close

Вход

Забыли?

вход по аккаунту

?

Childhood multiple sclerosis Clinical features and demonstration of changes in T cell subsets with disease activity.

код для вставкиСкачать
Chddhood Multiple Sclerosis: Chcal Features
and Demonstration of Changes in T Cell
Subsets with Disease Activity
Stephen L. Hauser, MD," Michael J. Bresnan, MD,t Ellis L. Reinherz, MDJ and Howard L. Weiner, MD'
Using monoclonal antibodies that identify T cell subsets in human beings (T4 = inducer cell; T5 = suppressor/
cytotoxic cell), we have previously shown that most patients with multiple sclerosis (MS) have decreased T5 cells
and an elevated T4 :T5 ratio during periods of disease activity. We have recently studied three children with MS
beginning at 4 years 11 months, lOV2 years, and 2 years 11 months of age. Clinical symptoms included a relapsing
brainstem syndrome in the first, Devic syndrome and recurrent optic neuritis in the second, and multiple attacks
with accumulating neurological deficits in the third. Two of these children represent the youngest cases of MS yet
reported. In each child, circulating T5 cells were reduced or absent during an acute exacerbation of disease; following stabilization, T5 cells returned and the T4 :T5 ratio became normal. No changes in T cell subsets were seen
in a group of age-matched healthy children or in children suffering from other neurological diseases. Our finding
that young children with active MS have a pattern of T cell abnormalities identical to that of adult MS patients
suggests that the same pathophysiological process which causes MS in adults occurs in young children as well.
Hauser SL, Bresnan MJ, Reinhert EL, Weiner HL: Childhood multiple sclerosis: clinical features and
demonstration of changes in T cell subsets with disease activity. Ann Neurol 11:463-468, 1982
Multiple sclerosis (MS) is rarely encountered in early
childhood, and the child with suspected MS may
present a difficult diagnostic problem. No reliable
laboratory test short of biopsy or autopsy is pathognomonic for MS, and thus the diagnosis generally
requires both demonstration of white matter lesions
disseminated in time and space and reasonable exclusion of other disease processes.
Using monoclonal antibodies directed against
human T lymphocyte subsets, we recently described
abnormalities of circulating T cells in adult patients
with active MS [14]. Anti-T3 is a monoclonal antibody that recognizes an antigen present on all circulating T cells; anti-T4 recognizes the T-inducer
(helper) subset and anti-T5, the T-suppressor/
cytotoxic population [ 131. Under normal circumstances, T cells (defined by anti-T3) constitute 60
to 70% of circulating lymphocytes; approximately
two-thirds of these T lymphocytes are T-inducer cells
(T4-antigen positive), and the remaining one-third
are T-suppressorlcytotoxic cells (expressing the T5
antigen).
In active MS, numbers of circulating T cells (T3)
are reduced and a subset imbalance is present
characterized by depletion of T-suppressor/cytotoxic
cells (T5)and by an increase in the ratio of inducer to
suppressor/cytotoxic (T4 :T5) cells. With remission,
reconstitution of normal T lymphocyte subsets occurs although the absolute number of T celIs (T3)
may remain depressed. Similar changes are not
present in normal controls or in adult patients with
other diseases of the central nervous system.
We recently studied T cell subsets in three young
children with MS and found a pattern of T cell
changes identical t o that seen in adults with the disease.
From the *Department of Neuroscience, Children's Hospital
Medical Center, and the Division of Neurologv, DeDartment of
Received June 19, 1981, and in revised form Aug 21. Accepted for
Dubkation Aue 25. 1981.
Methods
Human peripheral mononuclear cells were isolated from
fresh heparinized blood by gradient density centrifugation
with Ficoll-Hypaque (Pharmacia Fine Chemicals, Piscataway, NJ). Production and characterization of the monoclonal antibodies anti-T3 (OKT3), anti-T4 (OKT4), and
anti-T5 (OKT5) have previously been described [ l l l .
