Expression patterns of ciliopathy genes ARL3 and CEP120 reveal roles in multisystem development.

BACKGROUND: Joubert syndrome and related disorders (JSRD) and Jeune syndrome are multisystem ciliopathy disorders with overlapping phenotypes. There are a growing number of genetic causes for these rare syndromes, including the recently described genes ARL3 and CEP120. METHODS: We sought to explore the developmental expression patterns of ARL3 and CEP120 in humans to gain additional understanding of these genetic conditions. We used an RNA in situ detection technique called RNAscope to characterise ARL3 and CEP120 expression patterns in human embryos and foetuses in collaboration with the MRC-Wellcome Trust Human Developmental Biology Resource. RESULTS: Both ARL3 and CEP120 are expressed in early human brain development, including the cerebellum and in the developing retina and kidney, consistent with the clinical phenotypes seen with pathogenic variants in these genes. CONCLUSIONS: This study provides insights into the potential pathogenesis of JSRD by uncovering the spatial expression of two JSRD-causative genes during normal human development.

Optimum dose of vitamin D for disease prevention in older people: BEST-D trial of vitamin D in primary care.

This trial compared the effects of daily treatment with vitamin D or placebo for 1 year on blood tests of vitamin D status. The results demonstrated that daily 4000 IU vitamin D3 is required to achieve blood levels associated with lowest disease risks, and this dose should be tested in future trials for fracture prevention. INTRODUCTION: The aim of this trial was to assess the effects of daily supplementation with vitamin D3 4000 IU (100 µg), 2000 IU (50 µg) or placebo for 1 year on biochemical markers of vitamin D status in preparation for a large trial for prevention of fractures and other outcomes. METHODS: This is a randomized placebo-controlled trial in 305 community-dwelling people aged 65 years or older in Oxfordshire, UK. Outcomes included biochemical markers of vitamin D status (plasma 25-hydroxy-vitamin D [25[OH]D], parathyroid hormone [PTH], calcium and alkaline phosphatase), cardiovascular risk factors and tests of physical function. RESULTS: Mean (SD) plasma 25(OH)D levels were 50 (18) nmol/L at baseline and increased to 137 (39), 102 (25) and 53 (16) nmol/L after 12 months in those allocated 4000 IU, 2000 IU or placebo, respectively (with 88%, 70% and 1% of these groups achieving the pre-specified level of >90 nmol/L). Neither dose of vitamin D3 was associated with significant deviation outside the normal range of PTH or albumin-corrected calcium. The additional effect on 25(OH)D levels of 4000 versus 2000 IU was similar in all subgroups except for body mass index, for which the further increase was smaller in overweight and obese participants compared with normal-weight participants. Supplementation with vitamin D had no significant effects on cardiovascular risk factors or on measures of physical function. CONCLUSIONS: After accounting for average 70% compliance in long-term trials, doses of 4000 IU vitamin D3 daily may be required to achieve plasma 25(OH)D levels associated with lowest disease risk in observational studies.

Glanzmann thrombasthenia in Pakistan: molecular analysis and identification of novel mutations.

Glanzmann thrombasthenia (GT) is an inherited genetic disorder affecting platelets, which is characterized by spontaneous mucocutaneous bleeding and abnormally prolonged bleeding in response to injury or trauma. The underlying defect is failure of platelet aggregation due to qualitative and/or quantitative deficiency of platelet integrin αIIbß3 resulting from molecular genetic defects in either ITGA2B or ITGB3. Here, we examine a Pakistani cohort of 15 patients with clinical symptoms of GT who underwent laboratory and molecular genetic analysis. In patients with a broad range of disease severity and age of presentation, we identified pathogenic mutations in ITGA2B in 11 patients from 8 different families, including 2 novel homozygous mutations and 1 novel heterozygous mutation. Mutations in ITGB3 were identified in 4 patients from 3 families, two of which were novel homozygous truncating mutations. A molecular genetic diagnosis was established in 11 families with GT, including 5 novel mutations extending the spectrum of mutations in this disease within a region of the world where little is known about the incidence of GT. Mutational analysis is a key component of a complete diagnosis of GT and allows appropriate management and screening of other family members to be performed.

