Increased cell division but not thymic dysfunction rapidly affects the T-cell receptor excision circle content of the naive T cell population in HIV-1 infection.

Recent thymic emigrants can be identified by T cell receptor excision circles (TRECs) formed during T-cell receptor rearrangement. Decreasing numbers of TRECs have been observed with aging and in human immunodeficiency virus (HIV)-1 infected individuals, suggesting thymic impairment. Here, we show that in healthy individuals, declining thymic output will affect the TREC content only when accompanied by naive T-cell division. The rapid decline in TRECs observed during HIV-1 infection and the increase following HAART are better explained not by thymic impairment, but by changes in peripheral T-cell division rates. Our data indicate that TREC content in healthy individuals is only indirectly related to thymic output, and in HIV-1 infection is mainly affected by immune activation.

[Pro and contra discussion about medical education]. / Pro-contradiscussie over medisch onderwijs.

Since the end of the last century, medical education is being renewed in many countries. There is a tendency toward integration of clinical and preclinical knowledge, presentation of basic science topics as themes of organ systems in conjunction with clinical cases, emphasis on professional attitude, context-related and small-scale learning and the own responsibility of the student. As a contribution to the discussion, the Nederlands Tijdschrift voor Geneeskunde (Dutch Journal of Medicine) and the Tijdschrift voor Medisch Onderwijs (Dutch Journal of Medical Education) have decided to publish articles in a pro and contra format.

[CanMEDS 2015: better doctors?]. / CanMEDS 2015: nog betere dokters?

Recently, the CanMEDS model, which forms the basis for competency-based learning in both undergraduate and postgraduate training, has been renewed by the introduction of CanMEDS 2015. The most prominent change is the emphasis on leadership skills, which is also reflected by the name change for the role of 'manager' to 'leader'. The addition of milestones provides clearly defined targets for learning and assessment, which facilitates the monitoring of the progression in competence. Furthermore, CanMEDS 2015 strongly focusses on the overall coherence of the separate competencies. CanMEDS, designed as a model that helps to train young doctors to become good doctors, also helps us - the trainers - to become better doctors ourselves.

Comparison of two once-daily regimens with a regimen consisting of nelfinavir, didanosine, and stavudine in antiretroviral therapy-naïve adults: 48-week results from the Antiretroviral Regimen Evaluation Study (ARES).

BACKGROUND: To improve the dosing frequency and pill burden of antiretroviral therapy, we compared two once-daily dosed regimens to a twice-daily dosed regimen. METHOD: HIV-1-infected, antiretroviral drug-naïve adults were randomized to either twice-daily nelfinavir and stavudine and once-daily didanosine (regimen A) or simplified once-daily dosed antiretroviral regimens consisting of nevirapine, didanosine, and lamivudine (regimen B) or saquinavir, ritonavir, didanosine, and lamivudine (regimen C). RESULTS: At 48 weeks of therapy, the proportion of patients with a blood plasma HIV-1 RNA concentration (pVL) <50 copies/mL by intention-to treat analysis was 42.3%, 50.0%, and 56.5% for regimens A (n = 26), B (n = 22), and C (n = 23), respectively. The time to a pVL <50 copies/mL for the first time was significantly shorter in regimen C, and there was significantly more progression to CDC events in regimen B. These differences are possibly due to differences in baseline characteristics. Adverse events were lowest for regimen C; more signs associated with mitochondrial toxicity occurred in regimen A. Increase in CD4 count was comparable between arms. CONCLUSION: No statistically significant difference in efficacy was found between the two investigated once-daily dosed treatment regimens (B and C) and the reference (A). Regimen C possibly had a better virological response and less toxicity than regimens A and B.

Bacteriuria in men infected with HIV-1 is related to their immune status (CD4+ cell count).

