December 2008 no white pages.indd ABSTRACT Atypical lymphocytosis due to infections is classically seen in viral and chronic bacterial infections. A four year old boy with acute streptococcal infection presented at Al-Nahdha Hospital, Muscat, Oman, with follicular tonsillitis and bilateral cervical lymphadenitis. The blood film showed 33% atypical lymphocytes. Serologically, immunoglobulin M (IgM) antibodies were positive for cytomegalovirus, herpes simplex virus, and Epstein Barr virus, but the patient responded dramatically to antibiotics. Key words: Atypical lymphocytes; Acute streptococcal infection; Lymphnode; Case report; Oman. An Unusual Case of Atypical Lymphocytosis *Suresh Venugopal, Jessy George, Salima S Al-Harthy SULTAN QABOOS UNIVERSITY MEDICAL JOURNAL NOVEMBER 2008, VOLUME 8, ISSUE 3, P. 353-355 SULTAN QABOOS UNIVERSITY© SUBMITTED - 31ST MARCH 2008 ACCEPTED - 18TH AUGUST 2008 Department of Laboratory, Al-Nahdha Hospital, Muscat, Sultanate of Oman *To whom correspondence should be addressed. Email: sure5155@omantel.net.om فاوِيَّات الال منطية مْ اللِّ ثْرَةُ لكَ اعتيادية غير حالة احلارثي سالم سليمة جورج، جسي فينوجوبال، سوريش أربع عمره ولد حالة هنا ندرج املزمنة. واجلرثومية الفيروسية االلتهابات في يالحظ ما عادة االلتهابات النمطية بسبب الال فاوِيَّات اللِّمْ ثْرَةُ كَ ملخص: الفحص أظهر لقد في اجلهتني. العنقية يَّة فِ اللِّمْ دِ قَ والْتِهابُ العُ اللوزتني في التهاب هيئة على ظهرت والتي يَّات دِ قْ بالعِ حاد بالتهاب مصاب سنوات ، وفيروس الَيا للخَ مُ خِّ ُضَ امل ــروسُ ي للفَ إيجابيا (M) املناعي اجللوبيولني أضداد كان .33% ــة الال منطي ــبة الكريات الليمفاوية نس أن ــريحة لش اهري احليوية. للمضادات كبير املريض بشكل استجاب هذا ومع بار إيبِشتاين- البَسيط ، وفَيروسُ رْبِسٌ الهِ عمان. ، حالة تقرير ، الليمفاوية الغدة احلاد ، يَّات دِ قْ العِ التهاب ، منطية الال الكلمات: اخلاليا الليمفاوية مفتاح Acute bacterial infections usually produce neutrophilic leucocytosis. Chronic bacte-rial and viral infections typically cause lym- phocytosis. However, acute streptococcal infections can lead to atypical lymphocytosis as well as elicit false positive viral antibody results. C A S E R E P O R T A 4 year old boy from Barka, Oman, came to the Ear, Nose and Throat (ENT) Department of Al-Nahdha Hospital, Muscat, Oman, on 4 November 2007 com- plaining of fever and difficulty in swallowing for the last 4 days. On clinical examination, both the tonsils were huge and studded with follicles. There were bi- lateral cervical lymphnodes, each measuring 7cm x 6cm, tender, soft and hot. The clinical diagnosis enter- tained was follicular tonsillitis with bilateral cervical lymphadenitis. The patient was immediately admitted to the ENT. A complete blood count (CBC) on admis- sion showed Hb = 11.5 g/dl. The total white blood cell count (WBC) count = 7.6 x 109/L and the platelet count = 237x109/L, which was normal, but the eryth- rocyte sedimentation rate (ESR) was 15 mm at 1 hour, which was mildly above the normal range of 10 mm at 1 hour. A sample sent for blood culture subsequently revealed no growth. The throat culture grew normal flora, but the swab showed gram positive cocci. The CBC was repeated 3 days later on 7 November and showed Hb = 10 g/dl; total WBC count = 14.7x109/L and platelet count = 141x109/L. A differential WBC count showed 33% atypical lymphocytes. We advised that a monospot test be done and the clinicians put the patient on a course of intravenous augmentin. The same day (7 November), the monospot test results were negative. We immediately requested an Epstein Barr virus (EBV) immunoglobulin M (IgM) antibody test and a TORCH (toxoplasmosis, other agents, ru- bella, cytomegalovirus, herpes simplex) test. Next day, the CMV (cytomegalo virus) IgM came out positive. We requested a polymerase chain reaction (PCR) test to detect CMV DNA. On 9 November, the herpes sim- plex IgM test came out positive. On 10th November, C A S E R E P O R T S U R E S H VE N U G O PA L , J E S S Y G E O R G E A N D S A L I M A S A L - H A R T H Y 354 the EBV IgM antibody test also came out positive. Clinically, the