An autoaggressive process against bystander tissues in HTLV-I-infected individuals: a possible pathomechanism of HAM/TSP

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a well-defined clinico-pathological entity in which the virus infection and the host immune responses are involved in the pathomechanism. It is generally agreed that the virus infection precedes the development of HAM/TSP and the infection is persistent during the course of disease. However, what plays the key role for the development of HAM/TSP remains to be elucidated. In this article, we emphasise the importance of the unique nature of HTLV-I-infected cells, which may have a potential ability to produce viral antigens outside of the blood flow, and we also review a variety of evidences supporting the following proposal. In our hypothesis, the supply of infected T cells from blood flow to central nervous system (CNS) is primary for the development of CNS lesions. Both anatomically determined hemodynamic conditions and adhesion molecule-mediated interactions between circulating infected T cells and endothelial cells may contribute to the localization of the main lesions. Following an induction of the HTLV-I antigens on the surface of infected T cells in CNS compartment, expansion of the responses of immunocompetent T cells against the viral proteins may result in CNS tissue damage which may be mediated by released cytokines. This is the first attempt to implicate a bystander damage mechanism in a human disease as an essential pathomechanism.

Identification of human T cell leukemia virus type IIb infection in the Wayu, an aboriginal population of Colombia

Human T cell leukemia virus type II (HTLV-II) is endemic in a number of native American populations and high rates of infection have also been demonstrated in intravenous drug abusers (IVDAs). Studies of virus isolates in the latter population have shown the existence of two closely related subtypes of the virus, HTLV-IIa and HTLV-IIb. To characterize the viruses present in native Americans, we analyzed by nucleotide sequence analysis the proviruses from the Wayu, an aboriginal population residing in Colombia, South America. The results showed HTLV-IIb infection in this population, and also demonstrated remarkable conservation of sequence when compared to the proviruses in IVDAs.

Benign monoclonal T cell proliferation in HTLV-I infection

A spectrum of carrier states in human T lymphotropic virus type-I (HTLV-I) infection is proposed. The suspected process of clonal selection of HTLV-I infected cells results in the spectrum of nonfatal states from polyclonal to monoclonal virus integration. This idea is based on the discovery that monoclonal proviral HTLV-I DNA was detected in the fresh peripheral blood lymphocytes from some patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a nonfatal chronic neurological disorder.

Endemic human T cell leukemia virus type II infection in southwestern US Indians involves two prototype variants of virus

Human T cell leukemia virus (HTLV) type II is endemic in certain American Indians, and high rates of infection occur in intravenous drug users (IVDUs). North American IVDUs are infected with two distinct variants, HTLV-IIa and -IIb. If IVDUs became infected as a result of interaction with members of an American Indian population, both viral forms should be demonstrable in such populations. Nucleotide sequence analysis of 630 bases of the env gene encoding the gp21 protein was done on DNA from 12 New Mexico Indians (8 Pueblo, 4 Navajo). All samples were typical subtype a or b viruses. Seven of the 8 Pueblo and 2 of 4 Navajo had subtype b; the rest had subtype a. The results are compatible with an indigenous New World origin for both subtypes of HTLV-II.

Nucleotide sequence analysis of human T cell leukemia virus, type II (HTLV-II) isolates

A study by Hall et al. (J Virol 1992;66:2456-2463; Ref. 11) has suggested the existence of two closely related molecular subtypes of HTLV-II, which were tentatively designated HTLV-IIa and HTLV-IIb. To confirm this nucleotide sequence analysis of 986 bp of the env gene region encoding the entire surface glycoprotein, gp46, and the amino terminus of the transmembrane glycoprotein, gp21, of 10 HTLV-II isolates was carried out. The results clearly established the existence of two subtypes and demonstrated a 4.3% divergence in sequence in this region. Analysis of other gene regions of the provirus, including the pol (1544 bp), gag (448 bp), and the entire LTR (743 bp) of two representative isolates of each subtype, showed a sequence divergence of 3.8 to 5.7%, with greatest divergence occurring in the LTR. In addition to single nucleotide changes, the gag regions encoding the structural protein, p19, of the HTLV-IIb isolates were also found to have a 66-bp deletion that would be expected to result in a p19 protein having a 22-amino acid deletion in the carboxy-terminus region. Attempts to exploit this to differentiate the two subtypes serologically were unsuccessful in that recombinant p19 proteins of both subtypes were found to be antigenically cross-reactive. The finding of two molecular subtypes of HTLV-II may have important implications for a better understanding of the biological and pathogenic properties of the virus, and will be useful in characterizing the viruses present in endemic foci in American Indian populations.

