الفهرس 
The Immune SystemOnly 14 pages are availabe for public view
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Abstract
Astrong association has been postulated between organic acidemia and immunodeficiencies Compared to normal subjects, patients with organic acidemia have higher morbidity and mortality during infections. Good knowledge of probable defects in immune system can lead to administration of suitable broad spectrum antibiotics to reduce morbidity and mortality.
We sought to assess T-lymphocytes and natural killer cells in pediatric patients with methylmalonic (MMA) or propionic acidemia (PA). For this purpose, a cross sectional study was conducted at the genetic unit of Children’s hospital, Faculty of Medicine, Ain-Shams university where patients with diagnosed methylmalonic or propionic acidemia were enrolled consecutively.
A detailed medical history was taken including, present, developmental and family history, history of recurrent infection, site and duration of infection, history of consanguinity or sibling deaths. All patients underwent general and local examination.
Laboratory evaluation was done including: a complete blood picture and assessment of T-lymphocyte subsets (CD3+, CD4+, CD8+) and NK cells (CD56+) by flow-cytometry. Also, candida intradermal skin test was done in non lymphopenic patients to screen for T cell function. Finally, venous blood gases were assessed with measurement of the anion gap.
The enrolled patients showed that 23 patients were MMA and 7 patients were PA with a female predominance in the form of female: male ratio of 8:7. Age of studied patients ranged from 6-86 months with mean of 37.93 months and SD ± 23.20.
Our results showed that among the 30 enrolled patients, we found that chest infection was the most commonly encountered in the form of upper respiratory tract infection followed by GIT infection in the form of gastroenteritis. Five patients had history of pneumonia. None of the enrolled patients had recurrent skin infection, septicemia or recurrent herpes infection.
BCG vaccine was received by 26 (86.7 %) out of 30 enrolled patients. Out of the 26 vaccinated patients, 24 patients (92.3%) had evident BCG scar while 2 patients (7.7%) didn’t have BCG scar.
The results showed that there is relative decrease in the number of T lymphocytes among some of enrolled patients: low levels of CD3% in 4 cases and low levels of absolute CD3 counts in 14 cases; low levels of CD4% in one case and low level of absolute CD4 counts in 9 cases; low levels of CD8 % in one case and low levels of absolute CD8 counts in 8 cases with decreased level of CD4/CD8 ratio in 12 patients. Regarding NK cells, there is low levels of CD56 % in 5 cases and low level of absolute CD56 counts in 8 cases.
Candida skin test was done in 14 out of 30 enrolled patients, with induration diameters being significantly larger among MMA than PA patients, while both groups were comparable in the prevalence of positivity of the reaction.
MMA and PA were comparable in their clinical and laboratory pattern. Controlled and uncontrolled metabolic disease did not show significant differences.
We concluded that, although our patients with MMA or PA showed variable decrease in relative and absolute counts of T lymphocyte subsets and NK cells, yet they had normal candida intradermal tests.
Our study is limited by the small sample size and absence of clinical correlation of the infection pattern and the lymphocyte counts to the residual affected enzyme activity. Also, relatively short disease duration might have affected our results.
Further studies are warranted with larger sample size and long duration of follow-up to estimate the real effect of organic acidemia on the immune system whether adaptive or innate and the relation to disease duration and metabolic disease control.