OBJECTIVE: Reports from the United States that urinary tract infections (UTI) are more common in homosexual than in heterosexual men have not been confirmed in Europe. The occurrence of several UTI in men infected with HIV-1 has been recorded in The Netherlands. We therefore analysed the relationship between the presence of bacteriuria and the immune status (CD4+ cell count) in these HIV-1-infected patients. DESIGN: Urinary cultures were obtained prospectively for 2 years, during the first visit and every 6 months thereafter, when signs and symptoms of UTI occurred and when patients had fever of unknown origin. CD4+ cell counts were measured at the same time. SETTING: The study was performed at the University Hospital, Utrecht, The Netherlands. PATIENTS, PARTICIPANTS: One hundred and thirty HIV-1-infected men attended our hospital. Data from 98 were analysed. Eighty-nine (91%) of these men were either homo- or bisexual. MAIN OUTCOME MEASURES: Positive urinary culture. RESULTS: Group 1 (CD4+ cell count less than 200 x 10(6)/l) consisted of 47 patients; 30% had at least one period of bacteriuria, with 21 episodes. Group 2 (CD4+ cell count 200-500 x 10(6)/l) consisted of 27 patients; 11% had at least one period of bacteriuria, with five episodes. We did not find bacteriuria in the 24 patients in group 3 (CD4+ cell count greater than 500 x 10(6)/l). The rate of bacteriuria per patient-month, 4 (group 1) versus 2 (group 2), differed significantly (P less than 0.001). A significant relationship between CD4+ cell count and bacteriuria was found (P = 0.00003); no relationship, however, was found with anal intercourse, hospitalization, Karnofsky score, follow-up, or age. CONCLUSION: We conclude that men infected with HIV and presenting with a CD4+ cell count less than 200 x 10(6)/l are at increased risk for bacteriuria.

Replacing ritonavir by nelfinavir or nelfinavir/saquinavir as part of highly active antiretroviral therapy leads to an improvement of triglyceride levels.

In a randomized, parallel arm, open-label study, the effect of switching from ritonavir to either nelfinavir or nelfinavir plus saquinavir as part of a triple antiretroviral regimen was investigated in 16 patients with undetectable HIV-1 loads. Patients continued to use the same nucleoside reverse transcriptase inhibitors as before the switch of protease inhibitor. The period of follow-up was 48 weeks. In all patients HIV-1 load remained undetectable, whereas CD4 cell counts remained stable. Furthermore, lipid markers improved after the switch.

Liposomal amphotericin B (AmBisome) compared with amphotericin B both followed by oral fluconazole in the treatment of AIDS-associated cryptococcal meningitis.

OBJECTIVE: Amphotericin B deoxycholate initial therapy and fluconazole maintenance therapy is the treatment of choice for AIDS-associated cryptococcal meningitis. However, the administration of amphotericin B is associated with considerable toxicity. A potential strategy for reducing the toxicity and increasing the therapeutic index of amphotericin B is the use of lipid formulations of this drug. DESIGN AND METHODS: HIV-infected patients with cryptococcal meningitis were randomized to treatment with either liposomal amphotericin B (AmBisome) 4 mg/kg daily or standard amphotericin B 0.7 mg/kg daily for 3 weeks, each followed by fluconazole 400 mg daily for 7 weeks. During the first 3 weeks, clinical efficacy was assessed daily. Mycological response was primarily evaluated by cerebrospinal fluid (CSF) cultures at days 7, 14, 21 and 70. RESULTS: Of the 28 evaluable patients, 15 were assigned to receive AmBisome and 13 to receive amphotericin B. Baseline characteristics were comparable. The time to and the rate of clinical response were the same in both arms. AmBisome therapy resulted in a CSF culture conversion within 7 days in six out of 15 patients versus one out of 12 amphotericin B-treated patients (P = 0.09), within 14 days in 10 out of 15 AmBisome patients versus one out of nine amphotericin B patients (P = 0.01), and within 21 days in 11 out of 15 AmBisome patients versus three out of eight amphotericin B patients (P = 0.19). When Kaplan-Meier estimates were used to compare time to CSF culture conversion, AmBisome was more effective (P < 0.05; median time between 7 and 14 days for AmBisome versus > 21 days for amphotericin B). AmBisome was significantly less nephrotoxic. CONCLUSIONS: A 3-week course of 4 mg/kg AmBisome resulted in a significantly earlier CSF culture conversion than 0.7 mg/kg amphotericin B, had equal clinical efficacy and was significantly less nephrotoxic when used for the treatment of primary episodes of AIDS-associated cryptococcal meningitis.