Synovial fluid T cells in HTLV-I positive RA

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Frequent clonal proliferation of human T-cell leukemia virus type 1 (HTLV-1)-infected T cells in HTLV-1-associated myelopathy (HAM-TSP)

Human T-cell leukemia virus type 1 (HTLV-1) integrates its proviruses into random sites in host chromosomal DNA. Random integration of the proviruses was observed in asymptomatic HTLV-1 carriers and patients with HTLV-1-associated myelopathy (HAM/TSP). However, clonal integration has been reported in patients with adult T-cell leukemia (ATL), including that in the smoldering, chronic, and acute states, indicating clonal expansion of infected cells. In this study, we found that about 20% of HAM/TSP patients and their seropositive family members harbored subpopulation(s) of clonally proliferated cells infected with HTLV-1, although they still maintained randomly infected cells as a major population. These clones were stable during examination periods of 4 months to 3 years. However, these carriers or HAM/TSP patients did not show any significant indication of ATL. This extremely high frequency of clonal expansion of HTLV-1-infected cells indicates that some clones of HTLV-1-infected cells have a tendency to proliferate more efficiently than the other population without malignant transformation.

In vivo cellular tropism of human T cell leukemia virus type II (HTLV-II)

To investigate the in vivo cellular tropism of human T cell leukemia virus type II (HTLV-II), subpopulations of fresh peripheral blood mononuclear cells from infected individuals were isolated and analyzed by polymerase chain reaction for the presence of provirus. In eight of nine patients, HTLV-II was detected exclusively in the CD8+ T lymphocyte population. In the remaining patient, provirus was also detected in CD4+ T lymphocytes. Provirus was not detected in B lymphocytes or monocytes of any patient. These results suggest that in vivo HTLV-II has a preferential, and perhaps in some cases, an exclusive tropism for CD8+ T lymphocytes. The findings contrast sharply with those on HTLV-I where there is a preferential tropism for CD4+ T lymphocytes. Although HTLV-II infection has not been consistently associated with any lymphoproliferative disorders, the results suggest that if these occur, they may be different from those known to be associated with HTLV-I.

High-performance liquid chromatography and post-column derivatization with diphenyl-1-pyrenylphosphine for fluorimetric determination of triacylglycerol hydroperoxides

Triacylglycerol monohydroperoxides (TG-mHPO) were selectively detected at the picomole levels after post-column reaction with diphenyl-1-pyrenylphosphine (DPPP). TG-mHPO were separated on two types of reserved-phase columns, an ODS column and a phenylated silica gel column, which were useful for determining TG-mHPO at their molecular species levels and their class levels, respectively. After the separation, DPPP solution was mixed with the eluent followed by reaction in a stainless-steel coil 20 m x 0.5 mm I.D. at 80 degrees C, then the fluorescence intensity of DPPP oxide was measured (lambda ex. 352 nm, lambda em. 380 nm). Using these systems, TG-mHPO were determined in the range 2-1000 pmol. The relative standard deviations were 2.3-2.8%.