Case Report: Whole-exome analysis of a child with polycystic kidney disease and ventriculomegaly.

Autosomal recessive polycystic kidney disease (ARPKD) is an inherited ciliopathy leading to progressive kidney and liver disease. Biallelic mutations in the PKHD1 gene underlie this condition. We describe a child with bilaterally enlarged cystic kidneys, portal hypertension, and cerebral ventriculomegaly. Molecular genetic investigations using whole-exome sequencing and confirmation using Sanger sequencing revealed a homozygous pathogenic mutation in PKHD1 underlying the clinical phenotype of ARPKD. Whole-exome data analysis was used to search for additional rare variants in additional ciliopathy genes that may have contributed to the unusual brain phenotype. Aside from a rare hypomorphic allele in MKS1, no other pathogenic variants were detected. We conclude that the homozygous pathogenic mutation in PKHD1 underlies the ciliopathy phenotype in this patient.

Neurological rehabilitation following heat illness in the UK Armed Forces.

Heat illness remains a significant threat to health in the UK Armed Forces despite recent improvements in the prevention of cases. A small number of heat illness survivors develop long-term neurological sequelae. Here we briefly review the background literature and present our experience of treating UK Armed Forces patients with neurological consequences of heat illness. In our cohort of patients, we observed significant improvements in subjective symptoms and objective assessments following a period of neurological rehabilitation at the Defence Medical Rehabilitation Centre. We conclude with recommendations for further research and for the incorporation of screening for neurological disability following heat illness into service policy.

A mutant wfs1 zebrafish model of Wolfram syndrome manifesting visual dysfunction and developmental delay.

Wolfram syndrome (WS) is an ultra-rare progressive neurodegenerative disorder defined by early-onset diabetes mellitus and optic atrophy. The majority of patients harbour recessive mutations in the WFS1 gene, which encodes for Wolframin, a transmembrane endoplasmic reticulum protein. There is limited availability of human ocular and brain tissues, and there are few animal models for WS that replicate the neuropathology and clinical phenotype seen in this disorder. We, therefore, characterised two wfs1 zebrafish knockout models harbouring nonsense wfs1a and wfs1b mutations. Both homozygous mutant wfs1a-/- and wfs1b-/- embryos showed significant morphological abnormalities in early development. The wfs1b-/- zebrafish exhibited a more pronounced neurodegenerative phenotype with delayed neuronal development, progressive loss of retinal ganglion cells and clear evidence of visual dysfunction on functional testing. At 12 months of age, wfs1b-/- zebrafish had a significantly lower RGC density per 100 µm2 (mean ± standard deviation; 19 ± 1.7) compared with wild-type (WT) zebrafish (25 ± 2.3, p < 0.001). The optokinetic response for wfs1b-/- zebrafish was significantly reduced at 8 and 16 rpm testing speeds at both 4 and 12 months of age compared with WT zebrafish. An upregulation of the unfolded protein response was observed in mutant zebrafish indicative of increased endoplasmic reticulum stress. Mutant wfs1b-/- zebrafish exhibit some of the key features seen in patients with WS, providing a versatile and cost-effective in vivo model that can be used to further investigate the underlying pathophysiology of WS and potential therapeutic interventions.

Calcium oxalate crystal deposition in the kidney: identification, causes and consequences.

Calcium oxalate (CaOx) crystal deposition within the tubules is often a perplexing finding on renal biopsy of both native and transplanted kidneys. Understanding the underlying causes may help diagnosis and future management. The most frequent cause of CaOx crystal deposition within the kidney is hyperoxaluria. When this is seen in native kidney biopsy, primary hyperoxaluria must be considered and investigated further with biochemical and genetic tests. Secondary hyperoxaluria, for example due to enteric hyperoxaluria following bariatric surgery, ingested ethylene glycol or vitamin C overdose may also cause CaOx deposition in native kidneys. CaOx deposition is a frequent finding in renal transplant biopsy, often as a consequence of acute tubular necrosis and is associated with poorer long-term graft outcomes. CaOx crystal deposition in the renal transplant may also be secondary to any of the causes associated with this phenotype in the native kidney. The pathophysiology underlying CaOx deposition is complex but this histological phenotype may indicate serious underlying pathology and should always warrant further investigation.

