CGRP blockade by galcanezumab was not associated with reductions in signs and symptoms of knee osteoarthritis in a randomized clinical trial.

OBJECTIVE: This study tested whether galcanezumab, a humanized monoclonal antibody with efficacy against migraine, was superior to placebo for the treatment of mild or moderate osteoarthritis (OA) knee pain. METHOD: In a multicenter, double-blind, placebo- and celecoxib-controlled trial, patients with moderate to severe OA pain were randomized to placebo; celecoxib 200 mg daily for 16 weeks; or galcanezumab 5, 50, 120, and 300 mg subcutaneously every 4 weeks, twice. The primary outcome was change from baseline at Week 8 in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscore measured by 100 mm visual analog scale (VAS). The trial was considered positive if ≥1 dose of galcanezumab demonstrated ≥95% Bayesian posterior probability of superiority to placebo and ≥50% posterior probability of superiority to placebo by ≥9 mm. A planned interim analysis allowed termination of the study if posterior probability of superiority to placebo by ≥9 mm was ≤5%. Secondary endpoints included WOMAC function subscore and Patient Global Assessment (PGA) of OA. Safety and tolerability were also assessed. RESULTS: The study was terminated after interim analysis suggested inadequate efficacy. Celecoxib significantly reduced WOMAC pain subscore compared with placebo [-12.0 mm; 95% confidence interval (CI) -23 to -2 mm]. None of the galcanezumab arms demonstrated clinically meaningful improvement (range: 1.5 to -5.0 mm) or met the prespecified success criteria. No improvement in any secondary objective was observed. Galcanezumab was well tolerated by OA patients. CONCLUSIONS: This study failed to demonstrate sufficient statistical evidence that galcanezumab was efficacious for treating OA knee pain. STUDY IDENTIFICATION: NCT02192190.

Direct in vivo evidence of activated macrophages in human osteoarthritis.

OBJECTIVE: Through binding to folate receptor-ß (FR-ß), the new (99m)Tc-EC20 (Etarfolatide) imaging technique detects activated but not resting macrophages in vivo. The goal of this study was to investigate macrophage-related inflammation in osteoarthritis (OA). METHODS: Twenty-five individuals (50 knees) with symptomatic OA of at least one knee underwent SPECT-CT imaging of both knees and planar imaging of the whole body after injection of Etarfolatide. Scans and knee radiographs were scored blinded to clinical information including knee and other joint site pain severity. Measures of association controlled for age, gender, body mass index (BMI) and employed repeated measures to adjust for correlation between knees. DESIGN: Activated macrophages were present in the majority (76%) of knees. The quantity of knee-related macrophages was significantly associated with knee pain severity (R = 0.60, P < 0.0001) and radiographic knee OA severity including joint space narrowing (R = 0.68, P = 0.007), and osteophyte (R = 0.66, P = 0.001). Macrophages were also localized to joints commonly affected by OA including hand finger joints (12%), thumb bases (28%), shoulders (26%), great toes (18%) and ankles (12%). The presence of joint pain at fingers, wrists, ankles and great toes was significantly positively associated with presence of activated macrophages at these sites (P < 0.0001-0.04). CONCLUSIONS: This study provides the first direct in vivo evidence for macrophage involvement in OA in a substantial proportion of human knees. The association of quantity of activated macrophages with radiographic knee OA severity and joint symptoms suggests that drugs targeting macrophages and macrophage-associated inflammatory pathways may have the potential to be both symptom and structure modifying.

Pharmacodynamic comparison of LY3023703, a novel microsomal prostaglandin e synthase 1 inhibitor, with celecoxib.

