High prevalence of comorbidities and use of concomitant medication in treated people living with HIV in Germany - results of the BESIDE study

Due to demographic changes in people living with HIV (PLHIV), physicians are challenged with age-related comorbidities and their management. In the absence of comprehensive data collection, the burden of comorbidities and co-medication in addition to antiretroviral therapy (ART) remains unclear for the German real-world setting. BESIDE was an observational, cross-sectional study evaluating the prevalence of comorbidities and use of co-medication in treated PLHIV. Regional distribution of study centers (n = 20), consecutive patient recruitment, and age-stratified sampling in alignment with national epidemiologic data aimed to ensure a representative sample (n = 453). The overall prevalence of comorbidities was 91.2%; 31.6% of patients had ≥4 comorbidities. The most common diagnoses were vitamin D deficiency (29.1%), depressive episode (27.8%), arterial hypertension (16.3%), and hypercholesterolemia (10.8%). 83.7% of patients were on co-medication; 21.2% taking ≥4 medications. The most common medications or supplements were vitamins (31.6%), anti-inflammatory agents (16.1%), renin-angiotensin system agents (12.1%), acid suppressants (11.7%), lipid modifying agents (10.8%); 1.3% of patients were on co-medication that should not be co-administered with ART, 41.5% on co-medication with potential for drug-drug interactions. The prevalence of comorbidities and use of co-medication among treated PLHIV in Germany is consistently high and increases across age groups, illustrating the complexity of HIV care involving appropriate ART selection.

Chronic hepatitis C patients prior to broad access to interferon-free treatments in Germany

In 2014, the first interferon-free treatment options for chronic Hepatitis C (CHC) became available in Europe introducing a new era of highly effective and well tolerated oral treatment options for CHC. The data from the cross-sectional study CURRENT-C highlights the epidemiological characteristics of patients with CHC in Germany. During the period that the study was conducted, the approval of the combination drugs for the treatment of CHC was imminent.Between June and November 2014, 1471 CHC-patients not receiving anti-HCV treatment were included nationwide in 40 German centers specializing in viral hepatitis. The mean age was 52.4 years with 41.2 % of the patients being female. Presumed route of infection in male patients was most frequently drug use (46.2 %) and blood products in females (22.8 %). The route of infection was unknown in 28.2 % of male and 43.1 % of female patients. Compared to male patients, female patients were older (55.6 vs. 50.1 years) and longer diagnosed with HCV (18 vs. 15 years). First language of the patients was most frequently German (72.2 %), followed by Russian (14.2 %), and Polish (2.9 %). HCV genotype (GT) 1 was found in 73.8 % (1a 29.0 %, 1b 38.4 %), GT2 in 3.5 %, GT3 in 18.3 %, GT4 in 4.2 %, GT5 in 0.2 %, and GT6 in 0.3 %. Liver cirrhosis was diagnosed in 15.7 % of the patients (17.1 % male, 13.7 % female). 43.2 % of the patients had already received HCV treatment, most frequently dual therapy with pegIFN + RBV (75.8 %) or triple therapy with telaprevir or boceprevir (20.3 %). Compared to treatment-naïve patients, pretreated HCV patients were older (55.1 vs. 50.3 years) and more frequently had liver cirrhosis as clinical diagnosis (22.2 % vs. 10.8 %). Patients scheduled for HCV treatment within the next 3 months had higher rates of pre-treatment (49.4 % vs. 37.0 %), and liver cirrhosis (21.4 % vs. 10.0 %).Compared to epidemiological data of Hüppe et al. 1 from 2003 to 2006, Klass et al. 2 stated in 2012 in a comparable setting that the German CHC population were older and had more advanced liver disease. The current data seem to support this ongoing trend towards more difficult to treat patients with an urgent need for new treatment options.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

[Cost of Illness of HIV Patients under Anteretroviral Therapy in Germany - Results of the 48-Week Interim Analysis of the Prospective Multicentre Observational Study 'CORSAR']

BACKGROUND

With the introduction of highly active combined antiretroviral therapy (c-ART) mortality and morbidity of HIV patients declined substantially. Earlier studies reported that c-ART was able to save health-care costs due to a reduction of other direct medical costs, particularly for inpatient treatments and concomitant medication. To date, analyses of costs and health-related quality of life (HRQOL) of patients under c-ART are lacking in Germany. Hence, this study aims to estimate the current cost of illness and HRQOL of HIV-patients under c-ART in different treatment lines.

