalized 1 year later (128 +/- 21 and 80 +/- 16). Decreased use of antihypertensive drugs were the cause of poor blood pressure control (1.8 +/- 1.3 vs 0.9 +/- 0.7, P < .01). Blood pressure control improved following delivery. The most frequent complications were preeclampsia (18.9%), intrahepatic cholestasis (13.5%), and urinary tract infections (13.5%). There were five rejection episodes. Seven miscarriages took place and one mole. Eleven pregnancies were uncomplicated.

CONCLUSION

Renal transplantation is the best treatment for fertile women with end-stage renal disease who want to become pregnant. However, pregnancy is risky for the mother, fetus, newborn, and allograft.

Entamoeba struthionis n.sp. (Sarcomastigophora: Endamoebidae) from ostriches (Struthio camelus)

In the present work we identify the species of Entamoeba from ostriches (Struthio camelus). The complete sequence of the small subunit ribosomal RNA gene from this organism has been compared with those published for other species of the genus and clear differences have been found. These results confirm previous data which showed differences on parasite morphology and class of host with the other Entamoeba species. Taking all these data together, it can be concluded that the organism from ostriches is a new species whose proposed name is Entamoeba struthionis n.sp. This species probably infects rheas (Rhea americana), but genetic analysis of isolates from this host should be performed to confirm morphological data. Also, comparison of gene sequences with data from other authors on cysts recovered from human stool samples showed the possibility that this amoeba may affect humans. Further studies are needed to determine the risk of transmission of this new species to humans.

Human cytokine responses to meso-endemic malaria on the Pacific Coast of Colombia

Studies of naturally-acquired immunity to malaria in endemic regions provide the potential for a greater understanding of the regulation of human immune responses to the malarial parasite. However, little is known about the acquisition of malaria-specific immunity in regions of unstable, meso-endemic or hypo-endemic transmission. Cytokine profiles - patterns in the expression of interleukin-4 (IL-4), interleukin-10, interleukin-12, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) - were therefore studied during the natural acquisition of immunity to Plasmodium falciparum and P. vivax among individuals from Buenaventura, a meso-endemic region on the Pacific Coast of Colombia. In general, specific type-1 immune responses, characterized by IFN-gamma expression, were more likely to develop during P. falciparum infection, whereas pro-inflammatory cytokine profiles (with TNF-alpha expression) were observed more frequently among the P. vivax infections. Type-2 cytokine profiles, characterized by dominant IL-4 expression, were infrequent. Expression of IL-4 probably occurs primarily after prolonged exposure to parasites (which would, by definition, not be common in a meso-endemic region).

Use of AFLP, plasmid typing and phenotyping in a comparative study to assess genetic diversity of Shigella flexneri strains

Shigella flexneri infections are one of the main causes of acute diarrhoea in Cuba. Twenty strains isolated from sporadic cases in nine different Cuban provinces were characterized. Serotyping, antibiotic-resistance typing, plasmid-typing and AFLP-typing were used to determine their suitability for use in epidemiological studies of S. flexneri. The predominant serotypes were serotype 6 (35%) and serotype 2 (35%). Eleven different plasmid profiles were detected (Diversity Index = 0.92). AFLP-typing discriminated 12 different patterns (DI = 0.95), these patterns were not coincident with plasmid-typing patterns. Both techniques combined distinguished 14 patterns among the 20 studied strains (DI = 0.99). There was no consistent relationship between plasmid-typing and AFLP-typing patterns or antibiotic-resistance typing patterns. Ninety-five percent of S. flexneri strains were multiresistant.

Parasites from farmed ostriches (Struthio camelus) and rheas (Rhea americana) in Europe

During a 4-year-period, more than 500 ostriches and several rheas, all born in European countries and raised in Spain and Portugal, have been analyzed for the presence of ectoparasites and endoparasites. A total of 29 parasite species have been found, most of them of the gastrointestinal tract. Some of the helminth species found may represent spureous parasitosis, as only the eggs (of an ascarid and a trematode) were found in some samples. From the organisms identified, the ectoparasites (lice-Struthiolipeurus rheae, S. nandu; mites-Dermoglyphus pachycnemis, Gabucinia bicaudata), helminths (cestoda-Houttuynia struthionis- and nematoda-Libyostrongylus sp., Codiostomum struthionis-) and the ciliate Balantidium struthionis are known as ratite specific parasites. Capillaria eggs and larvae were also found; there are no previous records of this parasite from ostriches, and the data available do not allow to do a temptative specific diagnosis. Among protozoa, most of the species now found are described for the first time in ratites. They include organisms also found in other birds (Trichomonas gallinae, Tetratrichomonas gallinarum, Chilomastix gallinarum, Spironucleus meleagridis and Pleuromonas jaculans), and organisms whose specific status cannot be established until further analysis are performed (Cryptosporidium sp., Eimeria sp. and/or Isospora sp., Entamoeba sp. of the one-nucleate and of the eight-nucleate mature cyst groups, Endolimax sp., Iodamoeba sp., Monocercomonas sp., Retortamonas sp., Giardia sp., Blastocystis sp. and euglenids).

