Cytomegalovirus colitis in a patient treated with efalizumab.

Discussion Efalizumab is a recombinant humanized monoclonal antibody used for chronic plaque psoriasis refractory to other systemic treatments (methotrexate, ciclosporin, PUVA therapy). The most frequent efalizumab side effects are influenza syndrome, infections, pruritus and arthritis [1–4] . Malignancies are not increased in patients treated with efalizumab [5] . A study of the clinical trial experience shows that efalizumab is not associated with an increased risk for infection, and 1.1% of efalizumab-treated patients are hospitalized for severe infections [6] . However, a recent case of visceral leishmaniasis infection has been reported underscoring that visceral leishmaniasis should be taken into account during efalizumab treatment, at least for patients living in endemic areas [7] . A disseminated eruptive giant molluscum contagiosum has been reported recently under efalizumab treatment too [8] . Watery diarrhea, tenesmus, hematochezia and abdominal pain are present in CMV colitis. The diagnosis is based on histological examination of colic biopsy, positive CMV antigen and high CMV IgM titer in peripheral blood samples, as in our patient. Reactivation of CMV was considered since CMV serology had been positive for IgG and negative for IgM at the beginning of the hospitalization. During the second week of infection, the IgM level was positive at 1.60 IU ml –1 . Moreover, the level of IgG anti-CMV avidity was high ( 1 0.95) which is in favor of an infection being present for more than 3 months. Fast improvement with systemic gancyclovir is another criterion for the diagnosis of CMV colitis. In Gottlieb et al. [9] , CMV seroconversion in 51 patients treated with efalizumab has been evaluated. Subjects with negative CMV IgM serology at the beginning remained negative at the end of the study. We report the first case of CMV colitis in a patient treated with efalizumab. In patients treated with efalizumab, diarrheas are reported (6% of patients) but poorly documented [4] . The incidence of CMV infection may be underestimated. Differential diagnoses such as Salmonella, Shigella, Clostridium or cryptococcal infections have been eliminated with stool cultures. Colonoscopy with biopsy should be proposed to patients who complain of persistent or recurring diarrhea. Efalizumab is a specific antibody to the CD11a of lymphocyte function-associated antigen type 1 (LFA-1). Infections are induced by altered function of T-cell lymphocytes, blocking LFA-1 (a cell adhesion molecule) on T cells, and this is not associated with lymphocyte depletion [6] . T cells play a decisive role rather than B cells in CMV infection. On the surface of CMV-infected cells, there is an upregulation of ICAM-1. LFA-1 is the ligand of ICAM-1 on leukocytes, which accompany lymphocyte activation