levoleucovorin and Severe-Combined-Immunodeficiency

In the folate cycle MTHFD1, encoded by MTHFD1, is a trifunctional enzyme containing 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase activity. To date, only one patient with MTHFD1 deficiency, presenting with hyperhomocysteinemia, megaloblastic anaemia, hemolytic uremic syndrome (HUS) and severe combined immunodeficiency, has been identified (Watkins et al J Med Genet 48:590-2, 2011). We now describe four additional patients from two different families. The second patient presented with hyperhomocysteinemia, megaloblastic anaemia, HUS, microangiopathy and retinopathy; all except the retinopathy resolved after treatment with hydroxocobalamin, betaine and folinic acid. The third patient developed megaloblastic anaemia, infection, autoimmune disease and moderate liver fibrosis but not hyperhomocysteinemia, and was successfully treated with a regime that included and was eventually reduced to folic acid. The other two, elder siblings of the third patient, died at 9 weeks of age with megaloblastic anaemia, infection and severe acidosis and had MTFHD1 deficiency diagnosed retrospectively. We identified a missense mutation (c.806C > T, p.Thr296Ile) and a splice site mutation (c.1674G > A) leading to exon skipping in the second patient, while the other three harboured a missense mutation (c.146C > T, p.Ser49Phe) and a premature stop mutation (c.673G > T, p.Glu225*), all of which were novel. Patient fibroblast studies revealed severely reduced methionine formation from [(14)C]-formate, which did not increase in cobalamin supplemented culture medium but was responsive to folic and folinic acid. These additional cases increase the clinical spectrum of this intriguing defect, provide in vitro evidence of disturbed methionine synthesis and substantiate the effectiveness of folic or folinic acid treatment.

Topics: Anemia, Megaloblastic; Cells, Cultured; Fatal Outcome; Female; Folic Acid; Folic Acid Deficiency; Humans; Hyperhomocysteinemia; Infant; Infant, Newborn; Leucovorin; Male; Methylenetetrahydrofolate Dehydrogenase (NADP); Minor Histocompatibility Antigens; Severe Combined Immunodeficiency; Young Adult

Hereditary folate malabsorption is a rare inborn error of metabolism due to mutations in the proton-coupled folate transporter (PCFT). Clinical presentation of PCFT deficiency may mimic severe combined immune deficiency (SCID). We report a 4-month-old female who presented with failure to thrive, normocytic anemia, Pneumocystis jirovecii pneumonia and systemic cytomegalovirus infection. Immunological evaluation revealed hypogammaglobulinemia, absent antibody responses, and lack of mitogen-induced lymphocyte proliferative responses. However, the absolute number and distribution of lymphocyte subsets, including naïve T cells and recent thymic emigrants, were normal, arguing against primary SCID. Serum and cerebrospinal fluid folate levels were undetectable. A homozygous 1082-1G>A mutation of the PCFT gene was found, resulting in skipping of exon 3. Parenteral folinic acid repletion resulted in normalization of anemia, humoral and cellular immunity, and full clinical recovery. PCFT mutations should be considered in infants with SCID-like phenotype, as the immunodeficiency is reversible with parenteral folinic acid repletion.

Topics: Base Sequence; DNA; Female; Flow Cytometry; Folic Acid; Genetic Variation; Humans; Immunophenotyping; Infant; Intestinal Absorption; Leucovorin; Male; Membrane Transport Proteins; Point Mutation; Polymerase Chain Reaction; Proton-Coupled Folate Transporter; Severe Combined Immunodeficiency; T-Lymphocytes

The therapeutic effect of antibodies raised by the immunogen Gastrimmune was compared with both a CCKB/gastrin receptor antagonist, CI-988, and 5-Fluorouracil/leucovorin in a gastric cancer model. The human gastric ascites cell line, MGLVA1asc, produced and secreted progastrin and glycine-extended gastrin as determined by radioimmunoassay and immunocytochemistry. Cells were also stained with an antiserum directed against the human CCKB/gastrin receptor. MGLVAI asc cells were injected i.p. into SCID mice. Antibodies raised by Gastrimmune immunization of rabbits (affinity for G17 of 0.15 nM and GlyG17 of 0.47 nM) were passively infused i.p. and significantly enhanced survival by up to 5 days (p=0.0024 from vehicle controls). The enhancement in survival was not significantly different from that achieved by treatment with 5-Fluorouracil and leucovorin. A CCKB/gastrin receptor antagonist, CI-988, did not affect survival with cells injected at 7.5 x 10(5) cells/mouse but significantly increased the survival of mice injected with a lower cell innoculum of 5 x 10(5) cells/mouse from 30 to 35 days (p=0.0186). At this lower innoculum antibodies raised by Gastrimmune induced complete survival in 2 animals with the remaining dead by day 36 (p=0.0022). Thus, both endocrine and autocrine pathways mediated by precursor and mature gastrin molecules may be jointly operational in the gastric cancer scenario and may be important targets for therapeutic agents.

Topics: Animals; Antibodies, Monoclonal; Antineoplastic Combined Chemotherapy Protocols; Ascites; Cancer Vaccines; Diphtheria Toxoid; Fluorouracil; Gastrins; Humans; Leucovorin; Mice; Mice, SCID; Severe Combined Immunodeficiency; Stomach Neoplasms; Tumor Cells, Cultured