Embryonic and foetal expression patterns of the ciliopathy gene CEP164.

Nephronophthisis-related ciliopathies (NPHP-RC) are a group of inherited genetic disorders that share a defect in the formation, maintenance or functioning of the primary cilium complex, causing progressive cystic kidney disease and other clinical manifestations. Mutations in centrosomal protein 164 kDa (CEP164), also known as NPHP15, have been identified as a cause of NPHP-RC. Here we have utilised the MRC-Wellcome Trust Human Developmental Biology Resource (HDBR) to perform immunohistochemistry studies on human embryonic and foetal tissues to determine the expression patterns of CEP164 during development. Notably expression is widespread, yet defined, in multiple organs including the kidney, retina and cerebellum. Murine studies demonstrated an almost identical Cep164 expression pattern. Taken together, these data support a conserved role for CEP164 throughout the development of numerous organs, which, we suggest, accounts for the multi-system disease phenotype of CEP164-mediated NPHP-RC.

Lead mineral transformation by fungi.

Pyromorphite (Pb5(PO4)3Cl), the most stable lead mineral under a wide range of geochemical conditions [1], can form in urban and industrially contaminated soils [2] [3] [4] [5]. It has been suggested that the low solubility of this mineral could reduce the bioavailability of lead, and several studies have advocated pyromorphite formation as a remediation technique for lead-contaminated land [3] [5] [6], if necessary using addition of phosphate [6]. Many microorganisms can, however, make insoluble soil phosphate bioavailable [7] [8] [9] [10], and the solubilisation of insoluble metal phosphates by free-living and symbiotic fungi has been reported [11] [12] [13] [14] [15]. If pyromorphite can be solubilised by microbial phosphate-solubilising mechanisms, the question arises of what would happen to the released lead. We have now clearly demonstrated that pyromorphite can be solubilised by organic-acid-producing fungi, for example Aspergillus niger, and that plants grown with pyromorphite as sole phosphorus source take up both phosphorus and lead. We have also discovered the production of lead oxalate dihydrate by A. niger during pyromorphite transformation, which is the first recorded biogenic formation of this mineral. These mechanisms of lead solubilisation, or its immobilisation as a novel lead oxalate, have significant implications for metal mobility and transfer to other environmental compartments and organisms. The importance of considering microbial processes when developing remediation techniques for toxic metals in soils is therefore emphasised.

Rapid onset intratubular calcification following renal transplantation requiring urgent parathyroidectomy.

BACKGROUND: Secondary hyperparathyroidism is a common complication of end-stage renal disease often requiring parathyroidectomy. Renal transplant with the restoration of normal renal function often allows resolution of hyperparathyroidism, avoiding the need for parathyroid surgery. However, a proportion of patients with hyperparathyroidism become overtly hypercalcemic after renal transplantation which poses management dilemmas between medical and surgical treatment. CASE: We present the case of a 48-yearold man with end-stage renal failure known to have secondary hyperparathyroidism who received a living related renal transplant. Postoperatively he developed prompt hypercalcemia, polyuria, polydipsia and rapid onset intratubular calcification, leading to acute tubular necrosis diagnosed on renal biopsy on Day 7 post transplantation. He underwent surgical parathyroidectomy with resolution of his hypercalcemia and improved renal transplant function. DISCUSSION: This case emphasizes the need for good management of secondary hyperparathyroidism together with close surveillance of PTH in patients awaiting renal transplantation. With good renal transplant function hyperparathyroidism usually resolves. Posttransplant surgical parathyroidectomy should be reserved for severe progressive end organ damage.

Lessons learned from a multidisciplinary renal genetics clinic.