METHODS

A multicenter, prospective observational study was carried out in 12 specialised German centres for infectious diseases: 8 private practices/outpatient centres and 4 specialised hospitals offering both inpatient and outpatient services. Demographic, clinical and medication data were derived from patient records. Resource utilisation, information on productivity, out of pocket costs and HRQOL (EQ-5D) were collected every 12 weeks via a patient questionnaire. All costs were calculated based on price information from publicly accessible databases.

RESULTS

N=1,154 patients were included in the analysis. Mean direct disease-related costs of -patients under c-ART amounted to 22,563 Euro/year. Patients beyond the 3(rd) line of treatment -incurred considerably higher costs 24,654 Euro/year. In the 1(st) treatment line, c-ART accounted for 83.2% of the total direct costs, in the 2(nd)/3(rd) line for 80.8% and in >3(rd) line for 83.4%, respectively. Indirect costs due to impaired productivity were higher in the 2(nd)/3(rd) treatment line (2,843 Euro) compared to the 1(st) (1,604 Euro) and >3(rd) (1,752 Euro) treatment lines, respectively. The average HRQOL (EQ-5D) varied between 0.77 (self-assessment via visual analogue scale) and 0.91 (utility score based on the German time trade-off tariff).

CONCLUSIONS

Over the last decade, cost of illness of HIV patients under c-ART decreased slightly with average costs per year still being substantial. Main cost driver of overall costs is c-ART. There have been, however, noticeable shifts between different cost domains.

A Multicenter, Open Labeled, Randomized, Phase III Study Comparing Lopinavir/Ritonavir Plus Atazanavir to Lopinavir/Ritonavir Plus Zidovudine and Lamivudine in Naive HIV-1-Infected Patients: 48-Week Analysis of the LORAN Trial

OBJECTIVE

The primary aim of the study was to compare the metabolic side effects of a nucleoside analogue-containing regimen with a nucleoside analogue-sparing double protease inhibitor regimen. A secondary goal was to test for efficacy of a double-PI regimen.

DESIGN

Multicenter, randomized, open-label, phase III clinical trial.

SUBJECTS

Adult HIV-1-infected individuals naïve to antiretroviral therapy with viral load above 400 HIV-RNA copies/ml were randomized (1:1) to either 400 mg lopinavir /100 mg ritonavir (LPV/r) BID plus 150 mg lamivudine/300 mg zidovudine (CBV) BID versus LPV/r BID plus 300 mg atazanavir (ATV) QD. Main outcome measure was the virologic failure in both groups, defined as viral load ≥50 copies/ml at week 48.

RESULTS

In the CBV/LPV/r-arm, 29 out of 35 patients [(83%; 95% confidence interval (CI) 66.9-92.2%] and 18 out of 40 patients (45%; 95% CI 29.7-61.5%) in the ATV/LPV/r-arm had a HIV-RNA level <50 copies/ml at week 48. The intent-to-treat analysis revealed inferior virologic response in the ATV/LPV/r arm (Chi-Q and Fisher´s Exact Test p<0.001) and resulted in premature termination of the trial. Eleven patients in the ATV/LPV/r-arm discontinued therapy because of virological failure. These failures mostly presented with low level replication (<1,000 copies/ml). Increases in CD4 cell counts was significantly more rapid in the ATV/LPV/r arm (p=0.02), but comparable at week 48.

CONCLUSIONS

ATV/LPV/r had less virologic efficacy than the conventional RTI-based regimen and resulted in a high virological failure rate with low level replication.

Cytotoxic CD4 T cells in viral hepatitis

CD4+ T cells are thought to contribute to antiviral immune responses by secretion of cytokines thereby providing help to CD8+ T and B cells. However, perforin-positive cytotoxic CD4+ T cells have been described in human immunodeficiency virus-positive patients suggesting a role not only of CD8+ but also of CD4+ T cells for killing virus-infected cells. We investigated 76 patients with viral hepatitis [15 hepatitis B virus (HBV), 22 HBV/hepatitis D virus and 17 hepatitis C virus (HCV)] for cytotoxic CD4+ T cells. The frequency of perforin-positive CD4+ T cells in viral hepatitis was highly variable ranging from < 1% to more than 25%. Perforin-positive CD4+ T cells displayed the phenotype of terminally differentiated effector cells (CD28-, CD27-). The highest frequencies of CD4+ cytotoxic T lymphocytes (CTLs) were found in patients with delta hepatitis (P = 0.04 vs HBV and HCV patients), and the presence of CD4+ CTLs was associated with elevated aspartate aminotransferase levels (P = 0.01) and decreased platelet counts (P = 0.03). Perforin-positive CD4+ T cells decreased in two individuals during spontaneous clearance of acute hepatitis C. Significant associations were found between the frequency of perforin-expressing CD4+ cells and age (P = 0.04), perforin-positive CD8+ cells (P < 0.001) and perforin-positive CD4-/CD8- lymphoid cells (P = 0.002). Differentiated CD27- effector CD4+ CTLs can be detected in patients with viral hepatitis. In particular in patients with more advanced liver disease, the accumulation of perforin-positive T cells with age could be one correlate for the more severe course of viral hepatitis in elderly individuals.

