Occurrence of Tubuloreticular Structures and Intracisternal Paracrystalline Inclusions in Endothelial Cells of Tissue from Different Epidemiological Types of Kaposi's Sarcoma

Abstract

Biopsied tissue specimens from 40 cases of classic, atypical classic, endemic, and AIDS-associated Kaposi's sarcoma (KS) were investigated by electron microscopy. To search for ultrastructural differences between non-AIDS-associated KS and AIDS-associated KS, the occurrence of the following 2 ultrastructural abnormalities of the rough-surfaced endoplasmic reticulum in KS cells was evaluated semi-quantitatively: tubuloreticular structures (TRS) and intracisternal paracrystalline inclusions (IPI). These peculiar structures were found in 23 of the 40 KS cases. Two types of TRS could be distinguished: loose TRS (LTRS) and compact ones (CTRS). LTRS were observed in endothelial cells of tissue from all the different epidemiological types of KS. CTRS were confined to AIDS-associated KS. IPI were present in endothelial tumor cells of only 3 non-AIDS-associated KS cases. The study shows that in cells of KS tissue only CTRS, but not LTRS, are an ultrastructural marker for AIDS-associated KS.

The significance of tubuloreticular inclusions as a marker of systemic stimulation by interferons in a case of focal and segmental glomerulosclerosis associated with cytomegalovirus (CMV) infection

“…TRIs are frequently identified in patients with autoimmune diseases (SLE, DLE, chronic polymyositis, dermatomyositis, scleroderma, Sjögren's) and viral infections (HIV, hepatitis B and C) [ 2 ]. In addition, its presence has been observed in tumors, especially sarcomas (like Kaposi's) [ 5 ], other diseases (infectious mononucleosis, histiocytosis X) and renal allografts. TRIs are almost always seen in the tissues of patients with HIV/AIDS, sometimes even before the diagnosis/manifestation of the disease [ 6 ].…”

Do viruses subvert cholesterol homeostasis to induce host cubic membranes?

“…Owing to their morphological and 3D complexity, 2D TEM images typically do not adequately represent the true nature of these membrane structures. Thus, such virusinduced membrane rearrangements have been described in the literature by approximately 15 different nicknames, including 'tubulocrystalline inclusion' in HCV-infected liver [57], 'convoluted mem-branous mass' in viral St. Louis encephalitis [58] and TRS in HIV [3] and in SARS-corona virus (SARS-CoV)-infected Vero cells [41]; in recent years, the TRS has become the most common denomination for such structurally organized membrane proliferations, which have even been suggested to serve as an ultrastructural marker [3] for HIV infection.…”

“…Notably, many of the virus-induced membrane proliferations are of highly ordered three-dimensional nano-periodic structure, termed cubic membranes (Box 1). A thorough review of the literature demonstrates that basically all types of viruses (plus-, minus-single, or double-stranded RNA or DNA viruses) could potentially be associated with striking membrane modifications in the infected host cell (Table 1), which have even been considered to serve as ultrastructural markers of infection [3]. In particular, infections with plussingle-stranded RNA viruses [(+)ssRNA], which are important human pathogens, appear to be always associated with the induction of host membrane proliferations, many of which indeed represent cubic membranes or precursors thereof.…”

Diagnóstico de infección por VIH por el hallazgo incidental de alteraciones ultraestructurales en una biopsia renal: Report of one case

“…Con menos frecuencia, las ITR se han observado en dermatomiositis, polimiositis, esclerodermia, síndrome de Sjögren, vasculitis ANCA (+) o infecciones por virus B y C de la hepatitis, citomegalovirus, parvovirus B19, HTLV I y Epstein Barr 3,4,8 . También se han visualizado en trasplantes renales, miositis por cuerpos de inclusión, histiocitosis, gliomas, linfomas y sarcomas 4,9 . En una revisión de 2.472 biopsias renales se encontraron ITR en células endoteliales glomerulares en 104 (4,2%); de ellos, 81% eran portadores de LES o una infección viral 8 .…”

“…A esta nefropatía se denomina "HIVAN" (HIV associated nephropathy). En ella, las ITR se observan en 80-90% de los casos 9 . También se han encontrado con escasa frecuencia ITR en BpR de pacientes con otras glomerulopatías, como enfermedad de Berger, enfermedad de cambios mínimos (ECM) y nefropatía membranosa.…”