Persistent infection of human lymphoid and myeloid cell lines with herpes simplex virus.

Herpes simplex virus (HSV) type 1 replicated and persisted in human T, B, and myeloid cell lines with different patterns of viral replication and various effects on cell growth. T cell line CEM supported the replication of HSV for over 400 days without detectable differences in cell growth as compared with uninfected cells. HSV persisted in B cell line NC37 and myeloid cell line K562 for up to 222 and 374 days, respectively, but led to a significant decrease in the number of viable cells by 7 weeks of infection. The average number of cells producing infectious virus was very low in these cell lines (range, 0.5 to 2.7+) compared with a larger proportion of cells exhibiting HSV antigens by immunofluorescence (range, 24 to 58%). In contrast, null cell line LAZ 221 failed to replicate HSV even though the viral infection led to a cessation of cell growth.     

DNA microarray analysis reveals novel gene expression profiles in collagen-induced arthritis

Global gene expression was analyzed in early and late collagen-induced arthritis (CIA). Of 8734 cDNAs analyzed, 330 were induced and 55 downregulated greater than twofold in early or late disease. Hierarchical clustering of these 385 cDNAs demonstrated five distinct expression patterns differentiating early from late disease and correlating with histopathologic changes in the paw. Of the 385 cDNAs, 185 are known, characterized genes, the majority of which are not described as playing a role in arthritis. However, several of these genes are involved in pathological processes relating to arthritis, including apoptosis, inflammation, and cellular proliferation. One interesting gene, follistatin-like gene, is highly expressed along the margin of contact between inflammatory synovial pannus and eroding bone, suggesting a role in joint destruction. These results demonstrate that global gene expression profiles distinguish early and late CIA and reveal several genes novel to arthritis the further characterization of which will advance our understanding of arthritis.     

What can natural infection of African monkeys with simian immunodeficiency virus tell us about the pathogenesis of AIDS?

The simian immunodeficiency viruses are a diverse group of viruses that naturally infect a wide range of African primates, including chimpanzees, African green monkeys (AGM) and sooty mangabey monkeys (SM). Although natural infection is widespread in feral populations of AGMs and SMs, this infection does not result in immunodeficiency. However, experimental inoculation of Asian macaque species results in an immunodeficiency syndrome that is remarkably similar in pathogenesis to human AIDS. Thus, SIVsm infection of macaques results in AIDS, and similarly experimental inoculation of pigtailed macaques with at least one SIVagm isolate, SIVIhoest or SIVsun, results in AIDS. The extent of plasma viremia in pathogenic infection is an excellent prognostic indicator of clinical course, with higher viral load being predictive of shorter survival and low viremia being predictive of long-term non-progression. Based upon this paradigm, one would have expected naturally infected animals to exhibit low levels of viremia. In reality, AGMs, SMs, mandrills and chimpanzees infected naturally with their own unique viruses display moderate to high levels of plasma viremia. A significant reduction in CD4+ T-cells in infected versus uninfected SMs suggests that the virus may be cytopathic to some degree. These infected animals still maintain adequate CD4+ T-cells over their entire life in captivity. A distinct characteristic of natural infection is the lack of immunopathology as demonstrated by normal lymph node morphology, lower expression of activation and proliferation markers on CD4+ T-cells, and a generally muted immune response to the virus. Naturally infected SMs and AGMs clearly mount antiviral cellular and humoral immune responses. Therefore, models suggesting immune tolerance to SIV are far too simplistic to explain the lack of disease in these animals. It is probable that a unique balance between T-cell renewal and proliferation and loss through activation-induced apoptosis, and virus-induced cell death has been achieved in SMs and AGMs. The study of the dynamics of T-cell production, proliferation and cell death in asymptomatic natural infection should, therefore, yield insights into the pathogenesis of AIDS.     

Local production of IgA- and IgM-rheumatoid factors in adult periodontal disease

The enzyme-linked immunospot assay was used to enumerate both the number and the frequency of spontaneous IgG, IgA, and IgM immunoglobulin-secreting cells and IgA- and IgM-rheumatoid factor (RF)-producing cells present in the gingivae and peripheral blood of adult periodontitis patients. Cells from 29 patients were incubated on plates coated with human IgG, Fc, or F(ab)₂ fragments and on plates coated with class-specific antihuman antibodies and secreted antibodies were subsequently visualized by means of an immunoenzymatic procedure. The data indicate that (1) IgA-RF- and IgM-RF-secreting cells are frequently present in the gingiva of adult periodontitis patients; (2) production of RF in gingivae of adult periodontitis patients occurs in the absence of demonstrable RF production by simultaneously obtained peripheral blood mononuclear cells, suggesting that local autoimmune reactions may occur in this disease; and (3) lack of correlation between IgA-RF and IgM-RF production in diseased gingiva suggests that the two RF isotypes are regulated independently of each other.     

