Convergent evolution of reverse transcriptase (RT) genes of human immunodeficiency virus type 1 subtypes E and B following nucleoside analogue RT inhibitor therapies.

Changes in the drug susceptibility, gene lineage, and deduced amino acid sequences of the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) subtype E following 3'-azido-3'-deoxythymidine (AZT) monotherapy or AZT-2', 3'-dideoxyinosine combination therapy were examined with sequential virus isolates from a single family. The changes were compared to those reported for HIV-1 subtype B, revealing striking similarities in selected phenotype and amino acids independent of differences in the RT backbone sequences that constantly distinguish the two subtypes. Particularly, identical amino acid substitutions were present simultaneously at four different positions (D67N, K70R, T215F, and K219Q) for high-level AZT resistance. These data suggest that HIV-1 subtypes E and B evolve convergently at the phenotypic and amino acid levels when the nucleoside analogue RT inhibitors act as selective forces.

A group of V3 sequences from human immunodeficiency virus type 1 subtype E non-syncytium-inducing, CCR5-using variants are resistant to positive selection pressure.

In a human immunodeficiency virus type 1 (HIV-1)-infected individual, immune-pressure-mediated positive selection operates to maintain the antigenic polymorphism on the gp120 third variable (V3) loop. Recently, we suggested on the basis of sequencing C2/V3 segments from an HIV-1 subtype E-infected family that a V3 sequence lineage group of the non-syncytium-inducing (NSI) variants (group 1) was relatively resistant to positive selection pressure (35). To better understand the relationship between the intensity of positive selection pressure and cell tropism of the virus, we determined the linkage between each V3 genotype and its function of directing coreceptor preference and MT2 cell tropism. The biological characterization of a panel of V3 recombinant viruses showed that all of the group 1 V3 sequences could confer an NSI/CCR5-using (NSI/R5) phenotype on HIV-1(LAI), whereas the group 2 V3 sequence, which was more positively charged than the group 1 sequence, dictated mainly a syncytium-inducing, CXCR4-using (SI/X4) phenotype. Phylogenetic analysis of C2/V3 sequences encoding group 1 or 2 V3 suggested that the variants carrying group 1 V3 are the ancestors of the intrafamilial infection and persisted in the family, while the variants carrying group 2 V3 evolved convergently from the group 1 V3 variants during disease progression in the individuals. Finally, a statistical test showed that the V3 sequence that could dictate an NSI/R5 phenotype had a synonymous substitution rate significantly higher than the nonsynonymous substitution rate. These data suggest that V3 sequences of the subtype E NSI/R5 variants are more resistant to positive selection pressure than those of the SI/X4 variants.

Clinical significance of serum soluble IL-2R levels in patients with adult T cell leukaemia (ATL) and HTLV-1 carriers.

The levels of soluble IL-2Ralpha (sIL-2Ralpha) in serum were measured in HTLV-1 carriers and ATL patients in order to evaluate their possible correlation with clinical status. Mean sIL-2R levels in ATL patients were found to be 9704 U/ml for the acute/lymphoma type, 1961 U/ml for the chronic type and 788 U/ml for the smouldering type. The level for asymptomatic HTLV-1 carriers was 475 U/ml, and 165 U/ml for healthy young adult HTLV-1- controls. The serial measurement of sIL-2R in ATL patients, healthy HTLV-1 carriers, and HTLV-1 carriers with diseases other than ATL showed a good correlation between serum levels of sIL-2R and the pathophysiological status of disease. Furthermore, an increase in the sIL-2Ralpha level in serum indicated the exacerbation of HTLV-1 infection and autoimmune diseases. The measurement of sIL-2Ralpha levels is therefore a very useful parameter for determining disease status.

Serum levels of parathyroid hormone-related protein are not elevated in patients with T-cell prolymphocytic leukemia.

T-cell prolymphocytic leukemia (T-PLL) is a rare post-thymic T-cell neoplasm which shares most clinical features with adult T-cell leukemia (ATL). We measured serum level of C-terminal parathyroid hormone-related protein (C-PTHrP) in patients with T-PLL and ATL. Serum C-PTHrP levels of eight patients with T-PLL (median 36.8 pmol/l; range 27.0-50.2 pmol/l) did not differ from those of 30 human T-lymphotropic virus type I (HTLV-I)-seronegative blood donors (median 37.0 pmol/l; range 22.6-54.0 pmol/l). The C-PTHrP levels in ten ATL patients (median 69.6 pmol/l; range 42.5-899.4 pmol/l) were significantly higher than those in healthy controls (p<0.0001) or T-PLL patients (p=0.001). We suggest that the serum level of PTHrP can provide useful information for differentiating between T-PLL and ATL.

Evolution and biological characterization of human immunodeficiency virus type 1 subtype E gp120 V3 sequences following horizontal and vertical virus transmission in a single family.

