[Severe lymphopenia in a patient with Crohn's disease]

We report on a 25-year-old female patient with Crohn's disease and profound lymphocytopenia while receiving corticosteroids and azathioprine. Discontinuation of azathioprine only resulted in a mild increase in CD4⁺ T cell numbers; however, therapy with the TNFα inhibitor adalimumab was initiated for a clinical flare and resulted in long-lasting clinical remission and rapid normalization of the lymphocytopenia including the respective lymphocyte subsets. Lymphocytopenia is frequently observed as a side effect of immunosuppressive therapy. This case illustrates that lymphocytopenia may also occur in relation to Crohn's disease activity as an extraintestinal manifestation and may then be efficiently treated by escalation of immunosuppressive therapy.