Langerhans cell histiocytosis-clinicopathological reappraisal and human leucocyte antigen association

Summary We have examined the clinicopathological correlates of 74 patients with histologically confirmed Langerhans cell histiocytosis. Factors that influenced disease outcome included, three or more organs/systems being involved, a disease onset before the age of 2 years, the involvement of certain vital organs/systems such as liver/spleen, bone marrow and lungs, and male gender. The total number of involved organs/systems was the single most important determinant of disease outcome. Mortality rate in patients with three or more organs/systems involved, was 26%, as compared with 0% in the group with one or two organs/systems involved (χ²= 11.2, P = 0.008). There were no familial cases in our series, but we looked for a possible immunogenetic association by tissue typing 46 Caucasian sufferers and comparing the results with 117 controls. We used normal peripheral blood lymphocytes in 39 cases, Epstein-Barr virus-transformed lymphoblastoid cell lines in 12 cases, and both peripheral blood and Epstein-Barr virus-transformed lymphocytes in five cases. The HLA-B7 antigen was significantly increased in Langerhans cell histiocytosis patients (19 of 46 = 41.3%) compared with 19 of 117 (16.2%) in the control group (χ²= 11.2, relative risk = 3.6, P value after correction = 0.013). Attempt to stratify the disease into single-system or multisystem disease did not result in any significant association.