Lymphocyte subpopulations were identified as described
earlier [14]. Briefly, 1 x LO6 Lymphocytes were incubated
with each of the monoclonal antibodies, followed by indirect immunofluorescence with fluorescein-conjugated
goat antimouse immunoglobulin G (G/M FITC; Meloy
0364-5134/82/050463-06$01.25 @ 1981 by the American Neurological Association 463
Table 1 . Analysis of Lymphocyte Populations i n Children with Multiple Sclerosis
Reactivity with Monoclonal Antibodies (%)
Subjects
Anti-T3
Anti-T4
Anti-T5
Healthy control
children (N =
Children with other
neurological diseases (N = 12)”*“
Patient 1
Acute relapse
Stabled
Patient 2
Acute relapse
Stable“
Stablef
Patient 3
Acute relapse
Stableg
67 t 3
41 t 2
20 t 1
2
39
20 t 2
2
52
*3
2
3
T4:T5
54
75
42
41
0
28
...
18
26
52
16
12
35
1
10
14
16.0
1.2
2.5
10
29
0
10
...
18
6
1.5
1.8
*
aResults expressed as mean
SEM.
bIdentical findings were present in healthy adults (N = 30).
‘Including cases of encephalitis (N = 2), viral meningitis (l), myasthenia gravis (l), Guillain-Bark syndrome ( l ) , idiopathic thrombocytopenic purpura with ataxia (I), pseudotumor cerebri (l), myoclonic epilepsy (2), Lennox-Gastaut syndrome (I), paroxysmal
choreoathetosis ( l ) ,and an unclassified degenerative disease of the central nervous system (1).
dTen days after relapse.
eFive days after relapse.
‘Five months after relapse.
%Onemonth after relapse.
Laboratories, Springfield, VA) and by analysis o n a
fluorescence-activated cell sorter (FACS-1; BectonDickinson, Mountain View, CA). A control ascites fluid
obtained from mice immunized with nonsecreting hybridoma lines was used for measurement of background
fluorescence reactivity.
Case Reports
Patient 1
This GY’-year-old girl was the product of a full-term, uncomplicated pregnancy. Early development was normal. At
age 4 years 11 months, she awoke one morning with diplopia and an unsteady gait, and was found to have a vertical
gaze paresis, right hemiataxia, and an ataxic gait. Lumbar
puncture demonstrated normal pressure, 3 white blood
cells (WBC) per cubic millimeter (679% lymphocytes), glucose of 40 mgidl, and protein of 25 mgidl. Computerized
tomographic (CT) scan was normal; electroencephalography revealed minimal posterior slowing; visual evoked
response (VER) latencies were prolonged bilaterally. No
evidence of viral infection or vasculitis was found. No
specific treatment was given, and her symptoms resolved
over a two-week period.
She was rehospitalized at age 6 years 1 month after developing diplopia, left-sided ptosis, and left facial numbness. At that time she had a left oculomotor nerve palsy
(sparing the pupil), a left trigeminal nerve sensory deficit,
and an equivocal right plantar response. Lumbar puncture
demonstrated 2 WBC/mm” ( 100% lymphocytes), normal
glucose and protein, and a normal immunoelectrophoresis
pattern. Repeat C T scan was unremarkable, and VER testing again demonstrated prolonged latencies bilaterally.
464 Annals of Neurology Vol 11 No 5 May 1982
Table 2. T Cell Subset Ratios in Control Subjects
and Patients with Childhood Multiple Sclerosis
Ratio of T4+:T5+ Cells
Subjects
>4
(4
Children with active MS
Children with inactive MS
Children with other neurological diseases
Healthv control children”
3
0
0
0
4
12
0
aldentical findings were present in healthy adults (N
___
=
10
30).
T-suppressorlcytotoxic cells (T5 cells) were absent from
peripheral blood during the acute phase of her illness.
When she was retested ten days later, at a time when her
deficits had stabilized, a return of circulating T 5 cells was
found (Tables 1, 2).
Patient 2
A 101/-year-old girl was hospitalized because of urinary
retention and acute monocular blindness. She had been
well previously except for migraine headaches. Three
weeks before admission she developed severe, constant
pain localized above the left eye. Two weeks later she complained of nonradiating low midline back pain and urinary
frequency and urgency; appendicitis was suspected, but
laparotomy at an outside hospital demonstrated only a distended bladder. O n the morning of admission she awoke
unable to see out of her left eye. O n examination, that eye
was blind and the pupil unreactive to direct light; fundus-
IB
vContro'
Anti-T3
Anti-Tq
Ant1-T~
fLUORESC&NC€ /NTENS/TY
F i g 1 . Fluctuations of T lymphocyte subsets in childhood multiple sclerosis:juorescence-activated cell sorter proftle of- 10,000
lymphocytes from Patient 2 during an acute relapse (A)and
ftve months later following clinical stabilization (B).Analysis
was performed with monoclonal antibodies against T3, T4,
and T5 cells by indirect immunojluorescence. Circulating T5
cells were completely absent during active disease (A),and this
subset was reconstituted with cessation of disease activity (8).