Randomized trial comparing saquinavir soft gelatin capsules versus indinavir as part of triple therapy (CHEESE study).

OBJECTIVE: To compare efficacy and tolerability of saquinavir soft gelatin capsule (SQV-SGC) formulation and indinavir, both given as part of a triple drug regimen containing zidovudine and lamivudine, in HIV-1-infected individuals. DESIGN: Randomized, open label, multicentre study. PATIENTS: A total of 70 patients who were antiretroviral-naive and who had a CD4 cell count < 500 x 10(6)/I and/or > 10000 HIV RNA copies/ml plasma and/or HIV-related symptoms. Subjects were assigned randomly to zidovudine 200 mg three times per day plus lamivudine 150 mg twice per day plus either SQV-SGC 1200 mg three times per day (SQV-SGC group) or indinavir 800 mg three times per day (indinavir group). Data are presented for all patients up to week 24. RESULTS: Mean baseline CD4 cell counts (+/- SE) were 301+/-29 x 10(6) cells/l and 310 +/-43 x 10(6) cells/l in the SQV-SGC and indinavir groups, respectively. The log10 median baseline HIV RNA load was 5.00 copies/ml in the SQV-SGC group and 4.98 copies/ml in the indinavir group. No difference in antiretroviral effect between the treatment arms could be demonstrated. Intention-to-treat analysis (last observation carried forward [LOCF]) at week 24 revealed that RNA levels decreased to < 50 copies/ml in 74.3% of patients in the SQV-SGC group and in 71.4% of the patients in the indinavir group (P = 0.78). In the on-treatment analysis the proportion of patients < 50 copies/ml at week 24 was 88.0% in the SQV-SGC group and 84.6% in the indinavir group (P = 0.725). Intriguingly, the mean increase of CD4 cells in the first 24 weeks was 162+/-20 x 10(6) cells/l in the SQV-SGC group and 89+/-21 x 10(6) cells/l in the indinavir group (P = 0.01), but preliminary data indicate that this difference in CD4 cell count gain may disappear after 24 weeks of treatment. Both regimens were generally well tolerated. CONCLUSION: During the first 24 weeks of the study, we found no difference in antiviral potency between the indinavir group and the SQV-SGC group. A significantly higher CD4 response in the SQV-SGC group was observed.

Pretransplant blood transfusions have an additive positive effect on kidney graft prognosis in D/DR-matched rhesus monkeys.

The effect of blood transfusions on kidney graft survival in D/DR-matched host-donor combinations was investigated in rhesus monkeys treated with azathioprine and prednisolone. If host-donor combinations were mismatched for D/DR and no transfusions were given (controls), graft survival ranged from 9 to 22 days. D/DR matching alone led to survival times of 13 to 66 days with 62% of the animals showing a prolonged survival time ( greater than 22 days). However, when three pretransplant blood transfusions were given in D/DR-matched combinations, the range of graft survival was even better: 19 to 73 days with 90% of the recipients surviving for longer than 22 days. The recipients in this group also had a better kidney function in the first weeks after transplantation than that of the nontransfused D/DR-matched group. Therefore, the beneficial effects of D/DR matching and pretransplant transfusions are additive in the rhesus monkey.

Influence of prophylactic treatment with gamma-immunoglobulins on renal function after kidney transplantation in rhesus monkeys.

The effect of prophylactic i.v. administration of high doses of human gamma-immunoglobulin (IgG) on kidney graft survival was investigated in rhesus monkeys treated with azathioprine and prednisolone. In nontransfused recipients not treated with IgG (controls), graft survival ranged from 9 to 22 days; if nontreated animals had been given three pretransplant blood transfusions, graft survival ranged from 9 to 61 days with 42% of the animals showing a prolonged survival time (greater than 22 days). However, in both transfused and nontransfused recipients, the additional pretransplant administration of IgG appeared to have an adverse effect: about 25% of the animals showed accelerated rejection. In addition, serum creatinine levels in IgG-treated recipients were significantly higher on the 3rd day after transplantation than in non-treated monkeys. We concluded that renal transplant patients should be treated with IgG for protection against life-threatening infections only if they have good kidney function.