GB virus C infection and quality of life in HIV-positive patients

It was recently shown that GBV-C infection is associated with prolonged survival of HIV-infected individuals. The GB virus C is the closest known relative of hepatitis C virus in man. The latter has been associated with significant impairment in quality of life, independent from the associated liver disease. We were thus interested in the impact of GB virus C infection on quality of life in HIV-infected individuals. We retrospectively analyzed a cohort of HIV-positive patients who previously answered the 'HIV-SELT' and the 'EQ-5D' questionnaires assessing quality of life and for whom data on GB virus C RNA status were available. In this study we identified no adverse effect of GB virus C on quality of life, but, in contrast, GB virus C viraemic patients showed better quality of life in all parameters for the scores in comparison to GB virus C-negative HIV-infected patients. HIV-positive patients with a GB virus C infection showed superior quality of life. These data further support the favourable course of HIV disease in GB virus C-positive patients.

[Immune restoration inflammatory syndromes]

Increase of prevalence of certain immunodeficiencies is caused by more frequent use of immunosuppresive treatment, by advances in supportive care of immunodeficient individuals and by the pandemic spread of HIV-infection respectively. Highly active antiretroviral treatment (HAART) is able to reconstitute the impaired immunity in the HIV-infected individual and therefore to reduce morbidity and mortality. On the other hand paradoxical exacerbation of inflammatory or opportunistic diseases may develop during immunoreconstitution. By their distinct pathophysiological, clinical and therapeutic particularities these disease have been summarized as Immune Restoration Inflammatory Syndromes (IRIS). This review summarizes the variety of immunoreconstitution disorders and describes possible diagnostic pitfalls. Potential therapeutic options and an algorithm for the classification of the syndrome are proposed.

[Immunologic control of HIV-1 infection. Fantasy or soon reality?]

The human immunodeficiency virus-1 (HIV-1) preferentially infects CD4+ cells, leading to their destruction. In contrast to other viral infections, the immune system is unable to keep the HIV infection under permanent control in most cases. This failure ultimatively results in immunodeficiency with occurrence of AIDS-defining diseases. In recent years, highly active antiretroviral therapy (HAART) has become available, and the number of AIDS cases and deaths have decreased dramatically. However, limitations of HAART become more apparent, demanding greater emphasis on search for alternative approaches. Stimulation and modulation of the immune response to HIV are new and promising strategies. A prerequisite, however, is the knowledge about immunologic defense mechanisms against HIV. In this article, the major factors of innate and acquired immune responses to HIV are described.

[Lipodystrophy syndrome. Therapeutic progress is still pending]

A common problem seen with the long-term use of highly active antiretroviral therapy (HAART) is the HIV-associated lipodystrophy syndrome. Clinical signs include a loss of peripheral subcutaneous fatty tissue, an increase in visceral or local fat, and altered glucose and lipid metabolism. The physical changes frequently impair quality of life, and the patient's adherence to treatment regimens. Metabolic changes may possibly represent cardiovascular risks with incalculable consequences over the long term. Although the lipodystrophy syndrome was first described in 1998. It still lacks a definition. So far, therapeutic strategies have remained ineffective or have had only limited success. Proposed treatments include general recommendations (diet, physical exercise, etc.), changing the antiretroviral therapy, and treatment with metabolically active medication.