I n addition, the number of T3 and T4 cells was reduced during the acute relapse.
copy revealed acute papillitis o n the left side. A sensory
level to pinprick at T12, mild paraparesis, hyperactive deep
tendon reflexes in the legs, and bilateral extensor plantar
responses were noted. Lumbar puncture revealed 70
WBC/mm3 (90% lymphocytes), glucose of 49 mgldl, and
protein of 78 mgldl. C T scan and auditory evoked potentials were normal; VER was normal in the right eye but
totally absent in the left.
T 3 and T 5 cells in peripheral blood were markedly reduced at the time the patient was admitted to the hospital
(see Table 1). She began receiving steroid therapy, and her
neurological deficits gradually improved; repeat T cell
studies five days later demonstrated reconstitution of the
suppressor/cytotoxic subgroup and an increase in the T3
population. Six weeks later recurrent monocular blindness
developed, this time in the right eye, and a diagnosis of
recurrent optic neuritis was made; steroids were again administered with improvement. Five months later, when she
was neurologically stable, results of repeat T cell studies
were normal (Table 1, Fig 1).
Patient 3
This 101/2-year-old girl was the product of a full-term, uncomplicated pregnancy. Early developmental milestones
were normal. T h e first symptom, gait imbalance, began at
age 2 years 11 months. Two months later she was hospitalized because of increasing gait difficulties and a fourday history of vomiting and lethargy. O n examination she
was afebrile and somnolent, and showed sustained rightbeating conjugate nystagmus in all positions of gaze and an
extensor left plantar response. Lumbar puncture revealed
90 WBC/mmj (50% lymphocytes), protein of 54 mgldl,
and glucose of 60 mgldl. Upon discharge from the hospital
she was severely ataxic, but she improved over a fourmonth period and findings on neurological examination
returned to normal.
She was hospitalized again at age 4$'2 years after four
weeks of progressive difficulty walking and feeding herself.
O n examination she was drowsy and had a low-grade fever,
spontaneous left-beating nystagmus, a left facial paresis,
axial and appendicular ataxia (left greater than right), and
bilateral extensor plantar responses. Lumbar puncture revealed 12 WBC/mm3 (25% lymphocytes, 75% polymorphonuclear leukocytes) and protein of 30 mgldl. Within
several days of admission a new left sixth nerve palsy appeared. Pneumoencephalography, left vertebral angiography, and technetium brain scan were normal; the electroencephalogram was abnormal because of excessive
slowing and high-voltage sharp activity. Steroids were administered, and within three weeks she had improved to
nearly baseline status.
Four months later (4 years 10 months old), approximately one week after an upper respiratory infection, she
became ill again. Over a five-day period she developed
fecal and urinary incontinence and inability to sit, walk, or
feed herself; a single right-sided seizure was noted. O n admission she was afebrile, lethargic, and irritable; opsoclonus, a right hemiparesis, spastic paraparesis, and severe
ataxia were present. Steroids were administered and the
patient made a substantial recovery; within two months her
ataxia had resolved and hemiparesis had improved. However, mild developmental retardation and choreiform
movements of the upper limbs were present. Infrequent
seizures persisted.
At age 10% years the patient was again hospitalized because of recurrent imbalance accompanied by headache.
She was alert but ataxic and had a flaccid quadriparesis,
worse on the right; reflexes were hyperactive and plantar
responses bilaterally extensor. Lumbar puncture revealed
11 WBC/mm3 (70% lymphocytes) and protein of 54 mgldl
with normal gamma globulin fraction and no oligoclonal
bands by immunoelectrophoresis. C T scan demonstrated
small ventricles and hypodense white matter lesions in both
frontal lobes (Fig 2A). The latency of the VER was prolonged unilaterally. Results of an extensive metabolic and
toxic screen were negative.
Measurement of T cell subpopulations during this acute
episode revealed complete absence of circulating T 5 cells
and reduced numbers of T3 and T 4 cells (see Table 1).