Plasmodium vivax malaria vaccine development

Plasmodium vivax represents the most widespread malaria parasite worldwide. Although it does not result in as high a mortality rate as P. falciparum, it inflicts debilitating morbidity and consequent economic impact in endemic communities. In addition, the relapsing behavior of this malaria parasite and the recent resistance to anti-malarials contribute to making its control more difficult. Although the biology of P. vivax is different from that of P. falciparum and the human immune response to this parasite species has been rather poorly studied, significant progress is being made to develop a P. vivax-specific vaccine based on the information and experience gained in the search for a P. falciparum vaccine. We have devoted great effort to antigenically characterize the P. vivax CS protein and to test its immunogenicity using the Aotus monkey model. Together with other groups we are also assessing the immunogenicity and protective efficacy of the asexual blood stage vaccine candidates MSP-1 and DBP in the monkey model, as well as the immunogenicity of Pvs25 and Pvs28 ookinete surface proteins. The transmission-blocking efficacy of the responses induced by these latter antigens is being assessed using Anopheles albimanus mosquitoes. The current status of these vaccine candidates and other antigens currently being studied is described.

First report of the genus Retortamonas (Sarcomastigophora: Retortamonadidae) in birds

In studies carried out on the parasites infecting ostriches (Struthio camelus) in Spain, trophozoites of Retortamonas sp. have been found in the intestinal contents of 28 out of 146 slaughtered ostriches. The species infecting ostriches could not be determined from the morphological data available. However, these findings are important as they constitute the first report of the genus Retortamonas in birds.

Atypical, fljB-negative Salmonella enterica subsp. enterica strain of serovar 4,5,12:i:- appears to be a monophasic variant of serovar Typhimurium

An fljB-negative, multidrug-resistant Salmonella enterica serovar 4,5,12:i:- phage type DT U302 strain (resistant to ampicillin, chloramphenicol, sulfonamide, gentamicin, streptomycin, tetracycline, and sulfamethoxazole-trimethoprim) emerged and spread in Spain in 1997. Sequences specific for Salmonella serovar Typhimurium and phage type DT 104 and U302 were present in this atypical Salmonella strain, suggesting that it is a monophasic Salmonella serovar Typhimurium variant.

Variants of the Plasmodium vivax circumsporozoite protein (VK210 and VK247) in Colombian isolates

Phenotypic diversity has been described in the central repeated region of the circumsporozoite protein (CSP) from Plasmodium vivax. Two sequences VK210 (common) and VK247 (variant) have been found widely distributed in P. vivax isolates from several malaria endemic areas around the world. A third protein variant called P. vivax-like showing a sequence similar to the simian parasite P. simioovale has also been described. Here, using an immunofluorescent test and specific monoclonal antibodies, we assessed the presence of two of these protein variants (VK210 and VK247) in laboratory produced sporozoite. Both sequences were found in parasite isolates coming from different geographic regions of Colombia. Interestingly, sporozoites carrying the VK247 sequence were more frequently produced in Anopheles albimanus than sporozoites with the VK210 sequence. This difference in sporozoites production was statistically significant (p <0.05, Kruskal-Wallis); not correlation was found with parameters as the total number of parasites or gametocytes in blood from human donors used to feed mosquitoes. Previous studies in the same region have shown a higher prevalence of anti-VK210 antibodies which in theory may suggest their role in blocking the development of sporozoites carrying the CSP VK210 sequence.

Expression and one-step purification of Plasmodium proteins in dictyostelium

Nearly full-length Circumsporozoite protein (CSP) from Plasmodium falciparum, the C-terminal fragments from both P. falciparm and P. yoelii CSP and a fragment comprising 351 amino acids of P.vivax MSPI were expressed in the slime mold Dictyostelium discoideum. Discoidin-tag expression vectors allowed both high yields of these proteins and their purification by a nearly single-step procedure. We exploited the galactose binding activity of Discoidin Ia to separate the fusion proteins by affinity chromatography on Sepharose-4B columns. Inclusion of a thrombin recognition site allowed cleavage of the Discoidin-tag from the fusion protein. Partial secretion of the protein was obtained via an ER independent pathway, whereas routing the recombinant proteins to the ER resulted in glycosylation and retention. Yields of proteins ranged from 0.08 to 3 mg l(-1) depending on the protein sequence and the purification conditions. The recognition of purified MSPI by sera from P. vivax malaria patients was used to confirm the native conformation of the protein expressed in Dictyostelium. The simple purification procedure described here, based on Sepharose-4B, should facilitate the expression and the large-scale purification of various Plasmodium polypeptides.