It has been suggested that immune-pressure-mediated positive selection operates to maintain the antigenic polymorphism on the third variable (V3) loop of the gp120 of human immunodeficiency virus type 1 (HIV-1). Here we present evidence, on the basis of sequencing 147 independently cloned env C2/V3 segments from a single family (father, mother, and their child), that the intensity of positive selection is related to the V3 lineage. Phylogenetic analysis and amino acid comparison of env C2/V3 and gag p17/24 regions indicated that a single HIV-1 subtype E source had infected the family. The analyses of unique env C2/V3 clones revealed that two V3 lineage groups had evolved in the parents. Group 1 was maintained with low variation in all three family members regardless of the clinical state or the length of infection, whereas group 2 was only present in symptomatic individuals and was more positively charged and diverse than group 1. Only virus isolates carrying the group 2 V3 sequences infected and induced syncytia in MT2 cells, a transformed CD4(+)-T-cell line. A statistically significant excess of nonsynonymous substitutions versus synonymous substitutions was demonstrated only for the group 2 V3 region. The data suggest that HIV-1 variants, possessing the more homogeneous group 1 V3 element and exhibiting the non-syncytium-inducing phenotype, persist in infected individuals independent of clinical status and appear to be more resistant to positive selection pressure.

CD4(+) cytotoxic T-cell clones specific for bcr-abl b3a2 fusion peptide augment colony formation by chronic myelogenous leukemia cells in a b3a2-specific and HLA-DR-restricted manner.

Although it is well known that CD8(+) cytotoxic T lymphocytes (CTLs) play an important role in the suppression of cancer cell growth, the significance of CD4(+) CTLs in resistance to cancer is obscure. In an attempt to elucidate the role of CD4(+) CTLs in immunosurveillance of chronic myelogenous leukemia (CML), we examined the immunologic functions of bcr-abl b3a2 fusion peptide-specific CD4(+) CTL clones. Seven CD4(+) T-cell clones that responded to stimulation with b3a2 peptide, but not with b2a2 peptide or physiological counterparts bcr b3b4 and abl 1A-a2 peptides, were established from two healthy individuals. Restriction elements of these clones were HLA-DRB1*0901. These CD4(+) T-cell clones exhibited b3a2 peptide-specific and HLA-DRB1*0901-restricted cytotoxicity and produced interleukin-3 (IL-3), IL-4, IL-10, interferon-gamma, tumor necrosis factor-alpha, and granulocyte-macrophage colony-stimulating factor in response to bcr-abl peptide stimulation, indicating they were Th0 clones. The numbers of HLA-DRB1*0901-positive b3a2, but not those of b2a2-positive or HLA-DRB1*0901-negative CML cell colonies increased when CML cells were cultured with b3a2-specific CD4(+) CTL clones. These data suggest that bcr-abl-specific CD4(+) CTLs recognize CML cells in an antigen-specific and HLA-DR-restricted manner, and that they do not inhibit, but in fact augment, CML cell growth.

[A comparative study of cefepime for chronic respiratory tract infections].

The clinical efficacy, safety and usefulness of Cefepime (CFPM), a new cephem antibiotics, in chronic respiratory infections were evaluated in a comparative study against Ceftazidime (CAZ). Each drug was administered by intravenous drip infusion at a dose of 1.0 g (nominal potency), twice daily for 14 days, and the following results were obtained: 1. A total of 170 cases were enrolled in this study. Efficacy rates ("good" or better responses) as evaluated by the subcommittee were 86.2% (56/65) in the CFPM group and 84.5% (60/71) in the CAZ group, with no significant difference between the two groups. 2. Efficacy rates ("good" or better responses) as evaluated by attending physicians were 83.3% (55/66) in the CFPM group and 84.5% (60/71) in the CAZ group with no significant difference between the two groups. 3. Bacteriologically, eradication rates were 83.3% (40/48) in the CFPM group and 88.2% (45/51) in the CAZ group, with no significant difference between the two groups. 4. Side effects occurred in none of the patients in the CAZ group and in 4 of the 66 patients in the CFPM group. There was a significant difference between the two groups (Fisher's test p = 0.0489). The incidence of abnormal laboratory findings were 17.6% (12/68) in the CFPM group and 21.1% (16/76) in the CAZ group. There was no significant difference between the two groups. 5. The utility rates evaluated by the subcommittee were 81.8% (54/66) in the CFPM group and 84.5% (60/71) in the CAZ group with no significant difference between the two groups. Only in the incidence of side effects, there was a significant difference between the two groups (Fisher's test p = 0.0489), but there was no significant difference in other items of efficacy, safety and usefulness between the two groups. These results indicate that CFPM is useful for the treatment of chronic respiratory tract infections.

Pseudothrombocytopenia and IgA-related platelet agglutinin in a patient with IgA nephritis.

A 41-year-old female was evaluated for asymptomatic proteinuria and thrombocytopenia. The renal biopsy disclosed mild to moderate mesangial proliferation, and the immunohistology showed granular deposition of dominant IgA and C3 in the mesangium, which is consistent with IgA nephritis. Thrombocytopenia was EDTA-dependent pseudothrombocytopenia type 1. Heparinized blood restored the platelet count to normal. Serological examinations revealed that the platelet agglutinin was IgA, and the platelet clumping required both EDTA and IgA-related agglutinin. Thus, the present case adds the combination of IgA nephritis and pseudothrombocytopenia to the spectrum of the so-called thromborenal syndrome. In view of recent findings that platelet agglutinins belong to immunoglobulins or fractions, occurring frequently in a variety of immunologically abnormal situations, IgA-related agglutinin as seen in this patient may have more than a chance association with IgA nephritis.