patient was afebrile, the lymphnode en- largement on both the sides had vanished, and he had responded very well to antibiotics. He was discharged on the same day. The PCR test result arrived on 12 November and did not detect any CMV DNA in the plasma. But an antistreptolysin O (ASO) titre done on the sample was increased and measured 400 IU. The boy came for a follow up in December 2007. Clinically and haematologically (CBC, differential WBC count and ESR) he was absolutely normal. D I S C U S S I O N This 4 year old boy had an acute onset of fever and dys- phagia. The dysphagia was due to the severe enlarge- ment of both the tonsils. Contributing to the above was bilateral, tender, soft and hot cervical lymph node swellings. His tonsils were studded with follicles and tender soft and hot. A diagnosis of lymphadenopathy fitted well with an acute bacterial infective pathology. Sensing the severity of the condition, the boy was ad- mitted to the hospital. The throat swab revealed many gram positive cocci, but the throat swab culture grew normal flora and the blood culture did not reveal any growth. This could be explained by the fact that this pa- tient was referred from Barka and was already on oral antibiotic treatment. It is well known that a prior anti- biotic treatment can lead to no growth on culture.1 The CBC repeated 2 days later on the automated haematology analyzers revealed mild anaemia, leuco- cytosis and mild thrombocytopenia. A blood film was prepared. The most striking feature on this film was the presence of numerous atypical lymphocytes with deep basophilic cytoplasm and large, round to oval to indented to irregular nuclei. No blasts were seen [Fig- ure 1]. A differential count revealed 16% neutrophils, 51% lymphocytes and 33% atypical lymphocytes. A diagnosis of atypical lymphocytosis was made. Viral infections are one of the commonest causes of lym- phocytosis and atypical lymphocytosis.2 Such a large percentage of atypical lymphocytes made the labora- tory entertain the diagnosis of viral infection. We advised a monospot test to rule out infectious mononucleosis, but the clinicians thought and acted otherwise. They were sure that it was an acute bacte- rial infection and put the patient on a course of intra- venous augmentin. To our surprise, the subsequent monospot test re- sult came out negative. We immediately requested an EBV antibody test to increase the specificity of the test and also asked for a TORCH test. Unlike the clinicians, we were pursuing the viral etiology. When CMV IgM antibody test came out positive, the laboratory enter- tained the diagnosis of cervical lymphadenitis due to acute CMV infection and requested a blood PCR test to detect CMV DNA. The next day, the herpes simplex virus IgM anti- body test came positive. We were puzzled. A day later when EBV IgM antibody also came positive for this patient, we were confused. A diagnostic dilemma set in. Was the patient suffering from cytomegalovirus in- fection or a herpes simplex virus infection or an EBV infection? We turned our attention to the patient in the ward. We were amazed to see the patient afebrile, with ton- sillar and lymphnode enlargement having disappeared, playing in the toy room and ready for discharge. After 7 days of antibiotic treatment, the sick looking boy was perfectly normal. The experience and expertise of the clinicians had won the case. The laborious laboratory scientists looked lost. The PCR test result arrived two days after the patient’s dis- charge and did not reveal CMV DNA in the plasma, confirming that the patient did not have CMV infec- tion. Did he have herpes simplex or EBV infection? Facilities for doing a PCR test for herpes simplex and EBV were not available. Fortunately, one of our scien- tists had done an ASO titre on this patient and it was increased and measured 400 IU. An ASO titre of >166 Todd units is seen in 80% of children with streptococ- cal pharyngitis.