Generation and characterization of malaria-specific human CD8(+) lymphocyte clones: effect of natural polymorphism on T cell recognition and endogenous cognate antigen presentationby liver cells

CD8(+) cytolytic T lymphocytes (CTL) play a fundamental role in the clearance of malaria parasites from the liver in mouse models. In humans, however, only low levels of parasite-specific CD8(+) T lymphocytes have been observed in individuals living in endemic areas. In the present study, we identified high levels of circulating CD8(+) T lymphocytes specific for a previously described HLA-A2-restricted CTL epitope of the circumsporozoite (CS) protein of Plasmodium falciparum in an adult living in Burkina Faso, as evidenced by IFN-gamma ELISPOT assay and MHC-tetramer technology. After cloning by limiting dilution culture, T cell recognition of natural CS variants of P. falciparum was studied. The results demonstrate that naturally occurring variations drastically affect residues critical for T cell recognition as only two out of nine sequences analyzed were efficiently recognized by the CTL clones. These clones were also used to analyze T cell recognition of the endogenously presented cognate antigen. We observed efficient antigen recognition of both HLA-A*0201-transfected murine antigen presenting cells and liver cells from HLA-A*0201/K(b)-transgenic mice upon infection with recombinant vaccinia virus encoding the CS protein (WR-CS). More importantly, we demonstrate for the first time efficient recognition of WR-CS-infected human liver cells.

HLA-A*0201 restricted CD8+ T-lymphocyte responses to malaria: identification of new Plasmodium falciparum epitopes by IFN-gamma ELISPOT

The role of antigen specific CD8+ T-lymphocytes in mediating protection against sporozoite-induced malaria has been well established in murine models. In humans, indirect evidence has accumulated suggesting a similar protective role for antigen-specific CD8+ T-lymphocytes. Nevertheless, the low frequency of circulating specific cells together with the lack of sensitive methods to quantify them has hampered the direct assessment of their function. Using a combination of short-term cell culture and IFN-gamma ELISPOT, we studied CD8+ T-lymphocyte responses to a panel of HLA-A*0201 binding peptides. In addition to confirming the response to already described epitopes, we also identified five new CD8+ T-lymphocyte epitopes. These epitopes are presented in pre-erythrocytic stages gene products of Plasmodium falciparum 7G8 strain and correspond to the following protein segments: circumsporozoite (CS) 64-72, 104-113, 299-308 and 403-411; liver stage antigen (LSA-1) repeat region; sporozoite surface protein 2 or thrombospondin related anonymous protein (SSP2/TRAP) 78-88 and 504-513. Four of these peptides are conserved amongst all published sequences of P. falciparum strains. We conclude that the modified IFN-gamma ELISPOT assay is a sensitive technique to monitor antigen-specific CD8+ T-lymphocyte responses in human malaria which may help in the improvement and assessment of the efficacy of malaria subunit vaccines.

Entamoeba sp. (Sarcomastigophora: Endamoebidae) from ostriches (Struthio camelus) (Aves: Struthionidae)

The first case of Entamoeba of the 1-nucleate mature cyst group in birds is described. Trophozoites and cysts of Entamoeba have been found in ostriches (Struthio camelus) from farms located all over Spain. The cysts are large (13.47microm mean diameter); they possess one nucleus when mature, with a large endosome and peripheral chromatine arranged in small granules; chromatoid bodies, when present, are large and elongated. Trophozoites are large (19. 88microm mean diameter), with a clear differentiation between ecto- and endoplasm, this containing numerous vacuoles; the nucleus is large and diffuse. The characteristics of this amoeba resembles but do not completely fulfill those of E. suis and E. chattoni; also, these species are from mammals.

Molecular characterization of HLA class I in Colombians carrying HLA-A2: high allelic diversity and frequency of heterozygotes at the HLA-B locus

Polymerase chain reaction using sequence-specific oligonucleotide probes (PCR-SSOP) typing was used to analyze HLA class I A, B and C alleles in three different Colombian populations. Fifty-nine samples were from Hispano-American Mestizos living in the urban areas of Cali (referred to here as Aso population). Forty-four and thirty samples were from the African Black populations of Zacarias (Zac) and Punta Soldado (PS), respectively. Samples were selected for expression of HLA-A2 by monoclonal antibody staining and allele-specific hybridization, and their HLA-A2 subtype distribution has been reported previously. Although only a limited number of samples was analyzed, the data suggest the existence of a remarkable degree of HLA class I polymorphism in the populations studied, with representatives of most serological classes. Despite their common African origin, the populations Zac and PS, both resident in malaria endemic regions, showed some striking differences in allelic distribution for all three class I loci. Furthermore, the samples from Aso and PS, but not Zac, showed a low percentage of blank alleles at the HLA-B locus (0 and 0.4%, respectively), suggesting the possibility of a heterozygote advantage for HLA-B alleles in Colombian populations.