Pyrimethamine treatment does not ameliorate lymphoproliferation or autoimmune disease in MRL/lpr-/- mice or in patients with autoimmune lymphoproliferative syndrome.
Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder of lymphocyte apoptosis leading to childhood onset of marked lymphadenopathy, hepatosplenomegaly, autoimmune cytopenias, and increased risk of lymphoma. Most cases are associated with heterozygous mutations in the gene encoding Fas protein. Prolonged use of immunosuppressive drugs that do ameliorate its autoimmune complications fail to consistently lessen lymphoproliferation in ALPS. A case series had described children with ALPS, whose spleens (SPL) and lymph nodes decreased in size when treated weekly with pyrimethamine and sulfadoxine; parallel in vitro studies showed only pyrimethamine to promote apoptosis. On the basis of that experience, we undertook additional in vitro lymphocyte apoptosis assays, and measured SPL weights, lymphocyte numbers, and immunophenotypes in Fas-deficient MRL/lpr-/- mice to gain further insights into the utility of combined pyrimethamine/sulfadoxine or pyrimethamine alone. Moreover, seven children with ALPS enrolled in a study of escalating dose of pyrimethamine alone given twice weekly for 12 weeks to determine if their lymphadenopathy and/or splenomegaly would diminish, as assessed by standardized computerized tomography. Neither pyrimethamine alone or with sulfadoxine in the MRL/lpr-/- mice, nor pyrimethamine alone in ALPS patients proved efficacious. We conclude that these drugs do not warrant further use empirically or as part of clinical trials in ALPS Type Ia as a lympholytic agent.
Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. koneti@nih.gov
V Koneti
VK
Rao
Kennichi C
KC
Dowdell
Janet K
JK
Dale
Faith
F
Dugan
Lesley
L
Pesnicak
Lilia L
LL
Bi
Victoria
V
Hoffmann
Scott
S
Penzak
Nilo A
NA
Avila
Thomas A
TA
Fleisher
Jennifer M
JM
Puck
Stephen E
SE
Straus
D000818:Animals; D017209:Apoptosis; D001327:Autoimmune Diseases / Q000188:drug therapy* / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D002648:Child; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D008232:Lymphoproliferative Disorders / Q000188:drug therapy* / Q000276:immunology* / Q000473:pathology; D051379:Mice; D019463:Mice, Inbred MRL lpr; D018345:Mice, Knockout; D011739:Pyrimethamine / Q000627:therapeutic use*; D013154:Spleen / Q000276:immunology / Q000473:pathology; D017211:Treatment Failure
D011739:Pyrimethamine