³ By now, things were getting clearer. We analysed the case comprehensively. Here was a patient who pre- Figure 1: Blood smear showing atypical lymphocytes A N U N U S UA L C A S E O F AT Y P I C A L LY M P H O C Y T O S I S 355 sented acutely with fever, swollen, follicle studded ton- sils and enlarged bilateral tender, soft and hot cervical lymphnodes. The throat swab had showed numerous gram positive cocci. The ASO titre was increased and the patient dramatically and completely responded to antibiotics. Taking into consideration, the presenting symptoms and signs, the laboratory data and clinical response, the diagnosis was crystal clear. The patient suffered from an acute streptococcal infection. However, two features demanded explanation. One was the high percentage of atypical lymphocytes in an acute bacterial infection and the second was the CMV IgM, herpes simplex IgM and EBV IgM, all positive in a patient with acute streptococcal infection. Lym- phocytosis often occurs in young children in response to infections which produce a neutrophil reaction in adults.4 This explains the lymphocytosis and atypical lymphocytes seen in our case with acute streptococcal infection which typically produces a neutrophilic leu- cocytosis in adults. However, it is worthwhile noting that according to the literature, lymphocytosis is usu- ally rare during such acute bacterial infections except in pertussis.5 The rarity and paucity of literature on this subject prompted the publication of this report. It is well documented in the literature that in response to stress, lymphocytes that are characterised by nu- clear and cytoplasmic distortion appear in the blood.5 Thus, another explanation for atypical lymphocytosis in this child could be the stress caused by dysphagia. False positive CMV IgM can be due to cross-reactions between infections caused by closely related viruses like the acute EBV infection. The CMV IgM axsym assay shows a lack of specificity in acute EBV infec- tion hence precautions must be taken when CMV IgM results are interpreted.6 The above mentioned pub- lished fact, plus the absence of CMV DNA in plasma in this patient, proves that the CMV IgM result was false positive. Acute herpes simplex virus infections typically produce pharyngitis and stomatitis and very rarely lead to such huge bilateral tonsillar enlarge- ment. Failure of a patient with suspected streptococ- cal throat infection to improve within 48 hours should evoke suspicion of infectious mononucleosis, 7 but our patient responded very well to antibiotics thus ruling out a primary infection by EBV. Thus in this patient with acute upper respiratory and lymphnode inflammation due to streptococci, well known for its immunological warfare, and taking into consideration the entire clinical, pathological and therapeutic scenario, IgM antibodies to CMV, HSV and EBV were false positive. C O N C L U S I O N Haematologically, a large number of atypical lym- phocytes can be seen in the blood film of a patient with severe, acute upper respiratory streptococcal in- fection. Immunologically, false positive IgM antibod- ies to CMV, HSV and EBV can be observed in patients with such severe acute streptococcal infections. R E F E R E N C E S 1. Mims CA, Playfair JHL, Roitt IM, Wakelin D, Williams R, Anderson RM, Medical Microbiology, Part 1. Lon- don: Mosby, 1993. 2. Hoffbrand AV, Catovsky D, Tuddenham EGD. Post- graduate Hematology, 5th ed. Oxford: Blackwell, 2005. 3. Behrman RE, Vaughan VC. Nelson Test book of Pedi- atrics, 12th ed. Philadelphia: WB Saunders Company, 1983. 4. Hoffbrand AV, Pettit JE, Moss PAH. Essential Hematol- ogy, 4th ed. Oxford: Blackwell, 2001. 5. Lee GR, Foerster J, Lukens J, Paraskevas F, Greer JP, Rodgers GM. Wintrobe’s Clinical Hematology, 10th ed. Philadelphia: Lippincott, Williams & Wilkins, 1999.. 6. Deyi YM, Goubau P, Bodeus M. False positive IgM an- tibody tests for Cytomgalovirus in patients with acute Epstein-Barr virus infections. Eur J Clin Microbiol In- fect Dis, 2000; 19:557-560. 7. Behrman RE,Vaughan VC. Nelson Test book of Pediat- rics, 12th ed. Philadelphia: WB Saunders Company,