March 1979 The Journal o f P E D I A T R 1 C S
391
An inherited defect of neutrophil mobility in Shwachman syndrome Selected immunologic functions were assessed in 14 patients with the Shwachman syndrome. Nine patients were neutropenic and four had low levels of lgA or o f lgM. Neutrophil mobility was significant!v defective in the group of patients as a ,,hole (in 12 it was below the lower limit of normal) and in their parents. No other consistent abnormalit/ in immunity was found. These results suggest that the defective neutrophil mobility is a feature of Shwachman syndrome which may contribute to the vulnerability of these patients to frequent infections. The defect appears to be a prima/:v genetic one, inherited as an autosomal recessive characteristic consistent with the assumed inheritance of Shwachman syndrome.
P. J. Aggett, M.Sc., M.R.C.P., D.C.H.,* J. T. Harries, M.D., F.R.C.P., M.Sc., D.CH., Betty A. M. Harvey, F.I.L.M.S., and J. F. Soothili, F.R.C.P., F.R.C.Path.,** L o n d o n , E n g l a n d
THE FEATURES of Shwachman syndrome include exocrine pancreatic insufficiency, bone marrow hypoplasia with neutropenia, metaphyseal chondrodysplasia, growth retardation, and frequent infections/'-' The susceptibility to infection has been attributed to neutropenia or immunoglobulin deficiency, or both. In some situations, defective mobility of polymorphonuclear leukocytes may be associated with neutropenia? We are not aware of previous studies of neutrophil mobility in Shwachman syndrome, so we measured this as well as some other immunologic functions in patients and their parents. SUBJECTS Fourteen patients, seven male and seven female, with Shwachman syndrome were studied. Their mean age was 11,2 years with a range of 1.4 to 28.9 years. They presented with steatorrhea or failure to thrive or both. Trypsin and lipase activities were deficient in their duodenal juice and their sweat sodium concentration was From the Departments o f Child Health and Immunology, Hospital for Sick Children and Institute of Child Health. *Supported b)' the Medical Research Council. **Reprint address: Department of Immunology, Institute of Child Health, 30 Guilford St., London, WCIN 1EH
0022-3476/79/300391 +04500.40/0 9 1979 The C. V. Mosby Co.
normal. Only Patient 12 achieved the third percentile for height, 12 patients had metaphyseal chondrodysplasia, and all had retarded bone age. Eleven patients had recurrent and severe infections requiring hospital care. An intermittent neutropenia (PMN < 1,500/mm :') was present in all but two patients, both of whom had other features of the syndrome. Abbreviations used PMN: polymorphonuclear leukocytes NBT: nitroblue tetrazolium Patient 14 gave a history of allergy, Patient 13 was on chlorpropamide therapy for diabetes mellitus, and Patient 9 was receiving prednisolone orally. All patients were free of infection when studied, Both parents of four patients and five other mothers were also investigated.* METHODS
Polymorphonuclear leukocyte mobility was measured by a modification by one of us (B. A. M. H.) of the micromethod of Addison and Babbage? Plastic containers and Hanks medium were used throughout. Reagents and equipment were prewarmed at 37~ Leukocytes *Detailed clinical and laboratory data available, upon request, from authors.