[Immune reconstituted inflammatory syndrome. Pitfalls of antiretroviral therapy]

The pandemic HIV infection, the more frequent use of immunosuppressive treatment, and the improved long-term prognosis of immunocompromised patients due to better supporting therapies have resulted in an increase in the prevalence of immunodeficiencies. Highly active antiretroviral therapy (HAART) can improve immunocompetence in HIV patients, even when the immunodeficiency is far advanced. This has resulted in an impressive and lasting lowering of the morbidity and mortality associated with HIV infection. However, immune reconstitution may exacerbate subclinical opportunistic infections or autoimmune diseases, or result in an unexpected, paradoxical aggravation of intercurrent inflammatory diseases. The atypical inflammatory conditions have a number of synonymous names: immune restoration disease (IRD), immune reconstitution syndrome (IRS), or immune reconstitution inflammatory syndrome (IRIS). In the light of specific differential therapeutic consequences, it is important to distinguish the clinical presentation from that of corresponding opportunistic infections. However, diagnostic and therapeutic standards for IRIS have not yet been worked out. The present overview also points to possible diagnostic pitfalls, and makes suggestions for a possible classification of the condition and the therapeutic options.

[Helper cells, viral load, genetic factors, co-infections. Prognostic factors in HIV-1 infection]

The ideal time to initiate antiretroviral therapy in asymptomatic patients with chronic HIV infection remains to be defined. The most relevant laboratory parameter is the CD4 cell count. Therapy should be started before the CD4 cells drop below 200/microliter and the immune system becomes compromised. In contrast to past recommendations, viral load should not be used as a single laboratory parameter for initiation of antiretroviral therapy in asymptomatic untreated patients. The determination of genetic factors to assess the prognosis of HIV patients has not yet been incorporated into daily clinical practice. While co-infection with GBV-C is a prognostically favorable factor for the course of the HIV infection, replicative hepatitis C is associated with increased mortality.

Infection with GB virus C and reduced mortality among HIV-infected patients

BACKGROUND

The flavivirus GB virus C (GBV-C, also designated hepatitis G virus) was identified in a search for hepatitis viruses, but no disease is currently known to be associated with it. We investigated the relation between coinfection with GBV-C and the long-term outcome in patients infected with the human immunodeficiency virus (HIV).

METHODS

A total of 197 HIV-positive patients were followed prospectively beginning in 1993 or 1994. Of these patients, 33 (16.8 percent) tested positive for GBV-C RNA, 112 (56.9 percent) had detectable antibodies against the GBV-C envelope protein E2, and 52 (26.4 percent) had no marker of GBV-C infection and were considered unexposed. We assessed the relation between GBV-C infection and the progression of HIV disease. We also tested 169 GBV-C-positive plasma samples with a quantitative branched-chain DNA (bDNA) assay in order to investigate possible correlations between GBV-C viral load and both the CD4+ cell count and the HIV load.

RESULTS

Among the patients who tested positive for GBV-C RNA, survival was significantly longer, and there was a slower progression to the acquired immunodeficiency syndrome (AIDS) (P<0.001 for both comparisons). Survival after the development of AIDS was also better among the GBV-C-positive patients. The association of GBV-C viremia with reduced mortality remained significant in analyses stratified according to age and CD4+ cell count. In an analysis restricted to the years after highly active antiretroviral therapy became available, the presence of GBV-C RNA remained predictive of longer survival (P=0.02). The HIV load was lower in the GBV-C-positive patients than in the GBV-C-negative patients. The GBV-C load correlated inversely with the HIV load (r=-0.33, P<0.001) but did not correlate with the CD4+ cell count.

CONCLUSIONS

Coinfection with GBV-C is associated with a reduced mortality rate in HIV-infected patients. GBV-C is not known to cause any disease, but it is possible that its presence leads to an inhibition of HIV replication. However, GBV-C infection could also be a marker for the presence of other factors that lead to a favorable HIV response.

Reconstitution of NK cell activity in HIV-1 infected individuals receiving antiretroviral therapy

We studied natural immunity mediated by natural killer (NK) cells in 62 HIV-1 infected individuals, 54 HIV-1 infected individuals receiving highly active antiretroviral therapy (HAART) for more than one year and 8 HIV-1 infected individuals without antiretroviral therapy. 22 individuals had a complete suppression of viral replication characterized by viral load values <50 copies/ml, whereas 32 individuals presented with persistent viral replication. The 8 untreated patients had an indication to start antiretroviral treatment. Lytic activity of NK cells was measured in a 51chromium release assay. In patients with persistent viral replication under HAART NK cell activity was significantly decreased compared to patients with effective control of HIV viremia. Patients with complete suppression of HIV replication displayed a similar NK activity to healthy control persons. Differences in antibody-dependent cellular cytotoxicity (ADCC) were not observed. Further studies will investigate whether decreased NK cell activity is a reason for or the consequence of persistent viral replication.