When the patient was retested one month later, during a
period of improving neurological function, restoration of
the T 5 population and increased numbers of T 3 and T4
cells were found. Six months later a repeat C T scan demonstrated ventricular enlargement (Fig 2B, C).
Analysis of Circulating T Cell Subsets
in Childhood MS
Table 1 summarizes the changes in circulating T cell
subsets observed in these three patients with childhood MS. As shown, healthy children have percentages of circulating lymphocytes identical to those
previously reported for adults [ 141; 67% of cells are
T lymphocytes (T3 cells) as defined by reactivity with
anti-T3 monoclonal antibody, 41% of cells react with
anti-T4 and thus belong to the T-inducer (T4)subset,
and 20% are T-suppressor/cytotoxic (T5) cells by
Hauser et al: T Cell Subsets in Childhood MS
465
as that observed for the T5 subset. When retested
after the disease had stabilized, the patients showed
partial or complete return of circulating T cell subsets
with restoration of a quantitative balance between
inducer and suppressor/cytotoxic cells. We expressed
these findings as a ratio of inducer to suppressor/
cytotoxic cells (i.e., the T 4 :T5 ratio) in peripheral
blood (see Table 2) as an index of altered immunoregulatory status in MS [14]. In normal controls
and in children with other neurological diseases, the
T4 :T5 ratio was approximately 2 and was always less
than 4. In each child with MS, the T4:T5 ratio was
greater than 4 when measured during an acute attack
and less than 4 when restudied after remission. A
typical fluorescence-activated cell sorter profile of
the changes in T cell subsets during active and inactive stages of childhood MS is shown in Figure 1 (Patient 2).
Fig 2. Serial CT .icun.s in Patient 3. The nonenhanced ican
illustrated in A was obtained during an acute relapse and
demonstratrs snzall oentricles and hypodense white matter lesions periventricalarly in both frontal lobes. A repeat scan six
months later ( B , C), following remission, reveals interval ventricular enlargement and persistence of the periventricular le~ions.
virtue of their specific labeling by anti-T5. In control
children with other neurological diseases, a similar
pattern of T cell subset percentages was found. In
contrast, T5-bearing cells were markedly depleted
from the peripheral blood of all three patients during
acute relapses of MS; in addition, there were reduced
numbers of T3-bearing cells in all three and of T4bearing cells in two (Patients 2 and 3 ) , although in no
case was the reduction of T 3 or T4 cells as complete
466 Annals of Neurology Vol 11 No 5 May 1082
Discussion
The clinical picture in each of these children consisted of a multifocal, relapsing-remitting disturbance
of central nervous system white matter. The initial
attack occurred at ages 4 years 11 months, 10%
years, and 2 years 11 months, respectively. In all patients the disease expression resembled common
adult patterns of MS; Patient 1 presented with a relapsing brainstem syndrome, and Patient 2 with
Devic syndrome followed by recurrent optic neuritis.
Patient 3 had a more severe form, exhibiting these
classic features of MS: (1) four discrete attacks within
an eight-year period, each episode followed by a sustained remission; (2) asymmetrical multifocal deficits
involving motor and cerebellar systems, con jugate
gaze centers, and optic nerve; and (3) white matter
lesions apparent in periventricular regions on CT
scan. Several features in this patient that are well described although not commonly seen in MS included
development of seizures and a movement disorder
[4, 81. In addition, the patient exhibited lethargy and
drowsiness during several attacks. Extensive screening for biochemical abnormalities gave negative results.
Evaluation of cerebrospinal fluid (CSF) demonstrated prominent mononuclear pleocytosis (up to 90
WBC/mm3) during the acute exacerbation in two patients (Nos. 2 and 3). CSF protein electrophoresis
was performed in two patients (Nos. 1 and 3); normal
levels of gamma globulin were found, and no oligoclonal banding was present. Elevated CSF gamma
globulin levels and oligoclonal banding are seen in
the majority of adult MS patients, although it is not
known whether these elevations have a pathogenetic
role [ 5 ] ;in childhood MS (as noted in the next paragraph) changes in CSF proteins have not been systematically studied.
