AFLAGELLARY FORMS OF TRICHOMONADS IN MULTIPLE SCLEROSIS LESIONS AT AUTOPSY AND IN CEREBROSPINAL FLUID OF LIVE PATIENTS:
PATHOGENIC FACTOR OR POSTMORTAL INVADERS?
Investigating the cause of clinically observed negative correlation between multiple sclerosis (MS) and chronic genital trichomoniasis, the detection of trichomonads (T/s/) in MS lesions at autopsy and in cerebrospinal fluid (CSF) of live patients was undertaken. Wet films are made of squeezed exudate from MS plaques and CSFs, and microscoped immediately after staining. In all five autopsied cases and in 2 of six CSFs, aflagellary pseudocystic forms of Ts were found. Since the cultures were negative in all observed cases, the species were not identified. Standard histological findings in all autopsied cases showed typical MS changes. The possibility of T participation in pathogenesis of MS, as well as the invasion ways of central nervous system (MS) were discussed.
Out of the three human T species, T vaginalis is the only one considered to be pathogenic, while T tenax seu oralis and T hominis seu intestinalis are considered as saprophytes. In literature, the last one is however stated to cause intestinal disturbances in tropical and subtropical areas (1). Investigations of human trichomoniasis evidenced the existence of immune response to all human species is proved, that raises suspicion if not refutes opinion of saprophytic T/man relationship of oral and intestinal species.
Clinical observations on competition of chronic T infections at remote organs are earlier reported (3). This phenomenon may be explained by the existence of common circulating antibodies, which disable establishing of competing focuses of T infections with the same or some other species. Such a crossed immunity suggests the idea for existing of an unique immune disturbance no matter what T species is about, as it was suggested earlier (4).
The abundant literature about MS point out the fact that immune events are of cardinal importance in pathogenesis of this disease(5). Although histological picture of MS with inflammatory signs indicates the involving of infective agents, however, in a few last decades about 20 different viruses have been incorrectly incriminated as etiologic cause (6). As our clinical observations indicate, very rare chronic trichomoniasis of the genital tract in MS female patients, they suggested the idea that in MS patients extragenital T infection existed. As the first step of the idea testing, the examination of MS lesions at autopy and CSF were performed.
MATERIALS AND METHODS
Five corpses of MS patients 24 hours after death and CSFs from 6 live MS patients were examined. Wet films of squeezed exudate from fresh MS plaques and CSF were stained with 1% Cresylblue in saline and microscoped immediately after staining under 400 times magnification. The exudates and CSFs (1-2 ml) were inoculated in Diamond’s TYM medium (7) enriched with 10% heat-inactivated horse serum and rice starch. All smear elements except live parasites are immediately colored, while Ts remain unstained for 2 or more minutes, depending on parasites vitality. In that feature parasites differ from leukocytes, which are of the same size and similar shape. Under the mentioned and higher magnification, in live aflagellary forms of Ts could be observed a lively endoplasmic motility, that is never visible in leukocytes (8).
In all examined corpses, Ts was found just in aflagellary form but only in 2 CSFs, of six live MS patients. Endoplasmic motility of up to date unidentified structures, possibly internalized flagellae (9), was a reliable proof that it were about Ts. The cultures were negative in all autopsied cases and CSFs, as it is a frequent case with Ts atypical localizations. Classic histological examinations showed typical MS changes in all autopsied cases.
T positive findings in all 5 autopsied cases and one third of CSFs of live MS patients raise question of when the infection happened: before or after death, as well as: is the parasite involved in pathogenesis of underlying process. Following trichomoniasis/MS parallels could point to a possible in vivo invasion.
Regarding that in all cases it was about motionless forms of Ts, it is unlikely to assume their active postmortal migration (lack of locomotive flagellary apparatus), especially as the invasion is directed toward tissue with already activated immune forces. The literature about trichomoniasis and MS indicates their strikingly symmetric manifestations: transmission, increased familial incidence, genetically influenced susceptibility, predominance by married women, varying latency and duration, unpredictable exacerbations and remissions, kinetics of development of immunity and its duration, occurrence of oligoclonal antibodies, reactive hyperplasia of connective tissue, etc… Direct cytopathogenic, tissue-disintegrating and immune T activity, as well as secondary allergic host/parasite interaction, cause very brad spectrum of clinico-pathological phenomena. Pathologic concequences of that interaction essentially depend on the structure of affected organ, while the expression of clinical symptoms depends on the organ dysfunctions. Thus, demyelination, as recognized consequence of oligodendrocytes dysfunction, may be result of T exotoxins activity na dwide range of cytoplasmic (proteolitic) enzymes, released after parasite cytolysis caused by thwe action of immune forces (lysines).