Multiple isolates and characteristics of human T-cell leukemia virus type II

Human T-cell leukemia (or lymphotropic) virus type II (HTLV-II) was isolated from eight HTLV-seropositive patients, six of whom were also infected with human immunodeficiency virus, by cocultivation of peripheral blood mononuclear cells (PBMCs) with BJAB, a continuous B-cell line. Restriction endonuclease mapping of the proviruses demonstrated consistent differences among isolates, and two distinct physical map patterns were observed. The results suggest the existence of two closely related molecular subtypes of HTLV-II, which are tentatively designated HTLV-IIa and HTLV-IIb. This finding was supported by preliminary nucleotide sequence analysis of the env gene region encoding the transmembrane glycoprotein gp21, which showed consistent differences between the two proposed virus subtypes. Exploitation of differences in restriction endonuclease sites allowed polymerase chain reaction amplification to detect and differentiate the two subtypes in fresh PBMCs of HTLV-seropositive intravenous drug abusers (IVDAs). The results of these studies confirm that HTLV-II infection is the prominent HTLV infection in seropositive IVDAs and also show that infection with both subtypes occurs. The finding of genetic heterogeneity in the HTLV-II group of viruses may have important implications for studies on its role in human disease and will be useful in characterizing the viruses present in newly discovered endemic foci in New World indigenous populations.

Cell surface phenotype of in vitro proliferating lymphocytes in HTLV-I-associated myelopathy (HAM/TSP)

The in vitro proliferation of peripheral blood lymphocytes (PBLs) without any mitogenic stimulation is one of the hallmarks of human T lymphotropic virus type I (HTLV-I) infection. Recent evidence suggests a difference in the degree of the phenomenon between HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and asymptomatic HTLV-I carriers (AC). In this article, we demonstrated several alterations in the features of the in vitro transformed lymphocytes between patients with HAM/TSP (n = 16) and AC (n = 8). The percentages of total CD8+ and CD8+CD28+ cells were significantly increased in the in vitro proliferating T lymphocytes derived from the patients with HAM/TSP when compared to those from AC. HAM/TSP was segregated from AC by the high degree of the proliferation of CD8+CD28+ cells. The expression of HTLV-I-specific antigens on the cultured PBLs was detected only in the subjects which showed low CD8+CD28+/CD4+ ratio of the in vitro proliferating lymphocytes. These findings suggest that this phenomenon distinguishes HAM/TSP from AC, not only in quantity but also in quality.

Angiographic morphology of the posterior communicating artery and basilar in patients with ICA-PComA aneurysm

The relationships between the angiographic morphology of the posterior communicating artery (PComA) and the basilar artery (BA) and saccular aneurysms at the internal carotid artery (ICA)-PComA junction were evaluated in 23 patients with ICA-PComA aneurysm and 46 controls. No significant differences were found in the height of the basilar top, the dislocation and inner diameter of the BA, and the distance between the basilar top and the ICA-PComA junction. However, the angle between the PComA and C2 portion of the ICA was larger and the PComA straighter in ICA-PComA aneurysm patients. Tension in the PComA and mechanical damage to the divergent angle of the PComA are probably important factors in the development of ICA-PComA aneurysms.

Concentration of activated T lymphocytes in extracorporeal blood circulation for plasma separation

To investigate whether the proportion of activated T lymphocytes changes in an extracorporeal blood flow, we compared paired samples collected at the inlet and outlet lines of an artificial circuit for plasma separation, using a dual-immunofluorescence flow cytometric technique. In our series of materials from patients with rheumatoid arthritis or systemic lupus erythematosus, the percentages of HLA-DR-positive cells in both CD4+ (P less than 0.01, n = 6) and CD8+ (P less than 0.05, n = 10) subsets were significantly increased in the outlet lines compared with the inlet lines, suggesting that activated T lymphocytes pass through an extracorporeal blood circuit more easily than resting T lymphocytes.

Arthritis in a human T lymphotropic virus type I (HTLV-I) carrier

The case is described of a 57 year old woman with polyarthritis fulfilling the 1987 revised criteria of the American Rheumatism Association for rheumatoid arthritis, accompanied by clinical carrier state infection of HTLV-I. Anti-HTLV-I IgM antibodies were detected by western blot analysis in her synovial fluid and serum. Atypical lymphocytes with nuclear convolutions were found in synovial fluid and synovial tissue obtained from the affected knee joint, suggesting in situ activation of HTLV-I infected lymphocytes in the affected synovial compartment. The HTLV-I antigens were detected (1.2%) in short term cultured synovial fluid lymphocytes, by indirect immunofluorescence. These findings supported the possibility that HTLV-I has a role in triggering or modifying inflammation in the synovial compartment.