VoL 94, No. 3, pp. 391-394
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The Journal of Pediatrics March 1979
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wells of a plastic plate (Flow multidisc FB20) an antibiotic assay disc (Whatman 13 mm diameter) was placed. To two of these a 0.2 ml aliquot of chemotactic factor was applied while 0.2 ml of medium was applied to the remaining pair. This is sufficient volume to saturate the disc and leave no free fluid in the well. A millipore membrane (3/~m pore size 13 mm diameter) was placed on each disc and onto this a plastic cap (L.P. 3 Luckham Ltd), filled (avoiding a meniscus) with approximately 0.25 ml of cell suspension, was inverted. The plates were incubated for three hours at 37~ in a moist chamber. The membranes were removed, washed in medium, fixed in propan-2-ol for 20 minutes, stained with hematoxylin, dehydrated, cleared, and mounted on a slide with Canada balsam. The • 40 objective of a microscope was focused on the membrane surface and focused down to the lowest level at which at least five cells were seen. The distance was measured on the micrometer of the microscope's fine adjustment. The mean of five observations on each of duplicate membranes was taken. Serum opsonization of yeast ~ and a qualitative NBT test ~ (including endotoxin stimulation) were studied. In lymphocyte preparations (Ficoll-Triosil), B and T lymphocytes were counted by surface immunoglobulin immunofluorescence and E rosettes, and thymidine uptake responses (expressed as stimulation index, stimulated counts/unstimulated counts) to PHA and Candida albicans were measured? Serum IgG, IgA, IgM, and C3 were measured by the single radial diffusion method ~' using antisera supplied by Wellcome Reagents Ltd. Serum IgE was measured by a double-antibody procedure TM using a commercial calibrated standard (Pharmacia). Statistical analysis was by t test, one tail. RESULTS
-CF + F Patients
-CF +CF Parents
-CF +CF HealthyAdults
Figure. Mobility (/tm), unstimulated (-CF), or stimulated (+CF) by chernotactic factor, of PMN from 13 patients with Shwachman syndrome, 13 of their parents, and 13 healthy adults studied in parallel. The lower limit of normal for stimulated mobility is shown ( ~). were separated by dextran sedimentation from 5 ml of heparinized blood; 2 • 109 PMN are required, and so smaller volumes can be used in patients with normal PMN counts. The cells were washed and after counting resuspended in medium at 2 • 10" m1-1 (2 • 10~/ml). Chemotactic factor was generated by adding 0.1 ml Escherischia coli endotoxin (Difco 1.5 mg/ml) to 0.5 ml of serum from a healthy donor in 4.4 ml of medium (in some experiments, patients' serum was used). Into each of four
The PMN count of the patients at the time of study ranged from 0.44 • 10.~/1 (440/mm ~) to 5.67 • 10'/1 (5,670/mm 3) with a mean of 1.66 x 10"/1 (1,660/mm"). The mean PMN count for the parents was 4.8 • 109/1 (4,800/mm 3) with a range between 2.97 • 10~/1 (2,970/ mm :~) and 7.0 • 109/1 (7,000/mm~). Ten of the 14 patients were neutropenic. Serial observations demonstrate that all have had values in the normal range and that some responded to infections by a marked PMN leukocytosis, as in previous descriptions. *,~ The neutrophils were morphologically normal. The mean unstimulated PMN mobility in the patients was 23.9 ~tm (range 0 to 42.9/~m) and the mean stimulated mobility was 41.9 jam (range 0 to 90,2 /~m). The corresponding values for the parents were 39.6 ~m (range 24.2 to 66.2 t~m) and 81.7/~m (range 39.8 to 120.5 ~m), while
Volume 94 Number 3 our normal ranges for a healthy adult population are 18 to 100 ~m and 78 to 140/~m, respectively. The unstimulated and stimulated PMN mobility of the patients was significantly lower than in those of the healthy adults run in the same batches (unstimulated t = 4.75, P < 0.0005; stimulated t = 9.47, P < 0.0005) and the stimulated values '1 of all but one were below 78 ~m (Figure). The lowest values were obtained from Patient 9, who was receiving prednisolone, which suppresses mobility+; her values were therefore excluded from the statistical analysis described above. The stimulated values of the 13 parents were also less than the controls (t = 2.42, P < 0.01; 5 were less than 78 /~m) as were the unstimulated values (t = 1.88, P < 0.05) though less so than their children. The three outstandingly high values included the two parents of Patient 5. Serum from three patients and two mothers generated chemotactic factor as readily as did normal serum (Table). Blood taken from Patient 2, while recovering from a general anaesthetic (trimeprazine, atropine, nitrous oxide, and halothane) for dental treatment, had lower values of PMN mobility (unstimulated 12.4 /~m; stimulated 19.3 #m) than the previous values (30.1 #m and 34.6/~m). IgA values in all but two patients (2 and 5) fell within department normal limits. Patients 1 and 6 had low serum levels of IgM. Of the 11 patients and 11 parents in whom it was measured, IgE was not detected in 3; two patients and three parents had levels above 400 IU ml/ml. C3 and "serum yeast opsonization were normal in all patients; one father had a low opsonization index. The stimulated NBT test was normal in all patients and parents studied. Spontaneous NBT reduction was increased ( > 10%) in seven patients and six parents. B lymphocyte counts were normal in all subjects studied. T lymphocyte counts were low in Patients 2 and 71 The lymphocyte response to PHA was positive in all patients and parents studied, but one patient and two parents had low values. All but two responded significantly to C albicans, and only one parent reacted poorly to both stimuli. DISCUSSION Our 14 patients with Shwachman syndrome had an intermittent neutropenia and occasional hypoimmunoglobulinemia. No consistent abnormality in cell-mediated immunity has been detected. We have also demonstrated a hitherto unreported defect in PMN mobility, which may contribute to the recurrent infections which occur in this syndrome. A similar defect in symptomless parents of the children suggests that the defect in PMN mobility is primary rather than secondary to other manifestations of the disease. The parents as a whole had values interme-
Neutrophil mobility in Shwachman syndrome
393
Table. Mobility (~m) of PMN from healthy controls and from three patients with Shwachman syndrome and two of their mothers stimulated by chemotactic factor generated in autologous serum or in control's serum
PMN
Serum
Patient Patient Control Control Mother Mother Control Control
Patient Control Patient Control Mother Control Mother Control
Patients
Mothers
8 I 12 I 14
8 [ 12
41 43 116 118
31 30 78 77
52 56 94 88 61 78 109 118
59 52 83 77
diate between those of the propositi and of the control population, and both parents had abnormal values in one of the four father and mother pairs studied. It is likely, therefore, that the parents are heterozygous and that this abnormality is inherited as an autosomal recessive characteristic. This mode of inheritance for Shwachman syndrome has already been deduced from th e prevalence in siblings.-' The association of the PMN mobility defect and the recognized features of the syndrome suggests that all are the effect of a single defective gene. The values in parents also suggest that the PMN mobility defect is closely related to the primary gene product. Polymorphonuclear leukocytes from healthy donors moved normally in sera from patients and mothers, demonstrating that the mobility defect was due to a cellular rather than a serum abnormality. We have therefore identified a discrete syndrome in which there is a primary defect of mobility of morphologically normal PMN. Prior to this, i n t h e sporadic families and patients reported+ the assertion that such mobility defects are primary has been insecure. Positive NBT reduction, both spontaneous and stimulated, indicates that particle ingestion occurs. This and the increase in mobility following a chemotactic stimulus suggest that some cell surface functions are operative, and that the PMN mobility defect may lie in the intracellular contractile mechanisms. Polymorphonuclear leukocytes mobility is known to be affected by drugs, including steroids+ by infections, and in diabetes mellitus. 4 A further reduction of PMN mobility induced by prednisolone and general anaesthesia, as with one of our patients (2), may be clinically important if patients with primary mobility defects, who are at special risk, are given these drugs. This may have contributed to the death of a patient with Shwachman syndrome, whose