BACKGROUND: Inherited renal disorders comprise a significant proportion of cases in both paediatric and adult nephrology services. Genetic advances have advanced rapidly while clinical models of care delivery have remained static. AIM: To describe a cohort of patients attending a multidisciplinary renal genetics clinic and the insights gained from this experience. DESIGN AND METHODS: A retrospective review of clinic cases and their molecular genetic diagnosis over a 5-year period. RESULTS: We report details of 244 individuals including 80 probands who attended the clinic. The commonest reasons for referral was familial haematuria which accounted for 37.5% of cases and cystic kidney disease, accounting for 31% of cases. Eighteen probands had a known molecular genetic diagnosis and were referred for genetic counselling and screening of at risk relatives and management plans. About 62 probands and their families were referred for a precise molecular diagnosis and this was achieved in 26 cases (42%). The most frequent new genetic diagnoses were COL4A5 mutations underlying familial haematuria and familial end stage renal disease. The clinic also allowed for patients with rare renal syndromes to be reviewed, such as ciliopathy syndromes, allowing detailed phenotyping and often a precise molecular genetic diagnosis to be provided. CONCLUSIONS: The integration of modern day genetics and genomics into multidisciplinary clinics often allows a precise diagnosis which benefits patients, their relatives and the clinicians providing care and future management.

Inhibitory effect of 3-hydroxybenzo(a)pyrene on the mutagenicity and tumorigenicity of (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene.

The 12 isomeric phenols of benzo(a)pyrene were tested for their ability to inhibit the mutagenic activity of (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene [B(a)P 7,8-diol-9,10-epoxide-2], an ultimate mutagenic and carcinogenic metabolite of benzo(a)pyrene. 3-Hydroxybenzo(a)pyrene [3-HO-B(a)P], a major metabolite of benzo(a)pyrene, was the most potent antagonist tested. Approximately 3 nmol of 3-HO-B(a)P, 14 nmol of 10-HO-B(a)P, and 5-8 nmol of 1-, 2-, 4-, 5-, 6-, 7-, 8-, 9-, 11-, and 12-HO-B(a)P inhibited the mutagenic activity of 0.05 nmol of B(a)P 7,8-diol-9,10-epoxide-2 by 50% in Salmonella typhimurium strain TA 100. The importance of the phenolic group for antimutagenic activity was indicated by the lack of antimutagenic activity of benzo(a)pyrene itself. 3-HO-B(a)P also inhibited the mutagenic activity resulting from the metabolic activation of benzo(a)pyrene and (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene by rat liver microsomes. This inhibition may have resulted from an effect of 3-HO-B(a)P on the metabolic activation of these carcinogens and/or from a direct effect on the action of B(a)P 7,8-diol-9,10-epoxide-2. In a mammalian cell culture system utilizing Chinese hamster V79 cells, 3-HO-B(a)P (8 microM) inhibited the mutagenicity of B(a)P 7,8-diol-9,10-epoxide-2 (0.2 microM) by 50%. Although 3-HO-B(a)P was a potent inhibitor of the mutagenic activity of bay-region diol epoxides of benzo(a)pyrene, dibenzo(a,h)pyrene, and dibenzo(a,i)pyrene in S. typhimurium strain TA 100, higher concentrations of 3-HO-B(a)P were needed to inhibit the mutagenicity of the chemically less reactive benzo(a)pyrene 4,5-oxide and the bay-region diol epoxides of benz(a)anthracene, chrysene, and benzo(c)phenanthrene. Both 3-HO-B(a)P and 10-HO-B(a)P accelerated the disappearance of B(a)P 7,8-diol-9,10-epoxide-2 from 1:9 dioxane-water solutions at pH 7 and 25 degrees C. 3-HO-B(a)P, the most effective antimutagen of the B(a)P phenols tested, was much more reactive with the diol epoxide than 10-HO-B(a)P, the least effective antimutagen. The rate constant for the reaction of 3-HO-B(a)P with the diol epoxide exhibited a nonlinear (greater than first-order) dependence on the concentration of the phenol. Evidence was obtained for covalent adduct formation between the diol epoxide and each of the two phenols.(ABSTRACT TRUNCATED AT 400 WORDS)

Mutagenicity of the enantiomers of the diastereomeric bay-region benzo(c)phenanthrene 3,4-diol-1,2-epoxides in bacterial and mammalian cells.