A novel point mutation (I137T) in the conserved 5-phosphoribosyl-1-pyrophosphate binding motif of hypoxanthine-guanine phosphoribosyltransferase (HPRTJerusalem) in a variant of Lesch-Nyhan syndrome

We identified a novel point mutation (I137T) in the hypoxanthine-guanine phosphoribosyltransferase (HPRT; EC 2.4.2.8) encoding gene, in a patient with partial deficiency of the enzyme (variant of Lesch-Nyhan syndrome). The mutation, ATT to ACT, resulting in substitution of isoleucine to threonine, occurred at codon 137 (exon 6), which is within the region encoding the binding site for 5-phosphoribosyl-1-pyrophosphate (PRPP). We suggest the mechanism by which the mutation-induced structural alteration of HPRT reduced the affinity of the enzyme for PRPP.     

Sputum Cytokine Levels in Patients with Pulmonary Tuberculosis as Early Markers of Mycobacterial Clearance

Sputum and serum from patients with active pulmonary tuberculosis (TB), healthy purified protein derivative-positive adults, and patients with bacterial pneumonia were collected to simultaneously assess local immunity in the lungs and peripheral blood. To determine whether cytokine profiles in sputum from TB patients and control subjects were a reflection of its cellular composition, cytospin slides were prepared in parallel and assessed for the presence of relative proportions of epithelial cells, neutrophils, macrophages, and T cells. Gamma interferon (IFN-γ) in sputum from TB patients was markedly elevated over levels for both control groups. With anti-TB therapy, IFN-γ levels in sputum from TB patients decreased rapidly and by week 4 of treatment were comparable to those in sputum from controls. Further, IFN-γ levels in sputum closely followed mycobacterial clearance. Although detected at fourfold-lower levels, IFN-γ immunoreactivities in serum followed kinetics in sputum. TNF-α, interleukin 8 (IL-8) and IL-6 also were readily detected in sputum from TB patients at baseline and responded to anti-TB therapy. In contrast to IFN-γ, however, TNF-α and IL-8 levels also were elevated in sputum from pneumonia controls. These data indicate that sputum cytokines correlate with disease activity during active TB of the lung and may serve as potential early markers for sputum conversion and response to anti-TB therapy.     

Vidarabine versus acyclovir therapy in herpes simplex encephalitis

We randomly assigned 208 patients who underwent brain biopsy for presumptive herpes simplex encephalitis to receive either vidarabine (15 mg per kilogram of body weight per day) or acyclovir (30 mg per kilogram per day) for 10 days. Sixty-nine patients (33 percent) had biopsy-proved disease; 37 received vidarabine, and 32 acyclovir. The mortality in the vidarabine recipients was 54 percent, as compared with 28 percent in the acyclovir recipients (P = 0.008). Six-month mortality varied according to the Glasgow coma score at the onset of therapy. For scores of greater than 10, 7 to 10, and less than or equal to 6, mortality was 42, 46, and 67 percent in the patients treated with vidarabine, as compared with 0, 25, and 25 percent in those treated with acyclovir. A six-month morbidity assessment using an adapted scoring system revealed that 5 of 37 patients receiving vidarabine (14 percent) as compared with 12 of 32 receiving acyclovir (38 percent) were functioning normally (P = 0.021). Eight vidarabine-treated patients (22 percent) and three acyclovir-treated patients (9 percent) had moderate debility. Patients under 30 years of age and with a Glasgow coma score above 10 had the best outcome with acyclovir treatment. We conclude that acyclovir is currently the treatment of choice for biopsy-proved herpes simplex encephalitis.     

Comparison of Directigen Group A Strep Test with a traditional culture technique for detection of group A beta-hemolytic streptococci.

The Directigen Group A Strep Test (DGAST), a new rapid method of detecting group A beta-hemolytic streptococci directly from throat swabs, was compared with a traditional culture technique for the detection of group A beta-hemolytic streptococci. Five hundred oropharyngeal swabs from pediatric and adult patients were cultured and then processed by using the DGAST. Of the 144 specimens positive by culture, 131 were DGAST positive (sensitivity, 90.9%). Of the 356 specimens negative by culture, 353 were DGAST negative (specificity, 99.2%). Twelve of the 13 false-negative DGAST results were from pediatric patients. One hundred isolates of non-group A beta-hemolytic streptococci were recovered, primarily groups C, F, and G. The DGAST is easy to perform, rapid, sensitive, and very specific for detection of group A beta-hemolytic streptococci directly from swabs. Supplementing the DGAST with a culture on a 5% sheep blood agar plate would enhance detection of group A beta-hemolytic streptococci, especially in pediatric patients.     

Effect of limited access to sucrose on overeating and patterns of feeding

Four groups of adult rats, housed on a 12-12, light-dark cycle, were allowed access to a nutritionally complete diet and water. Three of these groups were also offered a 32% solution of sucrose. The sucrose was available for either the 24-hour period, the 12 hours of light or the 12 hours of dark. Access to sucrose led to overeating and excessive weight gain. These effects were more pronounced when the sucrose was available for the 24-hour period or during the dark. Limited access to sucrose produced a reversal of the rat's usual circadian pattern of feeding when the sucrose was available during the light and increased the rat's nocturnal hyperphagia when it was available during the dark. Sucrose intake and the proportion of calories taken from sucrose were higher in the 24-hour access group and the dark access group than the light access group. Access to sucrose did not induce a pattern of dietary selection that compromised growth or health. It appears that access to a palatable carbohydrate solution can lead to overeating and major changes in the circadian organization of feeding behavior. These data emphasize the potent role that external factors can play in the control of ingestive behavior.