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PMN mobility was not measured, from postoperative pneumonia.l'-' There was no correlation between the neutrophil count and mobility in our patients. The neutropenia in patients with lazy leukocyte syndrome :~ has been attributed to a defect in PMN mobility and failure to migrate from marginating pools. The normal neutrophil counts in those of our patients' parents with impaired PMN mobility and in some patients with other forms of defective mobility H suggest that neutropenia is not necessarily an effect of abnormal mobility. The neutropenia in Shwachman syndrome therefore is presumably due to the bone marrow hypocellularity and maturation arrest, as originally suggested. 1 Patients with a syndrome of recurrent infections, especially of the skin, asthma, eczema, and elevated serum IgE levels have been descried to have defective leukocyte mobility, 1:~," but none had neutropenia. Only two of our patients had high IgE levels and neither of them had atopy. The one patient (14) with atopy had a high normal serum IgE level. Only one of the parents was atopic. This differentiates the reported PMN mobility defect from that associated with the hyper IgE syndrome, and suggests that defective neutrophil mobility does not necessarily predispose to atopy. A recent report 1~ stresses the variability of i m m u n o globulin deficiency in Shwachmman syndrome. In one reported family '~ such a deficiency and the disease coted have been inherited independently. The low serum IgA or IgM values in four of our patients support the view that hypoimmunoglobulinemia is indeed an inconstant associated feature of this condition. Measurement of the PMN mobility defect provides an additional diagnostic test for this rare syndrome which we have already found useful. The study in the parents may also be of value because the test may in addition permit heterozygotes to be identified. We thank Drs. D. Lawson, J.D. Maxwell, R.J. Pugh and J. Walker-Smith for allowing us to study their patients, Mrs. L Layward for the lymphocyte studies, and Professor C.O. Carter for advice.
The Journal of Pediatrics March 1979
REFERENCES
1. Shwachman H, Diamond LK, Oski FA, and Khaw KT: The syndrome of pancreatic insufficiency and bone marrow dysfunction, J PEOIATR65:645, 1964. 2. Shmerling DH, Prader A, Hitzig WH, Giedion A, Hadorn B, and Ki~hni M: The syndrome of exocrine pancreatic insufficiency, neutropenia, metaphyseal dysostics and dwarfism, Helv Paediar Acta 24:547, 1969. 3. Miller ME, Oski FA, and Harris MB: Lazy leucocyte syndrome, Lancet 1:665, 1971. 4. Wilkinson PC: Chemotaxis and inflammation, Edinburgh, 1974, Churchill Livingstone. 5. Addison IE, and Babbage JW: A raft technique for chemotaxis: a versatile method suitable for clinical studies, J lmmunol Methods 10:385, 1976. 6. Miller ME, Seals J, Kaye R, and Levitsky LC: A familial plasma-associated defect of phagocytosis, Lancet 2:60, 1968. 7. Park BH, and Good RA: NBT test stimulated, Lancet 2:616, 1970. 8. Hayward AR, and Greaves MF: Central failure of B lymphocyte induction in pan-hypogammaglobulinaemia, Clin Immunol Immunopathol 3:461, 1975. 9. Fahey JL, and McKelvey EM: Quantitative determination of serum immunoglobulins in antibody-agar plates, J Immunol 94:84, 1965. 10. Nye L, Merrett TG, Lar~don J, and White R J: A detailed investigation of circulating IgE levels in a normal population, Clin Allergy 5:13, 1975. 11. Farhoudi A, Harvey BAM, and Soothill JF: Clinicopathological findings in patients with primary and secondary defects of neutrophil mobility, Arch Dis Child 53:625, 1978. 12. Aggett PJ: In preparation. 13. Hill HR, and Quie PG: Raised serum IgE levels and defective neutrophil function in 3 children with eczema, and recurrent bacterial infections, Lancet 1:183, 1974. 14. Jacobs JC, and Norman ME: A familial defect ofneutrophil chemotaxis with asthma, eczema and recurrent skin infections, Pediatr Res 11:732, 1977. 15. Brueton MJ, Mauromichalis J, Goodchild MC, and Anderson CM: Hepatic dysfunction in association with pancreatic insufficiency and cyclical neutropenia: ShwachmanDiamond syndrome, Arch Dis Child 52:76, 1977. 16. Hudson E, and Aldor T: Pancreatic insufficiency and neutropenia with associated immunoglobulin deficit, Arch Intern Med i25:314, 1970.