The mutagenic activities of the enantiomers of the pair of diastereomeric bay-region benzo(c)phenanthrene 3,4-diol-1,2-epoxides were evaluated in histidine-dependent strains of Salmonella typhimurium and in an 8-azaguanine-sensitive Chinese hamster cell line. In strains TA 98 and TA 100 of S. typhimurium, the range in mutagenic activity observed for the four optically active isomers was less than 4- and 2-fold, respectively. The diol-epoxide with (1S,2R,3R,4S) absolute configuration and the benzylic hydroxyl group trans to the epoxide oxygen [(+)-diol epoxide-2] was the most active isomer in both strains. The enantiomeric (-)-diol-epoxide-2 isomer, with (1R,2S,3S,4R) absolute configuration identical to that of the exceptionally tumorigenic (+)-diol-epoxide-2 isomers of benzo(a)pyrene, benz(a)anthracene, and chrysene, was the least active isomer in strain TA 98 (27%) and the second most active isomer in strain TA 100 (90%). In Chinese hamster V79 cells (-)-diol-epoxide-2 was the most active of the four benzo(c)phenanthrene isomers, and a 4- to 5-fold range in mutagenic activity was observed. The differences in mutagenic activity between the four bay-region diol-epoxide isomers of benzo(c)phenanthrene in the three test systems are relatively small when compared with results from similar studies with optically active bay-region diol-epoxide isomers of three other polycyclic aromatic hydrocarbons, and may be explicable, in part, by a tendency of the hydroxyl groups of benzo(c)phenanthrene diol-epoxides to adopt comparable pseudodiequatorial conformations.

Mutagenicity of the bay-region diol-epoxides and other benzo-ring derivatives of dibenzo(a,h)pyrene and dibenzo(a,i)pyrene.

The mutagenic activities of dibenzo(a,h)(pyrene, dibenzo(a,i)pyrene, and a total of 11 of their benzo-ring derivatives were evaluated in bacterial and mammalian cells in the absence or presence of a mammalian metabolic activation system. trans-1,2-Dihydroxy-1,2-dihydrodibenzo(a,h)pyrene and trans-3,4-dihydroxy-3,4-dihydrodibenzo(a,i)pyrene, the expected dihydrodiol precursors of bay-region diol-epoxides, were metabolized to products which were more mutagenic to strains TA98 and TA100 of Salmonella typhimurium than were the metabolic products formed from their respective parent hydrocarbons. For each dihydrodiol, replacement of the benzo-ring double bond adjacent to the diol moiety with a single bond resulted in tetrahydrodiol derivatives which could not be metabolically activated, suggesting that one or both diastereomeric bay-region diol-epoxides were the bioactivated metabolites. The authentic bay-region diol-epoxide diastereomers of dibenzo(a,h)pyrene and dibenzo(a,i)pyrene in which the benzylic hydroxyl group and the epoxide oxygen are trans (diol-epoxide 2 series) were highly mutagenic in strains TA98 and TA100 of S. typhimurium and in cultured Chinese hamster V79 cells. Neither diol-epoxide was significantly, if at all, metabolized by epoxide hydrolase. The bay-region diol-epoxide of dibenzo(a,i)pyrene was from 1.5 to 5 times more active as a mutagen than the diol-epoxide of dibenzo(a,h)pyrene, and in strain TA98 of S. typhimurium as well as Chinese hamster V79 cells, it had activity comparable to that of the highly carcinogenic bay-region diol-epoxide of benzo(a)pyrene.

Microbial solubilization and immobilization of toxic metals: key biogeochemical processes for treatment of contamination.