To assess the safety, tolerability, and pharmacology of LY3023703, a microsomal prostaglandin E synthase 1 (mPGES1) inhibitor, a multiple ascending dose study was conducted. Forty-eight subjects received LY3023703, celecoxib (400 mg), or placebo once daily for 28 days. Compared with placebo, LY3023703 inhibited ex vivo lipopolysaccharide-stimulated prostaglandin E2 (PGE2 ) synthesis 91% and 97% on days 1 and 28, respectively, after 30-mg dosing, comparable to celecoxib's effect (82% inhibition compared to placebo). Unlike celecoxib, which also inhibited prostacyclin synthesis by 44%, LY3023703 demonstrated a maximal increase in prostacyclin synthesis of 115%. Transient elevations of serum aminotransferase were observed in one subject after 30-mg LY3023703 dosing (10× upper limit of normal (ULN)), and one subject after 15-mg dosing (about 1.5× ULN). Results from this study suggest that mPGES1 inhibits inducible PGE synthesis without suppressing prostacyclin generation and presents a novel target for inflammatory pain.

Gastric slow waves, gastrointestinal symptoms and peptides in systemic sclerosis patients.

Impaired gastric slow waves, frequent gastrointestinal (GI) symptoms and altered GI peptides have been reported in Scleroderma (SSc) patients. The aim of this study was to investigate the associations among these three important components in GI dysmotility. Seventeen fasted SSc patients underwent four channel surface electrogastrography, measuring % of normal gastric slow waves or dysrhythmia. Patients completed a questionnaire designed by us to assess demographics, upper and lower GI symptoms (symptom presence, frequency and impact on quality of life, QOL), by YES/NO, Likert Scales and Visual Analogue Scales 1-100 mm (called GI Dysmotility Questionnaire, GIDQ) and health-related QOL by SF-36. Fasting plasma vasoactive intestinal peptide (VIP) and motilin levels were measured by peptide immunoassays. There were significant correlations between percentages of gastric dysrhythmias (bradygastria or arrhythmia) and a number of major GI symptoms such as nausea, abdominal bloating and pain. The plasma level of VIP was correlated positively with % dysrhythmia but negatively with % normal slow waves. Motilin was positively correlated with slow wave coupling (coordination). No major differences were noted in the measured peptides or gastric slow waves between limited SSc and diffuse SSc. Correlations were noted between SF-36 domain scores and our GIDQ scores. In SSc patients, gastric dysrhythmias are correlated with certain GI symptoms. Correlations are also noted between plasma VIP/Motilin levels and gastric slow waves. Thus in SSc, gastric dysrhythmias may be predictive of development of certain dyspeptic symptoms. Plasma VIP may be involved in the development of dysrhythmias.

An allograft inflammatory factor 1 (AIF1) single nucleotide polymorphism (SNP) is associated with anticentromere antibody positive systemic sclerosis.

OBJECTIVE: To identify genetic associations between allograft inflammatory factor 1 (AIF1) and systemic sclerosis (SSc), or its subsets, using a single nucleotide polymorphism (SNP) in a replicate case-control study. METHODS: The frequencies of alleles and genotypes of an SNP, rs2269475, for the AIF1 gene were examined in two large independent cohorts of SSc patients (n = 1015 total), and compared with two groups of normal controls (n = 893 total). Both cases and controls were stratified by ethnicity (Caucasian, African American and Hispanic) and by autoantibody status [anti-centromere antibodies (ACA) and anti-topoisomerase I antibody (ATA)]. RESULTS: The minor T allele and CT/TT genotype frequencies of the AIF1 SNP were not observed more frequently in SSc patients of the three ethnic groups (individually or combined) when compared with controls. On the other hand, T and CT/TT frequencies were significantly increased in ACA-positive Caucasian SSc patients, and all ACA-positive SSc patients (the three ethnic groups combined), when compared with ACA-negative SSc patients and with normal controls, with odds ratios of approximately 1.5. CONCLUSION: The data demonstrate a genetic association between AIF1 and the ACA-positive subset of SSc. This polymorphism is a non-synonymous substitution and therefore likely to represent an important functional change in AIF1. Since vascular pathology is a prominent feature in ACA-positive SSc patients, the observed association with a vasculotrophic inflammatory gene is biologically plausible and warrants further research.

