primary infection known as chickenpox , mostly occurs in childhood , with mild clinical course in immunocompetent hosts , but it can cause significant morbidity in healthy adults with life threatening forms in immunocompromised persons .
vzv establishes latency in sensory ganglia , and can be reactivated years later as herpes zoster .
circulating vzv - specific antibody can prevent primary infection but innate and cellular responses are more important in its severity and duration ( 2 ) .
clinical studies suggest that t cell immunity plays a key role in the protection against vzv primary infection .
few studies found significant depression of cd4 + t lymphocytes , augmentation of cd8 + t - lymphocytes and changes in cd4/cd8 ratio but none of them were compared to clinical course of illness ( 3 , 4 ) .
we performed a prospective clinical study which included 69 immunocompetent persons with confirmed chickenpox in a period july 2014 - january 2016 .
patients were divided into two groups : group with mild clinical presentation who were treated as outpatients , and group with moderate , severe or life - threatening clinical presentation which were hospitalized .
study also included 30 healthy volunteers with age and sex similar to the other groups .
we checked general characteristics such as age , sex , complications , clinical course of illness , percentage values of cd4 + , cd8 + t - lymphocytes and cd4/cd8 ratio .
values for cd4 + , cd8 + t - lymphocyte percentage and cd4/cd8 ratio was obtained using facs canto , bd biosciences flow cytometer and bd multitest 6-color tbnk immunofluorescent test .
values with normal distribution were expressed as meanstandard deviation . to compare mean values for variables without normal distribution chi - square test was used .
one - way anova test was used for statistical evaluation of more than three groups .
correlation of monitored variables is determined by pearsons test . to determine influence of these variables to a clinical presentation we used logical regression ( backward method ) .
p - values less than 0.05 were considered statistically significant . clinical presentation of the illness cd4 + percentage values in the groups cd8 + percentage values for all groups cd4/cd8 ratio values for the groups
mean age in outpatient group was 28.47 years with standard deviation ( sd ) 10.3 while in the other group was 24.57 ( sd=14.14 ) , with no statistically significant difference between groups ( p>0.05 ) .
females were dominant in outpatients group ( 65%:35% ) , while males were in higher number in other group ( 71%:29% ) .
chi - squared test found statistically significant difference between these two groups ( p<0.05 ) .
the number of complications vary from zero to four per patient , and all were presented in a hospitalized patients .
mean value of cd4 + percentage for outpatient group was 44.06 ( sd 11.48 ) and for a group of hospitalised patients it was 28.20 ( sd=12.70 ) .
one - way anova test found statistically significant difference between group of hospitalised patients and outpatients , as well as hospitalised patients and control group ( p<0.0001 ) .
values for percentage of cd8 + t - lymphocytes were as follows : outpatients 30.15 ( sd=9.46 ) ; hospitalised patients 38.34 ( sd=15.52 ) ; control group 28.40 ( sd=7.34 ) .
one - way anova test found statistically significant difference between group of hospitalised patients and outpatients , as well as hospitalised patients and control group ( p<0.0001 ) .
cd4/cd8 ratio was 1.74 ( 0.40 - 8.10 ) in group of outpatients , 1.05 ( 0.10 - 3.60 ) in group of hospitalised patients and 1.73 ( 0.80 - 3.70 ) in a control group .
one - way anova test found statistically significant difference between group of hospitalised patients and outpatients , as well as hospitalised patients and control group ( p=0.006 ) .
using pearson s correlation factor we have found very strong negative correlation between cd4 + percentage value and clinical presentation ( r=0.61 , p<0.0001 ) ; strong positive correlation between cd8 + percentage value and clinical picture and also weak negative correlation between cd4/cd8 ratio and clinical presentation .
in addition we performed regression analysis to determine which of mentioned parameters have the strongest influence to clinical presentation .
values of cd4 + percentage have a very strong influence as a prognostic factor to clinical presentation and possible severity of clinical picture ( beta coefficient = 0.56 , p<0.0001 ) .
results of our study correlate with other studies regarding age and sex of the patients , where most of the them with complications were males , age 21 - 40 , primary because of preexisting medical conditions ( 5 ) .
several studies suggest that cellular immunity has a key role in control of vzv primary infection ( 6 , 7 ) .
patients with primary agamagloblinaemia develop mild clinical form , while patients with deficiency of cellular immunity develop severe and life - threatening forms of chickenpox ( 8) .
so far , there is no prognostic marker for a severity of clinical picture and outcome of the disease , which can be measured in short time and predict further development of the illness . in our study
we tried to investigate if values of cd4 + and cd8 + t - lymphocytes percentage , so as cd4/cd8 ratio , can be considered as relevant prognostic factors for clinical course of chickenpox .
we measured values of these parameters from blood samples taken from the patients in acute phase of disease , 24 - 72h after development of the rash , and correlate with presented complications and severity of clinical picture .
values of cd4 + t - lymphocytes mostly decrease in acute phase of all viral infection , so as vzv , with recovery during the time . for significant number of diseases
it can be strong prognostic factor for possible coinfections and complications in clinical course ( 3 , 9 , 10 ) . in our study decrease of cd4
+ percentage was very significant , compared to the group with mild clinical form and control group .
also cd8 + percentage value increased in acute phase of illness among hospitalized patients with presented complications .
early studies suggest similar dynamic of these subsets of t - lymphocytes ( 11 ) .
significant difference between these patients and outpatients , so as control group , was confirmed with anova test .
cd4/cd8 ratio is very important in follow - up of some viral diseases and other medical conditions ( 12 , 13 ) .
we found significant decrease in values of cd4/cd8 in hospitalized patients , while values in group of outpatients and controls were almost the same .
further comparison using regression analysis found values of cd4 + percentage of t - lymphocytes as a strong predictive factor for clinical course of the disease .
also values of cd8 + t - lymphocyte percentage were in a strong correlation with clinical pictures .
according to the results of our study , we can consider values of cd4 + and cd8 + t - lymphocyte subsets as strong predictive factor for a clinical course of chickenpox in immunocompetent patients .
values of cd4 + t - lymphocytes have the strongest influence , while cd4/cd8 ratio stays as a prognostic factor , but not so strong like in other viral diseases , such as hiv .
 objective : to investigate possible prognostic values of cd4 + , cd8 + t - lymphocytes , cd4/cd8 ratio to clinical course of chickenpox in immunocompetent hosts.materials and methods : we performed a prospective study which included 69 immunocompetent patients with chickenpox who were addmited to clinic for infectious disease , clinical center university of sarajevo , in a 18 month period . 
 all patients were divided into two groups depending on clinical presentation on admission . 
 patients with mild clinical form were dedicated to  outpatient  
 group , and patients with moderate , severe or life - threatening clinical forms were dedicated to  hospitalized  group . also 30 healthy volunteers are included in study as a control group . 
 we analyzed values of cd4 + , cd8 + percentage , cd4/cd8 ratio with comparison to clinical course of chickenpox . 
 all specimens were taken in acute phase of illness.results:values of cd4 + percentage were significantly declined in a group of hospitalized patients , compared to group of outpatients and control group . 
 values of cd8 + percentage were higher in a group of hospitalized patients , while cd4/cd8 values were lower in comparison to a group of outpatients and control group.conclusion:we found significant correlation between these parameters and clinical course of chickenpox . 
1. INTRODUCTION
2. MATERIALS AND METHODS
3. RESULTS
4. DISCUSSION
5. CONCLUSION