Microorganisms play important roles in the environmental fate of toxic metals with a multiplicity of physico-chemical and biological mechanisms effecting transformations between soluble and insoluble phases. Such mechanisms are important components of natural biogeochemical cycles for metals and metalloids with some processes being of potential application to the treatment of contaminated materials. This paper will concentrate on three selected aspects which illustrate the key importance of microorganisms in effecting changes in metal(loid) solubility, namely toxic metal sulfide precipitation by sulfate-reducing bacteria, heterotrophic leaching by fungi, and microbial transformations of metalloids, which includes reduction and methylation. The basic microbiology of these processes is described as well as their environmental significance and use in bioremediation.

Calcium phosphate and calcium oxalate crystal handling is dependent upon CLC-5 expression in mouse collecting duct cells.

Defects in an intracellular chloride channel CLC-5 cause Dent's disease, an inherited kidney stone disorder. Using a collecting duct model, mIMCD-3 cells, we show expression of dimeric mCLC-5. Transient transfection of antisense CLC-5 reduces CLC-5 protein expression. Binding of both calcium phosphate (hydroxyapatite) and calcium oxalate monohydrate (COM) crystals overlaid onto mIMCD-3 cultures was affected by altered CLC-5 expression. Calcium phosphate crystal agglomerations (>10 microm) were minimal in control (9%) and sense (13%) CLC-5-transfected cells, compared to 66% of antisense CLC-5-transfected cells (P<0.001). Small calcium phosphate crystals (<10 microm) were found associated with 45% of sense CLC-5-treated cells, of which the majority (11/14 cells) appeared to be internalised within the cell. Calcium oxalate agglomerations (>10 microm) were also largely absent for controls or sense mCLC-5 transfectants (11% and 9% of cells, respectively) with COM crystal agglomerates predominating in antisense CLC-5 transfectants (66%, P<0.0001). We conclude that collecting duct cells with reduced CLC-5 expression lead to a tendency to form calcium crystal agglomeration, which may help explain the nephrocalcinosis and nephrolithiasis seen in Dent's disease.

Circadian activity of the endogenous fibrinolytic system in stable coronary artery disease: effects of beta-adrenoreceptor blockers and angiotensin-converting enzyme inhibitors.

OBJECTIVES: To examine circadian changes in the sympathovagal balance, the activity of the renin-angiotensin system and hemostatic variables in patients with stable coronary artery disease, and the effects of beta-adrenoceptor blockade and angiotensin-converting enzyme inhibition. BACKGROUND: Sympathovagal balance and key components of the fibrinolytic system show circadian variability. The effects of beta-adrenergic blocking agents and angiotensin-converting enzyme inhibitors on these autonomic and hemostatic rhythms are not well defined. METHODS: Twenty patients with coronary artery disease underwent 24-h Holter monitoring for heart rate variability and blood sampling (6 hourly for 24 hours) after three consecutive treatment phases, (firstly with placebo, then bisoprolol, and finally quinapril). The effects on sympathovagal balance, hemostatic variables and the renin-angiotensin system activity were measured. RESULTS: The fibrinolytic capacity showed marked circadian variation at the end of the placebo phase (p = 0.002), plasminogen activator inhibitor-1 (PAI-1) activity peaking at 06.00 AM when tissue plasminogen activator (tPA) activity was at its nadir. Sympathovagal balance showed a sharp increase at approximately the same time but plasma renin activity did not rise until later in the day. Inspection of the 24-h profiles suggested that bisoprolol reduced sympathovagal balance and the morning peak of PAI-1 activity and antigen, with a small increase in tPA activity, although these changes were not significant. Quinapril produced a substantial rise in renin (p = 0.01) but did not significantly affect either PAI-1 or tPA. Sympathovagal balance was unaffected by quinapril. CONCLUSIONS: In patients with stable coronary artery disease, angiotensin-converting enzyme inhibition with quinapril does not affect either sympathovagal balance or the endogenous fibrinolytic system. Our data suggest that the sympathoadrenal system may modify fibrinolytic activity, judged by the response to beta-adrenoreceptor blockade with bisoprolol.

Association of anal dysplasia and human papillomavirus with immunosuppression and HIV infection among homosexual men.

