human t - lymphotropic virus type  ( htlv- ) was first identified in humans in 1980 ( 1 ) and 1982 ( 2 ) .
a type c retrovirus , htlv- , is the causative agent of two distinct human diseases , adult t - cell leukemia ( atl ) or lymphoma , and a chronic progressive demyelinating disorder known as htlv--associated myelopathy / tropical spastic paraparesis ( ham / tsp ) ( 3 ) .
it is estimated that 10 to 20 million people worldwide are infected with htlv- ( 4 ) .
whole blood components , platelets and packed red blood cells , but not fresh frozen plasma , are sources of virus transmission ( 7 ) .
the probability of seroconversion in a recipient of contaminated blood is about 44% ( 8) .  
patients with thalassemia need infusion of four to six blood units per month and therefore the risk of blood - borne diseases caused by viruses such as htlv - i , hepatitis b virus ( hbv ) , hepatitis c virus ( hcv ) , and human immunodeficiency virus ( hiv ) increase in these patients ( 9 ) .
however , few studies on the association between htlv- infection and malignancy risk have been published ( 10 ) .
there are some case reports regarding finding htlv- in lymphoid malignancies except atl ( 11 ) .
it is still controversial whether or not htlv- infection affects the incidence of several malignancies .
found an association between htlv- and lymphoid malignancies in the dominican population ( 12 ) .
most of htlv - i - infected individuals remain asymptomatic throughout their lives and in a few subjects htlv - i - associated diseases will appear .
this infection is endemic in southern japan , the caribbean basin , central africa , central and south america , the melanesian islands in the pacific basin , and in the aboriginal population in australia ( 13 ) . in iran
, this virus has been found in isolated pockets in which htlv- infection is endemic ( khorasan , the northeastern province of iran ) .
the prevalence of htlv- infection in mashhad , khorasan was 0.77% among seeming healthy blood donors ( 14 ) .
however , we have few data about the prevalence of htlv- and htlv - ii in patients with hematological disorders and malignancies in iran . according to another reports , the prevalence of htlv - i infection in mashhad , neishbour , and sabzevar was 2.1% , 3% and 1.6% , respectively ( 15 , 16 ) .
however , the virus is less frequent in other parts of iran including urmia ( 0.34% ) in northwest and chaharmahal and bakhtiari ( 0.62% ) in southwest of iran ( 17 , 18 ) .
the aim of this study was to determine the prevalence of htlvs among patients with chronic myelogenous leukemia ( cml ) , acute lymphoblastic leukemia ( all ) , acute myelogenous leukemia ( aml ) , lymphoma , hemophilia and thalassemia , and hemophilia .
therefore , this study was conducted to detect htlv- and htlv - ii in patients with hematological disorders from isfahan province , center of iran .
in this cross - sectional study , 101 patients with confirmed hematological disorders admitted to the oncology and thalassemia unit of seyed al - shohada hospital , isfahan , iran , were enrolled during april to october 2012 .
hematological disorders were as follows ; leukemia ( 20 cases ) , lymphoma ( four cases ) , thalassemia ( 67 cases ) and hemophilia ( 10 cases ) . about 5 ml blood was collected from each patient without adding any anticoagulant .
dna was extracted from each 100 l blood serum using high pure extraction kit ( cinnapure cell dna kit , cat no .
pcr amplification was performed with two sets of primers , pol ( forward , ccctacaatccaaccagctcag ; reverse , tggagtaacttactaggttag ) for htlv- ( genbank accession no .
j02029 ) ; and tax ( forward , cgattgtgtacaggccgattg ; reverse , cctgtacaccaggcagtctgga ) for htlv- ( genbank accession no .
m10060 ) ; resulting in amplicons of 668 bp and 628 bp , respectively , according to dehee et al .
it contained 5 l dna sample , 1 l of each primer ( 10 pmol , tag copenhagen , denmark ) , 0.5 l taq dna polymerase ( 500 uta7506c cinnagen , iran ) , 2.5 l pcr buffer 10x , 1 l dntp mixture ( 10 mm , dn7603c , cinnagen , iran ) , 1 l mgcl2 ( 50 mm , tp7506c , cinnagen , iran ) and 13 l distilled water . for htlv- ,
the reaction mixture was incubated for five minutes at 95c and then subjected to 40 cycles consisting of 30 seconds at 94c , 30 seconds at 57c , and one minute at 72c , and a final extension for seven minutes at 72c in a dna thermal cycler ( corbett , research , cgi-960 , australia ) . for htlv- , the reaction mixture was incubated for five minutes at 95c and then subjected to 40 cycles consisting of 30 seconds at 94c , 30 seconds at 62c , and one minute at 72c , and a final extension for seven minutes at 72c .
