340 Archives ofDisease in Childhood 1996; 74: 340-342 Severe combined immunodeficiency (SCID) associated neutropenia: a lesson from Arch Dis Child: first published as 10.1136/adc.74.4.340 on 1 April 1996. Downloaded from monozygotic twins

Tim Niehues, Klaus Schwarz, Marion Schneider, Horst Schroten, Elisabeth Schr6der, Volker Stephan, Volker Wahn

Abstract non-genetic aetiology and requires specific A case of severe combined immuno- initial management. deficiency (SCID) in monozygotic twin sisters was detected at 3 months of age with neutropenia in one twin and a normal Case reports differential count in the other. The CASE 1 neutropenic twin, suffering from severe Twin I was referred to our clinic at the age of skin ulcers, was successfully treated with 3 months with a history of fever, diarrhoea, granulocyte colony stimulating factor (G- and deep skin ulcerations; Pseudomonas CSF). Discordant occurrence of neutro- aeruginosa and enterococci were detectable on penia in identical twins shows that there culture. After an apparently normal pregnancy may be a non-genetic cause for the the girl and her twin sister (case 2) had been neutropenia in SCID. Suppression of born to healthy, consanguineous Turkish myelopoiesis was probably induced by parents. A 2 year old sister is healthy. On activated maternal T cells. The neutro- admission twin 1 was in a good general condi- penia in this case may thus be classified as tion with a weight of 5500 g (25th centile for SCID associated neutropenia, as opposed Turkish girls). Physical examination revealed to reticular dysgenesis, in which the several deep skin ulcerations on both thighs neutropenia is G-CSF refractory and is each at least 2x2 cm in size. A complete blood most probably caused by a genetic stem count showed a decreased haemoglobin level cell defect. A response to G-CSF in a (7.0 g/dl) and packed cell volume (22%), a neutropenic child with SCID can be clini- normal platelet count (326 000/pAl) and 1600 cally beneficial and might help to distin- leucocytes/,ul with a differential blood count of

guish between G-CSF unresponsive 77% lymphocytes, 7% monocytes, 10% http://adc.bmj.com/ reticular dysgenesis and G-CSF respon- banded cells, and 6% polymorphonuclear sive SCID associated neutropenia. neutrophils (absolute neutrophil count: (Arch Dis Child 1996; 74: 340-342) 256/,ul). Cord blood results were not available. Antigranulocyte antibodies were not detected. Keywords: severe combined immunodeficiency (SCID), neutropenia, granulocyte colony stimulating The bone marrow showed a developmental factor (G-CSF). arrest at the stage of promyelocytes. Because the girl developed chronic rotavirus infection, was of on September 30, 2021 by guest. Protected copyright. University of B and T cell function evaluated. Levels Dusseldorf, immunoglobulins were low (IgG <91 mg/dl; Dusseldorf, Germany The association of severe combined immuno- IgM <14 mg/dl; IgA <8 mg/dl). Mature T cells were with an Department of deficiency (SCID) with congenital agranulocy- markedly decreased, Paediatrics tosis has been defined as reticular dysgenesis.1 increased relative percentage of B cells. The T Niehues Consistent with a genetic stem cell defect the complete surface marker profile is given in the H Schroten report described monozygotic twins table. Peripheral blood B and T cells were V Stephan original V Wahn with a complete absence of both neutrophils in separated immunomagnetically and T cells peripheral blood and myelopoietic stem cells in were identified as being of maternal origin by Department of the bone marrow. In contrast to the original HIA typing. The response of peripheral blood Transfusion Medicine M Schneider report, further cases described as reticular dys- lymphocytes to mitogens was markedly genesis showed variable numbers of neutro- decreased (table). The thymus could barely be Department of Human phils in peripheral blood and cells of the detected by sonography. Adenosine deaminase Genetics E Schr6der myelopoietic lineage at all maturational stages and purine nucleoside phosphorylase levels in bone marrow.2 3 Ownby et al even observed were normal. Severe B and T cell dysfunction University of Ulm, a variable degree of myeloid deficiency in led to the diagnosis of SCID. Ulm, Germany brothers, which makes a genetic stem cell The skin infections and ulcers barely Department of defect unlikely.2 Thus the aetiology of the responded to different intravenous antibiotic Paediatrics II neutropenia and the precise role of SCID and regimens. Therefore, 1 pug/kg of granulocyte K Schwarz neutropenia in the syndrome of reticular dys- colony stimulating factor (G-CSF) (Neupo- Correspondence to: genesis are not clear. gen, Amgen, Munich) was given subcuta- Prof Dr med Volker Wahn, Zentrum fuir We had the unique opportunity to study two neously on alternate days. A response was Kinderheilkunde der genetically identical individuals with SCID. noted on day 6 and neutrophil counts above Heinrich Heine Universitat Dusseldorf, Moorenstr 5, Only one twin presented with severe neutro- 2000/pul could be maintained. Ulcers com- 40225 Dusseldorf, Gerrnany. penia, showing that there is an initial presenta- pletely healed within two weeks. After with- Accepted 12 December 1995 tion of neutropenia in SCID which has a drawal of G-CSF, neutrophil counts again fell Severe combined immunodeficiency associated neutropenia 341