Systematic review: pathophysiology and management of gastrointestinal dysmotility in systemic sclerosis (scleroderma).

Gastrointestinal dysmotility in systemic sclerosis (scleroderma) is prevalent in 90% of patients, increasing morbidity and in some cases mortality. The resultant gastrointestinal complications are usually extensive, involving many regions of the gut from the oesophagus to the anus. Collagen replacement of vascular and enteric smooth muscle results in hypomotility, lumen dilatation, tensile rigidity and eventual loss of organ functions. The aim of this paper is to provide an overview of systemic sclerosis-related gastrointestinal dysmotility and available/potential therapeutic options. We evaluated published data on the pathophysiology and management of gastrointestinal dysmotility in systemic sclerosis patients using the MEDLINE database for English and non-English articles from 1966 to July 2005. Based on this systematic review, lifestyle and medical therapy approaches are preferred as they often improve and/or ameliorate symptoms. Surgery is only recommended with serious, rare complications such as bowel perforation or ischaemia. Alternative therapies such as acupuncture-based therapies are well tolerated, with clinical improvement and may be of potential therapeutic benefit for systemic sclerosis gastrointestinal dysmotility. Further elucidation of initiating and persistent mechanisms of systemic sclerosis-related gastrointestinal dysmotility will optimize the development of a multidisciplinary and more directed treatment regimen.

Transient or occult HIV infections may occur more frequently than progressive infections: changing the paradigm about HIV persistence.

Evidence of transient HIV infections was found in 8 subjects at high-risk for HIV infection among 47 longitudinally studied over 2-5 (average approximately 3.5) years, whereas only two subjects developed progressive infection. All of these subjects developed serum antibodies (Ab) to conformational epitopes of HIV gp41 (termed "early HIV Ab"), but the 8 transiently infected subjects lost this Ab within 4-18 months, and did not seroconvert to positivity in denatured antigen EIA or Western Blot (WB). However, the two progressively infected subjects eventually seroconverted in the EIA and WB tests within one to two months after the appearance of "early HIV Ab". HIV env and nef sequences were directly PCR amplified from the peripheral blood mononuclear cells (PBMCs) of two of the eight transiently infected subjects during the time of "early HIV Ab"-postivity, and these showed significant sequence divergence from the HIV strains in the laboratory, indicating that they were not laboratory contaminants. Genome identity typing ("paternity-typing") of PBMC samples obtained at the time of "early HIV Ab"-positivity, and later when Ab was absent from each of the 8 subjects, showed that blood samples were not mixed-up. This provides further evidence that transient or occult infection with HIV does occur, and perhaps at a greater frequency than do progressive infections.

Excitatory amino acids, TNF-alpha, and chemokine levels in synovial fluids of patients with active arthropathies.

The aim of this study was to assess the synovial fluid (SF) neurotransmitter excitatory amino acid (EAA) levels, including glutamate (Glu) and aspartate (Asp), in the context of SF levels of other amino acids, TNF-alpha and chemokines from patients with active arthropathies. The SF was collected from patients with active rheumatoid arthritis (RA), gout, or osteoarthritis (OA). The SF samples were analysed for levels of neurotransmitters glutamate and aspartate, tumour necrosis factor-alpha (TNF-alpha), Regulated upon Activation Normally T-cell Expressed and Secreted (RANTES), macrophage inhibitory factor-1 alpha (MIP-1alpha) and interleukin 8 (IL-8). SF WBC counts were also determined. Correlations between SF EAA, TNF-alpha and chemokines were determined by the Pearson product-moment correlation. Primary cultures derived from SF from active RA and gout patients were incubated with added l-glutamate, to assess if exposure to Glu could increase TNF-alpha levels. There were significant elevations in SF EAA, SF TNF-alpha and SF RANTES in RA patients compared to gout or OA patients. Significant correlations between SF EAA and SF RANTES, MIP-1alpha and IL-8 levels were seen, and SF EAA and SF TNF-alpha or SF WBC levels approached significance. Addition of exogenous neurotransmitter glutamate significantly increased TNF-alpha levels in primary cell cultures derived from RA and gout patients. The SF neurotransmitter EAA levels significantly correlated to selected SF chemokine levels, in clinically active RA, gout and OA patients, independent of disease. Added Glu resulted in significantly increased TNF-alpha levels in primary synovial cell cultures. These data expand the relationship of SF neurotransmitter EAA levels to SF cytokines and chemokines in patients with clinically active arthritis, and suggest that neurotransmitters Glu and Asp contribute to peripheral inflammatory processes.