genomic dna of htlv--infected cell line , tl - om1 , was used as positive control .
the pcr products were analyzed by electrophoresis on agarose gel ( 1% ) and stained with ethidium bromide .
in this cross - sectional study , 101 patients with confirmed hematological disorders admitted to the oncology and thalassemia unit of seyed al - shohada hospital , isfahan , iran , were enrolled during april to october 2012 .
hematological disorders were as follows ; leukemia ( 20 cases ) , lymphoma ( four cases ) , thalassemia ( 67 cases ) and hemophilia ( 10 cases ) . about 5 ml blood was collected from each patient without adding any anticoagulant .
dna was extracted from each 100 l blood serum using high pure extraction kit ( cinnapure cell dna kit , cat no .
pcr amplification was performed with two sets of primers , pol ( forward , ccctacaatccaaccagctcag ; reverse , tggagtaacttactaggttag ) for htlv- ( genbank accession no .
j02029 ) ; and tax ( forward , cgattgtgtacaggccgattg ; reverse , cctgtacaccaggcagtctgga ) for htlv- ( genbank accession no .
m10060 ) ; resulting in amplicons of 668 bp and 628 bp , respectively , according to dehee et al . (
it contained 5 l dna sample , 1 l of each primer ( 10 pmol , tag copenhagen , denmark ) , 0.5 l taq dna polymerase ( 500 uta7506c cinnagen , iran ) , 2.5 l pcr buffer 10x , 1 l dntp mixture ( 10 mm , dn7603c , cinnagen , iran ) , 1 l mgcl2 ( 50 mm , tp7506c , cinnagen , iran ) and 13 l distilled water .
for htlv- , the reaction mixture was incubated for five minutes at 95c and then subjected to 40 cycles consisting of 30 seconds at 94c , 30 seconds at 57c , and one minute at 72c , and a final extension for seven minutes at 72c in a dna thermal cycler ( corbett , research , cgi-960 , australia ) . for htlv- , the reaction mixture was incubated for five minutes at 95c and then subjected to 40 cycles consisting of 30 seconds at 94c , 30 seconds at 62c , and one minute at 72c , and a final extension for seven minutes at 72c .
genomic dna of htlv--infected cell line , tl - om1 , was used as positive control .
the pcr products were analyzed by electrophoresis on agarose gel ( 1% ) and stained with ethidium bromide .
of 101 patients , 67 ( 66.33% ) and 34 ( 33.66% ) were female and male , respectively . according to the type of hematological disorders , the most cases with thalassemia were in the age group of 20 - 40 years ( table 1 ) .
most of the patients with leukemia ( 20 ) were in the age group of 1 - 6 years and in hemophilic cases ( 10 ) , most of the patients were in the age group of 40 - 60 years . in the lymphoma group ( 4 ) , all of the four cases were over 12 years .
the results showed that only one male ( 0.99% ) was positive for htlv - i in patients with thalassemia . according to the results of pcr , the overall prevalence of htlv - i infection in patients with thalassemia in isfahan was 1.49% .
lane 1 , 100 bp marker ; lane 2 , positive control ( tl - oml ) ; lane 3 , negative sample ; lane 4 , positive sample ; lane 5 , negative control .
approximately 5 - 10% of htlv - i - infected individuals develop either atl or ham / tsp .
some evidences have shown that it has also been associated with other diseases such as cutaneous t cell lymphoma ( ctcl ) , htlv - i - associated arthropathy ( haap ) , graves disease , uveitis , polymyositis , chronic respiratory diseases , lymphadenitis , and dermatitis ( 20 ) .
on the other hand , htlv- and htlv - ii infections are usually chronic and untreatable diseases ; so , adequate standards of diagnosis , prevention , care and support , as well as surveillance should be provided ( 21 ) .
htlv- infection is endemic in certain parts of the world ( 22 ) as well as in a northern city of iran , mashhad ( 14 , 16 ) . in the present study
, we tried to determine the prevalence of htlv - i and htlv - ii infections in patients with hematological disorders in isfahan province , iran .
although there is no defined treatment for patients infected with htlv- and htlv - ii , the accurate knowledge of the prevalence rates in different populations may be helpful in establishing prophylactic measures to reduce the rates of viral transmission from infected individuals . htlv- and htlv - ii are cell associated and spread in cells after blood transfusion , sexual intercourse , or breastfeeding .  