Immunological studies. Surface marker profile and mitogen reaction, and severe failure to thrive requiring response. Numbers indicate percentages oftotal peripheral blood lymphocytes staining with each marker byflow parenteral nutrition. cytometry or counts per minute (cpm) in the thymidine Arch Dis Child: first published as 10.1136/adc.74.4.340 on 1 April 1996. Downloaded from incorporation assay Discussion Twin I Twin H Control We have described genetically identical twins T and B cell markers with different phenotypes of SCID. Both twins CD3+ 30 19 87 CD4+ 13 1 58 displayed clinical as well as laboratory findings CD8+ 12 11 25 consistent with SCID. The most surprising CD20+ 51 67 6 finding was that only one twin was severely NK cell markers CD56/CD3- 6 1 5 neutropenic at presentation, although genetic Adhesion markers identity was demonstrated by DNA finger- CD2+ 35 19 92 printing. A possible alloimmune aetiology for CD1 la 94 97 97 CD18 96 96 100 the neutropenia was evaluated but no Activation marker/HLA expression antigranulocytic antibodies were detected. CD4/HLA-DR+ 11 0 1 Cellular immune mechanisms involving CD8/HLA-DR+ 8 10 0 HLA-ABC 99 95 100 maternal T cells were not further analysed. An Mitogen response (cpm) infectious cause could not entirely be excluded Medium alone 470 200 120 but seemed unlikely because neutropenia PHA 1380 1750 33940 OKT3 210 920 24000 recurred when G-CSF was discontinued, at a PWM 1700 160 31320 time when there was no clinical or laboratory SAC 2100 390 4820 evidence of infection. PHA=phytohaemagglutinin: PWM=pokeweed mitogen; It is well known that materno-fetal trans- SAC=staphylococcal protein A of Cowan I strain. fusion of T cells can be demonstrated in more than 50 per cent of patients with SCID.5 We below 500/pl within five days. As dependence believe that suppression of myelopoeisis in our on G-CSF was documented, treatment was case was most probably explained by a GvH continued until bone marrow transplantation. reaction caused by maternal T cells. As Desquamative exanthema developed on maternal T cells were found in both children, it hands, feet, face, and skull. As this was associ- seems likely that there were major differences ated with a rise in transaminases it was felt in the effector functions of maternal T cells most likely to be the result of graft versus host between the twins. In the neutropenic twin I a (GvH) reaction caused by maternal T cells. much stronger activation ofT cells (percentage During more than two months of hospital of HLA-DR+ T cells, see the table) was inpatient care before bone marrow transplan- observed. There was indirect evidence that tation our patient had severe failure to thrive. haematopoetic suppression also involved After the decision to carry out a bone marrow erythropoiesis, as routine evaluation of the transplant had been made, a central venous anaemia did not reveal any other cause, and http://adc.bmj.com/ catheter was inserted and parenteral nutrition the anaemia persisted, with haemoglobin con- given. centrations between 6 and 8 g/dl. In the original report describing reticular dysgenesis it was stated that there may be CASE 2 several grades of severity. Severe cases of Twin II was referred to our clinic one day after neutropenia in SCID resembling the original her twin sister for treatment of pneumonia. On report usually present at birth or in the first on September 30, 2021 by guest. Protected copyright. admission she weighed 4500 g (below 10th week, with almost no detectable neutrophils; centile for turkish girls) but was normal on these cases are fatal within days to weeks.1 6 7 physical examination. Laboratory investiga- Attempts to treat a severe case and her sister tions on admission were also normal except for using G-CSF (4-30 ,ug/kg) failed. A genetic a moderately increased y glutamyl transferase stem cell defect seems likely in these cases and an increased leucocyte count (24 300/,l because myelopoiesis was resistant to G-CSF with a normal differential count), as well as a in vivo as well as in the absence of maternal T slightly raised C reactive protein (1 8 mg/dl). cells in vitro.7 Pneumonia was confirmed by chest x ray. After In the most recent report of reticular dys- treatment with intravenous antibiotics she genesis, treatment with granulocyte macro- made a rapid recovery from the pneumonia. phage colony stimulating factor (GM-CSF) When the diagnosis of SCID was established in resulted in reconstitution of normal neutrophil twin I we also evaluated twin II for possible counts.3 A difference in stem cell sensitivity to immunodeficiency. Genetic identity with twin G-CSF or GM-CSF might explain the diver- I was confirmed by DNA fingerprinting in gent response. However, a different severity of granulocytes (data not shown), as desribed by neutropenia in SCID may account for the Wong et al.4 Using eight microsatellites, the reported difference. Less severe forms of SCID calculated probability of monozygosity was and neutropenia, including the GM-CSF 99-95% according to the Bayes principle of responsive case and our own, had most of the conditional probabilities. Laboratory examina- following features in common: a late manifes- tion revealed a very similar immunological tation (one to three months), a less profound phenotype (table). neutropenia at presentation (>100 neutro- In the course of the disease patient 2 also phils/ml), and a better overall prognosis.3 8 acquired chronic rotavirus gastroenterits, an Passively transferred immunity and breast exanthema most probably caused by GvH feeding might have prevented an earlier onset 342 Niehues, Schwarz, Schneider, Schroten, Schroder, Stephan, Wahn