Analysis of risk factors and comorbid diseases in the development of thrombosis in patients with anticardiolipin antibodies.

Our objective was to identify the role of various disease states and additional risk factors in the development of thrombosis in patients with anticardiolipin antibodies (aCL). We undertook a retrospective chart review of patients with aCL (IgG or IgM titres > 20 GPL or 20 MPL by ELISA). Patients with a thrombotic event were compared to patients without thrombosis for potential risk factors: age, gender, ethnicity, hypertension (HTN), diabetes (DM), hyperlipidaemia, tobacco use and sequential aCL determinations. The role of systemic lupus erythematosus (SLE), human immunodeficiency virus (HIV), hepatitis C and renal disease was also analysed. Statistical analysis was performed using the t-test, the chi(2) test and multivariate analysis. Of the 107 patients who had moderately positive aCL (IgM and/or IgG), 53 had a thrombotic event. The patients with thrombosis were significantly older than patients without thrombosis (mean age 46.6 vs. 38.75 years, respectively, P=0.014). No significant differences in gender, race, HTN, DM, hyperlipidaemia, tobacco use or concomitant diseases were identified in the two groups. Thrombosis was more frequent in patients who were seropositive for both IgG and IgM ( P=0.027). Thrombosis was observed in equal frequencies in patients with aCL on both determinations and in patients with aCL on only one of the two determinations. In patients with aCL on two determinations a high-titre IgG aCL was associated with thrombosis. Patients with renal disease and aCL on only one of the two determinations had fewer thrombotic events ( P=0.0046). Mean aCL IgM titres were higher in thrombosis groups containing venous thromboses than in the thrombosis group with arterial thrombosis only. We concluded that risk factors for thrombosis with a single aCL determination include older age and both IgM and IgG aCL. With persistent aCL, high-titre IgG aCL was associated with thrombosis.

Lack of association of a functionally relevant single nucleotide polymorphism of matrix metalloproteinase-1 promoter with systemic sclerosis (scleroderma).

Matrix metalloproteinase 1 (MMP-1) is necessary for degradation of interstitial collagen types I, II, and III, which are the major constituents of the extracellular matrix (ECM). Increased expression of MMP-1 has been correlated with invasiveness of certain malignancies and cartilage degradation in rheumatoid arthritis. Increased transcriptional activity of MMP-1 has been reported with a single nucleotide polymorphism (SNP) of the MMP-1 promoter. Systemic sclerosis (SSc) is characterized by increased accumulation and turnover of collagen and other components of ECM. Previous studies have reported increased expression of MMP-1 transcripts in SSc fibroblasts. Therefore, we sought to determine if SSc patients with early disease (< or =5 years) from a multi-ethnic cohort were more or less likely than ethnically-matched normal controls to have an increased frequency of the high promoter activity MMP-1 genotype and whether MMP-1 promoter genotypes correlated with any of the major clinical manifestations of SSc. The results show that the frequency of the high activity promoter genotype in either the heterozygous or homozygous state did not differ significantly between SSc patients and ethnically-matched controls, or between SSc patients with either diffuse or limited scleroderma. Furthermore, MMP-1 promoter genotypes did not significantly correlate with any of the major clinical manifestations of SSc.

Glutathione S-transferase genotypes in systemic sclerosis and their association with clinical manifestations in early disease.