There are few convincing reports of symptomatic
MS in the first decade of life. Many reported cases,
particularly those in the early literature, suggest alternative diagnoses such as acute disseminated encephalomyelitis or familial leukodystrophy. Acceptance of such cases as MS has led some authors to
the conclusion that adult and childhood MS may be
phenotypically distinct; nonetheless, a critical review
of the literature suggests otherwise. Wechsler [ 171, in
1922, described a boy who had a relapsing and remitting disorder involving pyramidal, corticobulbar,
and cerebellar systems with onset at age 6l/z years. A
clinical diagnosis of MS appears justified. A boy reported by Rimbaud and co-workers in 1938 ([l5],
Case 1) and another by Bonduelle et a1 in 1954 [2]
both presented with optic neuritis at age 7 years and
subsequently with a relapsing multifocal syndrome
typical of MS. Low and Carter [9] in 1956 described
two additional patients (Cases 1 and 2) with onset at 6
and 7 years of age; in one of their patients (Case 11,
severe relapses with accompanying stupor, reminiscent of those of our Patient 3, were described. In
both patients reported by Low and Carter, immunoglobulin levels in the CSF were normal. A retrospective review of the Mayo Clinic experience
from 1920 to 1952 included seven patients with
onset of disease between 7 and 10 years of age [6];
although no detailed clinical summaries were given,
five of 40 children developed seizures during their
clinical course. In 1965, Picard and Richardson [lo]
analyzed the case of a 6-year-old girl in whom visual
complaints developed followed by rapid progression
to coma and a fluctuating neurological state leading to
early death; the diagnosis of acute MS was made at
autopsy. An additional child, with onset at age 9, was
reported by Amati and Cioffi [ll.
The cases described in the present report appear to
include the two youngest children with documented
MS. More importantly, we have demonstrated that
abnormalities of circulating T cell subsets were associated with episodes of disease activity. In each child,
loss of T-suppressor/cytotoxic cells with an increase
in the ratio of inducer to suppressor cells was found
during the acute attack, and lymphocyte subsets were
reconstituted following clinical stabilization. We
have previously shown that identical fluctuations in T
cell subsets occur in adults with MS, and that these
changes are specific for MS since they do not occur in
other neurological diseases [14]. We did not find alterations of T cell subsets in normal children or in
children with other neurological disorders, including meningitis, viral encephalitis, myasthenia gravis,
and Guillain-Barre syndrome. Recently we have
studied a 25-month-old boy with acute transverse
myelitis in whom loss of circulating T 5 cells and reduction in T 3 and T4 cells was found. A diagnosis of
MS cannot be made at this point in his clinical course.
The activity of the immune system in human beings is modulated by a network of regulatory controls
mediated through inducer add suppressor T cells.
One function of suppressor T cells in vivo may be the
inhibition of autoimmune phenomena due to selfreactive clones of effector lymphocytes. A decrease
in circulating T-suppressorlcytotoxic cells (T5 cells)
has now been reported in a number of other suspected human autoimmune diseases in addition to
MS, including systemic lupus erythematosus, inflammatory bowel disease, graft versus host disease, hemolytic anemia, and atopic eczema [13]. 1i-1
addition, a 6-year-old girl with multiple autoimmune
diseases and an absent circulating suppressor/cytotoxic cell subset has recently been described [ 121.
Taken together, these findings suggest that abnormal immunoregulation may be common to all these
diseases.
In some individuals, immune regulation might fail
in an age-dependent manher, as may occur in certain
strains of “autoimmune” mice [ 3, 161. Alternatively,
an age-dependent susceptibility to an exogenous
factor that triggers an autoimmune response could
exist. In this regard, epidemiological evidence suggests that an environmental exposure may be involved in the pathogenesis of MS; the latency between exposure and the first symptoms of MS has
been estimated at fifteen years [7].The occurrence of
MS in the first decade of life and as early as age 3
years suggests either that an environmental exposure
is not a prerequisite for developing MS or that the
latency between exposure and onset of clinical disease
may be much shorter in susceptible children.
Our findings demonstrate that T lymphocyte subsets may be useful in the diagnosis and management
of children with MS, and they should help to define
more precisely the true incidence of MS in this age
group. More importantly, the demonstration in children of changes in T cell subsets identical to those we
have shown in adults expands the clinical spectrum of
MS as defined by immunoregulatory changes and
suggests a common pathogenesis for the MS attack in
both age groups.
