A Study on the Humoral and Complement Immune System of Patients with Organic Acidemia.

Patients with organic acidemia are prone to different infections, which lead to acidosis episodes. Some studies have evaluated the status of immune system in acidotic phase in these patients, but to the best of our knowledge no study has evaluated the immune system in non-acidotic phase of the disease. In this study, thirty-one patients with organic acidemia were enrolled. For evaluation of humoral immunity, serum IgA, IgG, IgE, IgM, isohemaggltuinin titer, anti tetanus and anti diphtheria IgG were measured. For screening of complement deficiencies, serum C3, C4, and CH50 were assessed. Eleven patients had Maple Syrup Urine Disease (MSUD), 10 had methylmalonic acidemia, 5 had isovaleric acidemia, 4 had glutaric aciduria, and 1 had propionic acidemia. Serum IgM level was less than normal in 2 patients. Serum isohemagglutinin titer was less than 1:8 in 2 other patients. IgA, IgE, and IgG were within normal range for all patients. Anti tetanus and anti diphtheria IgG levels were low in two patients with MSUD. No significant relationship was found between any of the measured parameters and history of recurrent admissions, recurrent infections and the type of their diseases. Five patients had high C3 level, 4 had high C4 level, and 5 had high CH50 percentage. Totally, 10 patients had high complement level, but no remarkable connection was noted between the type of the disease and complement level. Minor insignificant deficiencies in humoral immunity in non-acidotic phase of organic acidemia were found. Some components of complement system showed increase in some patients, which might be due to decreased pH in extracellular fluid.