Kidney transplantation in rhesus monkeys. Matching for D/DR antigens, pretransplant blood transfusions, and immunological monitoring before transplantation.

The effect of matching for D/DR antigens and of three pretransplant blood transfusions on kidney allograft survival was investigated in unrelated rhesus monkeys treated with standard immunosuppression. A control group consisting of host-donor combinations mismatched for one or two DR antigens (mixed lymphocyte culture (MLC) positive) and not receiving transfusions showed a MST of 13 +/- 1.2 days with a range from 9 to 22 days. The administration of pretransplant blood transfusions led to a MST of 28 +/- 5.4 days with 5 of 12 animals showing survival times of more than 22 days (i.e., a bimodal distribution of survival times). Recipients matched with their donors for two DR antigens and given transfusions showed an even better MST of 39 +/- 4.0 days. Under these conditions, MLC-negative combinations fared slightly better than MLC-positive ones: only 1 of 10 animals showed a survival time of less than 22 days and kidney function in the first weeks after transplantation was significantly better. When mixed lymphocyte reactions (MLC reactivity) between host and donor before and after the transfusions were compared, it was possible to predict to some extent the eventual fate of an allograft: increased mixed lymphocyte reaction predicted relatively short survival times, decreased mixed lymphocyte reaction relatively long ones (P less than 0.01).

Transplantation tolerance in heart transplant recipients as demonstrated by unresponsiveness in cell-mediated lympholysis.

Transplantation tolerance or adaptation to an allograft is associated with unresponsiveness to donor-specific transplantation antigens measured in in vitro cell-mediated lympholysis (CML). We here demonstrate in a longitudinal follow-up that CML nonreactivity develops in seven of ten patients following heart transplantation. The first manifestation of this nonreactivity manifested between 3 and 27 months after transplantation. CML nonreactivity correlated with time after transplantation and the percentage of activated lymphocytes in peripheral blood. CML nonreactivity was also associated with good graft function, i.e., in condition of nonresponsiveness patients did not manifest acute rejection. The only exception was seen in one patient in whom the immunosuppressive therapy was strongly reduced. A more detailed evaluation of this patient indicated that the underlying mechanism for CML nonreactivity is clonal anergy or active suppression of the alloreactive cells.

Endothelial and smooth muscle cells in the heart allograft response: isolation procedure and immunocytochemical features.

Studies on mechanisms for allograft rejection are focused on recognition of major histocompatibility complex (MHC) antigens. In addition, there is evidence for non-MHC-mediated alloreactivity, possibly evoked by tissue-specific antigens. To measure cellular immune responses toward tissue-specific alloantigens, we isolated endothelial cells and smooth muscle cells from small pieces of human atrium at the time of transplantation. Endothelial cells were scraped off the endocardium after trypsin digestion and cultured in fibronectin-coated dishes. Smooth muscle cells were obtained by outgrowth of small pieces of atrium in a culture flask. Morphologic and immunologic characterization showed only minor differences between endothelial and smooth muscle cells cultured from atrium and cells cultured from umbilical vein (endothelial cells) and artery (smooth muscle cells). Furthermore, we studied the proliferative immune responses with endothelial and smooth muscle cells as stimulator cells, with and without induction of MHC class II antigens on these cells by addition of interferon-gamma to the culture. Peripheral blood mononuclear cells showed a proliferative response to donor human atrium endothelial cells, even without pre-incubation with interferon-gamma. Human atrium smooth muscle cells caused only a weak triggering of the mononuclear cells, irrespective of interferon-gamma pre-incubation. Immunofluorescence studies demonstrated HLA-DR expression on these endothelial and smooth muscle cells. These observations may indicate a role for non-MHC, probably tissue-specific, alloantigens expressed by endothelial cells in human cardiac allograft rejection.

Effect of escalating doses of recombinant human granulocyte colony-stimulating factor (filgrastim) on circulating neutrophils in healthy subjects.