Supported in part by Grants AI12060, NS17182, CA10589, and
CAO6516 from the National Institutes of Health and by grants
from the Kroc Foundation and the National Multiple Sclerosis Society.
Dr Hauser is a postdoctoral fellow of the National Multiple
Sclerosis Society (FG542-A-I). D r Weiner is the recipient of
Teacher-Investigator Award KO-NS00237 from the National Institute of Neurological and Communicative Disorders and Stroke.
The authors wish to thank Diane Kilday for excellent secretarial
support.
Hauser et al: T Cell Subsets in Childhood MS
467
References
1. Amati F, Cioffi F: Osservazione di un caso di sclerosi a placche
giovanile. Acta Neurol (Napoli) 21:167-170, 1966
2. Bonduelle M, Bouysues P, Sallou C: La sclerose en plaques
chez I'enfant. Presse Med 62:563-564, 1954
3. Cantor H , McVay-Boudreau L, Hugenberger J, Nordorf K,
Shen EW, Gershon R K Immunoregulatory circuits among T
cell sets: 11. Physiologic role of feedback inhibition in vivo:
absence in N Z B mice. J Exp Med 147:1116-1125, 1978
4. Carter S, Sciarra D, Merritt H : The course of multiple
sclerosis as determined by autopsy proven cases. Assoc Res
Nerv Dis Proc 28:47 1-511, 1950
5. Delmotte P, Gonsette G: Biochemical findings in multiple
sclerosis: IV. Isoelectric focusing of the CSF gamma globulins
in multiple sclerosis and other neurologic diseases. J Neurol
215~27-37, 1977
6. Gall JC Jr, Hayles AB, Siekert RG, Keith HM: Multiple
sclerosis in children: a clinical study of 40 cases with onset in
childhood. Pediatrics 2 1:703-709, 1958
7. Kurland LT: The epidemiologic characteristics of multiple
sclerosis. In Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Vol 9, Multiple Sclerosis and Other Demyelinating Diseases. Amsterdam, North Holland, 1970, pp
63-84
8. Kurtzke JS: Clinical manifestations of multiple sclerosis. In
Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Vol 9, Multiple Sclerosis and Other Demyelinating Diseases. Amsterdam, North Holland, 1970, pp 161-216
9. Low NH, Carter S: Multiple sclerosis in children. Pediatrics
18:24-30, I956
468 Annals of Neurology
Vol 1 1
No 5
May 1982
10. Picard EH, Richardson EP: Rapidly evolving neurologic illness in a six-year-old girl. Case Records of the Massachusetts
General Hospital (Case 43-1965). N Engl J Med 273:760767, 1965
11. Reinherz EL, Kung PC, Goldstein G , Schlossman SF: A
monoclonal antibody with selective reactivity with functionally mature human thymocytes and all peripheral human T
cells. J Immunoi 123:1312-1317, 1979
12. Reinherz EL, Rubenstein A, Geha RS, Strelkauskas AJ, Rosen
FS, Schlossman SF: Abnormalities of immunoregulatory T
cells in disorders of immune function. N Engl J Med
30 1:1018- 1022, 1979
13. Reinherz EL, Schlossman SF: Regulation of the immune
response-inducer and suppressor lymphocytes in human beings. N Engl J Med 303:370-373, 1980
14. Reinherz EL, Weiner HL, Hauser SL, Cohen JA, Distaso JA,
Schlossman SF: Loss of suppressor T cells in active multiple
sclerosis: analysis with monoclonal antibodies. N Engl J Med
303:125-129, 1980
15. Rimbaud L, Riser, Geraud: De la sclerose en plaques chez
I'enfant. Rev Neurol (Paris) 69:477-481, 1938
16. Theofilopoulos AN, Eisenberg RA, Bourdon M, Crowell JS
Jr, Dixon FJ: Distribution of lymphocytes identified by surface markers in murine strains with systemic lupus erythematosus-like syndromes. J Exp Med 149:516-533,
1979
17. Wechsler IS: Statistics in multiple sclerosis: including a study
of the infantile, congenital, familial and hereditary forms and
the mental and psychic symptoms. Arch Neurol Psychiatry
3:59-75, 1922
Документ
Категория
Без категории
Просмотров
0
Размер файла
605 Кб
Теги
subsets, features, change, clinical, demonstration, activity, childhood, disease, sclerosis, multiple, cells
1/--страниц
Пожаловаться на содержимое документа