We thank Dr G Kogler (Bone Marrow Donor Centre, of symptoms.8 Aetiologically a GvH induced Dusseldorf, Germany) for separation and HLA-typing of mechanism seems likely in these less severe maternal T cells, Prof K Welte (Department of Paediatrics, sup- Hannover, Germany) for discussion and comments on bone Arch Dis Child: first published as 10.1136/adc.74.4.340 on 1 April 1996. Downloaded from cases. Both a primary stem cell defect and marrow morphology, Prof C Muller-Eckardt (Department of pression of haematopoiesis by maternal T cells Paediatrics, Giessen, Germany) for analysis of antigranulocytic antibodies, and Dr U Schauer (Department of Paediatrics, are compatible with the finding of normal Bochum, Germany) for investigation of the adenosine deami- neutrophil numbers in SCID following bone nase and purine nucleoside phosphorylase levels. marrow transplantation.8 Thus treatment of the defect is either linked to reconstitution with 1 De Vaal OM, Seynhaeve V. Reticular dysgenesis. Lancet 1959; ii: 1123-5. a normal stem cell/haematopoietic system or to 2 Ownby DR, Pizzo S, Blackmon L, Gall SA, Buckley RH. elimination of maternal T cells in the process Severe combined immunodeficiency with leukopenia (reticular dysgenesis) in siblings: immunologic and of conditioning for bone marrow transplanta- histopathologic findings. J7 Pediatr 1976; 89: 382-7. tion. 3 Azcona C, Alzina V, Barona P, Sierrasesumaga L, Villa- Elizaga I. Use of recombinant human granulocyte- Ownby et al suggested the descriptive term macrophage colony stimulating factor in an infant with 'SCID with leucopenia' instead of reticular reticular dysgenesis. EurJ Pediatr 1994; 153: 164-6. 4 Wong Z, Wilson V, Patel I, Povey S, Jeffreys AJ. Charac- dysgenesis.2 Now that haematopoietic growth terization of a panel of highly variable minisatellites cloned factors are in clinical use, it is useful to differ- from human DNA. Ann Hum Genet 1987; 51: 269-88. 5 Stephan JL, Vlekova V, Le Deist F, et al. Severe combined entiate between SCID associated neutropenia, immunodeficiency: a retrospective single-center study of which is less severe and potentially responsive clinical presentation and outcome in 117 patients. J Pediatr 1993; 123: 564-72. to treatment with GM-CSF/G-CSF, and the 6 Roper M, Parmley RT, Crist WM, Kelly DR, Cooper MD. more severe reticular dysgenesis, which Severe congenital leukopenia (reticular dysgenesis). Am J Dis Child 1985; 139: 832-5. appears to be refractory to G-CSF.7 7 Bujan W, Ferster A, Sariban E, Friedrich W. Effect ofrecom- Administration of G-CSF in a child presenting binant human granulocyte colony-stimulating factor in reticular dysgenesis (letter). Blood 1993; 82: 1684. with SCID and severe neutropenia should dif- 8 Levinsky RJ, Tiedeman K. Successful bone-marrow trans- ferentiate between these two conditions. plantation for reticular dysgenesis. Lancet 1983; i: 671-3. http://adc.bmj.com/ on September 30, 2021 by guest. Protected copyright.