The glutathione S-transferases (GSTs) are a family of enzymes involved in limiting oxidative damage to tissues. Null alleles for one or more of the GST enzymes, especially GSTM1, reportedly occur more frequently in patients with Sjögren's syndrome and systemic lupus erythematosus who possess certain autoantibodies. Because systemic sclerosis (SSc) is a disease in which oxidative damage has been hypothesized to contribute both to immune dysfunction and tissue damage, we sought to determine if patients from a multi-ethnic cohort of SSc patients with early disease (< or =5 years) were more likely than ethnically-matched normal controls to have null alleles for GSTM1 (M1) and/or GSTT1 (T1), and if the null allele status correlated with any major disease features. The data show that while M1 and T1 null genotypes were not significantly increased in SSc compared to ethnically matched controls, their frequencies (especially T1 nulls) were significantly higher among SSc patients with hypertension and pulmonary involvement. This suggests that GST genotype may be a genetic factor that contributes to clinical disease expression in SSc.

Systemic sclerosis in 3 US ethnic groups: a comparison of clinical, sociodemographic, serologic, and immunogenetic determinants.

OBJECTIVE: To determine whether ethnic factors influence the presentation, serologic expression and immunogenetics of systemic sclerosis (SSc), patients from 3 ethnic groups were compared for clinical features, SSc-associated autoantibodies, and human leukocyte antigen (HLA) class II alleles. METHODS: Fifty-four Hispanics, 28 African Americans, and 79 whites from Texas with recent-onset (less than 5 years) SSc enrolled in a prospective longitudinal study were assessed for sociodemographic, clinical, immunologic, immunogenetic, behavioral, and psychologic parameters using validated instruments and standard laboratory techniques. Serologic and immunogenetic characteristics from these patients and larger retrospective SSc cohorts of the same ethnic groups also were examined. RESULTS: Hispanics and African Americans in the prospective cohort were more likely to have diffuse skin involvement, skin pigmentary changes, digital ulcers, pulmonary hypertension (African Americans), and an overall lower sociodemographic status than whites, who had more facial telangiectasia and hypothyroidism. In the larger combined prospective and retrospective groups of SSc patients, whites were likely to have more anticentromere antibodies (ACA) and African Americans more anti-U1-ribonucleoprotein (RNP) and anti-U3-RNP (fibrillarin) autoantibodies. HLA-DQB1*0301 was significantly associated with SSc per se in all 3 ethnic groups; HLA-DRB1*11 correlated with the anti-topoisomerase I antibody response, and HLA-DRB1*01, DRB1*04, and DQB1*0501 with ACA. CONCLUSIONS: Important sociodemographic, clinical, and serologic differences exist between whites, African Americans, and Hispanics, despite shared genetic (HLA class II) predisposing factors. The impact of these differences on prognosis remain to be determined.

Pericardial effusion and cardiomyopathy following arthritis with parvovirus B19 infection: response to intravenous immunoglobulin.

We describe a 65-year-old female who presented with arthritis involving the small joints of her hand, wrists, and knee, fever, rash, and leukocytosis. During the course of her illness, she developed elevated transaminases, myositis, bilateral pleural effusions, a large pericardial effusion compressing the right atrium, and cardiomyopathy with impaired left ventricular function. The patient had evidence of acute parvovirus B19 infection by serology, although parvovirus specific DNA sequences from peripheral white blood cells were negative by polymerase chain reaction. This illness raised concern about possible collagen vascular disease. Low titers of antinuclear antibodies were present transiently, and other autoantibodies were undetected. Treatment with intravenous immunoglobulin resulted in dramatic resolution of her disease manifestations. Pericardial effusion and cardiomyopathy may be rare sequelae of parvovirus B19 infection. The apparent improvement with intravenous immunoglobulin could have been related to clearance of infection or down regulation of host immune response.

Amino acid release into the knee joint: key role in nociception and inflammation.

