Lymphocytes are a subset of white blood cells (WBC) that forms a framework of the immune system. They facilitate humoral and cellular immunity of the body against foreign proteins and pathogens. An increase in circulating lymphocytes (lymphocytosis) can be seen following infections such as infectious mononucleosis and pertussis, or in lymphoproliferative disorders. Lymphoproliferative disorders (LPD) are known complication of primary immunodeficiency (PID). Viruses can cause number of primary infections that leads to different complications and induces malignancies. Primary infections in infants and children are common and usually asymptomatic. Outcome of LPD is very poor. Mortality rate is approximately 75%.

Objectives: To determine the serum zinc levels in children with simple febrileseizures reporting at a tertiary care hospital of Sindh. Study Design: Cross sectional study.Place and Duration: Department of Paediatrics, Layari General Hospital Shaheed MuhtramaBenazir Bhutto Medical College from January 2015 to February 2016. Methodology: A sampleof 120 children (60 cases and 60 controls) was selected through non- probability (purposivesampling) by pre defined inclusion and exclusion criteria. 3 ml venous blood was taken from aperipheral vein. Blood was process, centrifuged and sera were used for the analysis of serumzinc. Data of cases and controls was analyzed on Statistix 10.0 software (USA). P-value of≤0.05 was considered statistically significant. Results: Age of controls and cases was notedas 13.68±8.74 and 15.75±9.11 months respectively and most common age group was 12 - 24months in the cases. Male children predominated. Means± SD serum zinc was 79.03±24.17and 62.82±14.66 in controls and cases respectively (P=0.0001). Low serum zinc was noted in66.6% of cases compared to 40% in controls (P=0.0001). Conclusion: We noted low serumzinc levels in children with febrile seizures which may provoke febrile seizures. Children with lowserum zinc levels are prone to febrile seizures.