[Efficacy of leukocytapheresis and low-dose prednisolone treatment in a patient with HTLV-I-associated myelopathy (HAM)]

The patient, a 66-year-old woman, was admitted because of a two year history of slowly progressive gait disturbance. A diagnosis of HTLV-I-associated myelopathy (HAM) was made on the basis of the clinical and serological criteria. Although the ordinary dose of oral prednisolone (PSL) is more than 30 mg in the treatment of HAM, we treated this patient by low-dose (5-10 mg) oral PSL administration. A series of leukocytapheresis performed before the PSL treatment halted the progression of symptoms transiently. Alterations in peripheral blood lymphocyte (PBL) subpopulations and augmented autologous proliferative response of PBLs improved concurrently with the resolution of neurological symptoms after the low-dose PSL treatment. The result suggests that some cases with HAM may respond with PSL treatment in low doses.

[Accessory use of protease-inhibiting agents for disease remission in a patient with autoimmune hemolytic anemia associated with B-CLL]

Protease inhibiting agents, which have inhibitory effects on complement system, were used to treat a patient with autoimmune hemolytic anemia (AIHA) associated with B cell chronic lymphocytic leukemia (B-CLL). Although this patient had failed to respond thoroughly to prednisolone, the additional use of protease inhibitors induced a disease remission of hemolytic anemia. The result suggests that complement components are of importance in the pathogenesis of hemolysis in AIHA, and supports the accessory use of protease inhibiting agents in autoimmune hematologic diseases associated with the complement activation and hypersplenism.

Activated T lymphocytes in cerebrospinal fluid of patients with HTLV-I-associated myelopathy (HAM/TSP)

In order to detect activated T lymphocytes in the cerebrospinal fluid (CSF) of patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we studied CSF lymphocytes in untreated patients with HAM/TSP and other neurological diseases (OND). Dual-immunofluorescence staining technique was performed using fluorescence microscopy. No significant difference in the CD4+/CD8+ ratio of CSF lymphocytes was observed between HAM/TSP patients and patients with OND. However, both CD4+ and CD8+ CSF lymphocytes of HAM/TSP patients contained higher percentages of HLA-DR-positive cells than those of patients with OND (P less than 0.05), suggesting that the activated CSF T lymphocytes were composed of both CD4+ and CD8+ subsets in patients with HAM/TSP.

Type IIa hyperlipoproteinemia masquerading as cerebrotendinous xanthomatosis

We describe an adult patient with type IIa hyperlipoproteinemia, presenting with Achilles tendon xanthomas, cataracts, dementia, ataxia, pyramidal tract signs, and peripheral neuropathy, which are commonly seen in cerebrotendinous xanthomatosis (CTX). However, the diagnosis of CTX was excluded on the basis of the cholestanol level and the normal cholestanol/cholesterol ratio in his serum and tendon. The pathomechanism for some of the clinical manifestations in type IIa hyperlipoproteinemia and CTX might be caused by a common biochemical disturbance.

In vitro modulation of lymphocyte proliferation by prednisolone and interferon-alpha in patients with HTLV-I-associated myelopathy (HAM)

One of the hallmarks of human T-lymphotropic virus type I (HTLV-I) infection is the proliferation in vitro of peripheral blood lymphocytes (PBLs) in the absence of growth factors. This phenomenon, the autologous proliferative response (APR), involves spontaneous growth of HTLV-I-infected T-cells and proliferation of T-cells in response to the infected cells. We studied the modulating effect of prednisolone (PSL) and interferon-alpha (IFN) on APR of PBLs obtained from five patients with HTLV-I-associated myelopathy (HAM). APR was significantly inhibited by PSL and IFN suggesting that APR is important in the pathogenesis of HAM.