Ts may penetrate into CSF from the nose, like amoebes in amoebic meningoencephalitis (10), or from other parts of respiratory tract, which are often colonized by those parasites (11). Those invasion ways may explain high association rate of MS with sinusitis (12), as well as posttraumatic occurrence of MS, probably after transient establishing of communication between sinuses and subarachnoid space. Invasion of CSF by Ts may explain the most frequent periventricular localization of MS plaques (90%). Besides the per continuitatem invasion, haematogenic dissemination is also possible during up to now enigmatic trichomonaemia (13,14,15), that can clear up the frequent perivenous accumulation of unidentified enigmatic lymphocytoid cells in the vicinity of massive neuronal demyelination. Local plasmocytosis, increased IgE in CSF and other inflammatory changes, which are all unexplained in MS, may be the consequence of local presence of unrecognized Ts in their regressive aflagellary form.
Obligatory present gliosis in MS process functionally corresponds to reactive parasitic fibrosis with identical biologic significance.
The well known proteolytic activity of T enzymes (16,17) explains dysfunction of oligodendrocytes, which, because of of consequent neuronal dysfunction, elicit their compensatory hyperplasia, often present in MS process too. Unique familial serotypes of Ts (18) could explain the occurrence of oligoclonal antibodies (IgG) either in trichomoniasis (19,20) and in MS(5). Transient genitor-respiratory (21) and genitorectal (22) relocation of T infections, noticed in clinical observations, as well as mammary colonization of Ts in fibrocystic mastopathy (23) parallel to genitor-CNS competition of T infections in this concept. Autosomal recessive inheriting of MS has its parallel in similar model of inheritance of susceptibility to parasitic infections (24).
Sudden and up to date unexplained MS epidamics (Iceland in World War I and Farroe Islands in World War II) may be understood by import of virulent tropical T strains in domestic human populations with weaker innate and acquired immune capacities, then in indigenous parasite hosts. To our knowledge, only report about T infection of CNS (25) confirms the possibility of parasities penetration and multiplication there, while the only report also, about experimental inoculation of Ts into CSF of many rodents indicates pathologic reactions, which strikingly resemble to MS (26). Inhibition of cell devision in a culture after adding of MS tissue also corresponds to similar inhibition due to the presence of Ts in cell culture (27).
Cases with beneficial effect of plasmapheresis and leukopheresis in MS therapy may be understandable by direct removing of trichomonal toxins and parasites themselves from the circulation. If the intestine is site of parasitres entry into lymphatic circulation, then it could explain known association of MS with Crohn’s disease and ulcerative colitis, as well as occasionally positive effect of ductus thoracicus draining in MS therapy. Furthermore, favorable effect of hyperbaric oxygenation of MS patients could be explained by inhibitory effect of oxygen on obligate anaerobic Ts. Similar explanation may be applied also on beneficial effect of MS diet, which probably inhibits parasites multiplication.
The above exposed considerations strongly support the assumption that the CNS invasion happens in vivo, thus seriously candidating T species for an important unless decisive factor in pathogenesis of that disease. If testing in vivo of the proposed concept proves decisive or only additional contribution of those parasites to MS pathogenesis, it will be inevitable to set a strategic target to lure them outside from CNS and to direct them toward an organ where they are commonly being eliminated (nose, pharynx, larynx, genital tract) and later to prevent reinfection. Thus, it could be avoided irreversible CNS damages caused by immunity mediated T/man clash in highly differentiated tissue with weak regeneration capacity.
Although the number of cases is still small and research had been performed at autopsy and CSF only, we believe that this preliminary report with proposed concept, offer a hope of solving the MS enigma. Further research on MS patients is needed to better elucidate relationship between the MS and T infection, and to identify species of the parasites.
Presented in part of the 10th European Immunology Meeting, Edinburgh, September 10-12, 1990.
We wish to thank Prof. H. Kulenovic (Institute of Physiology, Faculty of Medicine) for preparing the paper and Prof. M. Podzo (Parasitological laboratory, Clinics for Opstetrics and reproduction, Veterinary Faculty, Sarajevo, Yugoslavia) for the laboratory help.
Out of the three well recognized human Trichomonas species, T vaginalis is the only one proved to be pathogenic, while T tenax and T hominis are considered as saprophytes. Contrarily, voluminous literature about T species shows the obligatory immunogenic activity of all 3 species. Moreover, the existence of crossed immunity to all human T species is proved, so explaining competitive exclusion of T infections at remote organs. Such a common interspecific immunity suggests the idea for existing of an unique immune depression caused by T species.
Our clinical observations indicate complete absence of chronic genital trichomoniasis in female Multiple sclerosis patients, so suggesting the idea that MS patients are colonized by extragenital trichomonads.
Five corpses of MS patients 24 hours after death and CSFs from 6 live MS patients were examined. Stained wet smears of squeezed exudate from fresh MS plaques and microscoped immediately. The exudates and CSFs were inoculated in modified Diamond’s media.
In all 5 examined corpses, Trichomonads are found just in aflagellary form but only in 2 of six CSFs, of live patients. The cultures were negative in all autopsied cases and CSFs, as it is a frequent case with Trichomonads from atypical localizations.
Classic histopathological examinations showed typical MS changes in all autopsied cases. The authors discussed possibility that trichomonads may in vivo invade central nervous system and at least participate in pathogenesis of MS changes.