Detection of Toxoplasma Gondii DNA in Primary Intraocular B-Cell Lymphoma

Abstract

Primary intraocular lymphoma, a variant of primary central nervous system lymphoma with ocular involvement, is a large B-cell non-Hodgkin's lymphoma. Some cases of primary intraocular lymphoma have been reported to be associated with microorganisms including Epstein-Barr virus (EBV) and human herpes virus-8 (HHV-8), but not parasites. We analyzed 10 cases of primary intraocular lymphoma using microdissection and PCR. Tumor and normal cells were microdissected from ocular tissue on slides and subjected to PCR for genes from Toxoplasma gondii, EBV, and HHV-8. We detected Toxoplasma gondii, not HHV-8 or EBV, DNA in the lymphoma but not in normal cells of two cases that resembled ocular toxoplasmosis clinically. We speculate that Toxoplasma gondii may play a role in some forms of primary intraocular B-cell lymphoma.

Biopsy techniques and yields in diagnosing primary intraocular lymphoma

“…It must be stressed that time is of the essence because lymphoma cells rapidly begin to degenerate. Centrifugation of the submitted sample at 1,000 rpm and pipeting the supernatant into another tube for enzymelinked immunosorbent assay (ELISA) assay and molecular investigation (PCR for infective virus) are recommended [23][24][25][29][30][31]. The sediment in the original tube is then resuspended in 0.2-1 ml of RPMI and cytocentrifuged again.…”

“…After a 360° conjunctival incision and isolation and tying of the rectus muscles a three-port pars plana vitrectomy is performed (in addition to endolaser application in the area to be biopsied if it was not placed prior to the surgery). The vitreous specimen (dilute and undilute) is sent for cytologic and microbiologic analyses as well as cytokine (IL-10 and IL-6) levels [1,2,24,25,30,31,57]. A nearly full-thickness scleral flap is made, leaving one side attached to act as a hinge.…”

Primary Intraocular Lymphoma

“…160 Toxoplasma gondii DNA has also been found in B-cell lymphoma cells in 2 out of 10 PIOL samples, leading to speculation on the role of this organism. 181 One suggestion is that an infectious antigen driven B-cell expansion is the primary trigger, which then becomes clonal. 30 Another hypothesis poses haematological transfer of neoplastic cells from nodal and extranodal sites to ocular and central nervous system structures.…”

Molecular pathology of primary intraocular lymphoma

“…73 More recently, we reported a preliminary study on the association between Toxoplasma gondii and PIOL. 74 Although only a few cases of B-cell lymphomas are reported to be initiated by these microorganisms, the possible etiology of EBV, HHV-8, and T gondii requires further examination.…”

“…133 The detection of T gondii gene in PIOL cells of rare cases suggests that T gondii may be able to transform B cells and induce their proliferation. 74 Investigations including molecular epidemiology are under way in our laboratory.…”