Orchitis: a rare complication of infectious mononucleosis

Epstein-Barr virus-associated infectious mononucleosis with acute epididymitis: a case report

Background

Infectious mononucleosis due to the Epstein–Barr virus is an infectious disease that causes the appearance of atypical lymphocytes in the peripheral blood; it mainly presents with fever, tonsillar pharyngitis, and lymphadenopathy. In addition to hepatitis, splenomegaly, and rashes, it can involve different organs. Here, a case of epididymitis as a rare complication in a patient with Epstein–Barr virus-associated infectious mononucleosis was reported.

Case presentation

A healthy 23-year-old man visited an outpatient clinic with fever and pharyngitis. Tonsillar pharyngitis, lymphadenopathy, atypical lymphocytes in the peripheral blood, liver dysfunction, and splenomegaly were observed. The patient was diagnosed with infectious mononucleosis based on clinical signs. The next day, the patient developed left testicular pain and was immediately transferred to the emergency outpatient ward. Pain, redness, and swelling were observed in the left scrotum. Ultrasonography revealed swelling of the epididymis and increased blood flow, and the patient was hospitalized with a diagnosis of left epididymitis. The patient’s symptoms improved with symptomatic treatment and was discharged on day 16 after admission. Changes in antibody titers established a definitive diagnosis of infectious mononucleosis caused by the Epstein–Barr virus. Based on the disease course, the patient was also diagnosed with infectious mononucleosis associated with unilateral epididymitis.

Conclusions

This is the first case report of Epstein–Barr virus-associated infectious mononucleosis complicated with acute epididymitis. Infectious mononucleosis can cause numerous organ-related complications; thus, physicians and healthcare workers should remain cognizant of Epstein–Barr virus-associated complications throughout the body and not just in the primary organs affected by infectious mononucleosis.

Immunophenotype and TCR-Vbeta repertoire of peripheral blood T-cells in acute infectious mononucleosis

Although a number of studies on the phenotypic changes that occur after T-cell activation have already been published, the specific immunophenotypic features of T-lymphocytes and the frequency at which TCR-variable region (TCR-V) restricted T-cell expansions occur "in vivo" during acute viral infection still remains to be established. We report on the immunophenotype and TCR-V repertoire of peripheral blood T-cells from 28 patients with acute infectious mononucleosis. Immunophenotypic studies were performed by flow cytometry using direct immunofluorescence techniques and stain-and-then-lyse sample preparation protocols with three- and four-colour combinations of monoclonal antibodies directed against a large panel of T- and NK-cell associated markers, activation- and adhesion-related molecules and TCR-Vbeta, -Vgamma and -Vdelta families. Nearly all patients (27/28) showed a massive expansion of CD8(+)/TCRalphabeta(+) T cells, the majority (>90%) of which displayed an immunophenotype compatible with T-cell activation: CD2(+high), CD7(+low), CD11a(+high), CD38(+high), HLA-DR(+high), CD28(+/-low), CD45RO(+high), CD45RA(-/+low), CD11b(-/+low), CD11c(+/-low), CD16(-), CD56(-), CD57(-), CD62L(-), CD94(-), CD158a(-), CD161(-), NKB1(-). Additionally, the levels of both CD3 and CD5 were slightly decreased compared to those found in normal individuals. Late-activation antigens, such as CD57, were found in small proportions of CD8(+)/TCRalphabeta(+) T-cells. Increased numbers of CD4(+)/TCRalphabeta(+) T-cells, TCRgammadelta(+) T-cells and NK-cells were also noticed in 17, 16 and 13 of the 28 cases studied, respectively. Evidence for activation of CD4(+)/TCRalphabeta(+) and TCRgammadelta(+) T-cells relied on changes similar to those described for CD8(+)/TCRalphabeta(+) although less pronounced, except for higher levels of both CD5 and CD28 in the absence of reactivity for CD11c on CD4(+)/TCRalphabeta(+) T-cells and higher levels of CD161 and CD94 on TCRgammadelta(+) T-cells. Small expansions of one or more TCR-Vbeta families accounting for 12 +/- 7% of either the CD8(+)/TCRalphabeta(+) or the CD4(+)/TCRalphabeta(+) T-cell compartment were found in 12 of 14 patients studied, whereas the distribution of the TCR-Vgamma and -Vdelta repertoires tested in 2 of the individuals with expanded TCRgammadelta(+) T-cells was similar to that observed in control individuals. The results presented here provide evidence for an extensive T-cell activation during acute viral infection and establish the immunophenotype patterns associated with this condition.