Progressive reduction of CMV-specific CD4+ T cells in HIV-1 infected individuals during antiretroviral therapy

Visualization of antigen-specific T cells has become an important tool in studying immune responses. The aim of this study was to analyze CMV-specific CD4+ T cells in healthy and HIV-infected individuals. Peripheral blood mononuclear cells (PBMC) were examined for antigen-induced intracellular cytokine responses. We found significant numbers of CMV-specific CD4+ T cells detectable in most CMV-IgG+ HIV-1 infected individuals, whereas CMV-specific CD4+ T cells could not be demonstrated in CMV-IgG- patients. Median frequency of CMV-specific CD4+ T cells were lower in HIV-infected subjects who had been treated with highly active antiretroviral therapy (HAART) for more than 1 year than in untreated HIV-infected individuals. In patients under therapy for less than 1 year median CMV-specific CD4+ T cell responder frequency was higher than in subjects treated for more than 1 year but lower than in untreated subjects. HIV suppression with HAART might lead to a progressive reduction of CMV-specific CD4+ T cells indicating an efficient elimination of an opportunistic pathogen.

Immunologic and virologic studies in long-term nonprogressors with HIV-1 infection

BACKGROUND

It is not known whether clinical latency in long-term nonprogressors (LTNP) with HIV-1 infection is due to a strong HIV-1 specific immune response of the host or to virologic factors. -

METHODS

Peripheral blood mononuclear cells (PBMC) of 6 LTNP were analyzed for their phenotype, proliferation rates, natural killer (NK) cell activity, antibody dependent cellular cytotoxicity (ADCC), and CCR5 chemokine receptor genotype. Furthermore sequence analyses of the HIV-1 gene were performed. -

RESULTS

Phenotypic analyses of lymphocyte subsets revealed increased CD8+ as well as HLA-DR+ expressing cells in LTNP and patients with progressive disease (PRO). Proliferation assays in LTNP and PRO showed a reduction of stimulation by polyclonal mitogens (PHA, ConA, PWM) of up to 60%. NK activity was within normal ranges in LTNP but reduced in PRO. 1 LTNP exhibited heterozygosity for CCR5-D32. A mutant HIV nef gene was not discovered by PCR in any of the LTNP. HIV-V3 loop PCR in 5 LTNP revealed the HIV-1B (NSI) subtype. In 2 patients further sequence analyses of the HIV-1 genome showed homozygous mutations in the Sp1 and NF-kB binding sites.

CONCLUSION

The non-progression of HIV-1 infection in some LTNP seems to be due to single mutations in the viral genome resulting in a less replicative HIV-1 subtype or to a mutant chemokine receptor leading to a reduced HIV-1 entry into CD4+ cells. NK cell activity might be an additional contributing factor in controlling viremia.

The IgG Fc receptor family

IgG immune complexes are of central importance in the humoral immune system and strongly implicated in the pathogenesis of hematologic and rheumatic autoimmune disorders. Cross-linking of receptors for the Fc domain of IgG antibodies (FcgammaRs) triggers a wide variety of effector functions including phagocytosis, antibody-dependent cellular cytotoxicity, and release of inflammatory mediators, as well as immune complex clearance and regulation of antibody production. In this way, FcgammaR provide an essential feedback between the humoral and cellular immune response. In the past, significant advances have been made in the molecular dissection of FcgammaR function using cellular transfection systems. Current approaches designed to target and change individual FcgammaR genes in mice have given further insight into their specific contributions to systemic processes, also indicating them to be important immunoregulatory receptors involved in various disease states of allergy, autoimmunity, and inflammation. Future work on targeting FcgammaR binding sites in combination with humanized FcgammaR mouse models will lead to novel therapeutic strategies in the treatment of IgG-mediated human disease in which FcgammaR activation plays an integral part.

Pre-TCR signaling components trigger transcriptional activation of a rearranged TCR alpha gene locus and silencing of the pre-TCR alpha locus: implications for intrathymic differentiation

A rearranged TCR alpha transgene remains transcriptionally inactive in rag-2-/- thymocytes but can be induced by CD3-mediated signals with concomitant maturation of double-negative (DN) thymocytes to the CD4+CD8+ double-positive (DP) stage. Reciprocally, the same signals silence pre-TCR alpha (pT alpha) expression. In normal C57BL/6 thymocytes, TCR alpha expression is not detected in DN thymocytes while, in contrast, TCR beta expression is initiated at the most immature c-kit+CD44+CD25- stage and continues throughout thymocyte development. pT alpha expression is first detected at the intermediate c-kit +/- CD44+CD25+ DN stage, increases during transition to the more mature c-kit-CD44-CD25+ stage and is lost at the DP stage. Thus, although TCR beta and pT alpha expression are independent, the pre-TCR complex mediates signals controlling the appearance of alpha beta TCR through selective regulation of TCR alpha and pT alpha genes.