This study examined the release of several amino acids after induction of knee joint inflammation in rats using kaolin and carrageenan. During the initial 10-min collection after knee joint injection with the irritants, the concentration of glutamate and the nitric oxide metabolites, arginine and citrulline, doubled. This increase persisted for at least two hours. During the same time period aspartate concentrations remained unchanged. Direct knee joint administration of lidocaine prevented the increases in amino acid concentration measurable by microdialysis probe inserted into the joint. These data suggest the possibility that glutamate may be released by neuronal endings in the joint.

Excitatory amino acid profiles of synovial fluid from patients with arthritis.

OBJECTIVE: Previous studies in an experimental synovitis model in rats determined that administration of glutamate and aspartate into the joint produces hyperalgesic responses, while their receptor antagonists provide protection against the development of a hyperalgesic state. We examined concentrations of amino acids in synovial fluid (SF) to determine if increases might be relevant to human joint pathology. METHODS: One hundred forty-four repository SF samples from patients undergoing diagnostic or therapeutic arthrocentesis and 14 SF samples from 7 cadavers were analyzed by high pressure liquid chromatography and compared as arthritic and control cohorts. RESULTS: Compared to the average concentrations from the autopsy cases, the excitatory amino acids (EAA) glutamate and aspartate in SF from patients with synovitis were 54 and 28 times higher, respectively. Increases for all other amino acids ranged from 3 to 18-fold. The values for glutamate and aspartate were significantly higher than the mean increase for other amino acids compared using unpaired t tests (p < 0.0001). The mean ratio of glutamate and aspartate elevations over the mean increase for other amino acids was 4-fold and 2-fold, respectively. The EAA were highest in Reiter's, infectious arthropathies, and systemic lupus erythematosus, but did not appreciably segregate to diagnosis or SF white blood cell count. CONCLUSION: Our data provide evidence of increased glutamate and aspartate in the SF of humans with active arthritis, suggesting that glutamate mediated events may contribute to the pathogenesis of human arthritic conditions.

Inguinal lymph node foreign body granulomas after placement of a silicone rubber (Silflex) implant of the first metatarsophalangeal joint.

We describe a woman who developed foreign body granulomas 8 years after metatarsophalangeal (MTP) joint silicone rubber implantation for hallux rigidus. She developed overnight swelling and tenderness in the inguinal region on the ipsilateral side. Histological evaluation of the lymph node showed foreign body granulomas. Electron microscopy and dispersion x-ray analysis identified the foreign body material in the inguinal lymph node and fibrous capsule surrounding the implant as silicone. Foreign body granulomas of surrounding tissues and regional lymph nodes are infrequently reported postoperative complications in patients with small joint silicone rubber implants. A fractured or eroded implant surface attributed to wear is usually noted at prosthesis excision. Granulomas in normal or enlarged lymph nodes have been described in both symptomatic and asymptomatic patients, with intact or fractured prostheses. Many related joint and lymph node symptoms resolve with removal of the silicone rubber prosthesis.

Sera from HIV-1 infected individuals in all stages of disease preferentially recognize the V3 loop of the prototypic macrophage-tropic glycoprotein gp120 ADA.

The outer membrane glycoprotein gp120 and the transmembrane glycoprotein gp41 are predominant targets of the humoral immune response to infection by human immunodeficiency virus type 1. The third hypervariable region (V3 loop) is the principal neutralizing domain and is the primary target of neutralizing antibodies directed against the envelope proteins of HIV-1. The V3 loop is also the major determinant for HIV-1 cell-specific tropism. To further characterize the humoral immune response directed against the gp120 envelope proteins, we expressed two prototypic gp120 envelope proteins (LAI/HXB2 and ADA) and chimeric gp120 envelope proteins in stable transfected Drosophila melanogaster Schneider 2 cells. Sera from four infected adults over the course of infection [McNearney et al. (1992) Proc. natn. Acad. Sci. U.S.A. 89, p. 10,242] were assayed for reactivity with the respective envelope proteins. Sera obtained at early stages preferentially recognized the gp120 envelope protein ADA, whereas in later stages of infection the sera showed diminished reactivity with both gp120 LAI/HXB2 and gp120 ADA. Chimeric envelope proteins revealed that the humoral response was directed primarily against the V3 loop of gp120 ADA. Furthermore, 22 sera from HIV-1 infected individuals in different stages of the disease were tested. Reactivity of sera with the gp120 envelope protein ADA was seven-fold higher than with the gp120 envelope protein LAI/HXB2. Our results suggest that the humoral immune response is preferentially elicited against the V3 loop of the prototypic macrophage-tropic gp120 envelope protein ADA.