The safety profile, tolerability, pharmacodynamics, and pharmacokinetics of four doses of recombinant human granulocyte colony-stimulating factor (filgrastim) were assessed in healthy volunteers in a double-masked, placebo-controlled, parallel-group trial. Healthy subjects received subcutaneous injections of filgrastim 75 microg (n = 8), 150 microg (n = 4), 300 microg (n = 4), 600 microg (n = 8), or placebo (n = 6) daily for 10 consecutive days. Blood samples were drawn daily immediately before the injection and on days 1 and 10 serially throughout the day. Increased absolute neutrophil counts (ANCs) were seen within 90 minutes of drug administration in subjects in all dose groups, peaking approximately 12 hours after administration. This increase was dose related in subjects in the three lower dose groups. The time to peak ANC on day 10 was approximately 9 hours, with a daily ANC profile in all four dose groups that was similar to the profile on day 1. In all dose groups, ANCs were near baseline within 48 hours of discontinuation of filgrastim. Mild, reversible thrombocytopenia was reported in 4 of 10 subjects in the highest dose group. Two subjects in the filgrastim 600-microg group were withdrawn for adverse events. Filgrastim had a good safety profile and caused dose-related increases in ANC when administered to healthy volunteers for up to 10 days.

Deficient antipneumococcal polysaccharide responses in HIV-seropositive patients.

In a prospective study, serological responses and opsonic activity towards Streptococcus pneumoniae were measured in 60 HIV-infected patients and 25 controls after the administration of the 23-valent pneumococcal vaccine (PneumovaxR). Serum samples were collected before vaccination and at weeks 1, 2, 4, and 12 after vaccination and were tested for the presence of antibodies against a mixture of capsular polysaccharide antigens (pool) and against type 3 and type 4 antigens (PS3 and PS4), using an ELISA. A serological response was defined as a two-fold or greater increase in serum titer after vaccination. Opsonophagocytosis was measured in patients with a definite response against PS3. Generally, prevaccination antipneumococcal antibody titers were clearly higher in HIV-infected patients than in healthy controls. After vaccination, antipool antibody responses were found in 76% of vaccinated patients; 24% of the patients were non-responders. In patients with more than 0.300 x 10(9) CD4 + cells per liter the percentage of responders was 94%; in patients with fewer than 0.300 x 10(9) CD4 + cells per liter this percentage was 68% (P < 0.05). The antipool response in control subjects was 92%. A serological response to PS3 and PS4 was found in 29% and 49% of the patients, respectively, and was correlated with CD4 + cell count. In controls, these percentages were 48% and 92%, respectively. In 30% of responding patients, antibody titers dropped already to prevaccination levels by week 12 after vaccination. Opsonophagocytosis was not significantly improved by vaccination, probably because of a relatively high preexisting opsonic activity. Although prevaccination conditions may have had an important influence on the study outcome, the results are not in favor of a significant beneficial effect of vaccination with PneumovaxR on antibody formation in HIV-infected patients. This raises further questions as to the relevance of pneumococcal vaccination in this population.

Antibody response to tetravalent influenza subunit vaccine in patients infected with human immunodeficiency virus type 1.

The capacity of patients infected with human immunodeficiency virus (HIV) to develop an adequate antibody response to influenza vaccination in relation to the CD4 cell count has been studied in a prospective study. A total of 73 subjects (54 HIV-infected patients and 19 healthy control persons) were vaccinated with influenza subunit vaccine containing 15 mug hemagglutinin of each of the following strains: A/Beijing/353/89(H3N2), A/Singapore/6/86(H1N1), B/Panama/45/90, and B/Beijing/1/87. Hemagglutinin inhibition (HI) antibody titers were determined prior to vaccination, 3 weeks afterwards, and at the end of the influenza season. The percentage of subjects with HI antibody titers above the assumed protective level was significantly lower in the HIV-infected patients for all 4 vaccine strains compared with those in the control group (7-26% and 42-74%, respectively). There was an association between CD4 cell count and antibody response to the B/Panama strain only. The serologic response to tetravalent subunit influenza vaccine is severely impaired in the majority of HIV-infected patients compared with control subjects. The results of this study challenges the recommendation to vaccinate HIV-infected patients.

