Abstract: Objective To investigate the pathological changes and pathogeneses of spleen in severe acute respiratory syndrome(SARS) with immunohistochemical observation and quantitative analysis of the expressions of interleukin6 (IL-6)，interferon β (IFN-β) and IFN-γ inducible protein10 (IP-10). Methods Three specific antibodies were used to detect the expression of IL-6，IFN-β and IP-10 in the spleens of six cases who died of SARS and six normal cases as the controls with immunohistochemistry. The results were analyzed with image analysis system. Results In the splenic red pulp of SARS patients, lots of cells expressed IL-6 averagely, as bolus in cytoplasm and nucleus, and compared with normal cases, average absorbance (AEM>A/EM>) in IL-6 positive cells had significant difference (EM>P/EM><0.05). The IFN-β positive cells dispersed in splenic red pulp of SARS patients, yellow bolus was in cytoplasm and nucleus, compared with normal cases, AEM>A/EM> in IFN-β positive cells had significant difference (EM>P/EM><0.05). There were lots of IP-10 positive cells in splenic red pulp of SARS patients, the positive productions as bolus were in cytoplasm and nucleus, and compared with normal cases, AEM>A/EM> in IP-10 positive cells had significant difference (EM>P/EM><0.05). In the relic splenic corpuscle and periarterial lymphatic sheath, immunostainings of these three cytokines were all negative. Conclusion Immunohistochemical intensities of IL-6, IFN-β and IP-10 in spleen of SARS patient

Key words: Severe acute respiratory syndrome (SARS), Interleukin-6, Interferon-β, IFN-γ inducible protein-10, Spleen, Immunohistochemistry, Human