Nef and LTR sequence variation from sequentially derived human immunodeficiency virus type 1 isolates.

Variation in HIV-1 nef and LTR DNA sequences was assessed longitudinally during disease progression in four HIV-1-infected subjects. Point mutations were found among quasispecies obtained at a single time point in each individual, with increasing diversity with disease progression in two of three patients for whom sufficient data were available for analysis. Deletions and rearrangements were more common in late than early stages of disease. Continued sequence evolution in HIV-1 quasispecies with nef deletions along with coexistence of nef-bearing quasispecies suggest that nef-deleted quasispecies are capable of replication in vivo, possibly complemented by quasispecies lacking such deletions and/or by adaptation to a specialized niche within the patients.

Expression of complement receptor 2 (CR2) on HTLV-1-infected lymphocytes and transformed cell lines.

The expression of complement receptor 2 (CR2) has been demonstrated in established HTLV-1-transformed cell lines and in 12 studied de novo infected peripheral blood lymphocytes cultures, using 2 HTLV-1 sources. The simultaneous detection of CR2 and HTLV-1 antigens in both co-cultivated and supernatant-infected peripheral blood lymphocytes suggest that the increased CR2 expression is in tandem with the increasing HTLV-1 antigen expression. CR2 up-regulation seen during polyclonal activation is presumably in response to a viral protein, although a cellular factor has not been ruled out. Increasing CR2 expression during early infection suggests its possible involvement in selection or development of subsequent transformation events. Variable levels of CR2 in immortalized cell lines argue against its obligate expression of function in the maintenance of the transformed state. The expression of CR2 in cellular activation of T cells may be stage restricted. This study also expands the cellular distribution for CR2.

Evolution of sequence divergence among human immunodeficiency virus type 1 isolates derived from a blood donor and a recipient.

Four neonates who were infected with a single unit of blood from a human immunodeficiency virus-1 (HIV-1)-infected adult (patient 1) were studied. Two of the infected children (patients II and III) developed symptomatic HIV-1 disease and died within the first 3 y of life. One child (patient IV) died at 8 mo of age of clinical problems that may have been HIV-related. In contrast, one child (patient V) has remained asymptomatic for 7.5 y and has exhibited a very gradual decline in CD4+ cell number. A previous study had shown very limited sequence diversity of isolates from patients I, II, and III (McNearney T et al.: Proc Natl Acad Sci USA 87:1917-1921, 1990). The current study examined additional HIV-1 sequences encoding the principal neutralizing V3 loop of the surface envelope protein of isolates from patients I and V. Amplified sequences were obtained using the polymerase chain reaction from a cultured isolate and uncultured peripheral blood leukocytes, and nucleotide sequences were determined for 13 clones from patient I and 19 clones from patient V. Clones derived from the cultured isolate exhibited less predicted amino acid sequence diversity on average (0-5.2%) than did sequences from uncultured leukocytes (0-19.8% differences). All clones were more closely related to those from patients II and III (0-19.8% amino acid differences) than to other North American or European isolates (18.8-27.0% amino acid differences) or African isolates (41.0-48.0% amino acid differences). Substitutions occurred at sites predicted to modulate host cell tropism and proteolytic cleavage of the V3 loop.(ABSTRACT TRUNCATED AT 250 WORDS)