ivated phosphoinositide 3-kinase δ syndrome 1 (APDS1) is a primary immunodeficiency disease caused by gain-of-function mutations in

PIK3CD

. Clinical features of autoimmune disease have been reported in patients with APDS1. In this study

we reported three patients with APDS1 presenting with systemic lupus erythematosus (SLE) phenotype. The clinical manifestations included recurrent respiratory tract infection

lymphoproliferation

Coombs-positive hemolytic anemia

decreased complement fractions

positive antinuclear antibodies

renal complications related to SLE associated diseases

which met the clinical spectrum of APDS1 and the classification criteria of SLE. The immunological phenotype included an inversion in the CD4:CD8 ratio

an increase in both non-circulating Tfh CD4

+

memory T and circulating Tfh populations

a low level of recent thymic emigrant T cells

overexpression of CD57 on T cells

and a decrease in B cells with fewer antibody class switch recombination. These phenotypes detected in patients with APDS1 presenting with SLE were resemble that in patients with APDS1 presenting without SLE. Meanwhile

we described the effect of glucocorticoids and rapamycin therapy on patients with APDS1. The phosphorylation of S6 at Ser235/236 was inhibited in patients with APDS1 who underwent glucocorticoids therapy

including two who presented with SLE phenotype. The phosphorylation of AKT at Ser473 and phosphorylation of S6 at Ser235/236 were inhibited in other patients with APDS1 who underwent rapamycin therapy. Here

we showed the coexistence of immunodeficiency and SLE phenotype in APDS1

and the inhibition of rapamycin in activated Akt-mTOR signaling pathway.