Abstract
BACKGROUND: An elevated CD4/CD8 T-cell ratio on flow cytometry (FCM) analysis has been reported in the literature to be associated with Hodgkin lymphoma (HL). The purpose of our study was to determine the diagnostic significance of an elevated CD4/CD8 ratio in lymph node fine needle aspiration (FNA) specimens. DESIGN: Between 1996 and 2002, out of 837 lymph node FNAs submitted for flow cytometry analysis, 85 cases showed an elevated CD4/CD8 ratio, defined as greater than or equal to 4, without definitive evidence of a lymphoproliferative disorder. The cytologic diagnoses of these 85 cases were grouped into four categories: reactive, atypical, Hodgkin lymphoma (HL), and non-Hodgkin lymphoma (NHL). Histologic follow-up was available in 17/85 (20%) of the cases. RESULTS: 5 of the 64 cases in which FCM and cytology did not reveal evidence of a lymphoproliferative disease had tissue follow-up because of persistent lymphadenopathy and high clinical suspicion. 3/5 (60%) confirmed the diagnosis of reactive lymphadenopathy. The two remaining cases (40%) were positive for lymphoma (1HL, 1NHL). 8/15 cases called atypical on cytology had histologic follow-up. 7/8 (87.5%) cases were positive for lymphoma (3HL, 4NHL). 3/4 cases called HL on cytology had tissue follow-up and all 3 (100%) confirmed the diagnosis of HL. One case diagnosed as NHL on cytology was found to be a diffuse large B-cell lymphoma. In summary, out of 17 cases with histologic follow-up 4/17 (24%) were reactive with CD4/CD8 T-cell ratio of 4.1-29, 7/17 (41%) were HLs with CD4/CD8 T-cell ratio of 5.3-11, and 6/17 (35%) were NHLs with CD4/CD8 T-cell ratio of 4.2-14. CONCLUSION: An elevated CD4/CD8 ratio on FCM is a nonspecific finding which may be seen in both reactive and lymphoproliferative disorders. The cytomorphologic features of the smear are more relevant than the sole flow cytometric finding of an elevated CD4/CD8 ratio.