patients with hematological disorders who need repeated blood transfusion are among the most high - risk groups for this infection ( 23 , 24 ) .
htlv- and htlv - ii , related to thalassemia and hemophilia by blood transfusion , have been reported in previous publications . in iran , also , there is some evidence suggesting the relatively high prevalence of the virus in these patients .
farias de carvalho et al . found a seroprevalence of 28.9% among patients with t - cell lymphoid malignancies in brazil ( 25 ) .
adedayo and shehu found a 38.6% htlv- seropositivity in all hematological malignancies in india ( 12 ) .
found an htlv-1 prevalence of 26.1% in 88 cases of non - hodgkin s lymphoma in japan ( 26 ) .
the prevalence rate of htlv- and htlv - ii infections was 18% in southern chile in patients with malignant hematological diseases , and 27% in patients with chronic lymphoproliferative disorders , as barrientos et al . reported ( 27 ) .
monavari et al . reported that the prevalence of htlv- among patients with malignant hematological diseases in tehran was 12% ( 28 ) .  
the information about htlv- and htlv - ii prevalence in different populations and patients is crucial , because it may be useful in establishing prophylactic measures to decrease the rates of viral transmissions from infected individuals .
whereas the gold standard method for the diagnosis of htlv infection is the detection of htlv genome in specimens of patients , it seems that the prevalence of htlv- infection in our study population was 0.99% .
pcr is an extremely sensitive technique , but sometimes has some limitations which lead to unexpected results . on the other hand
, the presence of antibodies does not affect the results and the few copy number of the target sequence will appear in pcr product .
negative control was the indicator of cross - contamination and the pcr product of negative control did not show any expected amplicon length . in the present study , we could not find any association between gender , age and occupation and htlv - i . in conclusion ,
our study showed that the prevalence of htlv - i infection in patients with thalassemia in isfahan was 1.49% , but none of the samples contained the genome of htlv - ii .
therefore , it is necessary to carry out a large epidemiological study in this part of iran . although the prevalence of htlv - i and htlv - ii infection among patients with hematological disorders in isfahan province compared to other regions of iran is not too high , htlv screening should be performed prior to blood transfusion to decline the risk of virus transmission in these patients .
patients with htlv- and htlv - ii infection may acquire this infection via blood transfusion , despite all of the precautions for screening the blood supply .
therefore , the present study suggests that serious consideration must be given to prevent htlv - i and htlv - ii infection via transfusion in hematological disorders .
routine serological screening for htlv - i and htlv - ii antibody and detection of htlv- and htlv - ii genome in blood donors is indicated to permit the deferral of blood product donations by asymptomatic htlv- and htlv - ii carriers .
 background : human t - cell lymphotropic virus types  and  ( htlv- and htlv - ii ) are deltaretroviruses which may cause leukemia , lymphoma and htlv - associated myelopathy / tropical spastic paraparesis ( ham / tsp ) . 
 in addition , htlv-1 may be related to thalassemia and hemophilia cases after blood transfusion.objectives:the aim of this study was evaluation of the prevalence of htlvs in patients with hematological disorders ( leukemia , thalassemia , lymphoma and hemophilia).patients and methods : this cross - sectional study was conducted during april to october 2012 . 
 a total of 101 serum samples were collected from patients and were stored at -20c . 
 dna was extracted from serum by an extraction kit . 
 the extracted dna was tested by polymerase chain reaction ( pcr ) for detection of htlv- and htlv - ii pol and tax gene sequences , respectively . 
 samples were collected from 67 ( 66.33% ) , 20 ( 19.80% ) , 4 ( 3.96% ) , and 10 ( 9.90% ) patients with thalassemia , leukemia , lymphoma and hemophilia , respectively.results:one thalassemia sample was htlv- positive , but none of the samples contained the genome of htlv - ii . 
 the prevalence of htlv- in this study in patients with hematological disorders was 0.99%.conclusions : the prevalence of htlv- in hematological disorders was similar to that of other parts of iran . 
 the present study revealed that htlv- screening should be performed before blood transfusion to reduce the risk of virus transmission in patients with hematological disorders . 
 more study should be performed to detect these viruses in blood donors . 
1. Background
2. Objectives
3. Patients and Methods
3.1. Population Study
3.2. Sampling
3.3. DNA Extraction
3.4. Polymerase Chain Reaction
4. Results
5. Discussion