OBJECTIVE: To examine and quantify the association between anal squamous intraepithelial lesions (ASIL), anal human papillomavirus (HPV) infection and immunosuppression among HIV-seropositive and HIV-seronegative homosexual men. DESIGN: Cross-sectional study among homosexual men presenting at a community-based clinic for HIV serologic screening. RESULTS: Anal HPV DNA was detected in 55 and 23% of 285 HIV-seropositive and 204 HIV-seronegative men, respectively, by Southern transfer hybridization (STH) [odds ratio (OR), 4.0; 95% confidence interval (CI), 2.7-6.2], and in 92 and 78% by polymerase chain reaction (PCR) (OR, 3.1; 95% CI, 1.6-5.8). ASIL was noted in 26% of HIV-seropositive men and in 8% of HIV-seronegative men (compared with men with negative cytologic findings: OR, 5.6; 95% CI, 3.0-10.5), with high-grade lesions noted in 4% of HIV-seropositive and in 0.5% of HIV-seronegative men. Among HIV-infected men, ASIL, detection of specific anal HPV types, and detection of high levels of anal HPV DNA (i.e., levels of HPV DNA detectable by both STH and PCR) were all associated with immunosuppression. Nevertheless, HIV-seropositive men with CD4 counts > 500 x 10(6)/l had a higher prevalence of both anal HPV and ASIL than men without HIV infection. Overall, detection of HPV at high levels was associated with ASIL. However, after adjustment for level of detectable HPV DNA, the risk of ASIL among HIV-seropositive men with CD4 counts < 500 x 10(6)/l was increased 2.9-fold (95% CI, 1.4-6.2) over that of HIV-seropositive men with CD4 counts > 500 x 10(6)/l. CONCLUSION: Given the high rates of ASIL in HIV-seronegative and both immunosuppressed and non-immunosuppressed HIV-seropositive homosexual men, natural history studies are now needed to assist in the development of strategies for the detection and management of such lesions. The increased prevalence of ASIL seen among immunosuppressed HIV-seropositive men may be the result of both a non-specific increase in productive HPV infection and HIV-induced immune alterations of HIV-related neoplasia.

Prospective study of high grade anal squamous intraepithelial neoplasia in a cohort of homosexual men: influence of HIV infection, immunosuppression and human papillomavirus infection.

OBJECTIVE: To determine the risk of developing high grade anal squamous intraepithelial neoplasia (HG-AIN) in relation to HIV infection and immunosuppression, after controlling for the effects of human papillomavirus (HPV) infection. DESIGN: Prospective cohort study of 158 HIV-seropositive and 147 HIV-seronegative homosexual men presenting to a community-based clinic with initially negative anal cytologic and colposcopic findings. METHODS: Subjects completed self-administered questionnaires, underwent cytologic screening, and standardized unaided and colposcopic examination of the proximal anal canal for presence of abnormalities suggestive of AIN. Anal specimens were screened for HPV DNA. RESULTS: HG-AIN developed in eight (5.4%) and 24 (15.2%) HIV-seronegative and -seropositive men, respectively. Risk of HG-AIN among HIV-seronegative men was associated with detection of anal HPV types 16 or 18 by Southern transfer hybridization (STH), detection of HPV 16 or 18 at the lower levels by polymerase chain reaction but not by STH, and with number of positive HPV tests; HG-AIN risk among HIV-seropositive men was associated with detection of HPV 16 or 18 only by STH, detection of HPV types other than 16 or 18, CD4 count < or = 500 x 10(6)/l, and number of positive HPV tests. HIV-induced immunosuppression remained an independent predictor of HG-AIN after adjusting for type and level of detection of HPV; HIV infection predicted HG-AIN risk after adjustment for number of positive HPV tests. CONCLUSIONS: The association of HG-AIN with HIV, independent of HPV type, level of HPV detection and number of positive HPV tests, suggests that this increased risk cannot be entirely explained by an effect of HIV on HPV detection. Future studies focusing on factors more specific to the local microenvironment in the anal canal should help clarify these issues.