CD8A and autoimmune pancreatitis: Later, Umemura et al. found that serum IgG4 concentrations in Japanese patients with AIP were significantly positively correlated with the number of susceptible Fc receptor-like 3 (FCRL3) genes alleles [21] expressed on B cells in 2006 and cytotoxic T lymphocyte antigen 4 (CTLA-4) [22] expressed on CD4+ and CD8+ T cells in 2008.