Recurrent toxoplasma chorioretinitis in a patient with a selective deficiency of NKT cells and CD8+ cytotoxic T lymphocytes associated with a genetic deficiency of the folate cycle. Case report

Abstract

This article describes a case study of recurrent Toxoplasma chorioretinitis in a young patient with cell immunodeficiency. Patient K., 37 years old, was admitted to ophthalmologist with complaints of decreased visual acuity and discomfort in the left eye. The history of the disease evidenced  that he had suffered at least 2 episodes of acute posterior uveitis in the past without finding out the etiological factor. Ophthalmological examination revealed an old scar on the retina of the right eye and signs of acute vitreous and chorioretinitis around the old scar on the retina of the left eye. By applying the method of paired sera, it was possible to establish the etiological factor of ophthalmic lesions — Toxoplasma gondii. Assessment of immune status demonstrated selective deficiency of CD8+ cytotoxic T lymphocytes and NKT cells. Obvious causes of secondary immunosuppression, including HIV, were ruled out. The Genetic Panel «Primary Immunodeficiencies» with sequencing of more than 400 genes of known primary human immunodeficiencies did not reveal pathology. However, persistent hyperhomocysteinemia was noted, and a genetic test for folate deficiency was performed. MTHFR A1298C in the heterozygous state and MTRR A66G in the homozygous state were detected, which was associated with the detected cell immunodeficiency, taking into account the results of studies on immune status in folic acid metabolism disorders and reports of severe opportunistic infections in humans with genetic deficiency of folate cycle. Treatment included spiramycin at a dose of 3 million IU orally three times a day for 14 consecutive days (to inhibit Toxoplasma), recombinant human a2b interferon at a dose of 3 million IU i/m every other day at night №15 (to compensate for the deficiency of NKT cells and CD8+ cytotoxic T lymphocytes), oxodihydroacridinylacetate sodium 2 mL i/m every other day at night №15, alternating with interferon (to compensate for the deficiency of NKT cells and CD8+ cytotoxic T lymphocytes) and local peribulbar injections of betamethasone № 3 (to eliminate the inflammation in the left eye). Improvement in visual acuity was observed on day 8 of treatment, and recovery of left eye function was observed at the end of the month of therapy. Due to the additional three‑month courses of recombinant human alpha2b‑interferon to compensate cell immunodeficiency, which were carried out during the next 2 years of  follow‑up, it was possible to prevent further recurrence of toxoplasma invasion.