Pulmonary intravascular lymphoma.

Intravascular lymphoma (IVL) is a rare form of non-Hodgkin lymphoma characterized by proliferation of malignant lymphoid cells limited to the lumen of small vessels. Clinical manifestations are nonspecific and result from vascular obliteration and hypoxia. The disease affects primarily the skin and central nervous system, often associated with rapid systemic dissemination and aggressive clinical course if appropriate therapy is not initiated early. Involvement of the lungs, kidneys, adrenal glands, and prostate may occur. Primary pulmonary IVL is exceedingly rare. We describe a case of primary pulmonary IVL in an HIV-positive man presenting with nonspecific constitutional symptoms. High-resolution computed tomography demonstrated centrilobular nodules with ground-glass attenuation and peribronchial ground-glass opacities. The diagnosis was confirmed by thoracoscopic biopsy and histologic findings consisted of accumulation of malignant lymphocytes within alveolar capillaries, pulmonary veins, and peribronchial arterioles. Immunohistochemistry confirmed positivity for CD20, a marker for B lymphocytes. Combined systemic chemotherapy including rituximab was started and resulted in significant clinical and radiologic improvement with long-term disease-free survival.

Pneumocystis jiroveci pneumonia prophylaxis is not required with a CD4+ T-cell count < 200 cells/microl when viral replication is suppressed.

OBJECTIVE: To determine the safety of discontinuing Pneumocystis jiroveci pneumonia (PCP) prophylaxis, in patients on effective antiretroviral therapy with CD4+ T-cell counts that have plateaued at < 200 cells/microl. METHODS: We prospectively evaluated a cohort of HIV infected patients at a multidisciplinary HIV clinic with sustained HIV RNA levels < 50 copies/ml and CD4+ T-cell counts that have plateaued at < 200 cells/microl and who have discontinued PCP prophylaxis. RESULTS: Nineteen patients fulfilled the above criteria. Eleven had been taking daily trimethoprim-sulfamethoxazole, seven were receiving monthly aerosolized pentamidine, and one patient never received any prophylaxis. The median CD4+ T-cell count at the time of discontinuation and at the most recent determination were 120 (range, 34-184) and 138 (range, 6-201) cells/microl, respectively. To date, patients have been off PCP prophylaxis for a mean of 13.7 +/- 10.6 months and a median of 9.0 (range 3-39) months for a total of 261 patient-months. To date, no patient has developed PCP. This is significantly different from the risk of developing PCP with a CD4+ T-cell count of < 200 cells/microl in untreated HIV infection (rate difference 9.2%; 95% confidence interval, 5.7 to 12.8%; P < 0.05). CONCLUSION: With sustained suppression of viral replication, PCP prophylaxis may not be necessary, regardless of CD4+ T-cell count. This illustrates a degree of immune recovery that occurs with virologic suppression that is not reflected in absolute CD4+ T-cell count or percentage and suggests that guidelines for P. jiroveci pneumonia prophylaxis may need to be re-evaluated.

Pulmonary hyalinizing granuloma in HIV/AIDS.

A 55-year-old man who was recently diagnosed with HIV/AIDS developed multiple bilateral pulmonary nodules after starting highly active antiretroviral therapy. Workup confirmed the diagnosis of pulmonary hyalinizing granuloma. This is the first described case of pulmonary hyalinizing granuloma in HIV/AIDS, and may represent a rare form of immune reconstitution inflammatory syndrome.

Update on HIV lipodystrophy.

When prescribed appropriately and taken adherently, antiretroviral therapy can consistently and durably suppress HIV replication, potentially translating into years of near normal health for HIV-infected persons. However, presently available antiretrovirals are associated with a cluster of physical and metabolic symptoms termed HIV lipodystrophy. This article reviews the state of knowledge about the pathogenesis and treatment of the various manifestations of these adverse effects.

Virological evaluation of the 'Ottawa case' indicates no evidence for HIV-1 superinfection.

An HIV-1 infected man who experienced rapid disease progression and poor response to therapy after starting a new sexual relationship with an infected partner is known as the 'Ottawa superinfection case'. Subsequent analysis of viral sequences of protease, reverse transcriptase, Gag p17, and Env V3 provided no evidence for the acquisition of genetically divergent viruses before disease progression or drug resistance during virological failure of combination therapy. Whether HIV-1 superinfection contributes to disease progression or the spread of drug-resistant HIV-1 remains unknown.

Normalization of natural killer cell function and phenotype with effective anti-HIV therapy and the role of IL-10.

OBJECTIVES: Natural killer (NK) cell function is likely to be important in controlling HIV infection and opportunistic pathogens. We therefore evaluated NK function and phenotype over the course of antiretroviral therapy (ART) and examined the potential mechanisms of altered NK activity in HIV infection. METHODS: We measured NK cell percentage, NK cytolytic activity (both by flow cytometry) and plasma IL-10 concentrations (by enzyme-linked immunosorbent assay) in 10 HIV-seropositive patients before and over one year of effective ART. To examine potential mechanisms of altered NK activity, we measured NK receptor expression in ART treated and untreated HIV-positive individuals by flow cytometry. As IL-10 enhances NK activity, we studied the effect of IL-10 on NK receptor expression and activity in peripheral blood mononuclear cells (PBMC) from HIV-seronegative individuals. RESULTS: NK cytolytic activity was elevated in HIV infection and decreased with ART to levels observed in HIV-negative individuals. A greater proportion of NK cells from untreated HIV-positive individuals expressed the NK receptors CD158a and CD161 than either HIV-negative volunteers or effectively treated HIV-positive patients. NK cells from PBMC incubated with IL-10 demonstrated increases in CD158a, CD161 and CD94 expression and increases in cytolytic activity. The treatment-associated decrease in NK activity paralleled a decrease in IL-10 production. CONCLUSION: The observation that IL-10 alters NK receptor expression similar to that observed in HIV infection, and the fact that NK receptor expression and activity normalize in parallel with ART-induced reduction of circulating IL-10 levels supports a role for IL-10 in NK cell activity and HIV immunopathogenesis.