Despite variation in studies, the predictors of pneumonia among HIV-infected children in US, India, in Sub Saharan countries, East Africa, and in Ethiopia underweight, WHO clinical staging), high viral load, cotrimoxazole preventive therapy(CPT), adherence level, anemia, low CD4 count, young age, and tuberculosis preventive therapy (TPT) were significant variables [4, 9–15], due to geographical and implementation variation additional investigation is necessary. The gene discussed is CD4; the disease is anemia (phenotype).