ROLE OF TARGET ORGAN INFECTION WITH CYTOMEGALOVIRUS IN THE PATHOGENESIS OF GRAFT-VERSUS-HOST DISEASE

Skin and rectal biopsy tissue from 34 allogeneic and 23 autologous BMT recipients was prospectively analysed for CMV using immunohistochemis try and PCR to investigate the hypothesis that target organ infection with CMV initiates and/or exacerbates GVHD. Biopsies were obtained pri or to and at 3, 8 and 26 weeks after BMT and whenever GVHD was suspect ed, Surveillance specimens of peripheral blood leucocytes (PBL), urine and throat swabs were obtained every 2 weeks until 12 weeks after BMT , and whenever CMV was suspected. Cryostat sections were analysed immu nohistochemically for CMV antigens and PBL and biopsies for CMV DNA by PCR, Of the 31 patients who engrafted, 28 (90%) developed GVHD clinic ally, confirmed histologically in 56 biopsies. GVHD proved clinically severe in 14 patients, 4 of whom had treatment-resistant GVHD, CMV was detected in PBL more frequently in patients with severe GVHD than in those with mild/moderate GVHD (29% vs, 7%). However, in all but one pa tient the onset of GVHD preceded detection of CMV. In biopsy specimens , CMV was detected in only 2 patients, 1 of whom had an exacerbation o f GVHD temporally associated with CMV. Thus, despite a high incidence of GVHD in this series, with 56 episodes of GVHD in 28 patients, only 1 patient had CMV in biopsy tissue temporally associated with GVHD. Th is suggests that biopsy infection with CMV is not a major factor in in itiating or exacerbating GVHD in this cohort. This study thus does not support a role for target organ infection with CMV in the pathogenesi s of GVHD.