T lymphocyte development in the absence of Fc epsilon receptor I gamma subunit: analysis of thymic-dependent and independent alpha beta and gamma delta pathways

During fetal development, early thymocyte progenitors transiently express low affinity Fc receptors for IgG (Fc gamma R) of both Fc gamma RII and III isoforms. Only the Fc gamma RIII isoform requires association of an Fc gamma RIII (CD16) alpha subunit with an Fc epsilon RI gamma homodimer for surface expression. To address the role of Fc gamma R in ontogeny, we studied thymic development in Fc epsilon RI gamma-/- mice. We fine that day 14.5 CD4-CD8- double-negative (DN) fetal thymocytes of Fc epsilon RI gamma-/- mice express mRNA of both Fc gamma RIIb1 and Fc gamma RIII. Surface expression of Fc gamma RII/III is readily detected on these cells. It appears that Fc gamma RIIb1, whose surface expression is Fc epsilon RI gamma independent, replaces Fc gamma RIII during thymic development in these animals. Moreover, subsequent development into CD4+CD8+ double-positive and CD4+CD8- and CD4-CD8+ single-positive subsets appears normal even in the absence of Fc epsilon RI gamma. However, alterations were noted in adult animals among the DN alpha beta TCR+ thymocytes and peripheral splenic DN T cells as well as CD8 alpha alpha + intestinal intraepithelial lymphocytes (iIEL). In contrast to conventional T lymphocytes, which do not express either Fc gamma RIII or Fc epsilon RI gamma, DN alpha beta TCR+ thymocytes and extrathymically derived alpha beta TCR+ and gamma delta TCR+ CD8 alpha alpha + beta- iIEL express TCR which incorporate Fc epsilon RI gamma as one of their subunits. Consistent with this, the TCR levels of these cells are lower than the TCR levels on cells from wild-type C57BL/6 mice. Despite the reduction in the level of surface TCR, the development of these cells was unaltered by the absence of Fc epsilon RI gamma. Thus, we observed alterations in adult DN alpha beta TCR+ thymocytes, splenic DN alpha beta TCR+ and DN gamma delta TCR+ large granular lymphocytes (LGL), and alpha beta TCR+ and gamma delta TCR+ CD8 alpha alpha+beta- iIEL, but no detectable changes in their major fetal thymic developmental pathways. Cultivation of peripheral DN alpha beta TCR+ and DN gamma delta TCR+ cells from Fc epsilon RI gamma-/- mice with interleukin-2 generates LGL which mediate natural killer activity. Unlike LGL from wild-type C57BL/6 mice, LGL from Fc epsilon RI gamma-/- mice lack Fc gamma RIII expression and could not mediate antibody-dependent cellular cytotoxicity through Fc gamma RIII.

[Mycobacterium genavense infection in AIDS]

Fever, loss of weight, anaemia, hepatosplenomegaly and lymphadenopathy developed in two HIV-infected patients. At first malignant lymphoma with septicaemia was thought to be the cause. In both patients Salmonella enteritidis was isolated by blood culture and found to be sensitive against the antibiotics that were given (5 g azlocillin and 2 g cefotaxime, three times daily each; additionally in case 2, metronidazole, 500 mg three times daily). Because bone-marrow biopsy demonstrated acid-fast rods, antimycobacterial treatment was started (isoniazid 300 mg/d, rifampicin 600 mg/d, ethambutol 1,200 mg/d and pyrazinamide 2 g/d). Despite this the patients died of septic shock. Histological examination revealed massive amounts of acid-fast rods in spleen, liver, gut and bone marrow. Polymerase chain reaction and sequencing identified the structure as that of the recently discovered M. genavense.

Ti gamma A + delta TCS1+ T cells in human thymus. Analysis of the T cell receptor

TcR1+ T cells in peripheral blood have been shown to express in an exclusive fashion either the Ti gamma A or the delta TCS1 epitope. Here, we characterize a subset of TcR1+ T cells in fresh thymus co-expressing the Ti gamma A and delta TCS1 epitopes. TcR1dim and TcR1bright clones can be distinguished. Biochemical and molecular studies on both types of clones generated from these thymocytes reveal a unique T cell receptor structure characterized by the use of a V gamma 9/C gamma 2-encoded 55-kDa gamma chain nondisulfide linked to a V delta 1-encoded delta chain.