Kinetics of liver macrophages (Kupffer cells) in SIV-infected macaques.

Since the liver drains antigens from the intestinal tract, and since the intestinal tract is a major site of viral replication, we examined the dynamics of liver macrophages (Kupffer cells) throughout SIV infection. Absolute numbers of Kupffer cells increased in the livers in acute infection, and in animals with AIDS. Significantly higher percentages of proliferating (BrdU+) Kupffer cells were detected in acute infection and in AIDS with similar trends in blood monocytes. Significantly higher percentages of apoptotic (AC3+) Kupffer cells were also found in acute and AIDS stages. However, productively infected cells were not detected in liver of 41/42 animals examined, despite abundant infected cells in gut and lymph nodes of all animals. Increased rates of Kupffer cell proliferation resulting in an increase in Kupffer cells without productive infection indicate SIV infection affects Kupffer cells, but the liver does not appear to be a major site of productive viral replication.

Hematologic abnormalities associated with simian immunodeficieny virus (SIV) infection mimic those in HIV infection.

BACKGROUND: Studies of hematologic abnormalities in HIV-infected patients are confounded by a multitude of factors. A retrospective data analysis of simian immunodeficieny virus (SIV)-infected rhesus macaques (RM) of Indian origin was performed to determine the prevalence of hematologic abnormalities free of these confounds. METHODS: Hematologic data from RM inoculated with SIV and without antiviral therapy were examined pre-inoculation, and throughout infection and the development of AIDS. RESULTS: Anemia, thrombocytopenia, lymphopenia, eosinophilia, and neutropenia all increased in prevalence with SIV infection. Significant increases in prevalence for both neutropenia and neutrophilia were also detected in SIV-infected macaques. SIV-infected macaques also had lower lymphocyte counts and increased prevalence of lymphopenia compared with non-infected subjects. The prevalence of eosinophilia was significantly increased during SIV infection. CONCLUSIONS: Concordance of hematologic abnormalities during SIV infection of macaques with similar changes in HIV infection of humans suggests that, like in HIV infection, hematologic abnormalities are major complications of SIV infection.

Acute and chronic T cell dynamics in the livers of simian immunodeficiency virus-infected macaques.

The mucosal immune system, particularly the gastrointestinal tract, is critically involved in the pathogenesis of human immunodeficiency virus (HIV) infection. Since the liver drains most of the substances coming from the intestinal tract, it may also play a role in the pathogenesis of HIV infection. Here we examined the percentages and absolute numbers of T cell subsets in the liver in normal and simian immunodeficiency virus (SIV)-infected macaques. Most of the T cells in the liver were CD8(+) memory cells, and most of these had an effector memory (CD95(+) CD28(-)) phenotype. CD4(+) T cells constituted approximately 20% of the liver T cell population, but the vast majority of these were also memory (CD95(+)) CCR5(+) cells, suggesting they were potential targets for viral infection. After SIV infection, CD4(+) T cells were markedly reduced, and increased proliferation and absolute numbers of CD8(+) T cells were detected in the liver. These data suggest that the liver is a major source of antigenic stimulation for promoting CD8(+) T cells and possibly a source for early CD4(+) T cell infection and destruction.

Modification of a common BAL technique to enhance sample diagnostic value.

Bronchoalveolar lavage (BAL) by means of bronchoscopy is a diagnostic tool frequently used for clinical and research purposes in nonhuman primates. Although many institutions use this procedure, the technique is not standardized. One technical aspect that can vary is the method by which fluid is recovered. The purpose of this study was to evaluate differences between 2 different BAL aspiration techniques. Bronchoscopy and BAL fluid collection were performed on 20 rhesus macaques (Macaca mulatta). Data collected for comparison included heart rate, oxygen saturation levels, rectal temperature, volume of fluid collected, total cell count, cell viability, differential cell count, and flow cytometry. Results showed no significant differences in the heart rate, oxygen saturation, or body temperature between the 2 groups. Likewise, differential cell counts and cell viability studies of the retrieved fluid did not differ between methods. Compared with the conventional technique, the modified aspiration technique led to an 8.3% increase in overall fluid yield and a higher concentration of cells recovered. These differences are statistically significant and likely will be clinically relevant in the context of diagnosis.

Cytologic diagnosis of generalized cutaneous sporotrichosis in a hunting hound.

A 1-year-old male Foxhound/Walker Hound mix was presented to the small animal internal medicine service at Louisiana State University School of Veterinary Medicine with a 6-week history of progressive, multifocal, ulcerative and draining, well-circumscribed lesions in a generalized distribution. Prior to referral, a presumptive diagnosis was made of sterile pyogranulomatous disease; immunosuppressive therapy was instituted but resulted in clinical deterioration. At presentation, the dog had marked neutropenia (1100 neutrophils/microL), and a mild toxic left shift (400 bands/microL). Cytologic findings in the exudates from a draining skin lesion included high numbers of markedly degenerate neutrophils (about 95% of nucleated cells) as well as low numbers of macrophages, small mature lymphocytes, and eosinophils. Low numbers of intracellular (within neutrophils and macrophages) and extracellular, pleomorphic, cigar-to-ovoid shaped organisms ( approximately 3x9 microm) consistent with Sporothrix were observed. Histopathologic examination of a skin biopsy showed marked, chronic, active, ulcerative, pyogranulomatous dermatitis and panniculitis, with intralesional yeast consistent with Sporothrix sp. The etiologic agent was confirmed as Sporothrix schenckii by macerated tissue fungal culture. The patient was treated with itraconazole, enrofloxacin, and clindamycin, with clinical resolution occurring over a 3-month period. This case is a rare example of the cytologic diagnosis of Sporothrix schenckii in a canine patient. Diagnosis of canine sporotrichosis is often challenging and usually requires tissue culture, as infected dogs typically harbor very few organisms. The patient's prior immunosuppressive therapy likely contributed to higher numbers of organisms in exudates from the cutaneous lesions, facilitating cytologic diagnosis.

Congenital Pelger-Huët anomaly in a horse.

A 1.5-year-old male Arabian horse was referred to the Louisiana State University Veterinary Teaching Hospital and Clinic for an open deep laceration involving two thirds of the right trunk. The initial CBC results included an inflammatory leukogram, characterized by a marked degenerative left shift consisting of only immature band neutrophils (7500/microL, reference interval 0-100/microL) with toxic changes and no segmented neutrophils (0/microL, reference interval 2700-6700/microL). On abdominal ultrasonography, free abdominal fluid was found and collected for analysis. Abdominal fluid had a marked increase in total nucleated cells (40,600 cells/microL) consisting of 74% nondegenerate neutrophils that all were hyposegmented, with mature condensed chromatin. Re-evaluation of neutrophil morphology on the initial blood smear confirmed hyposegmentation and mature condensed chromatin, similar to that observed in cells in the abdominal fluid. A diagnosis of Pelger-Huët anomaly (PHA) was made in this colt. Congenital PHA was documented on the basis of persistent neutrophil hyposegmentation on serial blood smears, ruling out of acquired causes of PHA, and findings of similar neutrophil hyposegmentation on blood smears from the colt's sire and the sire's siblings. To our knowledge, this is the first reported case of congenital PHA in a horse.