Model of Cellular and Humoral Immunity (IMAGE) Tokyo Medical and Dental University Caption This slide illustrates a model of cellular and humoral immunity regarding SAP. In normal individuals, SAP+ CD8+ T cells attack EBV-infected B cells via IFN-gamma, perforin, and granzyme, and EBV-infected B cells lead to cell death. SAP+ CD4+ T cells help immunoglobulin production from B cells via IL-10 and ICOS. In XLP1 patients, the SAP function is completely impaired, and the patients develop FIM or HLH and hypo- or dysgammglobulinemia. In XLP1 patients with somatic reversion, as demonstrated in this study, small populations of SAP+ T cells can rescue the function. The patients were not associated with FIM or HLH, and they presented with IgG3 and IgG4 deficiency only. Credit Department of Child Health and Development,TMDU Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.