Two rapid complementary methods to detect progressive zidovudine resistance mutations in mononuclear cells of HIV-infected patients.

The objective of the study was to evaluate a rapid screening technique for the presence of mutations in the viral reverse transcriptase gene of HIV following prolonged therapy with zidovudine in patients with AIDS. Peripheral blood mononuclear cells (PBMCs) of 14 HIV-infected patients were analyzed by micro-titer point mutation assay (PMA) before therapy with zidovudine and after at least 10 months of treatment. In addition, five of these were analyzed longitudinally. Three nontreated HIV-seropositive individuals were tested as controls. To confirm the validity of the PMA, patients' material was also analyzed with the single strand conformational polymorphism (SSCP) assay. After 10-55 months of treatment, at codons 41, 70, and 215 a shift from predominantly wild type strains to a mixture of wild type and mutant strains (21%-100% mutant sequences) appeared in the majority of patients' PBMCs. At codons 67 and 219, the wild type strain persisted after therapy in all but 3 patients. Most mutations were detected by SSCP as well as by PMA, except for one mutation at codon 41 and one at codon 70. However, when the two mutations were both present, SSCP and PMA were both able to detect these mutations. In conclusion, both PMA and SSCP are rapid and simple methods for screening for mutations causing drug resistance in zidovudine-treated HIV-infected patients. Although PMA is more labor-extensive than SSCP, the advantage of PMA over SSCP is that it permits the quantitative detection of point mutations coding for zidovudine resistance. The application of these assays may improve procedures of monitoring and modifying antiretroviral therapy on an individual basis.

Efficacy and safety of combination therapy with delavirdine and zidovudine: a European/Australian phase II trial.

The objective of the study was to investigate the safety and antiviral effect of three delavirdine dose regimens or placebo in combination with zidovudine in patients who were already taking zidovudine. Eighty-nine symptomatic HIV-1 seropositive individuals with CD4 cell counts between 50 and 350 cells/microl were included in this trial The influence of combination therapy on viral susceptibility to both zidovudine and delavirdine was investigated. Death or the occurrence, or re-occurrence of an AIDS-defining illness was considered as a clinical endpoint. The addition of delavirdine to the antiretroviral treatment regimen resulted in a significant, but transient, reduction in virus load, as determined by quantitative RNA measurements. CD4+ cell count did not change significantly. Susceptibility to zidovudine remained unchanged after 12 weeks of combination therapy, while 70% of the patients demonstrated a substantial decrease (> 10-fold) in sensitivity to delavirdine. Two patients suffered from an AIDS-defining disease during the study. No deaths occurred. Generally, the drug appeared to be safe. Skin rash was the most frequently observed adverse event (52%). In most patients the rash either resolved spontaneously or was treated successfully with a short course of antihistamines. The definite place of the compound in the management of HIV disease, in particular when given in combination with other antiretroviral agents, remains to be further explored.

Routine vaccination in HIV-infected patients: a review.

This paper reviews the literature from 1988 to November 1993 on the effectiveness of routine vaccination of HIV-infected adults. Data on the clinical benefit of vaccination in this particular group of patients are not available. In general, HIV-infected patients have suboptimal immunological responses to vaccines. In particular, an impaired responsiveness is found in patients with fewer than 200 x 10(6) CD4+ cells per litre. Consequently, it seems prudent to offer active immunization to HIV-infected subjects who are relatively immunocompetent. However, the usefulness of vaccination in those subjects who have a low CD4+ cell count is doubtful.

Competency-based training for internal medicine.

The Central College of Medical Specialities has presented guidelines for modernisation of all postgraduate speciality training programmes. These guidelines include the definition of seven general competency fields, each of them described in more detail with four key competencies. By 2006, all postgraduate speciality training programmes will be based on these competency fields. Furthermore, by then assessment of residents will be focused on the achievement of competence, rather than only on fulfilment of length of specified rotations, numbers of clinical experiences and numbers of performed skills. The application of this competency model emphasises the fact that the education of medical doctors entails more than providing them with the required theoretical and clinical knowledge and skills.