[Autoimmune lymphoproliferative syndrome: a case report and literature review]

We described 1 case of autoimmune lymphoproliferative syndrome (ALPS), first diagnosed in our hospital, and reviewed the recent literature. The 11-month old male patient presented with a history of splenomegaly and hepatomegaly since 1 month after birth. He suffered recurrent infectious diseases including cytomegalovirus infection, parvovirus B19 infection and chronic diarrhea disease. Besides, his symptoms included hemolytic anemia and thrombocytopenia. The laboratory abnormality indicated an expanded population of alpha/beta double-negative T cells (DNTs) (27.18% of lymphocytes, 35.16% of CD3+ T lymphocytes) in peripheral blood, and autoantibodies including antinuclear antibody, double-stranded DNA and rheumatic factor were positive. Hyper gamma globulinemia and positive direct Coombs tests were seen in the patient. His parents were both healthy and denied autoimmune diseases. We identified a heterozygous point mutation in exon 3 of the FAS gene carrying c.309 A>C, resulting in a single base pair substitution in exon 3 of FAS gene which changed the codon of Arg103 to Ser103. Unfortunately, we were unable to obtain the gene results of the child's parents. The patient was treated with glucocorticoids in our hospital and with mycophenolatemofetil in other hospital. And we were informed that his anemia condition relieved through the telephone follow-up, but he still suffered recurrent infections, hepatomegaly and splenomegaly still existed. As we all know ALPS is characterized by defective lymphocyte apoptosis, and thus cause lymphoproliferative disease and autoimmune disease, and increase the risk of lymphoma. It is more likely to be misdiagnosed as other diseases. ALPS should be suspected in the case of chronic lymphadenopathy, splenomegaly and autoimmune features. Flow cytometry approach is helpful for the diagnosis. Immunosuppressive drugs are the necessary treatment.